Use of Ketamine in Barbiturate Coma for Status Epilepticus

We described the use of adjunctive ketamine to terminate seizure activity and decrease the dose and duration of pentobarbital coma in 2 patients with refractory status epilepticus (SE).

A 56-year-old woman (patient 1) developed SE after cardiac arrest, which was refractory to antiepileptic agents and escalating doses of continuous midazolam. Midazolam was replaced with pentobarbital infusion with no significant change in electroencephalography. A continuous ketamine infusion was initiated as an adjunct to pentobarbital. After initiation of ketamine, seizure frequency decreased and sustained burst suppression was achieved. After 48 hours of induced burst suppression, pentobarbital was discontinued followed by ketamine and the patient remained seizure on oral anticonvulsants alone. Meanwhile, a 57-year-old woman (patient 2) with autoimmune encephalitis developed SE, which was refractory to first-line medications. Pentobarbital infusion was initiated with attainment of burst suppression on electroencephalography. Multiple attempts at weaning pentobarbital failed because of recurrence of seizures. To minimize the dose of pentobarbital needed, a continuous ketamine infusion was initiated as an adjunct to pentobarbital with maintenance of burst suppression at much lower doses of pentobarbital than before. Ketamine was continued for 19 days with titration of other antiepileptic therapy, without return of SE.

These cases demonstrate that ketamine may show promise as an adjunct to induced pentobarbital coma for refractory SE. Adjunctive use of ketamine may reduce the dose and duration of pentobarbital required, hence preventing complications associated with barbiturate therapy. Future studies are needed to define the optimal dose, timing, and role of ketamine infusions in the management of refractory SE.