Airway responsiveness to cold air and hyperpnea in normal subjects and in those with hay fever and asthma.

TLDR

Pulmonary mechanics were measured before and after hyperpnea with cold air inhalation in 20 normal controls, 16 hay fever subjects, and 44 asymptomatic asthmatics. Cold‑air hyperpnea had no effect on normal lung function, caused a modest −5.1 % drop in FEV1 in hay fever patients, and produced a pronounced −32.7 % fall in asthmatics, with little overlap between normals and hay fever but complete separation from asthmatics, indicating the test is highly sensitive and specific for airway reactivity.

Abstract

Multiple aspects of pulmonary mechanics were measured before and after bronchial challenges consisting of hyperpnea with cold air inhalation in 20 normal control subjects, 16 subjects with hay fever, and 44 asymptomatic asthmatics. These challenges had no effect on the lung function of the normal subjects. In the hay fever group, however, postchallenge mechanics changed a small, but significant, amount, e.g., mean decrease in forced expiratory volume in one second (FEV1) was -5.1 +/- 1.7% (SEM). The asthmatics had a much more marked response (mean fall in FEV1, -32.7 +/- 2.6%). There was considerable overlap between the responses of the normal subjects and those with hay fever, but no overlap at all between asthmatic and normal subjects. The only subjects with hay fever whose responses overlapped the asthmatic response were those who had histories of occasional episodes of wheezing. This pattern of response suggests that the use of hyperpnea and subfreezing air is a very sensitive and highly specific means of detecting increased air reactivity.