In this episode, I’ll discuss an article about hypotension from ketamine for rapid sequence intubation.
Hypotension is an undesirable effect of rapid sequence intubation, and can occur from the medications used to facilitate intubation or from decreased venous return due to positive pressure ventilation.
Because ketamine has a side effect profile that includes hypertension and tachycardia, it is assumed that when used for sedation during rapid sequence intubation that ketamine will have a lower incidence of hypotension. Some prospective studies support this premise.
However there is also literature that suggests hypotension from ketamine is a possible side effect. Two of these studies were discussed back in episode 525. A new retrospective analysis to address this issue was published recently in Academic Emergency Medicine.
The authors examined rates of out-of-hospital post-rapid sequence intubation hypotension in traumatic brain injury patients. The study looked at a time period from 2015 onward when ketamine was made available for use by paramedic for RSI in traumatic brain injury patients in Victoria, Australia.
After ketamine was allowed for RSI, there was a 5% increase in the rate of post-RSI hypotension, and this increased by 0.5% every 3 months thereafter.
The dose used by paramedics was 1.5 mg/kg IV. No information was provided in the study about the rate of administration for ketamine.
The results held up after adjustment for possible confounders, and the amount of missing data in the study was very small. In addition, as time passed, the average dose of ketamine given increased along with the rates of post-RSI hypotension. While these factors do not prove causation in a retrospective study, they do make it seem likely that effects on hypotension can be explained by ketamine use.
Hypotension in TBI is concerning as it can be associated with adverse outcomes, but prospective studies would need to compare other agents with ketamine before a determination on the ideal RSI induction agent could be made.
While hypotension is a manageable condition, it can be disastrous if it occurs when the team is not prepared to handle it. Thinking that ketamine is completely without risk of hypotension could instill a false sense of security that might leave clinicians underprepared. Clinicians should not select ketamine as an RSI induction agent believing there is no risk of hypotension, and should be prepared to treat hypotension should it occur after ketamine use.
Members of my Hospital Pharmacy Academy have access to practical training on airway pharmacology and the use of ketamine in critical care from a pharmacist’s point of view, along with many other resources to help in your practice. To get immediate access, go to pharmacyjoe.com/academy.
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