Summary Purpose To examine patterns of use, efficacy and safety of intravenous ketamine for the treatment of refractory status epilepticus (RSE). Methods Multicenter retrospective review of medical records and EEG reports in ten academic medical centers in North America and Europe, including 58 subjects, representing 60 episodes of RSE were identified between 1999 and 2012. Seven episodes occurred after anoxic brain injury. Key findings Permanent control of RSE was achieved in 57% (34/60) of episodes. Ketamine was felt to have contributed to permanent control (“possible” or “likely” responses) in 32% (19/60) including seven (12%) in which ketamine was the last drug added (likely responses). Four of the seven likely responses, but none of the 12 possible ones, occurred in patients with post-anoxic brain injury. No likely responses were observed when infusion rates were lower than 0.9mg/kg/h; when ketamine was introduced at least eight days after SE onset; or after failure of seven or more drugs. Ketamine was discontinued due to possible adverse events in five patients. Complications were mostly attributed to concurrent drugs, especially other anesthetics. Mortality rate was 43% (26/60), but was lower when SE was controlled within 24h of ketamine initiation (16% vs. 56%, p=0.0047). Significance Ketamine appears to be a relatively effective and safe drug for the treatment of RSE. This retrospective series provides preliminary data on effective dose and appropriate time of intervention to aid in the design of a prospective trial to further define the role of ketamine in the treatment of RSE.

Objective: To describe the time elapsed from onset of pediatric convulsive status epilepticus (SE) to administration of antiepileptic drug (AED).Methods: This was a prospective observational cohort study performed from June 2011 to June 2013. Pediatric patients (1 month-21 years) with convulsive SE were enrolled. In order to study timing of AED administration during all stages of SE, we restricted our study population to patients who failed 2 or more AED classes or needed continuous infusions to terminate convulsive SE. Results:We enrolled 81 patients (44 male) with a median age of 3.6 years. The first, second, and third AED doses were administered at a median (p 25 -p 75 ) time of 28 (6-67) minutes, 40 (20-85) minutes, and 59 (30-120) minutes after SE onset. Considering AED classes, the initial AED was a benzodiazepine in 78 (96.3%) patients and 2 (2-3) doses of benzodiazepines were administered before switching to nonbenzodiazepine AEDs. The first and second doses of nonbenzodiazepine AEDs were administered at 69 (40-120) minutes and 120 (75-296) minutes. In the 64 patients with out-of-hospital SE onset, 40 (62.5%) patients did not receive any AED before hospital arrival. In the hospital setting, the first and second in-hospital AED doses were given at 8 (5-15) minutes and 16 (10-40) minutes after SE onset (for patients with in-hospital SE onset) or after hospital arrival (for patients with out-of-hospital SE onset). Conclusions:The time elapsed from SE onset to AED administration and escalation from one class of AED to another is delayed, both in the prehospital and in-hospital settings. Status epilepticus (SE) is one of the most common pediatric neurologic emergencies.1 It has a mortality of 0%-3% 2-7 and morbidity that includes cognitive and neurodevelopmental impairments, epilepsy, and recurrent SE.2,8-10 SE is often refractory to the initial antiepileptic drugs (AEDs), 11,12 and refractory SE is associated with poor outcome. 12 Patient age, etiology, and SE duration all affect outcome, 5,9,13 but only SE duration is a potentially modifiable factor by rapid AED treatment. By convention, the treatment of convulsive SE is a sequence of AEDs, typically