Fixed-Dose Ketamine 250mg IM for Prehospital Agitation

May 27, 2024

Written by Samuel Rouleau

Spoon Feed
A retrospective study of 60 patients who received a fixed-dose ketamine of 250 mg by EMS observed that 6 were intubated in the ED. There was no association between weight-based dose of ketamine and risk for intubation.

Agitation? Jump into the K-Hole!
This was a single center, multi-EMS agency retrospective study that included 60 adults with hyperactive delirium with severe agitation (HDSA) who received a fixed dose of intramuscular (IM) ketamine in the pre-hospital setting. Importantly, the study population was young (median age 34.5 years old), and 45 (75%) were male. The dosing protocol was 250 mg of IM ketamine, and a second dose of 250 mg was permitted. 12 patients received a second dose of 250 mg of IM ketamine (500 mg total), and none of these 12 were intubated or had any adverse effects. 6 patients were intubated and subsequently extubated and discharged from the hospital without any complications. For adverse events, three patients required bag-valve mask ventilation, one due to laryngospasm, and another patient required frequent suctioning for copious secretions. After adjusting for weight, there was no correlation between weight-based dose and risk for intubation, even in those patients who had 500 mg total of IM ketamine.

How will this change my practice?
Pre-hospital ketamine for HDSA has received some bad press. Here are my thoughts on this study:

• This study has limits with regards to its generalizability. In a young patient with severe agitation, it is generally safe to give 250 mg of IM ketamine. However, proceed with caution outside of this narrow study population.
• This study is under-powered to draw conclusions about weight-based dosing and risk for intubation.
• The retrospective studies that have the strongest results adhere to the STROBE or Kaji guidelines. This study misses several of the criteria, such as not clearly stating primary and secondary outcomes and not performing abstractor interrater reliability assessment.

Source
Fixed dose ketamine for prehospital management of hyperactive delirium with severe agitation. Am J Emerg Med. Published online April 9, 2024. doi:10.1016/j.ajem.2024.04.011