Respiratory Mechanics (Egypt) 3-09 (Final Version)

8/14/2019 Respiratory Mechanics (Egypt) 3-09 (Final Version)

1/50

Airway Graphic Analysis toOptimize Patient-Ventilator

Interactions

Airway Graphic Analysis toOptimize Patient-Ventilator

InteractionsIra M. Cheifetz, MD, FCCM, FAARC

Professor of PediatricsChief, Pediatric Critical Care

Medical Director, Pediatric ICU

Duke Childrens Hospital

Ira M. Cheifetz, MD, FCCM, FAARCProfessor of Pediatrics

Chief, Pediatric Critical CareMedical Director, Pediatric ICU

Duke Childrens Hospital


2/50

Case ScenarioCase Scenario 5 mo (former 27 wk gestation) with CLD admitted

with RAD exacerbation & viral pneumonia.

Intubated shortly after admission for impendingresp failure.

PC/PS: RR 28, PIP 28, PEEP 7, PS 12 Sedated with infusions of midazolam & fentanyl.

Infant experiences an acute episode oftachypnea, subcostal retractions, and agitation.

5 mo (former 27 wk gestation) with CLD admittedwith RAD exacerbation & viral pneumonia.

Intubated shortly after admission for impendingresp failure.

PC/PS: RR 28, PIP 28, PEEP 7, PS 12 Sedated with infusions of midazolam & fentanyl.

Infant experiences an acute episode oftachypnea, subcostal retractions, and agitation.


3/50

Case ScenarioCase ScenarioAirway scalars

(pressure vs. time and flow vs. time) are:

Airway scalars(pressure vs. time and flow vs. time) are:


4/50

Case ScenarioCase ScenarioThe patients acute change in clinical

status is most consistent with:a.) worsening bronchospasm

b.) pain

c.) flow asynchrony

d.) trigger insensitivity

e.) air trapping

The patients acute change in clinical

status is most consistent with:a.) worsening bronchospasm

b.) pain

c.) flow asynchrony

d.) trigger insensitivity

e.) air trapping


5/50


6/50

Goal: Airway Graphic AnalysisGoal: Airway Graphic Analysis Optimize mechanical ventilation by

diagnosing and correcting abnormalitiesin the interaction between the patient and

the ventilator.

Optimize mechanical ventilation by

diagnosing and correcting abnormalitiesin the interaction between the patient and

the ventilator.


7/50

Airway ScalarsAirway ScalarsPaw (cm H2O)

Flow (L/min)

Vt (ml)


8/50

Airway LoopsAirway LoopsFlow - Volume Pressure - Volume


9/50

Patient - Ventilator InteractionsPatient - Ventilator Interactions Facilitate spontaneous breathing

Optimize patient WOB

Maximize pt-ventilator synchrony

inspiratory synchrony

expiratory synchrony

Facilitate spontaneous breathing

Optimize patient WOB

Maximize pt-ventilator synchrony

inspiratory synchrony

expiratory synchrony


10/50

Patient - Ventilator InteractionsPatient - Ventilator Interactions Inspiratory synchrony

flow synchrony

trigger synchrony

ETT effects / airleakavoid overdistention

Expiratory synchrony

Inspiratory synchrony

flow synchronytrigger synchrony




11/50

Flow SynchronyFlow Synchrony Flow synchrony is defined as the ideal

matching of inspiratory flow of a ventilatorbreath to the pt's inspiratory demandduring assisted or supported ventilation.

Asynchrony: Inadequate inspiratory flowat any point during inspiration causing anincreased or irregular pt effort.

leads to increased WOB

fighting the ventilator

Flow synchrony is defined as the ideal

matching of inspiratory flow of a ventilatorbreath to the pt's inspiratory demandduring assisted or supported ventilation.

