538: KETAMINE OR TRADITIONAL CONTINUOUS ANESTHETICS IN REFRACTORY OR SUPER-REFRACTORY STATUS EPILEPTICUS

Abstract

Introduction: Refractory (RSE) and super-refractory status epilepticus (SRSE) are challenging to manage due to the failure of traditional therapies to abort seizures. Agents that target the gamma-aminobutyric acid (GABA) receptor may be less effective in these scenarios secondary to receptor down regulation. However, antagonism of the upregulated N-methyl-D-aspartic acid [NMDA] receptor in RSE and SRSE with ketamine may result in improved seizure control. Few investigations of ketamine in RSE and SRSE exist, and no studies have compared the efficacy and safety of ketamine versus other traditional anesthetics (TA) for the resolution of status epilepticus (SE). Therefore, we aim to determine if the use of ketamine as compared to TA alone is associated with increased seizure resolution at 24 hours following last anesthetic initiation in patients with RSE and SRSE. Methods: We conducted a single-center, retrospective cohort study of patients admitted with RSE or SRSE from January 2012 through May 2022 and stratified by receipt of at least four hours of ketamine infusion or continuous TA such as midazolam, pentobarbital, or propofol. The primary outcome was seizure resolution within 24 hours of last anesthetic infusion initiation. Secondary outcomes included time to seizure resolution and SE relapse. Results: Of the 21 patients included, 5 received ketamine and 16 received TA. Baseline characteristics did not differ significantly between groups, including median age (59.1 vs 51.7 years), nonconvulsive SE (80.0% vs 56.3%), and history of epilepsy (60.0% vs 31.3%), in the ketamine and TA groups, respectively. Following last anesthetic initiation, ketamine was associated with a significant increase in seizure resolution within 24 hours (100% vs 44%; P=0.045) and reduced time to seizure resolution (median 2.1 [IQR 0.3-3.0] hours vs 27.9 [IQR 12.9-31.6] hours; P=0.001) compared to TA alone. There was no difference in SE relapse between groups (ketamine – 60.0% vs TA – 31.3%; P=0.325). Conclusions: The use of ketamine infusion in the setting of RSE and SRSE was associated with a significant increase in SE resolution at 24 hours of last anesthetic initiation compared to TA alone without an increase in relapse. Further evaluation of ketamine in the setting of RSE and SRSE is needed.