Abstracts

Rationale: Refractory status epilepticus (RSE) is usually treated with continuous intravenous (IV) medications with the goal of EEG burst suppression or seizure suppression. Standard advice is to titrate medications to at least 10 second inter-burst intervals; however, this has not been correlated with improved outcome. We examined EEG characteristics in patients who underwent IV anesthetic therapy (IV AT) for RSE to determine which, if any, characteristics were associated with successful lifting of IV AT (i.e., lifting without recurrence of status epilepticus [SE]).Methods: We screened 650 continuous EEG recordings from Johns Hopkins Hospital from 5/2012 to 2/2015 for SE, and included 14 adults treated with IV AT for SE (patients with anoxic injury were excluded). Burst suppression ratios and power spectra of bursts were calculated using Persyst 11 software. Length of bursts and inter-burst intervals for each patient were measured, and bursts were graded for the presence or absence of epileptiform activity. These characteristics were compared between successful and unsuccessful IV AT lifting attempts. Status epilepticus severity scores (STESS) were calculated for each patient and compared between groups, and final destination at discharge recorded.Results: 12 successful and 19 unsuccessful lifting attempts in 14 patients were studied. The burst suppression ratios and power spectra of bursts for IV AT lifting attempts were not significantly different between successful and unsuccessful lifting attempts (figure 1); the presence and amount of epileptiform activity in bursts was most indicative of success or failure (figure 2). The maximum amplitude of burst activity was also associated with successful lifting of burst suppression: maximum burst amplitude <125uV during suppression had 84.6% sensitivity and 61.1% specificity for successful lifting. The STESS were similar in patients discharged to home or rehabilitation compared to nonsurvivors or hospice-bound patients.Conclusions: The burst-suppression ratio and length of inter-burst intervals did not predict successful termination of RSE in this small cohort. This may suggest that rather a strict inter-burst interval target, suppression of epileptiform features of bursts could be the goal of IV AT for RSE.