If you’re working in the UK then you will know that there is currently a shortage of ketamine (I know!). Specifically we are struggling to get hold of the 10mg/ml strength that is so useful in EM and PHEM. At the moment we are using Swiss Ketamine (which does sound pretty cool to be honest) and also looking at alternative supplies, or by diluting stronger preparations (with the obvious potential problems as a result). We are looking at alternatives, and one of those would be to return to using Etomidate for our critically ill and injured patients. This was a drug that I became very familiar with as a trainee, but which fell out of favour over concerns about adrenal suppression, and with the wider acceptability of ketamine as an induction agent. I was also influenced by a paper from Kent, Sussex and Surrey air ambulance that indicated improvements in RSI KPIs when they moved from Etomidate to Ketamine. That said, as ketamine is becoming increasingly difficult to source perhaps we should reconsider etomidate as an induction agent?
Co-incidentally there is a great review on the SGEM website from our friend Ken Milne on a meta-analysis of Etomidate vs other agents. It’s a very fortuitous co-incidence, and if you’ve not already read and listened to Ken’s review then I recommend you do. As he’s done the hard yards on this one then I’ll keep it brief here. You should at the very least read the abstract below.
What kind of paper is this?
It’s a meta-analysis where multiple papers are pooled/analysed together to effectively increase sample size to find a more precise answer to a question. It’s an appropriate method, but as always we should be skeptical (thanks Ken 😉 ) and look at the methodology of the review as well. All too often I hear people say that meta-analysis is a very high level of evidence, and it is BUT (and this is really important) only if it is done well.
Tell me about the papers included?
A meta-analysis relies on the number and quality of the papers included. In this study they looked for any randomized controlled trials which compared etomidate with any other induction agent in critically ill adult patients undergoing endotracheal intubation. I think that’s OK as it is similar to the sort of papers I RSI in EM/PHEM, although there will be differences when compared to the critical care population.
What did they find?
Interestingly there were just 11 papers included, but that amounted to over 2700 patients which if it were a single trial would be an impressive number.
The headline figure is that Etomidate was associated with an increase in mortality (319/1359 [23%] vs. 267/1345 [20%]; risk ratio (RR) = 1.16; 95% confidence interval (CI), 1.01-1.33; P = 0.03; I2 = 0%; number needed to harm = 31) That NNH is pretty small considering the number of patients we see in practice.
Any concerns with the paper?
Not concerns as such but a number of issues for me that might make the results less applicable to my practice.
- These patients were not necessarily EM/PHEM patients and so may be different to my practice.
- The end points in the papers were often quite different, varying from a number of days to hospital stay.
- Some studies used a reduced dose (0.15mg rather than 0.3mg/Kg)
- Many trials were open label
- Lots of alternative agents were looked at (not just ketamine). If analysed just against ketamine, then ketamine still looks better.
The bottom line
Secondly, having read the paper and the review it is my view that there is very little to support a move away from ketamine as an induction agent. If we run out of the SwissKet, then we may have to explore other countries until the situation resolves (I hear around November is likely).
Significant modification of traditional rapid sequence induction improves safety and effectiveness of pre-hospital trauma anaesthesia https://pubmed.ncbi.nlm.nih.gov/25879683/
SGEM#405: WE’RE OFF TO NEVER-NEVER LAND – BUT SHOULD WE USE ETOMIDATE FOR THE RAPID SEQUENCE INTUBATION? https://pubmed.ncbi.nlm.nih.gov/37127020/
Simon Carley, “JC: Etomidate vs. Ketamine for emergency intubation. St Emlyn’s,” in St.Emlyn’s, January 21, 2022, https://www.stemlynsblog.org/jc-etomidate-vs-ketamine-for-emergency-intubation-st-emlyns/.
SGEM#356: DRUGS ARE GONNA KNOCK YOU OUT – ETOMIDATE VS. KETAMINE FOR EMERGENCY ENDOTRACHEAL INTUBATION
Etomidate versus ketamine for emergency endotracheal intubation: a randomized clinical trial. Intensive Care Med . 2022 Jan;48(1):78-91. doi: 10.1007/s00134-021-06577-x. Epub 2021 Dec 14