Tracheobronchial mucociliary clearance in asthma: impairment during remission.

Tracheobronchial mucociliary clearance was measured in eight non-smoking patients with asthma in complete remission. The patients were symptom free and required no medication whatsoever for one to six months before assessment. Mucociliary clearance was measured with an objective, radioaerosol technique. For comparison, mucociliary clearance of eight non-smoking, healthy subjects with physical characteristics and pulmonary function similar to those of the asthmatics was also measured on two occasions. In their first assessment the healthy subjects inhaled the tracer radioaerosol under experimental conditions similar to those used for the asthmatics; in the second assessment they inhaled the radioaerosol rapidly to simulate the asthmatic pattern of deposition. Under similar experimental conditions the radioaerosol was deposited more proximally in the asthmatic subjects than in the normal subjects and the difference was statistically significant (p less than 0.01). When, however, the depth of radioaerosol lung penetration was similar in the two groups, there was evidence of a significantly (p less than 0.01) poorer mucociliary clearance six hours after radioaerosol inhalation in the asthmatic than in the healthy group. These findings raise the question whether asthma ever remits completely.