ABSTRACT
In 1967 Northway et al. (1) first described bronchopulmonary dysplasia (BPD), a chronic lung disease occurring in premature infants with respiratory distress syndrome treated with supplemental oxygen and mechanical ventilation. Widespread airway inflammation and injury were prominent findings in these infants. Respiratory epithelial cell metaplasia, peribronchial fibrosis, airway smooth muscle hypertrophy, and lung parenchymal fibrosis alternating with emphysema were common pathologic findings. At that time, the majority of infants developing BPD were over 30 weeks of gestational age and had birth weights greater than 1000 g. BPD as a long-term complication was uncommon in younger, less mature infants because they did not survive. Recent advances in neonatal care including the widespread use of maternal antenatal steroids, exogenous surfactant replacement therapy, and gentler modes of ventilatory support have resulted in striking changes in both the gestational ages of infants presenting with BPD and the pathologic findings seen in infants with this syndrome. While the incidence of BPD in infants greater than 1000 g has decreased, there have been dramatic increases in survival rates and the incidence of BPD in very premature infants. The incidence of BPD defined as a need for supplement oxygen at 36 weeks of postmenstrual age is about 30% for infants with birth weights less than 1000 g and around 50% for infants less than 750 g (2-4).
