Early EEG Monitoring for Detecting Postanoxic Status Epilepticus during Therapeutic Hypothermia: A Pilot Study

To determine whether routine electroencephalography (EEG) detected electrical status epilepticus (ESE), masked by neuromuscular blockade, in comatose cardiac-arrest survivors receiving therapeutic hypothermia. Prospective 3-year study Medical ICU Fifty-one consecutive comatose cardiac-arrest patients treated between May 2005 and May 2008 using a standardized protocol of hypothermia with neuromuscular blockade. EEG was performed routinely as soon as possible after starting therapeutic hypothermia. EEG recordings were read by an independent neurophysiologist who was blinded to patient data. Median body temperature at EEG recording was 33.0A degrees C (range 32.4-33.8). ESE was found on 5 (10%) of the 51 EEG recordings: three patients had continuous rhythmic generalized spikes and two patients had continuous rhythmic focal spike-waves. Of the 17 (33%) patients who were discharged alive, 8 (8/51, 16%) had a CPC score of 1, 4 (8%) of 2, and 5 (10%) of 3. All patients with ESE died during their ICU stay. These preliminary results indicate that postanoxic status epilepticus can be masked by neuromuscular blockade during our protocol of therapeutic hypothermia. Routine EEG monitoring might be helpful in cardiac-arrest survivors receiving therapeutic hypothermia. Further studies including continuous EEG monitoring are needed to determine whether early diagnosis and treatment of ESE during therapeutic hypothermia improves the outcome.