Cold air inhalation challenge in the diagnosis of asthma in children.

A study was designed to determine the usefulness of cold air inhalation challenge testing in children with asthma and to determine the magnitude and duration of the response. A total of 17 children with asthma, mean age 11.7 years (range 6 to 16 years) and eight nonasthmatic children, mean age 11.5 years (range 7 to 15 years) were studied. The average response to isocapneic hyperventilation with cold air in the asthmatic children was a decrease in vital capacity of 10%, a decrease in forced expiratory volume in 1 second (FEV1) of 19%, a decrease in peak flow rate (PFR) of 24%, and a decrease in maximal midexpiratory flow rate (MMFR) of 36%. This was significantly different from the response to the same level of hyperventilation with warm, fully saturated air. The response to isocapneic hyperventilation with cold air in nonasthmatic children was significantly different from the asthmatic children's response with a mean decrease in vital capacity of 0.9%, a decrease in forced expiratory volume in 1 second of 2.5%, a decrease in peak flow rate of 7%, and a decrease in maximal midexpiratory flow rate of 10%. The response in the asthmatic children occurred four to eight minutes after challenge and resolved in eight to 12 minutes. Although the response was highly significant, none of the children developed respiratory distress. It was concluded that isocapneic hyperventilation with cold air is a safe and simple test for diagnosing asthma in children.