Chest physiotherapy

The aim is to expand collapsed alveoli, mobilise chest secretions, or re-inflate collapsed lung segments. Though anecdotal experience suggests benefit, no scientific validation of effectiveness has been reported. The current view is routine ‘prophylactic’ suctioning/bagging should be avoided in the critically ill.

Indications

• Mobilisation of secretions.

• Re-expansion of collapsed lung/lobes.

• Prophylaxis against alveolar collapse and secondary infection.

Contraindications/cautions

• Aggressive hyperinflation in already hyperinflated lungs, e.g. asthma, emphysema-though can be very useful in removing mucus plugs.

• Undrained pneumothorax.

• Raised intracranial pressure.

Techniques

Hyperinflation

Hyperinflating to 50% above ventilator-delivered VT, aiming to expand collapsed alveoli and mobilise secretions. VT is rarely measured, so

either excessive or inadequate hyperinflations may be given, depending on lung compliance and operator technique. Pressure-limiting devices

(‘blow-off valves’) or manometers can avoid excessive airway pressures. A recommended technique is slow inspiration, a 1–2s plateau phase, and then rapid release of the bag to simulate a ‘huff’ and mobilise secretions. Preoxygenation may be needed as PEEP may be lost and the delivered VT may be inadequate. Cardiac output often falls with variable blood pressure and heart rate responses. Sedation may blunt haemodynamic response. Full deflation avoids air trapping.

Suction

Removing secretions from trachea and main bronchi (usually right). A cough refl ex may be stimulated to mobilise secretions further. Tenacious secretions may be loosened by instillation of 2–5mL 0.9% saline. Falls in SaO2 and cardiovascular disturbance may be avoided by pre-oxygenation.

Percussion and vibration

Drumming and shaking actions over chest wall to mobilise secretions. Inspiratory pressure support (Bird ventilator) The aim is to increase FRC and expand collapsed alveoli.

Postural drainage

Patient positioning to assist drainage—depends on affected lung area(s).

Complications of chest physiotherapy

• Hypoxaemia: from suction, loss of PEEP, etc.

• Haemodynamic disturbance affecting cardiac output, heart rate, and blood pressure (may be related to high VT, airway pressure, hypoxaemia, agitation, tracheal stimulation, etc.).

• Direct trauma from suctioning.

• Barotrauma/volutrauma, including pneumothorax.

General care to avoid need for urgent physiotherapy

• Adequate humidifi cation avoids tenacious sputum and mucus plugs.

• Pain relief is important to encourage good chest expansion and cough.

• Position semi-recumbent to optimise use of respiratory muscles.

• Ensure nutrition is adequate to maintain muscle strength.

• Mobilisation and encouraging deep breathing may avoid infection.

Request	Don’t request
Collapsed lung/lobe with no air bronchogram visible, i.e. suggesting proximal obstruction rather than consolidation.	Clinical signs of chest infection with no secretions being produced.
Mucus plugging causing subsegmental collapse, e.g. asthma.	Radiological consolidation with air bronchogram but no secretions present.