NEWER MODES OF VENTILATION

DRPRATHEEBA DURAIRAJMDDA

5122007

Discovery of the potential for mechanical ventilation to produce ventilator-associated lung injury has resulted in the development of new lung protective strategies

AIM

To enhance respiratory muscle rest Prevent deconditioning atrophy of

muscles Improve gas exchange Prevent lung damage Improve patient synchrony Help in weaning process

Volume Ventilation

Stable consistent tidal volume delivery and minute ventilation which is independent of patientrsquos lung mechanics

BUT Pressures variable and difficult to control Resultant high peak pressure Slow rise to peak pressure distribution of ventilation may not be

optimized Set flow rate may not match patientrsquos demand Increased muscle workload from flow asynchrony may compromise patient comfort gas exchange cardiac function

Volume 500 mlPressure 3500 cm H20

Simple Volume System

Volume 500 ml

Volume 2000 mlPressure 3500 cm H20

Pop

Simple Volume System

PressureControl Ventilation

Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand

oxygenation

Disadvantages 1048707 Delivered tidal volume is variable and depends

upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance

1048707 May have adverse effects on volume delivery

PRESSURE

VOLUME

NEWER MODES

Clinicians Want the Best of All Possible Worlds

Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new

Basic principles

Trigger ndashmachine amp patient [flow presssure ]

Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash

volume flow pressure time

TYPES

INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Discovery of the potential for mechanical ventilation to produce ventilator-associated lung injury has resulted in the development of new lung protective strategies

AIM

To enhance respiratory muscle rest Prevent deconditioning atrophy of

muscles Improve gas exchange Prevent lung damage Improve patient synchrony Help in weaning process

Volume Ventilation

Stable consistent tidal volume delivery and minute ventilation which is independent of patientrsquos lung mechanics

BUT Pressures variable and difficult to control Resultant high peak pressure Slow rise to peak pressure distribution of ventilation may not be

optimized Set flow rate may not match patientrsquos demand Increased muscle workload from flow asynchrony may compromise patient comfort gas exchange cardiac function

Volume 500 mlPressure 3500 cm H20

Simple Volume System

Volume 500 ml

Volume 2000 mlPressure 3500 cm H20

Pop

Simple Volume System

PressureControl Ventilation

Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand

oxygenation

Disadvantages 1048707 Delivered tidal volume is variable and depends

upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance

1048707 May have adverse effects on volume delivery

PRESSURE

VOLUME

NEWER MODES

Clinicians Want the Best of All Possible Worlds

Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new

Basic principles

Trigger ndashmachine amp patient [flow presssure ]

Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash

volume flow pressure time

TYPES

INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

AIM

To enhance respiratory muscle rest Prevent deconditioning atrophy of

muscles Improve gas exchange Prevent lung damage Improve patient synchrony Help in weaning process

Volume Ventilation

Stable consistent tidal volume delivery and minute ventilation which is independent of patientrsquos lung mechanics

BUT Pressures variable and difficult to control Resultant high peak pressure Slow rise to peak pressure distribution of ventilation may not be

optimized Set flow rate may not match patientrsquos demand Increased muscle workload from flow asynchrony may compromise patient comfort gas exchange cardiac function

Volume 500 mlPressure 3500 cm H20

Simple Volume System

Volume 500 ml

Volume 2000 mlPressure 3500 cm H20

Pop

Simple Volume System

PressureControl Ventilation

Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand

oxygenation

Disadvantages 1048707 Delivered tidal volume is variable and depends

upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance

1048707 May have adverse effects on volume delivery

PRESSURE

VOLUME

NEWER MODES

Clinicians Want the Best of All Possible Worlds

Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new

Basic principles

Trigger ndashmachine amp patient [flow presssure ]

Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash

volume flow pressure time

TYPES

INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Volume Ventilation

Stable consistent tidal volume delivery and minute ventilation which is independent of patientrsquos lung mechanics

BUT Pressures variable and difficult to control Resultant high peak pressure Slow rise to peak pressure distribution of ventilation may not be

optimized Set flow rate may not match patientrsquos demand Increased muscle workload from flow asynchrony may compromise patient comfort gas exchange cardiac function

Volume 500 mlPressure 3500 cm H20

Simple Volume System

Volume 500 ml

Volume 2000 mlPressure 3500 cm H20

Pop

Simple Volume System

PressureControl Ventilation

Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand

oxygenation

Disadvantages 1048707 Delivered tidal volume is variable and depends

upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance

1048707 May have adverse effects on volume delivery

PRESSURE

VOLUME

NEWER MODES

Clinicians Want the Best of All Possible Worlds

Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new

Basic principles

Trigger ndashmachine amp patient [flow presssure ]

Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash

volume flow pressure time

TYPES

INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Volume 500 mlPressure 3500 cm H20

Simple Volume System

Volume 500 ml

Volume 2000 mlPressure 3500 cm H20

Pop

Simple Volume System

PressureControl Ventilation

Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand

oxygenation

Disadvantages 1048707 Delivered tidal volume is variable and depends

upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance

1048707 May have adverse effects on volume delivery

PRESSURE

VOLUME

NEWER MODES

Clinicians Want the Best of All Possible Worlds

Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new

Basic principles

Trigger ndashmachine amp patient [flow presssure ]

Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash

volume flow pressure time

TYPES

INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Volume 2000 mlPressure 3500 cm H20

Pop

Simple Volume System

PressureControl Ventilation

Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand

oxygenation

Disadvantages 1048707 Delivered tidal volume is variable and depends

upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance

1048707 May have adverse effects on volume delivery

PRESSURE

VOLUME

NEWER MODES

Clinicians Want the Best of All Possible Worlds

Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new

Basic principles

Trigger ndashmachine amp patient [flow presssure ]

Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash

volume flow pressure time

TYPES

INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

PressureControl Ventilation

Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand

oxygenation

Disadvantages 1048707 Delivered tidal volume is variable and depends

upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance

1048707 May have adverse effects on volume delivery

PRESSURE

VOLUME

NEWER MODES

Clinicians Want the Best of All Possible Worlds

Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new

Basic principles

Trigger ndashmachine amp patient [flow presssure ]

Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash

volume flow pressure time

TYPES

INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

PRESSURE

VOLUME

NEWER MODES

Clinicians Want the Best of All Possible Worlds

Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new

Basic principles

Trigger ndashmachine amp patient [flow presssure ]

Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash

volume flow pressure time

TYPES

INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Clinicians Want the Best of All Possible Worlds

Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new

Basic principles

Trigger ndashmachine amp patient [flow presssure ]

Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash

volume flow pressure time

TYPES

INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Basic principles

Trigger ndashmachine amp patient [flow presssure ]

Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash

volume flow pressure time

TYPES

INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

TYPES

INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

NON INVASIVE VENTILATION Negative pressure ventilators (Tank and

Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness

use of NIMV has increased in last

decade in various conditions to avoid complications of intubation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Types

Positive Pressure Ventilation

Negative Pressure Ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens

hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation

without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure

time index of respiratory muscles and diaphragmatic electromyographic activity -

Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation

NIMV also overcomes the effect of intrinsic PEEP

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option

Intermittent ventilation possible

Patient can eat drink and communicate

Ease of application and removal

Patient can cooperate with physiotherapy

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Contdhellip

Improved patient comfort Reduced need for sedation Avoidance of complications of

endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia

Ventilation outside hospital possible Correction of hypoxaemia without

worsening hypercarbia Ease to teach paramedics and nurses

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Disadvantages

Mask uncomfortableclaustrophobic Time consuming for medical and nursing

staff Facial pressure sores Airway not protected No direct access to bronchial tree for

suction if secretions are excessive Less effective

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Indications of NIMV

Hypercapnic acute respiratory failure

Acute exacerbation of COPD

Post extubation Weaning difficulties Post surgical respiratory

failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation

Syndrome

Hypoxaemic acute respiratory failure

Cardiogenic pulmonary oedema

Community acquired pneumonia

Post traumatic respiratory failure

ARDS Weaning difficulties Chronic Respiratory

Failure Immunocompromised

Patients

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Contraindications

Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing

and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Relative Contraindications

Extreme anxiety Massive obesity

Copious secretions

Need for continuous or nearly continuous ventilatory assistance

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Prerequisites for successful Non-Invasive support

Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and

respiratory rate within first two hours Normal functioning gastrointestinal tract

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Interface Interfaces are devices that connect ventilator tubing to

the face allowing the entry of pressurized gas to the upper airway

Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces

Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin

Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most

often in chronic respiratory failure

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Ventilators - conventional

Advantages FiO2 can be set Alarm amp monitoring

back up Back up ventilation Separate insp amp exp

limbs ndash prevent rebreathing

Inspiratory pressure gt 20 cm H2O can be set

Disadvantages Expensive Less flexible

ampportable Leak compensation

not present ndash requires tight interface

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

NPPV Ventilators

Advantages cheaper flexible ampportable Leak compensation

present ndash does not requires tight interface

Inspiratory pressure of 20 cm H2Ois maximum available

Disadvantages FiO2 cannot be set

Due to leak ndash high oxygen flows

Single limb ndash rebreathing

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively

assist inspiration CPAP by nasal mask provides pneumatic splint which

holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea

CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure

therefore increases cardiac output ndash effective for treatment of pulmonary oedema

Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]

Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm

H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED

IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory

time adjustable FiO2 -available

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

BI LEVEL PAP[contdhellip] INDICATIONS Worsening

hypoventilation hypoxemia

Chronic ventilatory muscle dysfunction

Post intubation difficulty Upper airway

obstruction ndashlaryngeal oedemastrictures

CONTRA INDICATIONS Unstable

Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory

parameters

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

PSV

Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation

PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern

Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Volume limited ventilation ventilators are usually set in assist-control mode with

high tidal volume (10-15 mlkg) to compensate for air leak

suitable in obesity or chest wall deformity who need high

inflation pressure neuromuscular diseases who need high tidal

volume for ventilation Proportional assist ventilation (PAV)

This is a newer mode of ventilation In this mode ventilator has capacity of responding

rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals

one can select the proportion of breathing work that is to be assisted

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Goals of NIMV

Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Protocol for Non Invasive Ventilation

Explain to the patient what you are doing and what to expect

Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the

patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort

Connect humidification system

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG

Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O

Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts

Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks

Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg

Increase FiO2 to improve O2 saturation to 90

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Complications and Side effects

AIR LEAK [80 -100]

MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly

over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction

FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension

MAJOR COMPLICATIONS Aspiration pneumonia - lt

5 Hypotension Pneumothorax

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

CRITERIA FOR FAILURE OF NPPV

MAJOR Respiratory arrest Loss of

consciousness Psychomotor

agitation Haemodynamic

instability Heart rate lt50 bm

MINOR Respiratory rate gt 35

mt pH lt730 Pao2 lt45mmHg

Intubate when one major two minor criteria

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

INVASIVE VENTILATION

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Pressure RegulatedVolume Control [PVRC]

Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled

assistcontrol

Establishes a ldquolearning periodrdquo to determine

patientrsquos compliance which establishes regulation of pressurevolume

Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Pressure RegulatedVolume Control (PRVC)

1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume

The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume

Results in breath-to-breath variation of inspiratory pressure

Limitations Only an AC mode and requires a change to

Volume Support for weaning Only guarantees volume distally and not at

patient airway

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

TV AIRWAY PRESSURE

PROBLEMS

VCV preset fn of mechpropertyof lungs

lung injury

PCV acc to mecha property of lung

preset hypoventilation

volutrauma

PRVC preset lower paw necessary

Benefits of both

Comparison with established modes

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Applications of PRVC

ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high

flow rates In whom VT has to be controlled ndashsurfactant

therapy

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Benefits

Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to

mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]

Pressure controlled ventilation allowing spontaneous ventilation

Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest

airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to

ventilator in VCV

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

BIPAP -SUBDIVISIONS

CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at

lower level APRV ndash BIPAP - spontaneous breathing

at higher level Genuine BIPAP - spontaneous breathing

at both levels CPAP - spontaneous breathing at single

CPAP level

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

paw

t

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Setting up BIPAP

Adjusted with ABG values High low PaCO2 Normal PaO2

VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2

mean airway pressure without altering VTRR

equidirectional alteration of P high P low

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

ADVANTAGES OF BIPAP

Less sedation Reduced atelectasis Ideal mode in pts with inadequate

spontaneous effort In face of deteriorating gas exchange

we can increase the invasiveness of ventilation without having to change mode

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Airway Pressure Release Ventilation

(APRV) Outlined in 1987 Continuous positive airway pressure with

regular brief intermittent releases in airway pressure

The release phase results in alveolar ventilation and removal of carbon dioxide

APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance

It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation

Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

APRV ndashCONTDhellip

Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation

APRV commences at an elevated baseline pressure and follows with a measured pressure release

During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels

Available on Draumlger and Puritan Bennett ventilators

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

APRV ndashCONTDhellip

Elevated baseline airway pressure during APRV may produce near complete recruitment

Minimizes low volume lung injury from cyclic recruitment

APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation

Needs a High flow CPAP circuit with release valve

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Advantages of APRV Lower peak airway pressures Lower minute ventilation

Decreased adverse effects upon circulatory function

Spontaneous ventilation the entire ventilatory cycle

Decreased need for sedation

Near elimination of neuromuscular blockade Recruitment of alveoli

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Indications for APRV ALI or low-compliance lung disease patients with airway disease

CONTRAINDICATIONS

Patients with Increased airway resistance

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation

The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation

P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus

accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than

40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0

cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure

Settings of APRV

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Pressure support ventilation

Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by

specific amount of positive pressure at airway

PS Terminated when insp Flow falls below a minimum trigger volume

Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

` ADVANTAGES Less WOB low pressure high volume work similar to

spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is

achieved with PS of 5 cm H2O

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Volume AssuredPressure Support (VAPS)

Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure

breath continues to guarantee volume - 1048707 PIP and inspiratory time increase

1048707 Guarantees volume on current breath (no previous breath averaging)

1048707 Combines the advantages of pressure and volume ventilation breath to breath

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Characteristics of VAPS 1048707 The ventilator continuously measures the flow and

pressure and calculates delivered volume Depending on the actual settings breath may be flow

volume or time cycled 1048707 If the target tidal volume has been delivered

inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set

flow will persist until the desired volume has been reached (volume cycled breath)

1048707 Safety limits include high pressure and maximum inspiratory time1048707

Used in the Management of acute and recovering lung disease

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Benefits of VAPS

1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Applications of VAPS 1048707 A patient who requires a substantial level of

ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony

1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change

Limitations 1048707 Will only increase pressure not lower pressure

with changing mechanics 1048707 Increases inspiratory time to assure volume

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Volume support ventilation

Support mode Has PVRC as back up mode Allows spontaneous if preset MV is

achieved If fails deliver preset TV MV in lowest

possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure

limitlower amp upper MV alarm

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Applications of VSV

Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations

in inspiratory pressure support

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

BENEFITS OF VSV

Low PIP Inspiratory pressure adapts to

mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Dual modes

Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop

Provide full partial ventilatory support Modify their operation within the confines of an individual

breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Proportional assist ventilation [PAV]

PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient

power adjusted by us to off set resistive amp elastic requirements

Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]

Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Independent lung ventilation

In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis

pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single

ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash

key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be

used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high

viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble

Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Perflurocarbon associated gas exchange [PAGE]

IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of

alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash

Improve dynamic compliance Used as surfactant amp vasodilatory agent

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean

airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at

minimum Indicated in ARDS amp Diffuse lung injury

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

High frequency ventilation

Very low TV lt anatomical dead space at rates gtnormal rate

HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

HFFI-High frequency flow interruption

A device interrupts gas flow or high pressure at frequencies gt 15 Hz

emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

High frequency percussive ventilation

Recently introduced High frequency breaths superimposed on

conventional breaths Pneumatically powered time cycled pressure

limited ventilator with inspiratory ampexpiratory oscillation

Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on

conventional 10 - 15 bmt

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

High frequency percussive ventilation

Phasitron mechanism At the heart of device is sliding venturi with jet orifice

at its mouth On inspiration a diaphragm connected to venturi fills

with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations

Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained

As gradient drops further into inspiration air entrainment decreases but jet pulsations continue

Cycles to expiration

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

High frequency oscillation

Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash

provide positive pressure high frequency breaths in inspiratory limb

A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

High frequency ventilation

Gas exchange

1 bulk gas flow 2 coaxial flow

3 molecular diffusion 4 pendulft Advantage

Lower peak airway pressure

FRC

Efficient gas exchange

Lower transpulmonary pressure

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

High frequency ventilation

INDICATION Bronchopleural

fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy

CONTRAINDICATION COPD

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Adaptive support ventilation

Excellent mode for initiating ventilation support amp weaning

Galileo ventilator Set patient weight PEEP pressure limit

ampvolume control [ 100 ml kg in adults 200mlkg in children ]

Breath to breath assessment is done PS is constantly adjusted

If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Neurologically adjusted ventilatory assist [NAVA]

Developed to overcome limitations of PAV

Electrical activity of inspiratory muscles ndash index of inspiratory neural drive

Processed signal ndashtransferred to ventilator to regulate ventilation

Research tool

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Biologically variable ventilation (BVV)

Mimics spontaneous breath ndash breath variability

Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar

recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation

Under research

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Automatic tube compression

New component of ventilatory support under trial

Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett

840 In intubated patient ndash pressure difference exists

between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach

PETT - Reflects energy required for convective transport of gases

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

ATC ndashCONTDhellip

V ampPaw measured at proximal end of ETT and fed into ATC controller by staff

Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube

Inspiratory PS in ATC mode equals actual pressure drop across the tube

By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration

Reduces WOB amp increases patients comfort

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

Advances amp Adjuncts in Pediatric Mechanical Ventilation

VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high

rates Prone ventilation ndashALI Recruitment of dorsal lung copious

drainage of secretions extra vascular lung water is reduced

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

CONTDhellip

VENTILATORY MODES

Adaptive support ventilation

PAV PRVC NIV BIPAP HFV

ADJUNCTS Inhaled NO Tracheal gas

insufflations PAGE surfactant therapy

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation

FUTURE

Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone

ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of

H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg

Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation