The package insert for natural surfactant calls for retreatment every 6 hours if the baby remains intubated and requires > 30% FiO2. In an effort to decrease drug use (less cost and risk), we compared this strategy (Lo) with delaying retreatment until >40% FiO2 and mean airway pressure > 7 cm H2O(Hi) were required. Subjects were stratified into “Complicated” (low Apgar or infection) and “Uncomplicated” and then randomized to Lo or Hi threshold retreatment after the first surfactant dose (Infasurf) was given, either as prophylaxis or rescue. 1200 babies from 6 centers were enrolled; 1059 have complete data as of 12/97. Conclusion: Lo threshold criteria results in lower mortality for complicated, but not uncomplicated babies. There is otherwise no long term benefit. We recommend that babies with uncomplicated RDS who have been given natural surfactant not be re-treated until requiring at least 40% FiO2 and > 7 cm H2O, while those with complicated RDS be treated using conventional criteria. Figure

figure 1

Figure 1