Deep Inspiration Avoidance and Methacholine Response in Normal Subjects and Patients With Asthma

In both groups, the longer the time interval between the end of inhalation and the first FEV1 measurement, the greater the fall in FEV1 (lower PC20). DI avoidance before inhalation does not enhance the fall in FEV1 in subjects with asthma, while it does in control subjects. Methacholine has a slight cumulative effect that is significant in patients with asthma (p = 0.007).