PC3070: EMS Administration of Intravenous Ketamine for Benzodiazepine Refractory Status Epilepticus

Introduction: Pediatric seizures remain a frequent condition encountered by prehospital providers. Fast, effective cessation is necessary to limit morbidity and mortality. Delays in the time to treatment of status epilepticus correlate directly with longer periods of seizures, increased need for continuous infusions of anti-seizure drugs, and increased sequelae (hypotension, respiratory suppression) and mortality. The acute management of benzodiazepine refractory status epilepticus remains challenging, as EMS providers often have few anti-seizure medications (ASD) options if seizure activity persists after initial treatment.

Case Description: A 21-year-old male with Angelman Syndrome, a rare genetic disorder associated with a variety of refractory seizure types, has had frequent encounters with EMS for status epilepticus. He has failed multiple anti-seizure medications and his epilepsy remains refractory to six maintenance anti-seizure medications and a vagus nerve stimulator. Through the assistance of physician medical control, his seizures were found to be responsive to intravenous Ketamine.

Discussion: Ketamine has been established as a safe and effective prehospital treatment for several indications including agitation, analgesia, and drug-assisted airway management. Given its effectiveness in these indications and a growing comfort with its use by EMS, there is interest in identifying new indications for this pharmacologic therapy. Ketamine is a NMDA receptor antagonist and inhibits glutamatergic transmission with a favorable side effect profile and rapid onset of action when used for RSE. Alternative treatments for RSE including phenobarbital, fosphenytoin, and repeated dosing of benzodiazepines have notable side effects, including hypotension, respiratory depression, and lethargy. They require IV access, infusion pumps, and are rarely carried or used by EMS providers, making them impractical and unfamiliar prehospital therapeutic options. 

Ketamine is regularly stocked and utilized by EMS providers for a host of applications, and it has already been shown to be effective in RSE in the hospital setting in retrospective studies. Although hemodynamic and respiratory monitoring are indicated when administering this medication, potential side effects such as hypo or hypertension, respiratory depression and, the more serious, laryngospasm are rare. Although further research is needed to help delineate exactly what role ketamine has in RSE, particularly in the prehospital setting, including when to use it and whether it can be as successful IM as IV, this case adds yet another potential application to the growing list of pre-hospital interventions for which ketamine has proven effective.

Conclusion: This case highlights a potential new therapeutic opportunity for ketamine in the treatment of refractory status epilepticus (defined as seizure activity that fails to respond to appropriately dosed antiepileptic medication) in a medically complex patient. Benzodiazepine refractory seizures were successfully stopped on three separate occasions with IV ketamine administered by EMS providers. Although only a single patient, this case report provides further evidence of ketamine as effective in the prehospital management of RSE, particularly in this patient with Angelman Syndrome where RSE is a common reason for presentation to the Emergency department.