Methacholine airway hyperresponsiveness measured just after control of acute severe asthma / 천식및알레르기

ABSTRACT

BACKGROUND: It has been shown that severe asthmatic attacks are related to airway hyperresponsiveness (AHR). However, there has been no study on AHR measured just after control of acute severe asthma. OBJECTIVE: To determine the degree of AHR following acute severe asthma and to evaluate the safety of AHR measurement in patients just recovering from a severe attack. METHOD: In 23 consecutive asthma patients just recovering from a severe attack (10 severe, 13 near-fatal), all medications except inhaled or systemic steroids were withdrawn temporarily for more than each action time. Then a methacholine bronchoprovocation test was performed in patients with FEV1 > or = 75% of predicted or personal best value. RESULTS: Mean duration required to control asthma was 5.6+/-3.6 days, and methacholine provo- cation test was performed at 12.6+/-5.2 hospital days. The patients showed significantly lower methacholine-PC20 (geometric mean 0.54 vs 1.64 mg/ml, p<0.05) and steeper slope of dose-response curve (p<0.01) compared to 62 outpatients. Initial FEV1 (r=0.470, p<0.05) and the duration required to control asthma (r=-0.623, p<0.01) were significantly related to methacholine-PC20. However, only 9 patients (39.1%) showed severe AHR, which was not significantly different from outpatients (25.8%). CONCLUSION: These results suggest that AHR is a risk factor of severe asthmatic attack and methacholine challenge just after control of acute asthma is relatively safe.