LAUSR

Abstract Objective  Classification of electroencephalogram (EEG) background has been established to predict outcome in neonates with hypoxic ischemic encephalopathy (HIE). However, the impact of phenobarbital therapy on the predictability of EEG background has not been studied. Our objective is to determine if EEG background after treatment with phenobarbital during therapeutic hypothermia (TH) remains a good predictor for brain injury in neonates with HIE. Study Design  This is a single-center, retrospective study of consecutive neonates with HIE who underwent TH and EEG monitoring from October 2017 to March 2021. Per institutional protocol, all infants received a dose of prophylactic phenobarbital and bumetanide therapy at the onset of TH for sedative and neuroprotective measures. The initial 3 hours of EEG background activity was classified based on national guidelines. Infants were separated into two groups based on EEG background scores: group 1 (normal–mild, n  = 30) and group 2 (moderate–severe, n  = 36). Brain magnetic resonance imaging (MRI) results were scored based on the National Institute of Child Health and Human Development (NICHD) criteria. Adverse outcomes were defined as death before MRI or NICHD brain injury score > 1A. Results  Infants in group 2 had lower Apgar scores at 5 minutes of age, severe acidemia, moderate to severe encephalopathy score, and earlier initiation of EEG monitoring than infants in group 1. Moderate to severe EEG background score was associated with presence of brain injury on MRI or death ( p  = 0.003), and this association remained significant even after adjustment for independent risk factors (odds ratio = 56.24 [95% confidence interval = 1.841–1718], p  = 0.021). Conclusion  Phenobarbital therapy does not affect the ability of EEG to predict adverse outcome in infants with perinatal asphyxia during TH. Key Points EEG has a clinical utility for predicting outcome in neonates with hypoxia–ischemia. Phenobarbital therapy is commonly used in neonates, and may impact EEG background findings. In spite phenobarbital therapy, moderate to severe EEG background abnormalities in infants with perinatal asphyxia during TH remain an excellent predictor for poor outcome.