Manual Hyperinflation (MHI) Guideline for Practice 2015
Version: This replaces the Manual Hyperinflation (MHI) Guideline for Practice, 2012
Review Date: September 2018
Contact: Ann Alderson, Band 7, Critical Care Physiotherapist Ext: 63327
and Catherine McLoughlin, Band 7 Critical Care Physiotherapist Ext: 56142
Disclaimer
This guideline has been registered with the Trust. However, clinical guidelines are guidelines only. The
interpretation and application of clinical guidelines will remain the responsibility of the individual clinician.
If in doubt contact a senior colleague or expert. Caution is advised when using guidelines after the review
date
Introduction/Indications for Use
MHI sometimes known as "bagging" is a technique that can be used as part of the management of
mechanically ventilated and tracheostomy patients. The physiotherapeutic technique involves the use of a
2 litre, single patient use resuscitation bag that is squeezed with a series of larger than baseline peak
airway pressures and tidal volume at a slow inflation rate, with the addition of a pause (Redfern et al.,
2001).
The effects are to:
-Optimise alveolar ventilation. By reducing atelectasis, this reduces ventilation perfusion mismatch and
improves gas exchange (Rothen et al., 1993 and 1995)
-Mobilise pulmonary secretions (Jones et al., 1992)
-Improve lung compliance (Hodgson et al., 1996)
MHI may be indicated in patients requiring mechanical ventilation and self ventilating tracheostomy
patients who have Chest x-ray changes of lung collapse and/or consolidation or by areas which are
poorly ventilated on auscultation.
The ability to monitor patients’ response (Heart rate, blood pressure and oxygen saturations) is required.
Hazards and Complications
Manual hyperinflation is a form of positive pressure ventilation and therefore, if performed inappropriately
carries the risk of complications. Barotrauma and volutrauma are terms used to describe the development
of extra alveolar air and fluid due to alveolar distention. (Dreyfuss and Saumon, 1996) The delivery of
high peak airway pressures and or volumes increases the risk of haemodynamic instability due to the
increase in intrathoracic pressure, which can decrease, stroke volume & cardiac output (Singer et al
1994), change blood pressure response, (Goodnough, 1985) and cause tachycardia (Partaz, 1992 and
Stone et al 1991)
MHI Guidelines 2015
Absolute Contraindications
1. Extra-alveolar air e.g. Bullae or Undrained Pneumothorax
2. Subcutaneous emphysema of unknown cause
3. Severe/widespread bronchspasm
Precautions (Discuss with Dr prior to performing MHI)
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Pneumothorax, with a bubbling chest drain
Low, high or labile blood pressure
Labile ICP
Some lung diseases, especially emphysema/ hyperinflated lungs
Cardiac arrhythmias
Post Lung surgery
High PEEP requirements combined with high Fi02 requirement
PEEP > 10cmH20 on mechanical ventilation
Equipment
A manometer should be incorporated into the circuit to allow airway pressures to be monitored during
manual hyperinflation (Redfern et al, 2001)
MHI Guidelines 2015
Procedure
Action
Assess the patients vital signs
Prepare the patient by giving explanation,
sedation and analgesia as required
Position the patient so that the lung to be
treated is uppermost
Connect the 2 litre re-breathing bag to the 02
supply and ensure the expiratory valve is
working & place a filter in the circuit between
the patient and the bag and attach the
manometer
Set the 02 flow rate to15 litres per minute)
Put the ventilator on Standby or use the preoxygenation suction facility to disable the alarm
Disconnect the patient from the ventilator and
attach the re-breathe bag to the airway via the
catheter mount or the closed suction circuit
mount
Using a two handed technique, initially deliver
a tidal volume breath (watching the patients
chest expansion)
Then perform MHI breaths. The manual
hyperinflation breath should be maintained for
at least 2 seconds, but no more than 7
seconds at a pressure of no more than 40
cmH20
Release the bag sharply on expiration to
simulate the Forced Expiratory technique
If indicated apply manual techniques such as
shaking or vibration at the end of expiration
and during expiration
Repeat the procedure several times as
indicated
Rationale
To ensure they are stable and in order to detect
changes in the patients condition
Minimises any distress to the patient thus, maximising
effectiveness of treatment
Optimises ventilation to the affected lung and assists
with the drainage of secretions (Sholten et al., 1985,
Stiller, 1990 and Novak, 1987)
Prevents hypoxia and ensures safety of equipment.
