Abstracts

Rationale: Refractory status epilepticus (RSE) is associated with high rates of morbidity and mortality. RSE is often treated with high doses of anesthetic agents which can have associated complications including respiratory depression and hypotension. Ketamine is an emerging RSE treatment but optimal dosing and timing are unknown. We studied provider attitudes and practices regarding the use of ketamine for RSE.

Methods: A literature review informed the development of a survey, developed jointly by epilepsy, pharmacy and neurocritical care professionals and hosted on SurveyMonkey. The survey was pilot tested on 12 providers and modified accordingly. Participants had to be involved in the care of critically ill patients with seizures. The survey was distributed to members of the Critical Care EEG Monitoring and Research Consortium, Neurocritical Care Society, American Academy of Neurology Synapse, American Epilepsy Society and the Canadian League against Epilepsy. Descriptive statistics are summarized.

Results: The 109 respondents were from the USA (70%), Canada (14%), South/Central America (5%), and Europe (4%). 88% worked in academic centers and 61% had formal EEG training. Specialties included neurology (62%), epilepsy (48%), and neurocritical care (31%). Preferred first-line agents for RSE were midazolam (53%), propofol (42%) and pentobarbital (2%). Although 63% of institutions routinely used ketamine, it was first line for RSE in only 1%. Circumstances leading to ketamine use included failure of midazolam/propofol to control seizures (81%) or hypotension on other anesthetic infusions (35%). Ketamine was added after midazolam failure at 2 mg/kg/hr (26%) or 1 mg/kg/hr (15%), or propofol failure at 80 mcg/kg/min (26%) or 50 mcg/kg/min (12%). Bolus dosing for ketamine was usually in the 1-4 mg/kg range with infusion rates from 1-10 mg/kg/hr; doses were mostly adjusted based on EEG interpretation (56%). Ketamine contraindications included hypertension (37%), elevated intracranial pressure (ICP) (24%), heart failure (18%), liver failure (8%), and acid-base anomalies (8%); 32% of participants were unsure about contraindications. Ketamine benefits included decreased use of vasopressors (53%) and more rapid control of RSE when used in combination with other anesthetic infusions (49%). 59% of participants found ketamine useful for RSE and 94% wanted to learn more about its use.

Conclusions: Our study shows that ketamine is used mainly as a second-line agent for RSE, most often as an adjunct to midazolam or propofol. Dosing for bolus and infusion rates varied widely and were primarily adjusted based on EEG findings. Ketamine benefits included decreased need for blood pressure support and more rapid control of seizures when used in conjunction with traditional anesthetic medications. Several contraindications were identified including hypertension, heart failure, liver failure and elevated ICP, although a third of participants were unaware of contraindications. More than half of participants found ketamine helpful for RSE, and most wanted to learn more about its use.

Funding: Please list any funding that was received in support of this abstract.: NJ is the Bludhorn Professor of International Medicine.