Abstracts

Rationale: Non-convulsive seizures (NCS) are increasingly recognized as a cause of persistent encephalopathy in the emergency department (ED). NCS is primarily diagnosed using electroencephalography (EEG), however EEG is often delayed or unavailable in many academic and community hospitals, especially in the ED. The resultant uncertainty in clinically diagnosing NCS is significant, and it leads to delayed or inappropriate treatment with anti-seizure medications (ASMs), unnecessary intubation, and increased morbidity. Point-of-care EEG (pocEEG), could fill this critical gap in the ED, as it has in inpatient and intensive care unit (ICU) settings. In this study, we describe the impact of pocEEG on the management of ED patients with suspected NCS.

Methods: We retrospectively identified 157 patients who underwent pocEEG monitoring in the ED at Mission Hospital (January 1, 2020 - December 31, 2020). We reviewed each patient’s medical record and extracted pocEEG findings (categorized as seizure, highly epileptiform patterns [HEP], and slow/normal activity; excluding repeat studies for the same patient) and ASM treatment information (pre-hospital, pre-pocEEG, post-pocEEG) to determine whether pocEEG led to appropriate ASM escalation or avoidance of inappropriate ASM escalation. We also measured the time from ED arrival to pocEEG initiation (hours) and tested its association with length of stay in the ED (hours) and hospital (days). Statistical significance was assessed using chi-square tests with Bonferroni correction (categorical data) and Pearson’s r (continuous data).

Results: Of 157 ED patients (mean age 57.7±22.4 years, 49% female), pocEEG revealed seizures in 22 (14%), HEP in 33 (21%), and slow/normal activity in 102 (65%). Most studies (53%) were performed after-hours (5p-8a), and most patients were admitted (54% ICU, 41% floor). Five patients (3%) were treated with ASMs prior to ED arrival, but 93 (59%) were treated in the ED prior to pocEEG monitoring and 80 (51%) were treated after pocEEG monitoring. By reviewing each patient’s ED course and the relationship between pocEEG monitoring and ASM treatment, we found a significant association between pocEEG findings and changes in management (p< 0.001). Patients with seizures were significantly more likely to be treated than patients with slow/normal activity (59% vs. 25%, p=0.002) and patients with slow/normal activity were significantly more likely to not have treatment escalation (28% vs. 0% for seizure/HEP patterns, p< 0.001). Time to pocEEG was positively correlated with LOS in ED (r=0.52, p< 0.001) and hospital (r=0.19, p=0.02).