Combined body plethysmographic, spirometric and flow volume reference values for male and female children aged 6 to 16 years obtained from "hospital normals".
UNLABELLED: Vital capacity (VC) and its subdivisions (IC and ERV), total lung capacity (TLC), residual volume (RV), peak expiratory flow (PEF), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximum flow volume curve (MEF75, MEF50, MEF25, MMEF, FEF75-85), airway resistance (Rtot, Reff) and the thoracic gas volume at resting expiratory position (FRC) were measured in 187 girls and 213 boys (hospital normals) aged 6 to 16 years. The measurements were carried out consecutively on the same subjects in the morning using a volume-constant plethysmograph (Master-Lab, E. Jaeger; programs: body plethysmography, spirometry and flow volume). Using multiple regression analysis the best fitting curves for the prediction of normal values for boys and girls were selected. Analyses of covariance were performed to compare the adjusted means of the spirometric and body plethysmographic variables of the male and female subjects. As expected, we found higher static and dynamic (FVC, FEV1, PEF) lung volumes in boys than in girls relating to height. The flows (MMEF, MEF50, MEF25, FEF75-85) were significantly lower in the male than in the female subjects of the same age justifying separate prediction equations, but the same equation for both genders may be used for the resistance variables Rtot and Reff. Our results are compared with those of previous studies. CONCLUSION: Lung volumes and flows differ significantly between girls and boys calling for separate reference values for female and male subjects of the same age.