Rationale: Newborns with hypoxic-ischemic encephalopathy (HIE) are at high risk for seizures, the majority of which have no clinical signs and therefore require continuous electroencephalographic (cEEG) monitoring for their detection. We sought to determine which neonates are at highest risk for seizures in order to optimize allocation of scarce cEEG resources. Methods: We identified neonates ≥ 34 weeks gestation, diagnosed with HIE who underwent at least 24 hours of protocol-based cEEG monitoring between 2016 and 2019. We quantified seizure incidence, timing and burden, and correlated these with potential risk factors such as HIE severity, use of therapeutic hypothermia, preceding suspected clinical seizures, amplitude-integrated EEG (aEEG) background and patterns suspicious for seizures, and use of anti-seizure drugs. Results: cEEG monitoring was completed in 158 patients, of whom 118 (75%) underwent therapeutic hypothermia. Preceding suspected clinical/aEEG seizures occurred in 136 (86%), but only 63 (40%) had cEEG-confirmed seizures. Average duration of recording was 20 hours and average time to first seizure was 1.5 hours after the start of the recording. Characterization of seizure burden and correlation with potential risk factors is ongoing. Conclusions: Although seizures are commonly suspected in neonates with HIE, they are confirmed in less than half of patients during cEEG monitoring, creating opportunities for more efficient risk-based allocation of cEEG monitoring resources. Funding: Please list any funding that was received in support of this abstract.: No funding was received.
