Abstracts

Rationale: Status epilepticus (SE) confers a high probability of death. Several risk factors associated with mortality have been identified, such as older age and seizure etiology. However, these characteristics do not account for the impact of an individual’s physiologic derangements. The APACHE II score (acute physiology and chronic health evaluation) was conceived as a measure of disease severity from a variety of ICU settings, and demonstrates good correlation with hospital death. The aim of this study was to determine whether the APACHE II score is associated with in-hospital mortality in ICU patients with SE.Methods: This was a retrospective study of patients diagnosed with SE at a university hospital (1/1/2005-10/31/2012). Status epilepticus was defined per the 2012 Neurocritical Care Society guidelines. APACHE II scores were calculated and categorized. Baseline characteristics included age, gender, post-operative status, seizure etiology (acute;cardiac arrest), seizure duration and nonconvulsive SE (NCSE). The primary outcome measure was observed in-hospital mortality. Analysis of the relative operating characteristic (ROC) was used to determine the performance of the APACHE II score in predicting observed mortality. Continuous and categorical data was assessed using 2-tailed t-testing and Pearson’s Chi2, respectively. Logistic regression analysis adjusted for covariates. Significance was set at p<0.05.Results: The final cohort of 151 subjects consisted of 68(45%) men, mean age=58 years, mean APACHE II score=17, mean SE duration=58 hours; 35(23%) were postoperative, 47(31%) underwent cardiac arrest, 89(59%) had an acute seizure etiology, and 53(36%) were in NCSE. Observed mortality was 40%(N=61). Overall, predicted APACHE II mortality underestimated observed mortality. ROC curves for categorized and continuous APACHE II scores were not predictive of observed mortality (area=0.517,p=0.727; area=0.465,p=0.470), although for APACHE II≤11.5, sensitivity=0.836 and specificity=0.822. Postoperative status, cardiac arrest and acute seizure etiology was significantly more common in deceased subjects. APACHE II category did not predict mortality in unadjusted, univariate and multivariate analysis.Conclusions: The APACHE II score does not predict mortality in ICU patients with SE, and tended to underestimate mortality rates in this cohort. This suggests that status epilepticus itself, or its associated features, confers additional risk of in-hospital death, regardless of physiologic disease severity.