Short-term effects of expiration under positive pressure in patients with acute exacerbation of chronic obstructive pulmonary disease and mild acidosis requiring non-invasive positive pressure ventilation.

Objective: To investigate the feasibility and the efficacy of expiration under positive pressure (PEP mask) as a chest physiotherapy in patients with exacerbation of chronic obstructive pulmonary disease (COPD) and acute hypercapnic respiratory failure (AHRF) requiring non-invasive positive pressure ventilation (NIPPV).

Design: A prospective, randomised, controlled study.

Setting: A respiratory intensive care unit.