Trajectory of Postnatal Oxygen Requirement in Extremely Preterm Infants.

Objective: To describe the trends in percentage oxygen requirement and mode of respiratory support delivered to extremely premature infants in the 12 weeks after birth.

Study design: This is a retrospective study of extremely premature infants (≤27^6/7 weeks) discharged from neonatal intensive care units managed by Pediatrix Medical Group between January 1, 2016, and December 31, 2021. Demographic and daily clinical data (mode of respiratory support and fraction of inspired oxygen [FiO₂]) were extracted from the Pediatrix Clinical Data Warehouse.

Results: A total of 16 386 infants with a median gestational age of 25 weeks and birthweight of 765 g were included. There were 3808 (23.2%) infants who died. Of the cohort, 6019 (43.1%) infants who survived to 36 weeks' gestation had bronchopulmonary dysplasia. Median FiO₂ at all gestations followed a biphasic pattern with a peak on day of life 1, reduction to a nadir by day 4 to 5, and an increase to a second peak around day 14. Infants born at lower gestational ages had a higher median FiO₂ at each time point. At lower gestations, there were higher proportions of infants receiving mechanical ventilation and a later introduction of noninvasive modes.

Conclusions: Extremely premature infants show a consistent biphasic pattern in percentage of supplemental oxygen required after birth.