Comparison of Two-Minute Tidal Breathing Method and Five Vital Capacity Breathing Method for Bronchial Provocation Test in Children

Yang, Jeong A; Jang, Kyung A; Kim, Kyae Sung; Chae, Kyu Young; Youm, Hye Young; Han, Man Yong

Abstract

PURPOSE
The results of the bronchial provocation test were different by the method of inhalation, but there was no data in children. We performed the provocation test by 2 different methods such as two-minute tidal breathing versus five vital capacity breathing and compared the datas. METHODS: Methacholine inhalation test was performed for the In 17 patients with suspected bronchial hyperresponsiveness in Pocheon university Bundang Cha hospital, under identical conditions, except for the method of inhalation. All the patients were performed two-minute tidal breathing (2 min-TB) in one test and five vital capacity breathing (5VCB) with interval 1 to 7 days. Baseline and postsaline FEV1 were also measured to compare effects by two inhalation methods. Methacholine PC20 was calculated by linear interpolation between the last two data parts on the dose-response curve, and the cut off value of bronchial asthma was 8 mg/mL. RESULTS: The rate of positive brochial provaction test in 5VCB was 88.24% which was not significantly lower than 70.59% in 2 min-TB. In 12 patients with positive bronchial provocation test in both inhalation methods, the mean PC20 in 5VCB (5VC-PC20) was 4.40 mg/mL, being significantly higher than 1.02 mg/mL in 2 min-TB (2 min-PC20) (P< 0.05). There was a significant positive correlation between 5VC-PC20 and 2 min-PC20 (R=0.76, P< 0.001). CONCLUSION: We conclude from this study that the results of bronchial provocation test in children are different according to methods of inhalation in using the same nebulizer. Therefore, when we analyze the result of bronchial provocation test, we need attention to factors which are nebulizer output and method of inhalation to influence the response to the test.