24 Persistent pulmonary hypertension and short-term neurological outcomes in infants with hypoxic ischemic encephalopathy undergoing therapeutic hypothermia

Abstract

Abstract Background Neonatal hypoxic ischemic encephalopathy (HIE) after perinatal asphyxia is a serious clinical condition that may result in permanent neurologic deficits or death. There is an increased incidence of persistent pulmonary hypertension of the newborn (PPHN) in asphyxiated infants. Due to the high disease burden of HIE, studying its altered cardiopulmonary hemodynamics might identify those patients at highest risk for adverse outcome early on. Objectives To investigate the relationship between severity of PPHN and the extent of short-term brain injury in infants with moderate to severe HIE who received therapeutic hypothermia (TH). Design/Methods Retrospective cohort study of 230 TH-treated HIE infants. PPHN was defined and graded clinically and based on echocardiography findings. The primary outcome was the presence of HIE changes on brain MRI and/or death within the first month of life according to the diagnosis and severity of PPHN. Secondary outcomes were the pattern of HIE on brain MRI; abnormal electroencephalogram (EEG) background, clinical, or electrographic seizures, or need for anti-ictal treatment; clinical and laboratory differences between HIE babies with and without PPHN. A logistic regression model was performed to identify PPHN severity as risk factor for moderate-to-severe brain injury or death. Results Brain injury was not found to be different between the two groups according to presence of PPHN whether clinically or based on echocardiography. However, the combined outcome of severe brain injury or death was higher in the clinical PPHN group vs non-PPHN (32.6 vs 22.8%, p=0.014), and early exit from TH due to severe PPHN was associated with the highest mortality (71.4%). Death was found to have a relationship with the severity of PPHN based on echocardiography, with the highest incidence in severe PPHN (36.0 vs 7.7% and 10.0% in the severe, moderate, and mild PPHN groups, respectively, p=0.002). Infants with clinical PPHN were sicker with higher ventilation needs and worse laboratory values compared to those without PPHN. None of the other outcomes were different among the two groups. Conclusion In infants with HIE treated with TH, PPHN was not associated with increased risk of brain injury as evident on MRI, nor clinical or electrographic seizure burden. However, mortality was higher in the most severe PPHN categories.