The Impact of Late Onset Arterial Hypotension on Respiratory Outcome in Extremely Premature Infants.

Background: In extremely premature infants, arterial hypotension in the first days after birth has been associated with an increased risk for bronchopulmonary dysplasia (BPD). Some infants present with hypotension at a later postnatal age, but the relationship between late onset hypotension (LOH) and BPD has not been evaluated.

Objective: To evaluate the association between LOH and BPD and to identify pre- and postnatal factors associated with LOH.

Methods: Prospectively collected data from a cohort of 23-28 weeks gestational age (GA) infants born during years 2005-2015 and alive at day 28 were analyzed. LOH was defined as the receipt of vasopressor treatment during days 8-28. BPD was defined as need for oxygen at 36 weeks postmenstrual age. Late mortality was defined as death after day 28.

Results: Of 1,058 infants in the cohort, 90 (9%) had LOH during days 8-28. Infants with LOH had a higher incidence of BPD than normotensive infants (55 vs. 21%, p < 0.001). Multivariate logistic regression analysis (LRA) showed that LOH was associated with an increased risk for BPD (OR 1.87, 95% CI 1.10-3.17). LOH was also associated with an increased risk for late mortality. LRA showed the risk for LOH increased with lower GA, sepsis and patent ductus arteriosus during days 8-28.

Conclusions: In this cohort of extremely premature infants, LOH was associated with an increased the risk for BPD. This association could be secondary to underlying factors that predispose to LOH and BPD or to the deleterious effects of LOH or its treatments on the lung. Further investigation is needed to assess causality.