Electroencephalography in survivors of cardiac arrest: comparing pre- and post-therapeutic hypothermia eras

Abstract

Electroencephalography in the setting of hypothermia and anoxia has been studied in humans since the 1950s. Specific patterns after cardiac arrest have been associated with prognosis since the 1960s, with several prognostic rating scales developed in the second half of the twentieth century. In 2002, two pivotal clinical trials were published, demonstrating improved neurologic outcomes in patients treated with therapeutic hypothermia (TH) after cardiac arrest of shockable rhythms. In the following years, TH became the standard of care in these patients. During the same time period, the use of continuous EEG monitoring in critically ill patients increased, which led to the recognition of subclinical seizures occurring in patients after cardiac arrest. As a result of these changes, greater amounts of EEG data are being collected, and the significance of specific patterns is being re-explored. We review the current role of EEG for the identification of seizures and the estimation of prognosis after cardiac resuscitation.