Concurrent Session 3D - Neo Neurosciences & Neuro Critical Care
Interaction between Electroencephalographic and Cerebral Metabolic Activity during therapeutic hypothermia in neonates born with hypoxic-ischemic encephalopathy
Friday, February 14, 2020
2:15 PM – 2:30 PM
Location: Max Bell - MB253
Introduction: Electroencephalography (EEG) discontinuity is an index of EEG background impairment which serves as a marker of hypoxic-ischemic encephalopathy (HIE) severity and a predictor of long-term neurodevelopmental outcome. The recovery of EEG background after therapeutic hypothermia (TH) is a good prognostic sign. The goal of this study is to assess if bedside optical monitoring can provide an early marker of EEG prognosis in HIE infants undergoing TH.
Methods: Twenty-nine neonates with moderate to severe HIE (Table1) underwent moderate TH (33-34°C for 72h) followed by rewarming (0.5°C/h over 6h). Bedside optical monitoring was used to measure cerebral oxygen extraction fraction (OEF), and indices of cerebral blood flow (CBFi) and cerebral oxygen consumption (CMRO2i) during TH day-2 (TH2), day-3 (TH3), rewarming, post-rewarming and discharge periods. Neonates who presented with EEG-confirmed seizures and/or abnormal neurological assessment (Table1) were classified as severe HIE (11/29) and the remaining neonates (18/29) were considered as moderate HIE. Spearman’s correlation was used to assess relationships between optical measures, HIE severity and EEG-discontinuity changes from hypothermia to normothermia.
Results: The severity of HIE was associated with low CMRO2i and OEF on TH2 and discharge (Table2). With normothermia, CMRO2i increased in moderate HIE infants suggesting metabolic recovery but decreased in severe HIE infants (Figure1). Table3 shows that high CMRO2i on TH3 was associated with an increase in EEG-discontinuity from TH3 to rewarming (ΔEEG1) followed by a decrease in EEG-discontinuity from rewarming to post-rewarming (ΔEEG2). Also, high OEF on TH3 was associated with ΔEEG1, whereas high CBFi on TH3 was associated with ΔEEG2.
Conclusion: Our results suggest that monitoring optical parameters, more importantly CMRO2i during TH can provide an early predictor of the changes in EEG background activity from hypothermia to normothermia. In conclusion, a better understanding of the interaction between neuronal and metabolic activity during TH may help to further individualize neuroprotection following HIE.