Methacholine Inhalation Challenge Test在診斷學齡兒童之氣管氣喘之價值

Objective: to assess the bronchial hyperresponsiveness in school children, we have modified Tiffeneau's procedure to establish a simple and reliable provocative test which we have found exceedingly useful in our clinic. Method: During a 6 months period from September 1991 to April 1992, 292 students were tested with methacholine. All subjects had been free of any respiratory infection or drugs for at least 3 weeks. A drop in FEV1 of 20% or greater from the baseline with any of the standard concentrations of methacholine is considered positive for the test. Results: The difference in response between the asthma and non-asthma subjects is highly significant (p=0.0004). The difference in response between the group with wheezing history, allergy history, wheezing in test, asthma in family, allergy or atopy in family and non-group are also highly signiflicant (p=0.024, p=0.0014, p=0.007, p=0.0016, p=0.033). Conclusion: In general, bronchial hyperresponsiveness is more severe in asthma group than in non-asthma group. High risk group includes wheezing history, allergy history, wheezing in test, asthma in family and allergy or atopy in family. Since bronchial hyperreactivity to methacholine may be a predictor of the future development of asthma, the 58 non-asthma positive subjects should be long term follow up.