Objective: To evaluate the long-term pulmonary sequelae of survivors of bronchopulmonary dysplasia (BPD) of sufficient severity to have required supplemental oxygen for at least 1 month after term.
Study design: Fifteen patients with a mean age of 1.1 years were matched to preterm infants of similar gestational age and age at time of study. Pulmonary function testing included spirometry, plethysmographic lung volumes, carbon monoxide diffusion capacity, and in 9 of 15 subjects with BPD, measurement of lung static elastic recoil pressures.
Results: The subjects with BPD had a mean expiratory volume in 1 second (FEV1) of 64% +/- 21% predicted (4 had an FEV1 < 50% predicted) compared with 85% +/- 11% (P < .01) for the preterm children in the control group. Subjects with BPD had a significant degree of gas trapping with a residual volume to total lung capacity ratio of 37% +/- 13% compared with 25% +/- 4% for the control group (P < .01). An inverse relationship was seen between the FEV1 and the time on supplemental oxygen (r = -0.84, P < .0001), with 3 of the 4 children whose FEV1 was < 50% requiring oxygen for more than 900 days. Those with the greatest degree of airflow limitation and gas trapping had the greatest abnormalities in both shape and position of the pressure volume curves of the lung.
Conclusion: Severe BPD may result in moderate to severe long-term abnormalities in pulmonary function tests.