Predictive Value of aEEG and Cerebral Oxygenation on Neurological Outcomes in Newborns With Mild Hypoxic-Ischemic Encephalopathy

Overview

Newborns with mild hypoxic-ischemic encephalopathy usually do not receive cooling treatment. However, some of these newborns may develop neurological problems later in life. This observational study aims to evaluate whether early brain monitoring and measurements of brain oxygen levels are associated with neurological outcomes in newborns with mild hypoxic-ischemic encephalopathy. Newborns will be monitored during the first 72 hours after birth as part of routine clinical care. Neurological assessments will be performed during early infancy and later follow-up. The findings of this study may help improve early risk assessment and support closer monitoring of newborns who may be at increased risk for unfavorable neurological outcomes.

Perinatal asphyxia resulting from impaired gas exchange may lead to hypoxemia, hypercapnia, and metabolic acidosis, causing injury to the brain and other organs in newborns. Perinatal asphyxia disrupts cerebral autoregulation, leading to primary and secondary energy deficiency, cerebral damage, and hypoxic-ischemic encephalopathy (HIE). HIE remains a significant cause of neonatal mortality and long-term neurological morbidity. HIE is clinically classified as mild, moderate, or severe based on neurological examination findings, most commonly using the Sarnat and Sarnat scoring system. Therapeutic hypothermia has been shown to reduce mortality and morbidity in term and near-term newborns with moderate to severe HIE when initiated within the first 6 hours after birth. However, therapeutic hypothermia is not routinely recommended for newborns with mild HIE due to the lack of sufficient evidence from randomized clinical trials. Although mild HIE is generally associated with a better prognosis, accumulating evidence suggests that a substantial proportion of newborns diagnosed with mild HIE may develop adverse neurodevelopmental outcomes during infancy and early childhood. Furthermore, the severity of encephalopathy may evolve, and some newborns initially classified as having mild HIE may progress to moderate encephalopathy within the first hours after birth. Early identification of newborns with mild HIE who are at increased risk for neurological deterioration remains challenging, particularly during the critical first 6 hours of life. Continuous bedside brain monitoring techniques may provide valuable prognostic information in this early period. Amplitude-integrated electroencephalography (aEEG) allows continuous assessment of cerebral electrical activity. It helps evaluate the severity of encephalopathy, detect seizures, and predict neurological outcomes in newborns with HIE. Additionally, near-infrared spectroscopy (NIRS) allows for non-invasive monitoring of cerebral oxygenation and cerebral fractional tissue oxygen extraction (cFTOE). However, data regarding the use of NIRS in newborns with mild HIE are limited, particularly during the early postnatal period. The primary objective of this prospective, multicenter observational cohort study is to investigate the association between early brain monitoring findings and short-term and long-term neurological outcomes in newborns with mild hypoxic-ischemic encephalopathy. Specifically, the study aims to evaluate early neurological findings and neurodevelopmental outcomes up to 24 months of age. Secondarily, this study aims to explore whether early aEEG and NIRS findings may help identify subgroups of newborns with mild HIE who are at higher risk for neurological deterioration and may benefit from closer monitoring and follow-up.