Twelve years' experience with bronchopulmonary dysplasia.

A retrospective study of 299 successive infants who were ventilated for respiratory distress syndrome (RDS) showed that 62 (21%) developed radiographic stage VI bronchopulmonary dysplasia (BPD). The largest, most mature, and least ill infants tended to survive without developing BPD; the smallest, least mature, and most ill infants tended to die without developing BPD. The patients who developed BPD tended to be intermediate in terms of weight, maturity, and severity of disease; they required longer exposures to elevated oxygen and assisted ventilation than patients who did not develop BPD. The data suggest that in addition to varying individual susceptibility (primarily degree of immaturity and initial severity of disease), elevated oxygen is more important than mechanical ventilation in the pathogenesis of BPD.