The aim of our study was to compare the short-term efficacy of three different chest physiotherapy (CPT) regimens (PD, postural drainage; PEP, positive expiratory pressure physiotherapy; HFCC, high-frequency chest compression physiotherapy) on patients with cystic fibrosis (CF) hospitalized for an acute pulmonary exacerbation. Sixteen patients with CF, 8 males, 8 females, aged 15-27 years (mean, 20.3 +/- 4), met the inclusion criteria: 1) age over 14 years; 2) mild or moderate airway obstruction; 3) sputum volume > 30 mL/day; 4) being proficient in PD and PEP CPT. Patients at admission had (mean +/- SD) forced volume in 1 second (FEV1) 52.2 +/- 21.9 percent predicted; Shwachman-Kulczycki clinical score 65.1 +/- 11 points; Chrispin-Norman chest radiography score 18.6 +/- 4.3 points. The three CPT regimens and a control-treatment (CONT) were administered in a random sequence, each patient receiving each treatment twice a day (in 50 minute sessions) for 2 consecutive days. During CONT and for 30 minutes after each session only spontaneous coughing was allowed. Wet and dry weight of sputum were recorded during the 50-minute sessions and 30 minutes afterward. Lung function was measured before and 30 minutes after each session. For each treatment a score was given by the patient for efficacy, and by both the patient and the physiotherapist for tolerance. Wet and dry weights of sputum collected during the sessions were greater for all CPT regimens than for CONT (P < 0.001, P < 0.0001). No significant differences between the three CPT regimens for both wet and dry weights were found when the number of coughs was taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)