On-line computerized spirometry in 738 normal adults.

Abstract

A completely automated method of on-line computerized spirometry has been described. For forced vital capacity (FVC) and one-second forced expiratory volume (FEV1), the mean difference between manual and computer measurements of the same spirogram was less than 13 per cent of the mean difference between manual measurements of successive spirograms obtained from the same subject. The computer method was used to measure the FVC, FEV1, maximal expiratory flow (MEF), and maximal mid-expiratory flow (MMF) of 604 normal men and 134 normal women. The age, height, and weight of each subject were also recorded. Means, standard deviations, and correlation coefficients were calculated for each variable. Reliable equations were derived for predicting the FVC and FEV1 of both men and women as functions of age and height. The coefficient of correlation between observed and predicted values was 0.63 or more. The equations developed for MEF and MMF showed low correlations between observed and predicted values. The data f...