Safety and Efficacy of Ketamine Without Intubation in the Management of Refractory Status Epilepticus: A Case Series

Abstract Purpose: Continuous infusion ketamine has demonstrated efficacy in the management of refractory status epilepticus (RSE) yet does not suppress respiratory drive like other continuous infusion anesthetics used for this indication. Utilizing ketamine early in the management of RSE represents a treatment option with potential to reduce morbidity. The aim of this study is to describe the safety and efficacy of ketamine infusions in RSE patients without intubation. Materials and Methods: We analyzed a retrospective cohort of adult patients who were not intubated at the time of initiation of a ketamine infusion for RSE. Seizure onset was determined to be the first clinical seizure or non-convulsive seizure reported on electroencephalogram (EEG) or the start time of EEG for patients in RSE at EEG initiation. Responders were defined as patients with documentation of resolution of seizures within 24 hours of initiation without the need for intubation or additional continuous infusion anesthetics. Results: A total of 28 patients were analyzed of a median age 62 years, 64.3% female, 82.1% African American, and 82.1% with structural seizure etiology. 78.5% of patients received an initial bolus averaging 0.9 mg/kg and the majority (89.3%) were initiated on an infusion at 10 mcg/kg/min; median duration of infusion was 39.8 hours. 71.4% of patients were assessed to be ketamine responders; six of the eight non-responders required intubation and an additional continuous infusion anesthetic. Responders were 80% more likely to have received ketamine five or more hours earlier than non-responders. Hypotension (SBP < 90 mmHg) occurred in 31.8% of patients receiving only ketamine, which did not correlate with duration or maximum dose of ketamine. Conclusion: Ketamine represents a safe and effective treatment option for RSE with potential to reduce morbidity associated with intubation. Early initiation may increase likelihood of success.