Written by Clay Smith
Ketamine was effective for treatment of agitation, but 30% of patients given higher doses IM by EMS were intubated once in the ED.
Why does this matter?
Often benzodiazepines or antipsychotics are used for sedating agitated patients. Benzos are associated with high rate of intubation (37% in some studies). Antipsychotics may prolong the QT. These agents may take up to 15 minutes to provide adequate sedation. Ketamine has been used for agitation as well. This is a compilation of the key studies on its use for agitation. Usually, the dose is 1mg/kg IV or 3mg/kg IM.
Down the K-hole
This was a systematic review (SR) of 18 studies, 650 patients, involving use of ketamine for agitation in the prehospital and ED setting. Twelve of the 18 were EMS studies. Most were small sample sizes; all were observational. Mean dose was 315mg IM, 4.9mg/kg (…that’s a lot). Given this, it is not surprising that 30% were intubated, most after having been given ketamine by EMS with intubation in the ED. Onset of action was around 7 minutes. Only 1.8% were intubated when ketamine was given in the ED only. Other adverse effects included: vomiting, 5.2%; hypertension, 12.1%; emergence reactions, 3.5; transient hypoxia, 1.8%; and laryngospasm, 1.3%. Dosing of ketamine IM was high in this SR. This may have led to over-sedation and the high intubation rate seen here. Perhaps if the dose was closer to 3mg/kg IM, fewer patients would have been intubated. Intubation was also much higher when given by EMS rather than in the ED. Was this just nervous emergency physicians who interpreted dissociation as not protecting their airway? It’s hard to know.
REBEL EM has a helpful post on chemical sedation of the agitated patient.
Ketamine for Rapid Sedation of Agitated Patients in the Prehospital and Emergency Department Settings: A Systematic Review and Proportional Meta-Analysis. J Emerg Med. 2018 Sep 6. pii: S0736-4679(18)30727-3. doi: 10.1016/j.jemermed.2018.07.017. [Epub ahead of print]
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Reviewed by Thomas Davis