EEG in hypothermia in term neonates with HIE

Abstract

Objectives Hypoxo-ischemic encephalopathy (HIE) is by far the most frequent etiology in neonatal encephalopathy). It is an important cause of neonatal mortality and long-term neurosensorial and cognitive impairment. Therapeutic hypothermia is nowadays the only therapeutic neuroprotective mean to decrease second state lesions within 6 hours after hypoxo-ischemia with an effect on mortality and morbidity rates as well as on seizures. The aim of our study was to precise EEG criteria in starting hypothermia decision and in prognosis evaluation with at least 2 years clinical follow-up. Methods We analyzed 120 newborns admitted, between January 2013 and February 2015, in the neonatal intensive care for suspicion of HIE. First EEG was done before 6 hours of life, it was surveyed continuously and analyzed twice a day during 72-hour hypothermia and in 12 hours following rewarming. Three grades classification were used according to French EEG classification. EEG characteristics were analyzed for the decision of hypothermia and to determine prognosis in hours following warming and compared to the neurodevelopment evaluation at 2 years old using standardized scales. Results The evolution of infants with initial grades 0 or 1 EEG was characterized by normal or mild neurodevelopment impairment. Infants with initial grade 3 on EEG, without improvement within the first 48 hours were always associated with severe outcome (severe neurological impairment or death). For the other initial grade 3, who improve within the first 48 hours under hypothermia, as well as the initial grade 2, a variable outcome, between normal to severe neurological sequelae, were noted. Conclusion Our results confirmed that Conventional EEG remains the gold standard for hypothermia decision and in prognostic evaluation [1] , [2] . However, prospective longitudinal studies in large cohort are necessary to better clarify grade 2 EEG abnormalities in order to improve the prognosis evaluation; specially background and specific EEG pattern.