Saturday 9 April 2022

Rapid agitation control with ketamine in the ED: A Randomized Controlled Trial

Agitated patient tearing apart the ED...? Which IM medication do you give?

These authors from a single ED in Vancouver randomized patients to either ketamine 5mg/kg IM vs. midazolam 5mg plus haloperidol 5mg IM.

Their primary outcome was time to adequate sedation as measured on a validated agitation score.  

(They tried to blind the dose but it’s hard to blind ketamine when we all know what it looks like. Either way, this was probably only a minor source of potential bias.)


Enrolment was cut a bit short at 80 patients due to the start a supposed global pandemic.

Median time to adequate sedation was 6 minutes in the ketamine group vs. 15 minutes in those randomized to midazolam/haloperidol. 

So, ketamine is the clear winner?!?!

There are two major reasons why this conclusion is wrong.

Firstly, they compared a grizzly bear dose of ketamine to a low dose of midazolam & haloperidol. For what it is worth, I usually start with midazolam 10mg and droperidol 10mg (unless there is reason to start lower… elderly, co-morbid, etc.) Droperidol works faster than haloperidol.

Secondly, they asked the wrong research question. I care less about how quickly someone is sedated and care much more about how well it works overall.  I’m sure a dose of IM sux would work pretty quick too. Or even a bullet to the head would have an immediate calming effect (but would be associated with excess mortality.)

How often did the ketamine group require re-sedation? How well did the patients wake up? Lots of adults complain about side effects of ketamine including dysphoria to emergence phenomenon. But what could go wrong with giving an agitated patient a medication similar to PCP?

To be fair to the researchers, it is difficult to objectively measure, “how well did it work?” It's complicated and there is some subjectivity in this question. Time to sedation is much easier to measure… but just because we can measure something accurately does not necessarily mean it is important. (This kind of reminds me of the streetlight effect).

In short summary, I’m willing to believe a big slug of ketamine will cause someone to drop quickly. But is this the best thing for the patient? I doubt it.



Barbic D, Andolfatto G, Grunau, et al. Rapid Agitation Control with Ketamine in the ED- A Blinded, Randomized Controlled Trial. Ann Emerg Med. 2021;78:788-795 [link to full text article]





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