Continuous video-EEG monitoring increases detection rate of nonconvulsive status epilepticus in the ICU

Abstract

Purpose: Status epilepticus (SE) is an important neurologic emergency requiring treatment on an intensive care unit (ICU). Although convulsive SE is self-evident, the diagnosis of nonconvulsive SE (NCSE) depends on electroencephalography (EEG) confirmation. Previous work showed that 82% of patients with SE had NCSE in our ICU. We hypothesize that continuous video-EEG monitoring (CVEM) may increase the diagnostic yield in patients with SE, especially NCSE, and leave fewer patients undiagnosed.

Methods: We retrospectively assessed the EEG reports of 537 patients with suspected SE during three comparable 9-month periods, two groups before (groups 1 and 2) and one (group 3) after CVEM introduction. Differences in monthly rates of SE between groups were assessed using the Mann-Whitney U-test.

Key findings: The rates of diagnosis increased significantly after implementation of CVEM (p = 0.0546). There was no significant difference in monthly rates of NCSE diagnosis between groups 2 and 1 (difference = 0.78 new diagnosis/month; p = 0.374). Differences between groups 3 and 2 (2.89; p = 0.0173), between groups 3 and 1 (3.67; p = 0.006) and between group 3 and pooled groups 1 and 2 (3.28; p = 0.002) were statistically significant.

Significance: Frequency of NCSE diagnosis increased significantly after implementation of CVEM and was higher than the increment of performed investigations alone. Such an effect may result from the combination of longer observation periods during CVEM, greater and permanent availability of EEG recordings, and heightened awareness of NCSE. Future studies may corroborate improvement of diagnosis and outcomes in patients with disorders of consciousness by CVEM.