Background: Postanoxic electrographic status epilepticus (ESE) is considered a predictor of poor outcome in resuscitated patients after cardiac arrest (CA). Observational data suggest that a subgroup of patients may have a good outcome. This study aimed to describe the prevalence of ESE and potential clinical and electrographic prognostic markers.
Methods: In this retrospective single study, we analyzed consecutive patients who suffered from CA, and who received temperature management and were monitored with simplified continuous EEG (cEEG) during a five-year period. The patients' charts and cEEG data were initially screened to identify patients with clinical seizures or ESE. The cEEG diagnosis of ESE was retrospectively reanalyzed according to strict criteria by a neurophysiologist blinded to patient outcome. The EEG background patterns prior to the onset of ESE, duration of ESE, presence of clinical seizures, and use of antiepileptic drugs were analyzed. The results of somatosensory-evoked potentials (SSEPs) and neuron-specific enolase (NSE) at 48 h after CA were described in all patients with ESE. Antiepileptic treatment strategies were not protocolized. Outcome was evaluated using the Cerebral Performance Category (CPC) scale at 6 months, and good outcome was defined as CPC 1-2.
Results: Of 127 patients, 41 (32%) developed ESE. Twenty-five patients had a discontinuous EEG background prior to ESE, and all died without regaining consciousness. Sixteen patients developed a continuous EEG background prior to the start of ESE, four of whom survived, three with CPC 1-2 and one with CPC 3 at 6 months. Among survivors, ESE developed at a median of 46 h after CA. All had preserved N20 peaks on SSEP and NSE values of 18-37 μg/l.
Conclusion: Electrographic status epilepticus is common among comatose patients after cardiac arrest, with few survivors. A combination of a continuous EEG background prior to ESE, preserved N20 peaks on SSEPs, and low or moderately elevated NSE levels may indicate a good outcome. This article is part of a Special Issue entitled "Status Epilepticus".
Keywords: Cardiac arrest; Seizure; Simplified continuous electroencephalogram; Status epilepticus; Therapeutic hypothermia.
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