Continuous EEG Monitoring: Value and Limitations in Postanoxic Coma Management

A large retrospective multicenter study suggests continuous EEG (cEEG) adds little unique prognostic information when performed early after cardiac arrest, with most early recordings indeterminate for outcome.

That distinction matters at the ED resuscitation‑to‑ICU handoff, where immediate decisions about escalation, withdrawal considerations, and resource allocation often precede access to prolonged neuromonitoring. The study therefore reframes how teams should weigh early cEEG against more rapid bedside indicators during initial post‑ROSC management.

Data from a retrospective multicenter study of 699 patients evaluated early cEEG between 24 and 72 hours after return of spontaneous circulation and classified prognoses at 12‑ and 24‑hour timepoints. The analysis found 13.0% with favorable, 16.2% with poor, and 70.8% with uncertain EEG‑based prognoses, and it showed that only a small fraction of recordings changed the overall prognosis. The methods were a multicenter retrospective analysis across three academic centers with cEEG impressions cross‑checked against clinical indicators to identify information uniquely contributed by EEG. These results suggest early cEEG more often yields indeterminate results than definitive answers in immediate post‑resuscitation decision‑making.

Pattern associations were consistent with prior literature: malignant suppressed backgrounds and unreactive, severely attenuated activity correlated with poor outcomes, while continuous, reactive rhythms and clear electrographic recovery trends aligned with better trajectories. Early status epilepticus predicted worse courses in some patients, but most recordings lacked sufficient specificity in isolation. Interpreting early EEG therefore requires integration with exam findings, hemodynamics, and other prognostic markers to avoid overcalling outcomes from single‑pattern observations.

The study also reports that only 6.7% of continuous EEG monitoring sessions provided unique additional prognostic information beyond clinical assessment—an operationally important point for resource‑limited EDs and ICUs. In practice, this supports selective deployment: prioritize cEEG for patients whose examinations and ancillary tests leave prognosis genuinely equivocal, and emphasize earliest clinical indicators such as pupillary responses and hemodynamic stability during the resuscitation‑to‑ICU handoff. Routine immediate cEEG for all postanoxic coma patients may warrant reconsideration where staffing or equipment are constrained.