Continuous electroencephalography in a surgical intensive care unit

Abstract

Our aim was to investigate the prevalence, risk factors, and impact on outcome of nonconvulsive seizures (NCSz), nonconvulsive status epilepticus (NCSE), and periodic epileptiform discharges (PEDs) in surgical intensive care unit (SICU) patients with continuous electroencephalography (cEEG) monitoring. This was a retrospective study of SICU patients who underwent cEEG monitoring for altered mental status over a 6-year period. We report the frequency of NCSz (including NCSE) and PEDs on cEEG. The primary outcome was death or severe disability at hospital discharge. Multivariable logistic regression was used to identify whether NCSz (including NCSE) and PEDs were independently associated with poor outcome (death, vegetative state or severe disability). Of 154 patients, the mean age was 64 ± 14 years old, and 40% were women. The majority of patients were admitted following abdominal surgery (36%) and liver transplantation (24%). Sepsis developed in 100 (65%) patients. Sixteen percent (n = 24) had NCSz [including 5% (N = 8) with NCSE], and 29% (N = 45) had PEDs. All eight patients with NCSE were septic. Clinical seizures prior to cEEG and coma were more common among patients who developed NCSz or NCSE compared to patients without NCSz or NCSE (70 vs. 27%; p < 0.01; 75 vs. 52%; p = 0.046 and 63 vs. 34%; p = 0.09, respectively). NCSzs (including NCSE) were independently associated with poor outcome (20 vs. 3%, OR 10.4, 95% CI 1.0-53.7; p = 0.039). In this retrospective study of SICU patients with cEEG monitoring for altered mental status, NCSz and periodic discharges were frequent and NCSz were independently associated with poor outcome. NCSz were more common when clinical seizures occurred before cEEG.