EXPIRATORY FLOW RATES DETERMINED BY WEDGE AND WATER SPIROMETER IN CHILDREN AND YOUNG ADULTS

Abstract

SUMMARY A comparison between measurements made with a conventional water spirometer and those with a wedge spirometer on 82 healthy normal subjects from 6 to 18 years of age and from 111.5 to 176.5 cm in height was made. Fourteen children with symptomatic asthma were also studied. It was found that the FVC and FEV 1 were similar on both instruments. The values for V̇ 50 and MMEF were different, because V̇ 50 is an instantaneous measurement, whereas MMEF is a mean obtained over a wide range of lung volumes. It is suggested that V̇ 50 may be a more sensitive index of airway obstruction than the regular MMEF measurement.