Cardiorespiratory function in asymptomatic survivors of neonatal respiratory distress syndrome.

We measured cardiopulmonary function at rest and during exercise in 15 healthy survivors of neonatal respiratory distress syndrome (RDS) and compared the results with those in 15 normal subjects. The mean birth weight of the RDS group was 1,771 g, and 12 of the 15 patients had required endotracheal intubation. The oxygen scores ranged from 79 to 3,322. Five of the 15 RDS patients had abnormal results of pulmonary function studies at rest. Peak expiratory flow was lower (P less than 0.05) in the RDS group (2.98 liters/min) than in the control group (3.57 liters/min). A negative correlation was noted between the forced expiratory flow between 25 and 75% of vital capacity and the oxygen score in these patients. Exercise tolerance was below normal in two of the RDS patients, both of whom also had abnormal pulmonary function at rest. One patient in the RDS group had systemic arterial hypertension at rest and during exercise. No significant differences in exercise tolerance or the cardiorespiratory response to exercise were observed between the two groups.