Many years ago I did my CTR (the Clinical Topic Review*) for my FCEM exam on facilitating intubation in the C-spine immobilised patient. The actual CTR is lost in the mists of time, but the BestBet still exists 1 and you can read that back in 2001 the evidence was weak, but I thought there was sufficient evidence to recommend that we use it routinely in the ED. Since then the use of a gum elastic bougie (Ed – which is neither gum, nor elastic, nor a bougie) has been recommended as standard practice by many services such as Sydney HEMS and others. We aim for a philosophy of maximising the chances of first pass success and so our argument has always been that you should use all the tools available for your first attempt at intubation. Since our belief is that the bougie is best, then that’s what we have advocated in Virchester.
However, there is still some skepticism around the use of the bougie. Some of my anaesthetic colleagues believe that the routine use of a bougie is just another way of saying that you’re crap at intubation. I think that’s harsh, but perhaps there may be some truth in the fact that if your laryngoscopy is poor, then you will need to use more adjunct devices in order to intubate. UK Anaesthetists are very good at laryngocopy (UK anaesthetic training is fantastic IMHO) and so I suspect (I don’t have the data to hand) that they probably get better views, but times are changing for them too. The increased use of Video Laryngoscopy means that I am seeing my anaesthstic colleagues routinely asking for the bougie on a much more frequent basis than ever before. OK, before I open that Pandora’s box any further lets get to this week’s paper on the use of bougies in the ED. At first glance and on twitter I thought that this was the paper to definitively answer my questions about the use of bougies in the ED (spoiler alert it’s not).
You can find the paper here 2 and if you click on the the title below it will take you to the paper. As always we strongly recommend you read the full paper before you make up your own mind on the quality of the evidence.
What kind of paper is this?
It’s an RCT which is excellent as that’s the type of design that we want to see when we are comparing different interventions. Patients were block randomised between bougie vs. stylet and in stratified blocks to ensure that roughly equal number of patients with c-spine immobilisation and obesity were in both groups.
Tell me about the patients.
This is where I started to get a little less enthusiastic about the study. This paper is set in a single emergency department in the US where ED clinicians perform all the intubations. That’s a little different from my own practice where there are a mix of intubators. It’s also a single US centre. Single centre studies are often difficult to reproduce, and the US is rather different to jolly old England. We need to be mindful of the fact that this may represent quite a different population of patients and clinicians.
In terms of numbers then this is a pretty small study. Just 757 patients were enrolled in the trial with roughly 50:50 allocated to bougie or tube plus stylet. Hang on you might say! 757 patients is a lot, and it is really. However, we need to consider not just the number, but also the incidence of potentially difficult airways in the ED (those in whom a bougie might really make a difference). The authors quote a figure of 60% incidence of difficulty 2,3, but that seems high to me as compared to UK experience.
What did they actually do?
Interestingly the comparison was between the use of a bougie and that of an ETT plus stylet. Personally I’m not a big fan of stylets, there is no particualar reason why not, I just never really trained with them and have not found an advantage over a bougie. The comparison is interesting though. In our practice the ED docs are traines to always use a bougie, but many anaesthetists prefer a plain tube (no bougie) and so the comparison in this paper is perhaps different to the comparison that would take place in a UK ED. I would suggest that intubation with a stylet is probably more successful than a plain tube and so perhaps any findings in this study would be magnified in a bougie vs. plain analysis (but that’s a guess, I don’t really know for sure).
Clinicians could use the laryngoscope of their choice, and that was largely either a CMAC or a Glidescope. The use of Direct Laryngoscopy (which is what we usually use in Virchester) was low.
What are the main results?
The primary outcome was first pass success and in this regard the bougie performed much better with 96% of patients intubated first time with the bougie as compared to 82% with the stylet. That’s an absolute difference of 14% and thus a number needed to treat of 7 which would be remarkable. Secondary outcomes are a little less definitive. There is some suggestion that the bougie was even more helpful in those patients with predicted difficulty such as c-spine immobilisation. Many of the secondary analyses were not planned and as such we need to treat them with some caution (although my inherent bias is that I agree with the findings!). They saw only small differences in other outcomes such as hypoxia (no real difference) and oesophageal intubation (a non significant difference).
We’ve already spoken about this being a US single centre study. That matters as it’s likely to be very different, but we should also look at the intubators. The vast majority were junior ED docs and that might be a factor in the results. In the UK, if I ask for anaesthetic support I get a really well trained and typically excellent and well experienced senior trainee or consultant. In the ED not all of our team in Virchester have advanced airway skills, but those of us who do are frequently critical care consultants (or who have had additional crit care/anaes experience). They are not typical of the intubators in this study and thus I really don’t think we can generalise that well to a UK population. I think it’s also important to note that most intubations were done with the CMAC blade as opposed to direct laryngoscopy. We don’t have a CMAC, but do have access to a McGrath in ED. My limited experience with VL suggests that you are more likely to want to use a bougie with VL and thus this too might lead to bias. Indeed the practice before the trial was for intubators to use VL with a bougie (and thus they were probably more experienced at it).
Obviously there was no opportunity to mask clinicians to the technique used and that may have introduced bias into the results.
So what does this mean?
It’s tricky to get this into perspective. We should always be cautious of trials that back up our strongly held a-priori beliefs as this one does for me. The results seem to reinforce my practice that has been in place for the last 17 years, but in truth this study is not really the same as what we do in Virchester. Although I pretty much always use a bougie and I always teach to use a bougie for ED intubations, I do it in conjunction with a Macintosh or McCoy blade.
Reluctantly then I cannot say that this study is definitive for my practice, as it’s a little difficult to translate to the UK. However, there are some useful learning points and as we see a trend to an increased use of VL in the ED (our anaesthetists usually ask for the McGrath these days) then I see some future learning and reinforcement of practice. Additionally there is no evidence here for the bougie being a bad technique and recent debates on twitter identified that the complication from bougie use is incredibly low (though not zero). For my EM docs it reinforces my inherent bias that we should be using bougies in nearly all intubations in the ED.
Start the twittersphere.
Any mention of airways and intubation techniques seems to create a tsunami of opinion and in some cases outright venom in the twittersphere. We need to be better than that. This paper is just one part of the debate and in advance of any nasty comments I will reinforce my view that you can’t turn someone into a great airway doc simply by giving them a bendy stick. It’s a lot more complicated than that and you really should be acting within your competencies before messing about with anyone’s airway.
You can also read more about this paper on the excellent EMCRIT blog 4.
— the EMCrit Crew (@emcrit) May 18, 2018
The bottom line.
If you’re an ED doc then don’t blame it on the bougie, it’s (probably) your friend and facilitator of first pass success.
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*The CTR has now been (very unwisely IMHO) replaced by the QIP (Quality Improvement Project5).