Evaluation of the airflowmeter in the assessment of airways obstruction.

The airflowmeter, a new inexpensive instrument measuring severity of airways obstruction in arbitrary units, was found to correlate well with standard respiratory function tests, and to be more sensitive than FEV1 in detecting changes in obstruction. Despite the distortion of maximal expiratory flow-volume relationship induced by the resistance of the meter, and the considerable variability between instruments, the airflowmeter should prove useful for regular monitoring of patients with variable airways obstruction.