Continuous Electroencephalogram in Comatose Postcardiac Arrest Syndrome Patients Treated With Therapeutic Hypothermia

Abstract

Therapeutic Hypothermia (TH) is the only therapeutic intervention proven to significantly improve survival and neurologic outcome in comatose postcardiac arrest patients and is now considered standard of care. When we discuss prognostication with regard to comatose survivors postcardiac arrest, we should look for tools that are both reliable and accurate and that achieve a false-positive rate (FPR) equal to or very closely approaching zero. We retrospectively reviewed data that were prospectively collected on all cardiac arrest patients admitted to our ICU. Continuous electroencephalogram (cEEG) monitoring was performed as part of our protocol for therapeutic hypothermia in comatose postcardiac arrest patients. The primary outcome measure was the best score on hospital discharge on the 5-point Glasgow-Pittsburgh cerebral performance category (CPC) scores. A total of 58 patients were included in this study. Twenty five (43%) patients had a good neurologic outcome (CPC score of 1-2). Three (5.2%) patients had nonconvulsive status epilepticus, all of whom had poor outcome (CPC = 5). Seventeen (29%) patients had burst suppression (BS); all had poor outcome. Both nonconvuslsive seizures (NCS) and BS had a specificity of 100% (95% confidence interval [CI], 84%-100%), positive predictive values of 100% (95% CI, 31%-100%), and 100% (95% CI, 77%-100%), respectively. Both NCS and BS had FPRs of zero (95% CI, 0.0-0.69, and 0.0-0.23, respectively). In comatose postcardiac arrest patients treated with hypothermia, EEG during the maintenance and rewarming phase of hypothermia can contribute to prediction of neurologic outcome. Pending large multicenter prospective studies evaluating the role of cEEG in prognostication, our study adds to the existing evidence that cEEG can play a potential role in prediction of outcome in postcardiac arrest patients treated with hypothermia.