Introduction

The aims of respiratory physiotherapy include mobilization and aid in expectoration of bronchopulmonary secretions, improving the efficiency of ventilation and maintaining or improving exercise tolerance. Physiotherapy has a key role to play in the prevention and treatment of respiratory complications after cardiac surgery.

This chapter starts by detailing the possible effects of cardiac surgery and general anaesthesia on the respiratory system. It then discusses the physiological basis and current evidence for the most commonly used physiotherapy techniques in the cardiac critical care unit. The management of both the spontaneously ventilating and intubated patient is considered.

Respiratory complications after cardiac surgery

It is well recognized that left lower lobe collapse occurs in the majority of patients after cardiac surgery. Reasons for this include:

1. • perioperative compression of the lobe;

2. • occasional injury to the phrenic nerve; and

3. • postoperative pain.

Other contributory factors leading postoperative atelectasis include:

1. • the effects of the median sternotomy/thoracotomy incision;

2. • internal mammary artery dissection;

3. • the use of cardiopulmonary bypass; and

4. • prolonged recumbency.

A certain amount of micro-atelectasis after surgery is inevitable, partly due to a reduction in functional residual capacity (FRC) secondary to general anaesthesia. If FRC falls below closing volume, then atelectasis occurs in the dependent lung. The efficiency of the mucociliary escalator (composed of mucus-secreting goblet cells, cilia and a viscous mucus gel layer) is also reduced.