Outcomes of infants with hypoxic ischemic encephalopathy and persistent pulmonary hypertension of the newborn: results from three NICHD studies

Objective: To determine the association of persistent pulmonary hypertension of the newborn (PPHN) with death or disability among infants with moderate or severe hypoxic ischemic encephalopathy (HIE) treated with therapeutic hypothermia. Methods: We compared infants with and without PPHN enrolled in the hypothermia arm from three randomized controlled trials (RCTs): Induced Hypothermia trial, “usual-care” arm of Optimizing Cooling trial, and Late Hypothermia trial. Primary outcome was death or disability at 18–22 months adjusted for severity of HIE, center, and RCT. Results: Among 280 infants, 67 (24%) were diagnosed with PPHN. Among infants with and without PPHN, death or disability was 47% vs. 29% (adjusted OR 1.65, 0.86–3.14) and death was 26% vs. 12% (adjusted OR 2.04, 0.92–4.53), respectively. Conclusions: PPHN in infants with moderate or severe HIE was not associated with a statistically significant increase in primary outcome. These results should be interpreted with caution given the limited sample size.