A NEW METHOD FOR BRONCHIAL-PROVOCATION TESTING IN ASTHMATIC SUBJECTS USING A DRY POWDER OF MANNITOL

We developed a bronchial provocation test (BPT) with a dry powder prep aration of mannitol. The mannitol was inhaled from gelatin capsules co ntaining 5, 10, 20, or 40 mg to a cumulative dose of 635 mg, and was d elivered via an Inhalator, Halermatic, or Dinkihaler device. We studie d the airway sensitivity to inhaled mannitol, the repeatability of the response, and the recovery after challenge in 43 asthmatic subjects 1 8 to 39 yr of age who had a 20% decrease in FEV1 in response to inhali ng a 4.5% NaCl. We compared this with the airway response to methachol ine in 25 subjects. The geometric mean (CM) for the dose of dry mannit ol required to reduce the FEV1 by 15% of the baseline value (PD15) was 64 mg, with a 95% confidence interval (CI) of 45 to 91. Subjects resp onsive to mannitol had a PD20 to methacholine of < 7.8 mu mol, with a GM of 0.7 mu mol (CI: 0.4 to 1.2). For the first of two challenges to mannitol the PD15 was 59 mg (CI: 36 to 97) and for the second the PD15 was 58 mg (CI: 35 to 94) p = 0.91 (n = 23). Spontaneous recovery to w ithin 5% of baseline occurred within 60 min and within 10 min after 0. 5 mg terbutaline sulfate was inhaled. Arterial oxygen saturation (Sa(O 2)) remained at 93% or above during mannitol challenge. Subjects toler ated the inhalation of the mannitol well. A dry powder preparation of mannitol may be suitable to develop for bronchial provocation testing.