I. LUNG VOLUMES

Publisher Website
Google Scholar
Abstract
A three-year longitudinal study of a variety of lung function tests in 147 normal children has been carried out to permit better separation of growth effects (by covariance analysis) from individual variation, to supply information not previously available, and to permit study of the interrelationships of the tests in normal subjects. In this, the first of a series of papers, we have presented the results of the study of lung volumes. Height is the best single indicator of physical size for predicting normality. Comparison of residual variances indicates that the use of multiple independent variables offers little advantage. Although there is reason to believe that the lung volumes do not increase in a simple exponential relationship to height after birth, after 5 years of age the lung volumes do increase as approximately the cube of height. When the values of the exponents obtained from regression analyses of the lung volumes on different independent variables are adjusted by the dimensional relationships of the variables, several points become evident. Among them are: (1) the various independent variables (except sitting height) are all reflecting the same general body growth; (2) the exponents for the FRC in girls are less than those for vital capacity in boys or girls and less than the FRC in boys; (3) there is a difference between boys and girls in the exponent for age. The latter only reflects the relatively smaller body growth of girls for each age increment. Analyses of covariance made possible by the longitudinal studies indicate that about three-fourths of the residual variance obtained from the ordinary regression of log vital capacity on log height (and one-half of that of log FRC on log height) is due to a quality inherent in the individual. Knowledge of this factor permits future estimates of a person's lung volume with greater precision.

This publication has 0 references indexed in Scilit: