Development of airway function in infancy after preterm delivery

Objective: To assess airway function at 1 year and compare this with similar measurements made shortly after birth in preterm infants without clinical neonatal respiratory disease. Study design: Infants born at ≤36 weeks' gestational age were eligible if they required no neonatal ventilatory support and were otherwise healthy. Paired measurements of maximal expiratory flow at functional residual capacity (V′maxFRC) were obtained ~3 weeks after birth in 24 preterm infants (gestational age [mean ± SD], 33.2 ± 2.2 weeks) and repeated at a corrected postnatal age (mean ± SD) of 57.0 ± 12.2 weeks. V′maxFRC values were expressed as Z scores by means of sex-specific prediction equations. Results: V′maxFRC was within normal range for all infants shortly after birth (mean ± SD Z score: −0.06 ± 0.92). By 1 year, Z scores had reduced significantly [mean (95% CI) 2nd-1st test: −1.94 (−2.27, −1.60)]. V′maxFRCZ scores at 3 weeks were highly correlated with those at 1 year of age (Spearman correlation coefficient 0.64). Conclusions: Airway function during the first year shows considerable tracking. Even in the absence of neonatal respiratory disease, preterm delivery is associated with altered airway development during early infancy. (J Pediatr 2002;141:652-8)