Positive expiratory pressure physiotherapy for airway clearance in people with cystic fibrosis.

Background: Chest physiotherapy is widely prescribed to assist the clearance of airway secretions in people with cystic fibrosis (CF). Positive expiratory pressure (PEP) devices provide constant back pressure to the airways during expiration. This may improve clearance by building up gas behind mucus via collateral ventilation. Given the widespread use of PEP devices, there is a need to determine the evidence for their effect.

Objectives: To determine the effectiveness and acceptability of PEP devices compared to other forms of physiotherapy as a means of improving mucus clearance and other outcomes in people with CF.

Search Strategy: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group trials register comprising of references identified from comprehensive electronic database searches and handsearching of relevant journals and abstract books of conference proceedings. The electronic database CINAHL was also searched from 1982 to 2001. Most recent search of the Group's register: November 2003.

Selection Criteria: Randomised controlled trials in which PEP was compared with any other form of physiotherapy in people with CF.

Data Collection And Analysis: Two reviewers independently applied the inclusion and exclusion criteria to publications and assessed the quality of the included studies.

Main Results: Thirty-three studies were identified and twenty studies involving 429 participants met review inclusion criteria. Most included studies had low scores on a scale of study quality. Sixteen of these studies involving 257 participants were cross-over in design. Data were not published in sufficient detail in these studies to perform meta-analysis.Forced expiratory volume in one second (FEV1) was the most frequently measured outcome. Single interventions or series of treatments continued for up to one month demonstrated no significant difference in effect between PEP and other methods of airway clearance on FEV1. Long-term studies had equivocal or conflicting results regarding the effect on FEV1. Patient preference was reported in nine studies. In all studies with an intervention period of at least one month, measures of patient preference were in favour of PEP. The results for the remaining outcome measures were not examined or reported in sufficient detail to provide any high level evidence.

Reviewer's Conclusions: There was no clear evidence that PEP was a more or less effective intervention overall than other forms of physiotherapy. There was limited evidence that PEP was preferred by participants compared to other techniques but this finding is from studies of low quality.