A series of randomized, controlled trials/studies were conducted. In the first clinical study, full term infants with severe respiratory pathology where surfactant inactivation was important were assigned randomly to exogenous surfactant versus control groups to determine if surfactant was efficacious and safe in this kind of lung injury. In the second study, infants of less than 29 weeks gestation received prophylactic exogenous surfactant, but were assigned randomly to receive it immediately following birth or after initial stabilization at 10-15 minutes, to address a then critical current issue in surfactant therapy for RDS. In the third study, infants who had moderate RDS despite exogenous surfactant therapy were randomly assigned to high frequency jet or conventional ventilation groups to determine if this mode of ventilation therapy would reduce barotrauma and the incidence and/or severity of bronchopulmonary dysplasia (BPD). In addition to these three clinical trials, another study involved therapy using superoxide dismutase (SOD) along with surfactant as a multi-modal approach treating premature infants with RDS and lung injury secondary to hyperoxia and mechanical ventilation. This study depended on results of animal studies with SOD in Project 5. Finally, the study addressed the long term evaluation and surveillance of survival, rehospitalizations, health status, pulmonary sequelae, and school performance of those infants enrolled in the randomized clinical trials, as necessary for long-term outcome assessments.