Standards of pulmonary function in children.

Pulmonary function tests were performed on 139 healthy, normal children (62 boys and 77 girls) between the ages of 4 and 18 years. The following variables were measured: residual volume (RV), functional residual capacity (FRC), vital capacity (VC), total lung capacity (TLC), the ratios FRC/TLC and RV/TLC, one-second forced expiratory volume, maximal mid-expiratory flow, maximal inspiratory flow, maximal breathing capacity, peak expiratory flow, mixing efficiency per cent, arterial carbon dioxide tension by the rebreathing technique, and steady-state pulmonary diffusing capacity for carbon monoxide. Thoracic gas volume and airway resistance were measured in 42 boys and 41 girls. The results of the static and dynamic lung volumes are presented in both graphic form and regression equations, using the standing height as the independent variable. Prediction formulas for FRC/TLC and RV/TLC and mixing efficiency per cent are presented according to age. Both the body surface area and standing height were used for...