Positive expiratory pressure therapy better maintains pulmonary function than postural drainage and percussion in patients with cystic fibrosis

Objective. To compare the effects of long-term positive expiratory pressure (PEP) therapy and conventional postural drainage and percussion (PD and P) on pulmonary function in patients with cystic fibrosis. Design. Randomised observer-blind trial of year duration. Setting. Therapy was carried out in the patients' homes. Patients. Forty patients with cystic fibrosis aged 6-17 years. All were judged to be competent and compliant in performing PD and P at home. The investigators withdrew four children (two from each group) from the study because of poor compliance with the prescribed therapy. Intervention. Therapy was carried out twice daily for one year. Conventional PD and P consisted of 3-5 minutes of percussion, deep breathing and vibrations, forced expirations and coughing in each of five or six postural drainage positions. Total therapy time was 30 minutes. PEP therapy was performed in sitting. The patient breathed in and out through the mask 15 times against a resistance of 10-20 cm H₂O. Depth of inspiration was tidal volume and expiration was slightly active. After removing the mask, patients performed two or three forced expirations and 1 or 2 minutes of relaxed controlled breathing. This sequence was repeated six times and required about 20 minutes to complete. Compliance was monitored with daily recording of treatments and a monthly questionnaire. Main outcome measures. The primary outcome was change in FEV₁, expressed as percentage predicted for age, sex and height. Other outcomes were change in FVC, Shwachman and Huang scores, Brasfield scores of chest radiographs, and patients' own impressions of therapy. Pulmonary function, clinical assessments and chest radiographs were assessed by blind observers. Main results. On average, FEV₁ and FVC declined by about 2 per cent each over one year in patients receiving PD and P, and increased by 7 per cent and 6 per cent respectively, in those receiving PEP therapy. These differences were statistically significant. There were no significant differences between groups with respect to other variables, although patients reported that PEP therapy mobilised more sputum and was easier to perform. Conclusion. PEP therapy maintains pulmonary function of patients with cystic fibrosis better than PD and P.