Asynchrony: Inadequate inspiratory flowat any point during inspiration causing anincreased or irregular pt effort.

leads to increased WOB

fighting the ventilator


12/50

Flow AsynchronyFlow Asynchrony


13/50



14/50



15/50

Optimal Pt - Vent SynchronyOptimal Pt - Vent Synchrony Allows for optimal use of nutritional

support Slutsky, Chest, 1993

Decreases VILI in neonates Rosen, Ped Pulm, 1993

Improves pt comfort and reduceswork of breathing

Ramar, Respir Care Clin, 2005

Allows for optimal use of nutritional

support Slutsky, Chest, 1993

Decreases VILI in neonates

Rosen, Ped Pulm, 1993

Improves pt comfort and reduceswork of breathing

Ramar, Respir Care Clin, 2005


16/50

Patient - Ventilator SynchronyPatient - Ventilator Synchrony Pt-vent synchrony should be optimized by

assessing the pt - ventilator interfacebefore administering sedation.

Increased sedative use in the 1st 24 hrs ofventilation LOV in pediatric pts with ALI.

Randolph (PALISI Network), JAMA, 2002

Pt-vent synchrony should be optimized by

assessing the pt - ventilator interfacebefore administering sedation.

Increased sedative use in the 1st 24 hrs of

ventilation LOV in pediatric pts with ALI.

Randolph (PALISI Network), JAMA, 2002


17/50










18/50

Trigger SensitivityTrigger Sensitivity Trigger sensitivity = pt effort required to

initiate a ventilator assisted breath A determinate of pt effort required (WOB)

What affects trigger sensitivity? pressure vs. flow triggering

proximal vs. distal sensing

ETT leaks / size

Trigger sensitivity = pt effort required toinitiate a ventilator assisted breath

A determinate of pt effort required (WOB)

What affects trigger sensitivity?

pressure vs. flow triggering

proximal vs. distal sensing

ETT leaks / size


19/50

Trigger InsensitivityTrigger Insensitivity


20/50

Trigger InsensitivityTrigger Insensitivity

15


21/50

Effects of ETT Leaks on TriggeringEffects of ETT Leaks on TriggeringProblem

ETT leak results in in airwaypressure and/or flow

may be sensed as a patient effort

Result

may initiate a ventilator assisted

breath in the absence of a patienteffort (autocycling)

Problem

ETT leak results in in airwaypressure and/or flow

may be sensed as a patient effort

Result

may initiate a ventilator assisted

breath in the absence of a patienteffort (autocycling)


22/50

Air LeakAir Leak


23/50

Air LeakAir Leak


24/50

AutocyclingAutocycling


25/50

AutocyclingAutocycling


26/50


flow synchrony

trigger synchrony




flow synchrony

trigger synchrony




27/50

Pulmonary Injury SequencePulmonary Injury SequenceFroese, CCM, 1997Froese, CCM, 1997Two injury zones during mechanical ventilationTwo injury zones during mechanical ventilation


28/50

OverdistentionOverdistentionAn in airway pressure at the end of inspiration

without a significant increase in delivered tidal

volume beaking at the end of inspiration.

An in airway pressure at the end of inspiration

without a significant increase in delivered tidal

volume beaking at the end of inspiration.

C20/ Ctotal < 1.0


29/50

Airway Obstruction SecretionsAirway Obstruction Secretions


30/50

Airway Obstruction SecretionsAirway Obstruction Secretions


31/50

Inspiratory SynchronyInspiratory SynchronyOptimal inspiratory patient - ventilator

synchrony is a function of:inspiratory flow

trigger sensitivity

ETT effects

appropriate lung inflation

Optimal inspiratory patient - ventilator

synchrony is a function of:inspiratory flow

trigger sensitivity

ETT effects

appropriate lung inflation


32/50


Expiratory synchronyend-expiratory lung volume

premature termination ofexhalation & intrinsic PEEP

expiratory resistance






33/50

End-expiratory Lung VolumeEnd-expiratory Lung Volume

Lung volume prior to inspiration (FRC)

A function of total PEEP and lungcompliance

Lung volume prior to inspiration (FRC)

