[Maximum expiratory flow rate (peak flow) in healthy persons and patients with bronchial asthma]

Lung function tests were done on 42 patients, 22 asthmatics and 20 normal volunteers. The peak flow and expiratory flows at different levels of the forced vital capacity curve were evaluated. The flow-volume curves were obtained with a conventional spirometer, and the peak flow was determined with a Wright flowmeter. The peak flow obtained by the two methods were within the normal range, although the values registered by the Wright flowmeter were consistently lower. A reduction of the expiratory flow in the distal part of the vital capacity curve was observed in asthmatics, suggesting small airways obstruction. In conclusion, peak flow is not of use in the detection of predominantly distal airways obstruction.