['To determine whether the use of a mucus clearance device (MCD) [Flutter; Axcan Scandipharm; Birmingham, AL] could improve the bronchodilator response to inhaled ipratropium and salbutamol delivered by a metered-dose inhaler in patients with stable, severe COPD.', 'Twenty-three patients with severe COPD were studied. Mean +/- SD age was 71.7 +/- 6.3 years. Mean FEV(1) was 0.74 +/- 0.28 L or 34.5 +/- 12.7% predicted.', 'Patients were tested in random order on 2 subsequent days after using an MCD or a sham MCD. A bronchodilator (four puffs; each puff delivering 20 microg of ipratropium bromide and 120 microg of salbutamol sulfate) was administered by metered-dose inhaler with a holding chamber after use of the MCD or sham MCD. Spirometry was performed before and after use of the MCD or sham MCD, and at 30 min, 60 min, and 120 min after the bronchodilator. Six-minute walk distance was tested between 30 min and 60 min; oxygen saturation, pulse, and a dyspnea score were recorded before and after walking.', 'Immediately after use of the MCD, but not the sham MCD, there was a statistically significant (p < 0.05) improvement in FEV(1) and FVC (11 +/- 24% vs 1 +/- 7% and 18 +/- 33% vs 6 +/- 18%, respectively). Whether patients were pretreated with the MCD or sham MCD, there was a significant improvement in FEV(1) and FVC compared to baseline with combined bronchodilator therapy. At 120 min, the change in FEV(1) after treatment with the MCD was greater than with the sham MCD (186 +/- 110 mL vs 130 +/- 120 mL; p < 0.05). When comparing the MCD to the sham MCD, 6-min walk distance was greater (174 +/- 92 m vs 162 +/- 86 m; p < 0.05), with less dyspnea before and at the end of walking.'] Does use of a mucus clearance device enhance the bronchodilator response in patients with stable COPD?