Prehospital Ketamine Administration in Benzodiazepine Refractory Status Epilepticus: A Case Series Review

Benzodiazepines are the treatment for seizures in prehospital settings, but fail in up to 40% of cases, leading to benzodiazepine refractory status epilepticus (BRSE). Early treatment of BRSE is essential to prevent neurological damage and death. Ketamine, an N-methyl-D-aspartate receptor antagonist used by emergency medical services (EMS) for a variety of indications, has potential as a safe, effective prehospital treatment for BRSE. However, safety and efficacy data for early treatment of patients with seizures are limited.

We retrospectively analyzed patients treated by EMS clinicians with ketamine for BRSE at a single urban ground-based EMS system between September 1, 2021, and December 1, 2023. Ketamine dose and route, patient characteristics, and airway interventions are described. Data were gathered from EMS records.

Forty-two patients aged 8 months to 79 years, were included. Ketamine was administered intramuscularly in 22 with an average dose of 3.3 mg/kg, and intravenously or intraosseous in 20, with an average dose of 2.2 mg/kg. Ketamine stopped seizures in 38 patients (90.5%). Transient hypoxia occurred in 9 patients (22%). Respirations were supported with bag-valve-mask ventilation in 13 patients (31%), a supraglottic airway in three (7%), and one patient was endotracheally intubated (2.4%).

Ketamine appears safe and effective for prehospital treatment of BRSE. Monitoring and intervention for respiratory complications appears necessary, but rates of these complications are consistent with expected rates from seizures and appropriate benzodiazepine dosing. These findings support ketamine's use in EMS for BRSE. Larger prospective studies are needed to confirm safety and efficacy.