Effectiveness of positive expiratory pressure on patients over 16 years of age with cystic fibrosis: systematic review and meta-analysis

INTRODUCTION: Cystic fibrosis (CF) is an autosomal recessive disease that involves the cells that produce mucus and sweat, affecting many organs, especially the lungs. Positive expiratory pressure (PEP) devices generate a pressure opposite to that exerted by the airways during expiration, thus improving mucociliary clearance. OBJECTIVES: To evaluate the efficacy of PEP devices as a resource to facilitate the mucus removal and other outcomes in people with CF, as well as the possible adverse effects derived from their use. MATERIAL AND METHOD: A systematic review and meta-analysis was conducted according to PRISMA standards. The descriptors were ‘cystic fibrosis’, ‘PEP’, and ‘physiotherapy and/or physical therapy’. The search was performed in four databases: PubMed, PEDro, and Web of Science and Scopus, in July 2021. The inclusion criteria were randomized controlled trials (RCTs) over the last 10 years. The methodological quality of the studies was analyzed and meta-analysis was performed with Review Manager software. RESULTS: Ten RCTs met the objectives and criteria, with a total of 274 participants. The trials score a moderate methodological quality on the PEDro scale. No clear results were obtained on whether PEP provides better lung function than other breathing techniques (such as airway clearance); but it does achieve a higher rate of lung clearance than physical exercise. CONCLUSIONS: PEP is more effective than usual care or no intervention, although there is not enough evidence to confirm that PEP achieves improvements in forced expiratory volume in the first second (FEV(1)) compared with other techniques. It is a safe technique, without adverse effects.