Manual Hyperinflation

Presented by: Karishma H. KeswaniModerated by: Mr. A. Gopal Krishna

Contents

• Definition• Breathing systems• Non-rebreathing systems• Manual hyperinflation• Rebreathing systems• Summary• References

Definition

Inflating the lungs using oxygen and manual compression to provide a tidal volume (Vt) of 1.0l, requiring a peak inspiratory pressure of from 20 to 40 cm H2O.Using Vt exceeding baseline VtUsing a Vt that is 50% greater than that delivered by the ventilator

Breathing systems

• A gas pathway connected to the patient, through which gas flows occur at respiratory pressures, and into which a controlled composition of a gas mixture is dispensed.

• Extends from the point of fresh gas inlet to the point at which gas escapes to the atmosphere or a scavenging system.

Classification of breathing systems

1. Non-rebreathing systems2. Rebreathing systems

Non-rebreathing system: equipment

Air Viva

Laerdal bag

Non-rebreathing system: equipment

Laerdal bag

Components

1. Reservoir bag2. Non-rebreathing

valve OR Adjustable pressure limiting (APL) valve OR PEEP valve

3. Schimmelbusch mask

Reservoir bag

Reservoir bag

•composed of rubber or plastic •ellipsoidal in shape so that they can be grasped easily with one hand•Neck connects with breathing system•Tail is the opposite end

Volume of the bag

Adult Child Infant

OD bag 135(mm) 95 70Length 320(mm) 255 243Weight 360g 220 170Bag volume

1600(ml) 500 280

Mechanism

Mechanism of MHI

Mechanism of MHI

Slow deep inspiration:• Recruits collateral ventilation• Enhances interdependence to aid re-expansion of

atelectatic segments• Improves gaseous exchange• Assesses and potentially improves compliance

Inspiratory hold (at full inspiration):• Further utilizes collateral ventilation and interdependence;

therefore maximizes pressure distribution

Mechanism of MHI

Fast expiratory release:• Mimics a forced expiration (huff or cough)• Stimulates a cough

Hand-held PEEP• By grasping and holding the end of a semi-filled

bag throughout inspiration and expiration it is possible to maintain a low level of PEEP.

Indications

• To improve oxygenation pre- and postsuctioning.

• To mobilize excess bronchial secretions.• To reinflate areas of the collapsed lung.

Precautions

• Large emphysematous bullae, subcutaneous emphysema

• Open bronchopulmonary fistula• Inverse ratio ventilation• Systolic BP less than 80mmHg• Hypovolemia.• Agitation / aggression• Acute head injury, raised intracranial pressure• Large air leak• Peak airway pressures > 40-50cmH2O

Precautions

• Unstable cardiovascular system, arrhythmias or frequent ectopics

• Undrained pneumothorax• Severe bronchospasm• High peak inspiratory pressure (PIP)• Positive end-expiratory pressure (PEEP) >10

cmH2O• Acute pulmonary oedema

Precautions

• Unexplained haemoptysis• Recent pneumonectomy • Rib fracture• During renal dialysis, which tends to destabilize BP.• Hyperinflated lungs with intrinsic PEEP. • During weaning if patients with hypercapnic COPD

are dependent on their hypoxic drive to breathe.• Severe hypoxaemia with PEEP above 10 mm of Hg

Procedure guidelines

• Follow universal safety precautions• Assessment – indications / precautions for MHI.• Ensure optimal fluid status and cardiovascular

stability.• Consent.• The two caregivers providing the treatment should

be positioned on opposite sides of the bed.• Patient position: well-forward sidelying. If a different

area is to be targeted, it is placed uppermost.

• Observe chest expansion.• Tell the patient that s/he will feel a deep breath.

They should be free of distractions or nursing interventions.

• A PEEP valve may be used when the patient is on a PEEP > 10cmH2O and shows clinical signs of desaturation.

• Disconnect patient from the ventilator, attach the bagging circuit to the catheter mount, attach the reservoir bag to the ventilator tubing and mute the alarm or switch the ventilator to standby as per local policy in the Unit.

• Co-ordinate the delivery of the breaths with any respiratory efforts of the patient.

• Allow the patient to acclimatise by using small TVs initially.

• Minimise movement of the endotracheal or tracheostomy tube during MHI.

• Perform slow deep inspiration aiming to achieve a peak inspiratory pressure of 40 cmH2O.

• Hold the breath for 3s at the end of inspiration followed by rapid release of the bag.

• If the patient remains stable, use 6-8 MHI breaths and suction when indicated.

• Repeat the cycle of MHI.• Reconnect the patient to the ventilator – if the

ventilator has been turned off ensure it has been switched on.

• Document that the patient is reconnected to the ventilator as above and handover has been given to nursing staff

• The sidelying position should be continued so long as it is comfortable for the patient and convenient for the nursing procedures.

Paediatric MHI

• use 500ml bag• Turn the O2 flow rate to 4 – 6 liters• Bag squeeze using fingers rather than whole hand

interspersing one hyperinflation with 3 or 4 tidal breaths

• Pressure not more than 10 cm of H2O above the peak airway pressure for term babies and 5cm for preterm babies.

Precautions

• Preterm neonates

• Hypovolemia

• Low cardiac output

• Raised intra cranial pressure

• Emphysematous bullae

• Multiple cysts

• Undrained pneumothorax

• Termination• Assessment of efficacy• Infection control• Instillation of saline

Perceived benefits

• Removal of secretions• Re-inflation of atelectasis• Improved oxygenation• Stimulation of a cough reflex• Improved lung volumes• Improved lung compliance• Prevent nosocomial pneumonia

Hazards

• Reduced blood pressure• Reduced saturation• Increased intracranial pressure• Reduced respiratory drive

Rebreathing systems

• Allow the to-and-fro movement of inspiratory and expiratory gases within the breathing system.

• Carbon dioxide elimination is achieved by the flushing action of fresh gas introduced into this breathing system.

Rebreathing system: equipment

Magill rebreathing bag Mapleson C

Volumes

Bag volume Adult 2000 mlPediatric 1000 mlNeonatal 500 ml

Mapleson systesms

Mechanism of Mapleson systems

Mapleson system Non-rebreathing system

Simple, inexpensive, lightweight, easy to use, disassemble & reassemble

Yes Yes

Administration of 100% oxygen

No Yes

Heat & humidity loss No Yes

Tracheal tube kinking/displacement

No Yes

Fresh gas flow Variable High

Used in Malignant hyperthermia

No Yes

Dead space & rebreathing

Yes No

Used in Emergency situations

No Yes

Summary

References1. Denehy L. The use of manual hyperinflation in airway clearance.

Eur Respir J. 1999; 14: 958-652. Critical care network Northern Ireland. Northern health and social

care trust. Manual hyperinflation of adult patients in critical care. Apr 2010.

3. Ehrenwerth J, Eisenkraft J. Anaesthesia Equipment: Principles and applications. Elseiver; 1993

4. Davey AJ, Diba A. Ward’s Anaesthetic Equipment. 5th ed. Philadelphia: Elsevier Saunders; 2005

5. Sosis MB. Anaesthesia equipment manual. Philadelphia: Lippincott Williams and Wilkins; 1997

6. Dorsch JA, Dorsch SE. Understanding anaesthesia equipment. 5th ed. Philadelphia: Lippincott Williams and Wilkins; 2008

Thank you