The Reemergence of EEG Reactivity After Cardiac Arrest

Electroencephalogram (EEG) reactivity has been increasingly utilized in prognostication after cardiac arrest. Recent studies have demonstrated a false-positive rate of 0% in predicting poor outcome with a nonreactive EEG. The reemergence of reactivity after an initial nonreactive EEG has been noted in cases of drug intoxication, rewarming after hypothermia, and after discontinuing sedation. This is the first case describing the reemergence of EEG reactivity without the confounding factors listed above. We describe a case of resuscitated cardiac arrest with initial EEG demonstrating a lack of reactivity. A repeat EEG completed 3 days later revealed a reemergence of reactivity in the setting of normothermia, a negative drug screen, and the absence of sedation. The delayed recovery of EEG reactivity without previously established confounding factors is novel. Serial EEGs may be beneficial as the available literature on reactivity and prognostication is based on an average of 24 to 48 hours of EEG tracing. Prognostication after cardiac arrest continues to require a multimodal approach.