Mucus clearance in patients with chronic non-productive cough

The aim of this study was to measure mucus clearance in patients with chronic non-productive cough. We studied eleven patients suffering from non-productive cough for 1.5-21 years and seven healthy subjects. The cause of cough in the patients had not been established despite extensive examinations. Mucus clearance was measured using inhaled radiolabelled particles (Tc-99m) with the subject in supine posture. Clearance was measured during 1 hour at rest. Mucus clearance achieved by the forced expiration technique was then measured with the patient in the sitting posture. Mucus clearance at rest was significantly faster in the patients than in the healthy subjects (22 +/- 16 vs 9 +/- 5, p < 0.05). Clearance by the forced expiration technique did not differ between the patients and the healthy subjects (5.7 +/- 3.6 vs 3.7 +/- 1.1). The higher mucus clearance in the patients may be due to the presence of inflammatory mediators in the bronchial mucosa causing increased ciliary activity.