Prognostic indicators of non-convulsive status epilepticus in intensive care unit

To determine the rate of non-convulsive status epilepticus with/without prominent motor phenomena (SE-PM/ NCSE) and predictive value of electroclinical findings of continious electroencephalography (cEEG) monitoring of these patients and its association with prognosis in intensive care units (ICU).

We retrospectively collected data of 218 patients whose cEEG was performed in ICU between 2016 and 2018. The cEEG for NCSE diagnosis was evaluated according to Salzburg Consensus Criteria (SCC).

The mean age of patients was 57.09 ± 18.9 (16-95) years and 49.1% (107) were female. Of 218 patients, 32 (14.7%) had SE-PM/NCSE. According to SCC the rate of NCSE (NCSE + possible NCSE) was 9.6% (n = 21). Prior to cEEG recording, 38.9% (n = 85) of overall patients had a history of seizure/convulsion, and 22.7% (n = 21) of these patients diagnosed with NCSE based on cEEG. The mortality rates in critically ill patients were 41.3% (30.8%, 42.8%; for SE-PM and NCSE respectively). Prognosis was associated with age, epilepsy diagnosis, having convulsion/seizure history on follow-up, GCS, need for ventilation, kind of drugs, sepsis diagnosis, and minimum frequency of background activity of the cEEG (p = 0.001, 0.002, 0.001, 0.020, 0.001, 0.001, 0.001, 0.0001 respectively).

NCSE findings are mostly found in patients who were comatose and had seizure/convulsion history on follow-up. Mortality is higher in patients diagnosed with NCSE followed in the ICU compared to SE-PM.