COMPARISON OF AIRWAY REACTIVITY INDUCED BY COLD-AIR AND METHACHOLINE CHALLENGES IN ASTHMATIC-CHILDREN

Bronchial responsiveness to isocapnic hyperventilation with cold air (CAH) and to inhaled methacholine (MCH) was compared in 17 children with bronchial asthma. The response to cold air was expressed as the percent drop in FEV, from baseline at 4 min. after the challenge (Delta% FEV(1) CAH), and the response to methacholine as the provocative concentration required to reduce the FEV, by 20% from baseline (PC(20)MCH). Both tests were sensitive (94%) for detecting airway hyperreactivity. There was no statistically significant relationship between Delta% FEV(1) CAH and the log PC(20)MCH (r = 0.39; P = 0.12). In clinical practice, methacholine test is easier to perform, but in the research field cold air challenge may be preferable because it avoids potential drug effects. (C) 1995 Wiley-Liss, Inc.