Bougie is better (Driver 2018)

I love the bougie as a rescue technique for difficult airways, but many people use the bougie routinely on their first attempt. I discussed some previous retrospective data from this group in the March 2018 Articles of the Month. Now, they provide us with the best evidence to date, in the form of a RCT.

The paper

Driver BE, Prekker ME, Klein LR, et al. Effect of Use of a Bougie vs Endotracheal Tube and Stylet on First-Attempt Intubation Success Among Patients With Difficult Airways Undergoing Emergency Intubation: A Randomized Clinical Trial. JAMA. 2018; 319(21):2179-2189. PMID: 29800096

The Methods

This is a single-center, randomized, controlled trial.

Population: Any emergency department patient who was going to be intubated using a Macintosh blade (video or direct).

• Excluded: prisoners, pregnant patients, patients with known upper airway distortion.
• Emergency physicians, both senior residents and attending physicians, performed the intubation.

Intervention: Initial attempt at intubation using a bougie.

Comparison: Initial attempt at intubation using an endotracheal tube with stylet.

Outcome: The primary outcome was the rate of successful endotracheal intubation on the first attempt. (The primary outcome was specifically among patients with markers of a difficult airway. First pass success among all patients was a secondary outcome.)

• Other secondary outcomes: hypoxemia, first attempt duration, and esophageal intubation.

All aspects of the intubation aside from bougie vs endotracheal tube were left to the provider’s discretion. Timing of the intubation and success were determine by a trained research assistant who was watching the procedure.

The Results

757 patients were randomized, 380 of whom had a difficult airway characteristic.

Primary outcome: First pass success among patients with a difficult airway characteristic was 96% with the bougie and 82% with the endotracheal tube plus stylet (absolute difference of 14%, 95%CI 8-20%, NNT= 7, p<0.001).

The bougie first approach was also better in all comers (98% success vs 87%, ARR 11%, 95% CI 7-14%, p<0.001).

Complications were the same in both groups (17% vs 17%, p=0.83). Hypoxia occured in 13% with the bougie and 14% with the stylet (p=0.67). There was no extra trauma with the bougie.

There were 3 esophageal intubations with the endotracheal tube and stylet versus 0 with the bougie (p=0.08).

Unlike prior studies, the bougie group might actually have been intubated a little bit faster (if you look at the Kaplan-Meier curve). However, this is a little complicated, because other ways of measuring time to intubation showed no difference or that the bougie was a little slower. Basically, the shorter time was driven primarily by the higher rate of first pass success. If you look specifically at the subgroup of patients who were successful intubated on the first attempt, the bougie was statistically slower (38 vs 34 seconds, p<0.001), but I think 4 seconds is clearly clinically insignificant, especially when you consider all the other outcomes are actually better with the bougie.

My thoughts

Like any trial, there are a number of limitations here. The biggest limitation is that this is a single-center trial. The skill of the providers matters a lot in a study like this. The first pass success rates seen here are actually higher than other studies I have seen, but one could imagine that if your first pass success rate is already 98% without the bougie, it would be very difficult for a bougie to help. Most importantly, this group might be more skilled with the bougie than other groups, considering that outside the context of this trial, they use a bougie on the first attempt 80% of the time. (Driver 2017)

The providers weren’t (couldn’t be) blinded as to what device they were using. Provider preference could lead to cutting attempts short or persisting longer if the provider had a preexisting preference for or against a specific technique. Furthermore, there are a lot of moving parts in an intubation. The lack of blinding could have led to other unseen changes. For example, after seeing that they were assigned to the bougie group, providers might have positioned patients differently, chose different induction drugs, or altered other aspects of the intubation that would confound the results. That being said, all the factors listed in table 2 look very similar between the two groups.

The “difficult airway characteristics” were determined by the provider, and recorded after the intubation attempt. Whether something is a difficult airway characteristic was therefore probably influenced by whether or not the intubation attempt was successful. Subjectively defining the patient population in this way could affect the result, but any bias is likely mitigated by the fact that the bougie was also better in the larger population.

There were a number of protocol violations, and the number differed between the two groups. 8% of the intubations that were supposed to be done with a stylet were actually done with a bougie, as compared to 2% of intubations randomized to a bougie being performed with an endotracheal tube. This could indicate a bias towards the boogie, and may have introduced selection bias.

Prior observational studies have indicated that time to intubation is longer with the bougie, but the opposite effect was seen here. (Driver 2017) It is possible that in the prior observational research the bougie was selected in more difficult patients, leading to longer times to intubation.

Although it may bother some people in the FOAM world who love to pre-load their bougie, the technique studied here, and therefore the technique with the best evidence base, is the classic technique: intubate with just the bougie, and then load the endotracheal tube over the bougie after it is through the cords.

Personally, I think this will change by practice. To date, I have only been using the bougie as a rescue technique, or in patients with a predicted difficult airway. This is the best study we have to day, and based on the clear benefit to using the bougie demonstrated here, I will likely start routinely intubating with a bougie on the first attempt.

Bottom line

This is the best study we have to date examining this issue, and the outcomes were clearly better with the bougie, but we should be cautious when applying the results, as it is a single-center study, and the degree to which providers are trained and comfortable with a bougie could significantly impact the generalizability of these results.

Other FOAMed

EM Nerd -The Peculiar Case of the Parallel Pathways

EMCrit episode 226: Bougie and Positioning

REBEL EM: Bougie use in Emergency Airway Management (BEAM)

St. Emlyn’s: JC: Don’t blame it on the Bougie. St Emlyn’s

Also relevant: The Airway Series

• Part 1: Optimizing the basics
• Part 2: Is this patient ready for intubation?
• Part 3: Intubation
• Part 4: Cricothyroidotomy
• Part 5: Post intubation care

References

Driver B, Dodd K, Klein LR. The Bougie and First-Pass Success in the Emergency Department. Annals of emergency medicine. 2017; 70(4):473-478.e1. PMID: 2860126