Spirometric pulmonary function in healthy preschool children.

The purpose of this study was to evaluate spirometric lung function in normal children ages 3 to 6 yr. Spirometric measurements were obtained at nursery and daycare centers by experienced pediatric pulmonary function technicians. Of 307 children recruited, 259 fulfilled our criteria as normal. Of these, 82.6% (214) were able to perform technically acceptable and reproducible maneuvers during a testing session limited to 15 min. The regression model with log-transformed parameters of pulmonary function and height had the best correlations. After accounting for height in the model, other physical traits and health questionnaire items did not contribute significantly. PEFR, FVC, FEV1, and FEF25-75 all increased with increasing height; correlation coefficients were 0.73, 0.93, 0.92, and 0.67, respectively. The group mean coefficients of variation for replicate measurements of PEFR, FVC, FEV1, and FEF25-75 were 7.8%, 2.5%, 2.7%, and 8.3%, respectively. There was a significant decrease in the ratio FEV1/FVC with increasing height; the mean predicted FEV1/FVC was 0.97 at 90 cm height and 0.89 at 125 cm height. In conclusion, reproducible spirometry can be obtained in the majority of preschool children and has the potential to improve our assessment and management of pulmonary disease.