Evolving blood pressure dynamics for extremely preterm infants

Objective: To examine changes in arterial blood pressure (ABP) after birth in extremely preterm infants. Study Design: Prospective observational study of infants 23 0/7 to 26 6/7 weeks gestational age (GA). Antihypotensive therapy use and ABP measurements were recorded for the first 24 h. Result: A cohort of 367 infants had 18 709 ABP measurements recorded. ABP decreased for the first 3 h, reached a nadir at 4 to 5 h and then increased at an average rate of 0.2 mm Hg h −1 . The rise in ABP from hour 4 to 24 was similar for untreated infants ( n =164) and infants given any antihypotensive therapy ( n =203), a fluid bolus ( n =135) or dopamine ( n =92). GA-specific trends were similar. ABP tended to be lower as GA decreased, but varied widely at each GA. Conclusion: ABP increased spontaneously over the first 24 postnatal hours for extremely preterm infants. The rate of rise in ABP did not change with antihypotensive therapy.