The lungs in immature infants: how important is surfactant therapy in preventing chronic lung problems?

Seventy-five premature infants weighing between 600 and 3200 g were studied over a period of 1 year. All of the infants received surfactant therapy for hyaline membrane disease immediately after birth and, thereafter, up to four doses every 6 h. The roentgenographic findings in all patients were documented at birth and at 2 days, 7-10 days, and 21-28 days of life. Larger babies responded to surfactant therapy better than did smaller infants. The smaller infants, even after initial clearing, were prone to develop pulmonary edema and the bubbly lungs of bronchopulmonary dysplasia. These data suggest that small infants, while initially responding to surfactant therapy with clearing of their lungs, are still at considerable risk of developing chronic lung disease in the form of pulmonary edema and bronchopulmonary dysplasia. An explanation is offered for why this occurs; at the same time it is suggested that, in view of our findings and those in the literature, the problems of pulmonary edema and bubbly lungs be more clearly separated.