AT SAEM 2015

SAN DIEGO (FRONTLINE MEDICAL NEWS) – Ketamine sedates violent and highly agitated patients in the emergency department faster than other widely used agents and with a similar rate of adverse events, based on the results of a small observational study presented at the annual meeting of the Society for Academic Emergency Medicine.

Dr. Jeffrey Riddell and his colleagues at the University of California San Francisco, Fresno, reported results from a prospective cohort of 83 patients, 18-65 years old, who presented with acute agitation requiring sedation at a single urban ED.

Ketamine was given to 21 patients at a median dose of 70 mg IV or 250 mg IM. Another 9 patients received haloperidol (5 mg IM), 39 got lorazepam or midazolam (2 mg IV or IM), and 14 were treated with a combination of haloperidol, diphenhydramine, and lorazepam.

Ketamine proved the fastest acting, with a median time to sedation of 3 minutes. Median time to sedation was 8 minutes for haloperidol alone, 10 minutes for the benzodiazepines, and 17.5 minutes for the combination of sedative agents. Patient selection may have been at play in the longer time seen with the combination therapy, a result of clinicians selecting this option for the most agitated patients, Dr. Riddell said in an interview.

Adverse events measured in the study were dystonia, hypotension, hypoxia, and intubation. One of the 9 patients in the haloperidol group had an adverse event, as did 2 of 14 given the combination, 3 of 39 given benzodiazepines, and 3 of 21 given ketamine. “The study wasn’t powered to detect a clinically significant difference in side effects, but in this small subset [the rate of adverse events] looked similar,” Dr. Riddell said.

Ketamine’s onset of action, compared with the other agents, was all the more remarkable, he said, because physicians did not separate intramuscular and intravenous delivery forms. Intramuscular delivery is generally slower, therefore, intravenous sedation with ketamine could be even faster than 3 minutes.

Dr. Riddell said his team hoped that the observational study will form the basis for a randomized controlled trial with clinicians blinded to treatment allocation. “Only the ED pharmacist will be aware of the medication type,” he said.

The preliminary data on ketamine’s speed and safety “bore out what our experience was with it in the ED,” he said. “There’s still not a lot of good data about it for agitated patients in the ED, though there’s tons of data for procedural sedation. Extrapolating from that, we’re trying to show that it also works in the ED population that needs a medication for sedation.”

The study was funded by the National Institutes of Health through a grant from the University of California San Francisco Clinical and Translational Science Institute. The investigators declared no conflicts of interest.


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