- Inborn preterm infants 24+0 weeks-28+6 days weeks gestational age (defined by first trimester ultrasound or if not available based on the last menstrual period) who requires the use of surfactant within 24 hours of birth (either prophylactically, or for signs of developing respiratory distress), or who requires the use of continuous positive airway pressure (CPAP) (fraction of inspired oxygen concentration (FiO2) ≥ 0.30 on a mean airway pressure ≥ 4cm water (H2O)) within 24 hours of birth in order to maintain an oxygen saturation (SpO2) ≥ 85%.