A function of total PEEP and lungcompliance

Froese, CCM, 1997Froese, CCM, 1997


34/50

End-expiratory Lung VolumeEnd-expiratory Lung Volume

If EELV is too low:

lung compliance , Vt , RR may result in premature termination of

exhalation & intrinsic PEEP

opening pressure may result in risk of barotrauma If EELV is too high:

pulmonary overdistention develops

risk of volutrauma

If EELV is too low:

lung compliance , Vt , RR may result in premature termination of

exhalation & intrinsic PEEP

opening pressure may result in risk of barotrauma If EELV is too high:

pulmonary overdistention develops

risk of volutrauma


35/50

Optimize PEEPOptimize PEEP

dynamicvs. static

P-V curve


36/50










37/50

Premature Termination of ExhalationPremature Termination of Exhalation Failure of airway pressure, volume, &

exp flow to return to baseline prior tothe next vent assisted breath

Gas trapping causes intrinsic PEEP

Failure of airway pressure, volume, &

exp flow to return to baseline prior tothe next vent assisted breath

Gas trapping causes intrinsic PEEP


38/50

Intrinsic PEEP: Adverse EffectsIntrinsic PEEP: Adverse Effects WOB mean intrathoracic pressure cardiac output

trigger sensitivity VT in pressure limited breath (set PIP) PIP in volume limited and pressure

control (set P) breaths

WOB mean intrathoracic pressure cardiac output

trigger sensitivity VT in pressure limited breath (set PIP) PIP in volume limited and pressure

control (set P) breaths


39/50

Intrinsic PEEP: TreatmentIntrinsic PEEP: TreatmentNo treatment

expiratory time respiratory rate inspiratory timeflow cycling of the breath

No treatment

expiratory time respiratory rate inspiratory timeflow cycling of the breath


40/50


41/50


42/50

Intrinsic PEEPIntrinsic PEEPReasons for intrinsic PEEP to occur:

inadequate I:E ratio

respiratory rateinspiration is time cycled & not

responsive to changes in flow

Goal: shorten inspiratory time whilemaintaining appropriate tidal volume

Reasons for intrinsic PEEP to occur:

inadequate I:E ratio

respiratory rateinspiration is time cycled & not

responsive to changes in flow

Goal: shorten inspiratory time whilemaintaining appropriate tidal volume


43/50










44/50

Increased Expiratory ResistanceIncreased Expiratory Resistance

Obstruction to exhalation caused by:

airway obstruction ETT occlusion

bronchospasm

blocked expiratory valve

Prolonged expiratory phase causes:

gas trapping

WOB trigger sensitivity

Obstruction to exhalation caused by:

airway obstruction ETT occlusion

bronchospasm

blocked expiratory valve

Prolonged expiratory phase causes:

gas trapping

WOB trigger sensitivity


45/50



46/50



47/50



48/50

Expiratory SynchronyExpiratory SynchronyOptimal expiratory patient - ventilatorsynchrony is a function of:

complete exhalation

an ideal end-expiratory lung volume

elimination of premature terminationof exhalation & intrinsic PEEP

minimal expiratory resistance

Optimal expiratory patient - ventilatorsynchrony is a function of:

complete exhalation

an ideal end-expiratory lung volume

elimination of premature terminationof exhalation & intrinsic PEEP

minimal expiratory resistance


49/50

Airway Graphics to OptimizePatient - Ventilator InteractionsAirway Graphics to OptimizePatient - Ventilator Interactions

Evaluate airway pressures & tidal volume Choose appropriate inspiratory flow

Set trigger sensitivity appropriately

Evaluate extent of air leaks

Maintain adequate end-exp. lung volume

Avoid intrinsic PEEP Minimize expiratory resistance

Evaluate airway pressures & tidal volume

Choose appropriate inspiratory flow

Set trigger sensitivity appropriately

Evaluate extent of air leaks

Maintain adequate end-exp. lung volume

Avoid intrinsic PEEP Minimize expiratory resistance


50/50

Respiratory Mechanics (Egypt) 3-09 (Final Version)

Documents

Transcript of Respiratory Mechanics (Egypt) 3-09 (Final Version)