A review study suggests that positive expiratory pressure (PEP) devices are more effective than other airway clearance approaches in reducing pulmonary exacerbations in patients with cystic fibrosis (CF), but of similar effectiveness in other measures, like lung function and mucus drainage. The study, entitled “ Positive expiratory pressure physiotherapy for airway clearance in people with cystic fibrosis,” was published in Cochrane Database Systematic Reviews journal.

CF is characterized by mucus build-up in the tissue of organs such as the lungs, blocking the airways with mucus secretions and causing repeat respiratory infections. Chest physiotherapy is frequently used by physical therapists to improve breathing by indirectly removing these secretions from air passages. There are many approaches that can be taken, but PEP devices — which create constant back pressure to the airways behind the mucus — are in widespread use. It is believed that back pressure makes clearance easier by building up gas behind mucus via collateral ventilation and keeping the airways from closing.

Given their extensive use, the researchers tried to determine the effectiveness and acceptability of PEP devices compared to other methods of chest physiotherapy. They performed an in-depth bibliographic search by examining references from: 1) the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, 2) relevant journals and abstract books of conference proceedings, 3) the electronic database CINAHL from 1982 to 2013, and 4) a recent search (Dec. 2, 2014) of the Cochrane Group’s cystic fibrosis register.

From all references, only controlled studies involving CF patients where PEP devices were compared with other methods of chest physiotherapy were selected. The other techniques included active cycle of breathing techniques, postural drainage and percussion, oscillating PEP devices, bilevel positive airway pressure (BiPaP) and exercise, and thoracic oscillating devices. From a total of 26 identified studies, 25 including 733 CF patients fit the selection criteria. However, most studies had various drawbacks, such as: 1) low quality, 2) cross-over in design in 18 studies involving a total of 296 patients, and 3) lack of details and meta-analysis in most of the published references. The measured outcomes included the number of respiratory exacerbations, a direct measure of mucus clearance, weight of expectorated secretions, other pulmonary function parameters, a measure of exercise tolerance, ventilation scans, cost of intervention, and adherence to treatment. The studies’ most frequently measured outcome was forced expiratory volume in one-second (FEV1), an estimate of the amount of air exhaled during a forced breath.

Results suggest that single PEP interventions or continued PEP therapy up to three months were not significantly different on FEV1 when compared to other methods of airway clearance. Longer-term studies of PEP devices had unclear and sometimes contradictory outcomes on FEV1. However, participants reported preferring PEPs to other methods in 10 studies and in other studies involving intervention periods of at least one month.

Importantly, PEP was linked in the Cochrane register to a lower exacerbation rate in participants when compared to other therapeutic approaches.

Overall, these findings suggest that PEP devices may significantly decrease pulmonary exacerbations in some patients over other physiotherapy methods, and their use was preferred by a number of patients over the longer term. Furthermore, given the difficulties in comparing studies of chest physiotherapy, the researchers concluded that the patient’s preference for the approach used is probably the most important factor, since it affects adherence to the therapy. Each patient, they said, needs to be considered individually for choosing the optimal treatment method.