Adult-type pulmonary function tests in infants without respiratory disease

A new method that permits the measurement of adult-type maximal expiratory flow-volume curves and fractional lung volumes in sedated infants was recen tly described. The purpose of this study was to define the normal range for these new measures of pulmonary function in infants and young children. Me asurements of forced expiratory flows and fractional lung volume were made on 35 occasions in 22 children (ages 3-120 weeks) without respiratory disea se. Maximal expiratory flow-volume curves were measured by the raised lung volume, thoracoabdominal compression technique. Functional residual capacit y (FRC) was measured plethysmographically. Measurements of total lung capacity (TLC), residual Volume (RV), FRC, force d vital capacity (FVC), and forced expiratory flows at 25, 50, 75, 85, and between 25% and 75% of expired FVC (FEF25, FEF50, FEF75, FEF85, and FEF25-7 5, respectively) all increased in relation to infant length (P < 0.001). RV /TLC, FRC/TLC, and FEF25-75/FVC declined in relation to increasing length ( P < 0.001). The forced expiratory flow and fractional lung volume measureme nts using this method were similar to previously reported estimates using o ther methods. These estimates represent a reasonable reference standard for infants and y oung children with respiratory problems. Pediatr Pulmonol. 2000; 30:215-227 . (C) 2000 Wiley-Liss, Inc.