Refractory Status Epilepticus in Children: Intention to Treat with Continuous Infusions of Midazolam and Pentobarbital∗

Objective: To describe pediatric patients with convulsive refractory status epilepticus in whom there is intention to use an IV anesthetic for seizure control. Design: Two-year prospective observational study evaluating patients (age range, 1 mo to 21 yr) with refractory status epilepticus not responding to two antiepileptic drug classes and treated with continuous infusion of anesthetic agent. Setting: Nine pediatric hospitals in the United States. Patients: In a cohort of 111 patients with refractory status epilepticus (median age, 3.7 yr; 50% male), 54 (49%) underwent continuous infusion of anesthetic treatment. Main Results: The median (interquartile range) ICU length of stay was 10 (3-20) days. Up to four "cycles" of serial anesthetic therapy were used, and seizure termination was achieved in 94% by the second cycle. Seizure duration in controlled patients was 5.9 (1.9-34) hours for the first cycle and longer when a second cycle was required (30 [4-120] hr; p = 0.048). Midazolam was the most frequent first-line anesthetic agent (78%); pentobarbital was the most frequently used second-line agent after midazolam failure (82%). An electroencephalographic endpoint was used in over half of the patients; higher midazolam dosing was used with a burst suppression endpoint. In midazolam nonresponders, transition to a second agent occurred after a median of 1 day. Most patients (94%) experienced seizure termination with these two therapies. Conclusions: Midazolam and pentobarbital remain the mainstay of continuous infusion therapy for refractory status epilepticus in the pediatric patient. The majority of patients experience seizure termination within a median of 30 hours. These data have implications for the design and feasibility of future intervention trials. That is, testing a new anesthetic anticonvulsant after failure of both midazolam and pentobarbital is unlikely to be feasible in a pediatric study, whereas a decision to test an alternative to pentobarbital, after midazolam failure, may be possible in a multicenter multinational study.