Ketamine in the treatment of refractory and super-refractory status epilepticus: Experience from two centres

Purpose: There is insufficient evidence on the management of refractory status epilepticus (RSE) and super-RSE (SRSE). Ketamine is a N-methyl-D-aspartate receptor antagonist in the treatment of these entities. Our objectives were to study the effectiveness and safety of ketamine in the treatment of adult patients with RSE and SRSE, to determine the factors that can influence the response to ketamine, and to explore its use in patients without mechanical ventilation. Methods: Adult patients who had received intravenous ketamine for the treatment of RSE or SRSE at Hospital Universitario Clinico San Carlos (Madrid, Spain) or Hospital Universitari Vall d'Hebron (Barcelona, Spain) from 2017 to 2023 were retrospectively analysed. Results: This study included 58 adult patients, mean (standard deviation) age 60.2 (15.7) years, of whom 41 (70.7 %) were male; 33 (56.9 %) patients responded to ketamine without recurrence, with a low rate of adverse effects (8.6 %). The presence of SRSE at the time of ketamine initiation (OR 0.287, p = 0.028) and the time elapsed between status epilepticus onset and ketamine administration (OR 0.991, p = 0.034) were associated with worse response to ketamine. Patients treated without mechanical ventilation had similar rates of response without recurrence (62.5% vs 56.9 %) and lower mortality (37.5% vs 53.5 %) compared to the overall group. Conclusion: Ketamine is an effective drug with few adverse effects. Prompt administration should be considered in patients with RSE requiring anaesthesia, in patients with SRSE, and in patients with RSE who do not respond to standard antiseizure drugs and in whom mechanical ventilation is not advised.