Persistent pulmonary abnormalities in newborns: the changing picture of bronchopulmonary dysplasia.

Significant changes in the radiographic features of bronchopulmonary dysplasia (BPD) have accompanied recent advances in treatment of neonatal respiratory distress syndrome. Retrospective study of 709 newborns showed atypical radiographic findings in many patients with clinical BPD. While 12/20 infants with clinical BPD showed changes identical to Northway's stage 4 disease, the remaining 8 (40% of patients with significant respiratory dysfunction) had diffuse, fine infiltrates without emphysema. Radiographic progression from RDS through all Northway stages was observed in only 4 patients. Diagnosis of stage 2 BPD was complicated by the presence of PDA in 9/17 cases. Stage 3 BPD was identified with certainty in only 5 infants, but may have coexisted with PIE in as many as 22 cases. Nevertheless, there was close agreement between the radiographic findings and clinical severity of chronic lung disease. Mild (type 1) infiltrates following RDS may be distinguished from chronic pulmonary insufficiency of prematurity (CPIP) or "immature lung." In patients who require only short-term supplemental O2, type 1 changes may reflect delayed resolution of RDS in an underdeveloped lung. These same findings in infants with prolonged O2 dependence usually indicate a mild form of BPD. Coarse infiltrates and emphysema (type 2) are almost always associated with severe respiratory impairment.