Airway clearance techniques in cystic fibrosis

Abstract

Cystic fibrosis (CF) is characterised by the retention of sputum, reduced exercise capacity and breathlessness 1. To overcome the major problem of sputum retention, a variety of airway clearance techniques have been developed 2, 3, all of which have a clear goal: to reduce disease progression by augmenting the normal mucociliary clearance mechanisms and to facilitate expectoration. The range of techniques available has been summarised in a recent evidenced-based review 4. What is important about all of these therapies is that they need to have a justifiable reason for their inclusion in the highly demanding care packages that are required by CF patients. To date, there is little evidence to suggest that any one intervention is better than another; the only clear conclusion is that there may be some short-term benefit to airway clearance compared to no airway clearance 5. Both positive expiratory pressure (PEP) 6 and conventional chest physiotherapy 7 are as effective as other forms of airway clearance. Whilst the trials quoted in the Cochrane reviews 5–7 provide various degrees of quality of evidence, the key information that is missing from these studies is an understanding of the physiological principles by which these different techniques work. Physiologically, the techniques need to do the following. 1) Increase absolute peak expiratory …