Prediction of poor neurological outcome within 24 h from cardiac arrest: Can electrophysiology-based indices be helpful?

The vast majority of patients who are resuscitated from out of hospital cardiac arrest (CA) are unconscious during the first 24 h after return of spontaneous circulation (ROSC), as a result of hypoxic-ischaemic brain injury (HIBI). Two-thirds of these patients die before hospital discharge, mainly because of active withdrawal of life-sustaining treatment (WLST) based on prediction of a poor neurological outcome. In order to avoid an inappropriate WLST, prognostication after CA should be as accurate as possible. According to the 2015 ERC-ESICM Guidelines on Post-Resuscitation Care a poor neurological outcome can be predicted with high certainty (false positive rate [FPR] < 5%, narrow confidence interval) based on the bilateral absence of pupillary and corneal reflexes or the N20 wave of short-latency somatosensory evoked potentials (SSEPs) after 72 h or more from ROSC. However, recent evidence shows that an accurate prediction before this time point, namely within 24h from ROSC is feasible, based on electrophysiological indices. In this paper recent evidence on EEG-based predictors, classified according to the 2013 guidelines of the American Clinical Neurophysiology Society (ACNS) is presented and discussed.