Comparison of the Provocative Concentration of Methacholine Causing a 20% Fall in FEV_1 between the AeroEclipse II Breath-Actuated Nebulizer and the Wright Nebulizer in Adult Subjects with Asthma

摘要

Rationale: The American Thoracic Society guidelines for methacholine testing for the diagnosis of asthma recommends the 2-minute tidal breathing protocol with the Wright nebulizer, which produces more aerosol than required, generates a small particle size, and requires cleaning between tests. Objectives: To evaluate methacholine testing using a disposable, breath-actuated AeroEclipse II, which produces aerosol during inspiration and was developed for single-patient use. Methods: Forty-six adult subjects with asthma (19 men), aged 27.3 (SD, 9.5) years, with FEV_1 98.5 (SD, 18.1) % predicted participated in a randomized, crossover, observational study. Subjects were first screened using the Wright nebulizer, then assigned to 2 minutes of tidal breathing from the Wright or 20 seconds of tidal breathing from the AeroEclipse nebulizer on 2 separate days, in random order. Provocative concentration of methacholine causing a 20% fall in FEV_1 (PC_(20)) values were calculated by linear interpolation of log dose-versus-response curves, log-transformed, and compared using paired Student t test and Pearson correlation.