Prognostic Implications of Sleep Architecture for Patients Admitted to the Intensive Care Unit With Status Epilepticus

OBJECTIVE: Status epilepticus (SE) is associated with significant mortality. Sleep architecture may reflect normal brain function. Impaired sleep architecture is associated with poorer outcomes in numerous conditions. Here we investigate the association of sleep architecture in continuous EEG (cEEG) with survival in SE. METHODS: Retrospective single-centre study of all adult cEEGs in 2015-2019 with electrographic SE. Patients were dichotomized by the presence of sleep architecture (REM or non-REM) in any epoch per an epileptologist blinded to patient outcome. Categorical variables were assessed using Fisher's exact test. Two-sample t-tests and Wilcoxon rank-sum tests compared normally and non-normally distributed variables, respectively. Survival analysis at 6 months used the Mantel-Cox log-rank test. Multivariate analysis using Firth logistic regression assessed for confounders. RESULTS: Twenty-five adults (68% male) had electrographic SE (median cEEG duration 2 days, hospitalization 13 days). Mean number of intravenous sedatives was 1.44 and anti-seizure medication 2.96. Thirteen adults had sleep architecture, with shorter cEEG delays (median 1 vs. 2 days, p = 0.0104) and younger age (median 56 vs. 72.5 years, p = 0.0386). Sleep architecture was associated with better outcomes at 6-months (p = 0.0073), higher survival rates at 6-months (76.9% vs. 25%, p = 0.017), and longer survival durations at 6-months (160.9 vs. 73.3 days, p = 0.0034). cEEG delay was not associated with survival (p = 0.107). SIGNIFICANCE: In addition to younger age-a known positive SE prognosticator-sleep architecture during cEEG in adults with electrographic SE was associated with increased survival, possibly due to the resilience of younger brains generating sleep architecture in the face of SE, acting as a marker for improved prognosis.