Oscillating devices for airway clearance in people with cystic fibrosis

Chest physiotherapy is widely prescribed to assist the clearance of airway secretions in people with cystic fibrosis (CF). Oscillating devices generate intra- or extra-thoracic oscillations orally or external to the chest wall. Internally they create variable resistances within the airways, generating controlled oscillating positive pressure which mobilises mucus. Extra-thoracic oscillations are generated by forces outside the respiratory system, e.g. high frequency chest wall oscillation.

To determine the effectiveness and acceptability of oscillating devices compared to other forms of physiotherapy to improve respiratory function, mucus clearance and other outcomes in people with CF.

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and hand searches of relevant journals and abstract books of conference proceedings. Most recent search of the Cystic Fibrosis Trials Register: November 2008.

Randomised controlled studies and controlled clinical studies of oscillating devices compared with any other form of physiotherapy in people with CF.

Two authors independently applied the inclusion criteria to publications and assessed the quality of the included studies.

Two hundred and sixty-five studies were identified; thirty studies (total of 708 participants) met the inclusion criteria. Single treatment interventions (therapy technique used only once in the comparison) were excluded. Studies varied in duration from up to one week to one year in duration. Nineteen of the studies were cross-over in design. Data were not published in sufficient detail in most of these studies to perform meta-analysis.Forced expiratory volume in one second (FEV(1)) was the most frequently measured outcome. Results did not show significant difference in effect between oscillating devices and other methods of airway clearance on FEV(1) or other lung function parameters. Where there has been a small but significant change in secondary outcome variables such as sputum volume or weight this has not been wholly in favour of oscillating devices. Participant satisfaction was reported in eleven studies, but this was not specifically in favour of an oscillating device as some participants preferred breathing techniques or techniques used prior to the study interventions. The results for the remaining outcome measures were not examined or reported in sufficient detail to provide any high level evidence.

There was no clear evidence that oscillation was a more or less effective intervention overall than other forms of physiotherapy. More adequately-powered long-term randomised controlled trials are needed.