2. Manual hyperinflation
• 'Bagging' can be used as a technique to hand-ventilate
a patient or during physiotherapy.
• When hand ventilating, normal tidal volumes are
generally delivered, whereas to facilitate
physiotherapy larger breaths or hyperinflations are
necessary.
• Manual hyperinflation can be given either using a
Water's bag circuit or an Ambu-bag. A greater range of
volume is available with a Water's bag.
• For an adult a 2 or 3 litre Water's bag, connected to a
flow of 10- 15 litres of oxygen is commonly used.
3. • By altering the expiratory valve, volume and
therefore inspiratory pressure can be manipulated.
• The use of a manometer acts as a guide to inflation
pressures which are recommended to be less than
40cmH2O.
• If manual hyperinflation is indicated in a PEEP
dependent patient; a PEEP valve must be used to
maintain positive end-expiratory pressure during
treatment
4. Indications
• To aid removal of secretions
• To aid reinflation of atelectatic segments
• To assess lung compliance
• To improve lung compliance.
5. Therapeutic effects of manual hyperinflation
• The most common technique used is a slow
inspiration, and inspiratory hold followed by quick
expiratory release.
• A prolonged inspiratory hold is contraindicated in a
patient who is already hyperinflated (e.g.
emphysema).
6. Slow deep inspiration:
– Recruits collateral ventilation thus promoting
mobilization of secretions
– Enhances interdependence to aid re-expansion of
atelectatic segments
– Improves gaseous exchange
– Assesses and potentially improves compliance.
7. Inspiratory hold (at full inspiration):
– Further utilizes collateral ventilation and
interdependence as at higher volume; therefore
maximizes pressure distribution.
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.
8. Hazards of manual hyperinflation
• Reduction in blood pressure. During manual
hyperinflation the normal mechanism which
'sucks' the remaining blood from the inferior vena
cava to the right atrium during negative pressure
inspiration is lost.
• In addition, the positive pressure generated during
manual hyperinflation increases intrathoracic
pressure.
• Both mechanisms compromise venous return. The
resultant effect could be a reduction in stroke
volume and therefore a drop in blood pressure
9. • This risk is potentially increased when using a PEEP
valve, or during prolonged inspiratory holds.
• It should be noted that if a bolus of sedation is
given before treatment, this may lower the blood
pressure through vasodilatation.
Considerations for physiotherapy
• If the blood pressure drops during treatment,
smaller tidal breaths should be given. If the blood
pressure remains compromised the patient should
be put back onto the ventilator/ positioned
appropriately and a medical review requested.
10. Reduced saturations. Oxygen saturations can be
compromised by sputum plugging, collapse,
pneumothorax, bronchospasm and V/Q
mismatching.
Considerations for physiotherapy
• Reassessment will highlight the cause.
Intermediate measures such as increasing the FiO2
can be used.
11. Raised intracranial pressure. The presence of
increased levels of PaC02 in cerebral blood
vessels may lead to vasodilatation. The resultant
increased cerebral blood flow may increase ICP.
Considerations for physiotherapy
• To prevent fluctuations in ICP during manual
hyperinflation small fast breaths should be
interspersed between hyperinflations.
12. Reduced respiratory drive. PaCO2 levels may be
reduced during effective treatment. This may reduce
the patient's respiratory drive.
Considerations for physiotherapy
• After finishing manual hyperinflation, the patient's
spontaneous respiratory effort should be monitored.
13. Contraindications to manual hyperinflation
• Undrained pneumothorax (presence of patent
intercostal drain - treat as normal)
• Potential bronchospasm
• Severe bronchospasm
• Gross cardiovascular instability inducing
arrhythmias and hypovolemia
• Unexplained haemoptysis
• An absolute indication for treatment should be
present before manual hyperinflation is used on
patients requiring PEEP levels greater than 15
cmH20 plus maximal ventilatory support, or
patients with high peak and mean inspiratory
pressures.