Copyright ©ERS Journals Ltd 1998 European Respiratory Journal

Cystic fibrosis (CF) patients have viscous bronchial secretions, endobronchial infection and, hence, destruction of the lung and deterioration of lung function [1]. Sput-um expectoration, aided by chest physiotherapy (CPT), postural drainage, percussion and coughing, have been standard therapy for many years [1, 2]. Self-administered physiotherapy techniques, including the forced expiration technique (FET), active cycle of breathing technique (ACBT), autogenic drainage and the use of a positive expi-ratory pressure (PEP) mask provide personal independence for the patient and have largely replaced earlier techniques [3–11]. It is uncertain whether any of these newer meth-ods, or combinations of different techniques, are better than others [1, 11–14]. A new device to facilitate clearance of mucus is th