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Ketamine is a uniquely useful drug. I discussed the use of ketamine in critical care in episode 16.
Ketamine checks a lot of boxes and fills a lot of niches. Analgesia? Check. Sedation? Check. Respiratory drive maintained? Check. Neutral to positive cardiovascular effect? Check.
Ketamine is a very popular subject within the #FOAMed world on twitter.
When I asked on twitter whether ketamine in inpatient critical care was under utilized or overrated, I got a lopsided result:
Not everyone in the #FOAMed community has such a high opinion of ketamine. Take this anesthesiologist for example:
How about, avoid ketamine? The neurotoxic potential for this NMDA antagonist is real. Why cover it up with a benzo? https://t.co/b7y3Nr8Yu8
— Vincent J. Kopp (@VincentKopp) January 17, 2016
All of this leads me to wonder – is there a pro-ketamine bias within the #FOAMed community? Take this discussion for example:
— Sam Matta (@luigisdad) June 19, 2016
I think ketamine would be a fine agent for induction in a patient with asthma, but psychiatric distress from ketamine would have the potential to make things worse, not better if the patient was anxious and intubation was to be spared. Dexmedetomidine might do a better job providing anxiolytic properties without compromising respiratory drive.
Ketamine seems to consistently have excellent efficacy but increased side effects when compared to other treatments.
1. Ketamine is as effective as morphine for analgesia, but with an increased incidence of minor side effects.
2. Ketamine works faster than haloperidol to control acutely agitated prehospital patients, but causes more complications and increases the need for intubation.
Even ketamine’s main advantages – lack of respiratory depression & lack of hypotension are not true in all instances.
When ketamine is given via rapid IV push, periods of apnea can occur.
When ketamine is given to patients with shock and depleted catecholamine stores, hypotension can occur. A recent article put the risk of hypotension associated with ketamine given for RSI induction to be 26% in patients with a high shock index. The shock index is simply the heart rate divided by the systolic blood pressure.
While respiratory depression and hypotension are both manageable conditions, they can be disastrous if they occur when the team is not prepared to handle them. Thinking that ketamine is completely without risk of respiratory depression or hypotension could instill a false sense of security that might leave clinicians underprepared.
Then why is ketamine widely discussed among the #FOAMed community on blogs and twitter? Why would “the answer is always ketamine.” go over so well at a conference finale?
I think the reason is, with the use of social media for medical education, we are all effectively sitting in the same lounge or walking in the same hallway. We are discussing our difficult or fringe cases where the traditional first line therapy was either ineffective or contraindicated. Those are the cases where ketamine shines, and those are the cases that make the best blog posts, podcasts, and tweets.
Just remember that in these discussions, there is no editorial board and YOU are the peer reviewer.
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.