[Cold provocation test. A method for diagnosis of bronchial asthma].

This article describes the method of isocapnic hyperventilation, where cold air (-22 degrees C) containing 5% CO2 is used to induce a temporary obstruction of airways in patients with bronchial hyperreactivity. The method is quick, has few side effects and is suitable both in the diagnosis and assessment of asthma. Tested out on ten current asthmatics and 14 controls, a median fall in forced expiratory volume (FEV1) of 21.7% was observed in the asthmatic group as against a median fall in FEV1 of 1.4% among the controls.