321 Clinical Analysis of Salbutamol Responsiveness after Acetylcholine-induced Bronchoconstriction in Childhood Asthma

BACKGROUND: The bronchodilator is usually inhaled after the acethylcholine (Ach) inhalation test for asthmatic patients. We investigated clinical characteristics of asthma about the response to a inhalation of salbutamol after the Ach provocation test. METHODS: Asthmatic patients from 6 to 18 years old were examined. They inhaled aerosol with increased concentration of Ach to produce 20% or more decrease in FEV1.0 (RT-Ach point). After then they inhaled salbutamol, and respiratory function was examined after 0, 5, 10, and 15 minutes. We divided the patient into 4 groups (G0,G5,G10,G15) by the recovery time up to baseline FEV1.0 after inhalation of salbutamol. RESULTS: Pre-provocated baseline FEV1.0, the rate of actual FEV1.0 /predictive FEV1.0, RT-Ach and FEV1.0 at the point of RT-Ach were lower in the G0 than other groups significantly. Complication of exercise induced asthma (EIA) and increased rate of FVC after the inhalation of salbutamol were higher in the G0. Serum IgE, eosinophil count of peripheral blood was not different in these groups. CONCLUSIONS: We investigated about the response to salbutamol after the provocation of Ach for childhood asthma. Bronchial constriction and hyperresponsiveness exit prior to challenge Ach in the group of early response to β2-agonist after the provocation test.