So I've been teaching my version of the scalpel-finger-bougie cric method for a few years now. I've used it on actual patient cricothyrotomies with great success. If you are not familiar with the way I teach, you can see a ton of the EMCrit cric resources here. One component of the technique that I'd been teaching is a secondary confirmation of intratracheal placement via obtaining hold-up with the bougie somewhere in the right bronchial tree. A set of comments brought up the possibility that with enough effort, a false hold-up could be obtained:
@ketaminh @emcrit @the_TOTAL_EM @cliffreid it is possible to unintentionally intubate the right atria when trying to cric, with min effort
— Jason Bowman (@texprehospital) July 4, 2016
Well, that sounds less than good. So first I wrote to EM anatomy guru, Andy Neill.
From the most recent Gray’s anatomy Textbook (the big bible at the mo)“The pretracheal layer of the deep cervical fascia is very thin. It provides fascial sheaths for the thyroid gland, larynx, pharynx, trachea, oesophagus and the infrahyoid strap muscles. Superiorly, it is attached to the hyoid bone; inferiorly, it continues into the superior mediastinum along the great vessels and merges with the fibrous pericardium;”and“The retrovisceral space [this would be if you got your bougie between post trachea and oesophagus] is continuous superiorly with the retropharyngeal space. It is situated between the posterior wall of the oesophagus and the prevertebral fascia. Inferiorly, the retrovisceral space extends into the superior mediastinum. Should the prevertebral fascia merge with the connective tissue on the posterior surface of the oesophagus – usually at the level of the fourth thoracic vertebra – the retrovisceral space then has a distinct inferior boundary.”The suggestion here is that there’s a fascial plane from the pretacheal fascial space to the sup mediastinum but closed at that point and you would have to penetrate the fibrous pericardium with bougie to access the pericardial space (which i suppose you could do if you were really enthusiastic with your bougie!). You’d have to push even harder to actually penetrate the heart itself. The retrovisceal space has a clear boundary at T4 posteriorly which is still above the heart and more importantly much more posterior.Bottom line the communicating fascial planes won’t get you further than the superior mediastinum as far as i can work out.Though if you sharpened your bougie to a fine a point or used a chest drain trocar then i’m sure you could make it to the heart 😉
TLDW: It is possible, in the hands of adrenalized novices, to get a false hold-up sign with the bougie during cricothyrotomy. I no longer recommend this secondary confirmation.
Minh, before you comment, this has nothing to do with the hold-up sign during orotracheal intubation.
Now on to the Wee…
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Scott Weingart
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Thanks Scott. Again we feel privileged to learn from those that have gifted their bodies to the Human Body Donation Program. They are prepared in a manner similar to what is used by Rich Levitan in Baltimore. We have modified the preparation over the years and the resultant clinical cadavers truly provide human tissue experience that is often indistinguishable from that of the living.
Regarding our findings I agree that this warrants caution regarding holdup. However I don’t think it should be avoided (sit down Minh). I think the message is that you can get false positive holdup although usually after abnormal resistive pressures are used. This can occur early even at 8cm (which may not be sensed in a catecholed state). Clicks will never be felt using a conventional bougie I will post endoscopy video of bougie entering via CTM).
We still will recommend a combined end point of framed finger (finger surrounded by rigid cartilage), finger/bougie glide, easy passage and hold up recognizing its pitfalls.
Thanks so much for addressing this topic, folks. Having taught bougie-aided cric in dozens of cadaver labs, the conclusion I’ve come to is that holdup in a false passage occurs at 15cm (at least in adults) the vast majority of the time. Therefore, I still use holdup, but if it occurs at <15cm, I'm especially wary that bougie may not be in the trachea, and I'm going to palpate again with my finger prior to placing a tube over the bougie. I like Dr. Kovacs' combined end-point above, although of course, since I get paid to be paranoid, even with all of those elements being affirmative, I'll still remain paranoid about false passage until I see those nice boxy waveforms on the capnograph.
Edit: what I meant to say is: the conclusion I’ve come to is that holdup in a false passage occurs at less than 15cm (when *not* trying to be uber-aggressive) the vast majority of the time, and holdup in a cric’d trachea occurs at greater than 15cm (at least in adults) the vast majority of the time.
Hi Scott
While these are different circumstances, it is an example of an airway adjunct (cook airway exchange catheter) being misplaced, contributing to arrest. The post mortem showed the catheter through the right middle lobe and in the chest wall. How much of each step contributed to the arrest (for example, oxygen through the catheter at 15 lpm wouldn’t have helped even if it was wedged in the RML without perforation), I don’t know, but to answer the question if this sort of thing is possible, this example shows that it is. Rare, but possible.
It was enough to change my practice whenever I use a bougie/airway catheter.
http://www.anzca.edu.au/documents/ewing-case-report-km.pdf. (The link to the full report doesn’t seem to be working at present)
All the best
Ryan
Disclaimer: Zero experience with this in the emergency situation.
BUT, I visited a US top tier Level 1 trauma centre recently as an observer and they have a skin hook in their ‘finger-scalpel-bougie’ packs to hook the anterior wall of the trachea inferior to the incision forward, much in the manner of using a laryngoscope. They say this gives good direct vision of the trachea and makes insertion much easier.
Comments?
Hey Scott,
If you no longer recommend hold up for secondary confirmation and primary confirmation occurs by feeling the bougie pass next to your finger after your finger has already confirmed you are in the cartilage cage, what’s the point of using the bougie at all. Why not use the Scalpel-finger-tube method as per the Paix & Griggs article?
https://emcrit.org/wp-content/uploads/2014/08/EMA-Scalpel-FInger-Bougie.pdf
You would still get the same tactile confirmation of the tube passing by your finger.
Anand
the ET tube and your finger will never be able to occupy the same space
what happens instead is a passing alongside (as one is removed, the other enters)
there is a point at which the tube can go where-ever it likes during that move and it will eventually go where you don’t want it to
the bougie can be placed inside the airway with your finger still there
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