Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of prematurity. An immature lung has fewer developing alveoli and a fragile pulmonary capillary network. Mechanical ventilation can overdistend this tissue, oxygen can produce oxidative injury, and infection or inflammation can amplify both effects. Impaired angiogenesis further disrupts lung growth. The result is arrested alveolar development, abnormal pulmonary vascular development, and reduced respiratory reserve. This physiology explains why an infant with BPD may need oxygen or positive-pressure support long after the original respiratory distress syndrome has improved. The infant may breathe rapidly, use accessory muscles, fatigue during feeds, or have intermittent desaturation. BPD also increases the risk of pulmonary hypertension, recurrent respiratory infections, poor weight gain, and delayed progression with oral feeding. BPD is not simply “an infant who still needs oxygen.” The type and amount of respiratory support matter. A small increase in support may be more clinically meaningful than a single acceptable saturation because it shows that the infant is requiring more assistance to maintain that saturation.