Comparison of airway reactivity induced by cold air and methacholine challenges in asthmatic children

Abstract

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 FEV₁ from baseline at 4 min. after the challenge (Δ% FEV₁ CAH), and the response to methacholine as the provocative concentration required to reduce the FEV₁ by 20% from baseline (PC₂₀MCH). Both tests were sensitive (94%) for detecting airway hyperreactivity. There was no statistically significant relationship between A% FEV, CAH and the log PC₂₀MCH (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.