Cricothyroidotomy is a procedure that worried many emergency physicians. Partly because it’s a rare procedure, but also because we are likely to embarking on it at a time when things are ‘going wrong’. The most likely time will be during a failed intubation when stress levels will be high, the patient will be seriously unwell and time will be running out. The fear that many of us feel about this procedure are therefore quite understandable and similar to other immediate life saving interventions such as thoracotomy.
How many cricothyroidotomies have you performed or seen in your clinical practice?
The answer for most of us will be very low, and I suspect for the majority of readers the answer will be 0. All the more reason to spend a little time thinking about the procedure and preparing for it. Many of us will have practiced on courses such as ATLS and APLS, and even in simulation sessions which is great for familiarisation but as the video below shows, the reality is far different from the sterile classroom. Now would be a great time to review the video below, taken by our friend Rueben Strayer via EMCRIT (Scott Weingart).
So, with that little reminder of the procedure and perhaps a bit of mental simulation on how you might personally approach a cricothyroidotomy let’s crack on with the real world experience.
Last month the EMJ published a report on the experience of the London Air Ambulance with particular reference to the use of cricothyroidotomy over the last 20 years. Before we review the paper it’s worth noting that the London Air Ambulance service have published a lot of influential papers in pre-hospital care. Most are retrospective reviews of practice that clearly represent good data governance over many years. It is an approach that should be commended and emulated by other services.
The abstract is below, but as we always say, please read the full paper yourself and make your own decisions.
What kind of paper is this?
This is a retrospective study based on contemporaneous records taken as part of a prehospital air ambulance service. Retrospective studies are always potentially open to bias and rely on the standards of data entry over the time period assessed. It is often impossible to know how reliable the data is and we must take it on trust that the data entry was of high quality throughout.
What did they look at?
The authors looked at over 20 years of data to identify which patients had a cricothyroidotomy performed, why they had it performed and what the outcomes were.
Tell me about the main results.
Even in a pre-hospital service where cricothyroidotomy is arguably more likely, the number of procedures is low. Just 72 patients out of 37725 patients in 20 years. That’s an incidence of 0.19% or roughly once every 500 missions, or 3-4 a year in a busy service. The take home from this is that within the team there will simply be too few opportunities to become ‘experts’ simply through clinical exposure. Training, review and simulation seem to be obvious requirements. It is also clear from the data that the incidence has fallen off in recent years, probably due to a change in practice and the increased use of supra-glottic devices in failed intubation protocols.
From a patient perspective it is clear that this is an extremely sick group of patients. In part that reflects the nature of the service as the air ambulance is only tasked to patients with major trauma/severe illness, but it also reflects the type of injury/illness the patient has suffered, the environmental circumstances they are found in, and the characteristics of the patients themselves (for example, roughly a quarter of cases were burns).
The authors have divided the patients into primary cricothyroidotomies where the procedure is done without attempting oro-tracheal intervention first and secondary cricothyroidotomies when performed after failed intubation attempts.
17 patients in who 15 were in cardiac arrest so a really sick group with indications such as access, trismus and burns.
The majority of patients in the study (55 patients). Difficult laryngoscopy was a common theme, often related to access difficulites, but there was also a high incidence of laryngeal injury, which of course makes intubation and cricothyroidotomy difficult.
It’s reassuring that despite this being a rare procedure under difficult circumstances, the success rate is high with only 2/72 failures, and 6/72 requiring more than one attempt.
For those patients undergoing prehospital anaesthesia the rate of cricothyroidotomy was roughly 1 in 200.
What about outcomes?
The data on procedural success is reassuring, but sadly the outcomes for the patients is not. Just 5 patients are known to have survived to hospital discharge (and we don’t know their functional status).
We must be mindful that this study was conducted in a specialist service which will have specific and likely more frequent preparation and training for the procedure and thus the real world experience in your (my) hands may be different. We should also be cautious that the data is from a very long time period during which practice has changed considerably.
This study tells us that cricothyroidotomy is a rare procedure and it can be successful in the vast majority of cases, Sadly the patient outcomes are very poor. It is a procedure that we should continue to train for, and the high success rate here should make us slightly less fearful of it (with the right preparation and training).
Shadman Aziz, Elizabeth Foster, David J Lockey, Michael D Christian Emergency scalpel cricothyroidotomy use in a prehospital trauma service: a 20-year review https://pubmed.ncbi.nlm.nih.gov/33597217/
Chris Gray, “#smaccAIRWAY – Airway Masterclass at #smaccDUB,” in St.Emlyn’s, June 28, 2016, https://www.stemlynsblog.org/smaccairway/.
Scott Weingart, MD FCCM. EMCrit Podcast 131 – Cricothyrotomy – Cut to Air: Emergency Surgical Airway. EMCrit Blog. Published on August 26, 2014. Accessed on March 6th 2021. Available at [https://emcrit.org/emcrit/surgical-airway/ ].