To prevent contamination or the bag and/or the patients
lungs
Provides feedback to the operator of the airway
pressures being delivered
To ensure 100% oxygen is delivered & the bag fills
quickly
Prevents patient anxiety
To enable manual hyperinflation
To allow the operator to gain a feel of the patients lung
compliance and ensure an adequate Tidal Volume is
being delivered into the patients lungs
To ensure effective manual hyperinflation breaths and
recruit collapsed alveoli (Sholten, 1985, Rothen et al.,
1993 and 1999, Hodgson et al., 2000) Limits the
detrimental effects on Cardiovascular system
(Hodgson, 2000)
To mobilise secretions from more peripheral to central
airways (Nunn 1987, McKenzie 1987, Jones, 1991 and
Maxwell, 1998)
To assist secretion clearance and lung re- expansion
(Stiller 1990 and MacLean et al., 1989)
Effect optimal secretion clearance and recruitment of
collapsed alveoli (Hodgson, 2000)
Explain the procedure to the patient throughout
the entire process and always synchronize with
spontaneous ventilation
If the patient is coughing the expiratory
pressure valve should be released
Reduces the pressure built up in the lungs and reduces
the risk of barotrauma (Haak, 1987)
Perform suction if the patient coughs or
secretions are heard
Clears secretions preventing them being forced back
into smaller airways
Continue the above procedure until no further
treatment is indicated (e.g. if no more
secretions are heard or the chest is clear on
auscultation)
Effect optimal recruitment of collapsed alveoli and
secretion clearance (Hodgson, 2000)
MHI Guidelines 2015
Minimises stress and discomfort to the patient
Restore ventilatory support, ensuring that
adequate tidal and minute volume are being
achieved or re attach the patient to their
oxygen supply
Monitor the patient's vital signs during and after
the procedure and check that the expected
parameters have been restored.
Reauscultate the patients chest
Document on the patients chart and in the
medical notes that Manual Hyperinflation
treatment has been performed. Note any
changes in the patient's condition adverse or
otherwise
Re-establishes current ventilatory support
To ensure no adverse effects of manual hyperinflation
are occurring and that the patient is returned to a safe
environment
To evaluate the effects of treatment
Makes staff aware of the patients' response therefore,
safeguarding the patient's well being
References
Dreyfuss D and Saumon G. High inflation pressures and pulmonary oedema. Respective effects of high
airway pressure, high tidal volume and PEEP. American Respiratory Review of Respiratory Disease
1988; 137: 1159-1164
Goodnough SK. The effects of oxygen and hyperinflation on arterial oxygen tension after endotracheal
suction. Heart and Lung 1985; 14: 11-17
Haake R et al. Barotrauma: Pathophysiology, risk factors and prevention. Chest 1987; 91: 608-613
Hodgson C et al. An investigation of the early effects of manual lung hyperinflation in critically ill patients.
Anaesthesia and Intensive Care 2000; 28: 255-261
Jones A, Hutchinson R and Oh T. Effects of bagging on total static compliance of the respiratory system.
Physiotherapy 1992; 78: 661-666
King D and Morrell A. A survey on manual hyperinflation as a physiotherapy technique in intensive care
units. Physiotherapy 1992; 78: 747-750
MacLean D et al. Maximum expiratory airflow during chest physiotherapy on ventilated patients before
and after the application of an abdominal binder. Intensive Care Medicine 1989; 15: 396-399
Maxwell L and Ellis E. Secretion clearance by manual hyperinflation: Possible mechanisms.
Physiotherapy Theory and Practice 1998; 14: 189-197
Novack RA et al. Do periodic hyperinflations improve gas exchange in patients with hypoxaemic
respiratory failure ? Critical Care Medicine 1987; 15:1081-1085
Partaz J. Haemodynamic stability of the ventilated intensive care patient: A review. Australian Journal of
Physiotherapy 1992; 1992: 167-172
Redfern J et al. The use of a pressure manometer enhances student physiotherapists' performance
during manual hyperinflation. Australian journal of physiotherapy 2001; 47: 121- 131
MHI Guidelines 2015
Rothen HU et al. Re expansion of atelectasis during general anaesthesia: A computer tomography study.
British Journal of Anaesthesia 1993; 71: 788-795
Rusterholz B and Ellis E. The effect of lung compliance and experience on manual hyperinflation.
Australian Journal of Physiotherapy 1998; 44: 23-28
Scholten W et al. Directed manual recruitment of collapsed lung in intubated and non intubated patients.
Annals of Surgery 1985; 51: 330-334
Singer et al. Haemodynamic effects of manual hyperinflation in critically ill mechanically ventilated
patients. Chest 1994; 106: 1182-1187 Stiller K et al. Acute lobar atelectasis: A comparison of two chest
physiotherapy regimes. Chest 1990; 98: 1336-1340
Stone KS et al. Effect on lung hyperinflation and endotracheal suctioning on heart rate and rhythm in
patients after coronary artery bypass graft surgery. Heart and Lung 1991; 20: 443-450
MHI Guidelines 2015