Pulmonary function in extremely low birth weight infants with bronchopulmonary dysplasia before hospital discharge

Objective: To compare pulmonary function in extremely low birth weight (ELBW) infants with bronchopulmonary dysplasia (BPD) studied at 34–36 weeks postmenstrual age (PMA) with a reference group of “healthy” infants born at 34–36 weeks. We hypothesized that ELBW infants have decreased functional residual capacity (FRC) and respiratory compliance (Crs). Study design: Pulmonary function testing was performed at 34–36 weeks PMA in infants with BPD and within 96 h of age in infants delivered at 34–36 weeks. Results: Twenty BPD patients and 20 healthy infants were studied. FRC (18.9 versus 26.2 mL/kg; adjusted 95% CI 5.0, 10.9; P < 0.001) and Crs (0.80 versus 1.29-mL/cm H₂O/kg; 95% CI 0.31, 0.71; P < 0.001) were decreased in BPD patients. Respiratory resistance was increased in BPD patients. Conclusions: ELBW infants with BPD have decreased pulmonary function compared to healthy infants delivered at 34–36 weeks. This suggests that infants with BPD have smaller lung volumes.