Plethysmographic lung volumes in normal Chilean children and adolescents

Introduction: Plethysmographic measurement is the most reliable method for evaluating lung volumes in children. Current published normative data are based on studies in primarily Caucasian children. Objectives To establish Chilean normal values with new reference equations and to compare these results with previously published data. Subjects and Methods: Lung function was measured [slow vital capacity (SVC), inspiratory capacity (IC), expiratory reserve volume (ERV), functional residual capacity (FRC), residual volume (RV), total lung capacity (TLC), and RV/TLC] in 245 healthy Chilean school children and adolescents, using spirometry and plethysmography; 123 girls and 122 boys were studied, aged 7-18 years. Results: Almost all variables of pulmonary volume differed between boys and girls (P < 0.05). Zscores were significantly higher than zero in all age groups when compared with predicted values. We present predictive exponential equations for each variable of static lung volume; all of these variables had a strong correlation with height, but not weight. Summary: Normal values of lung volumes of Chilean school children and adolescents are significantly higher than the current predictive values. These differences may be related to differences in anthropometric characteristics. We recommend using these data in our population and postulate that Latin-American populations like ours may have similar lung volumes.