( S )-Ketamine in Refractory and Super-Refractory Status Epilepticus: A Retrospective Study

Objective The aim was to describe the safety and efficacy of ( S )-ketamine [( S )-KET] in a series of patients with refractory and super-refractory status epilepticus (RSE and SRSE) in a specialized neurological intensive care unit (NICU). Methods We retrospectively analyzed the data of patients with RSE and SRSE treated with ( S )-KET in the NICU, Salzburg, Austria, from 2011 to 2015. Data collection included demographic features, clinical presentation, diagnosis, electroencephalogram (EEG) data, anticonvulsant treatment, timing, and duration of treatment with ( S )-KET. Outcomes were seizure control and death. Results A total of 42 patients (14 women) with RSE and SRSE were treated with ( S )-KET. The median duration of status epilepticus (SE) was 10 days [first quartile (Q1) 5.0, Q3 21.0]; the median latency from SE onset to the first administration of ( S )-KET was 3 days (Q1 2.0, Q3 6.8). Prior to ( S )-KET administration, patients had received a median of two (Q1 2.0, Q3 3.0) anesthetics and three (Q1 2.0, Q3 4.0) antiepileptic drugs. Forty percent of patients (17/42) received propofol: 65 % prior to ( S )-KET; 35 % at the same time with ( S )-KET. Seven patients received a median bolus of ( S )-KET of 200 mg (Q1 200, Q3 250) followed by a continuous infusion, while 35 started with a continuous infusion (maximum rate median 2.55 mg/kg/h; Q1 2.09, Q3 3.22). In 64 % of patients (27/42), ( S )-KET was the last drug before SE cessation; in five patients, it was given with propofol at the same time. Median duration of administration was 4 days (Q1 2.0, Q3 6.8). Overall ( S )-KET treatment was well tolerated, adverse effects were not observed, and overall mortality was 45.2 %. Conclusions Treatment of SRSE in adult patients with ( S )-KET led to resolution of status in 64 %. No adverse events were found, indicating a favorable safety profile.