(The BOUGIE Study)
Driver et al., JAMA. doi:10.1001/jama.2021.22002
Published online December 8, 2021.
Bougie versus stylet is one of the most heated debates in emergency airway management.
This study, newly published in JAMA, found that in 1102 critically ill patients the bougie and stylet yielded the same first-pass success rate during laryngoscopy:
Bougie first-pass success: 80.4% (447 patients)
Stylet first-pass success: 83.0% (453 patients)
The study’s secondary outcome, development of severe hypoxia, was also largely a wash:
Hypoxia in bougie group: 11% (58 patients)
Hypoxia in stylet group: 8.8% (46 patients)
This large, well done, multi-center RCT is an important addition to the literature, and is likely to slow the momentum that had been building toward the use of the bougie as the introducer of choice based on earlier evidence suggesting higher first pass success.
By finding that the bougie and stylet yield equal first-pass success, this study seems to suggest that providers may continue to use whichever introducer they regularly train with and feel most comfortable with, and that the previous pressure to switch to the bougie to enhance first-pass success may be unwarranted.
This study looked specifically at sick ED and ICU patients. While it did not look at prehospital patients, it seems reasonable that the findings of the study apply to intubations in the prehospital environment.
It should be noted that the overall first-pass success was 80-83%. Our goal must ultimately be to achieve higher first-pass success (e.g. above 90%).
The study had important limitations, including:
The trial looked only at first-pass success. It did not address the question of whether, if the first-pass has been unsuccessful, it is beneficial to switch to a different introducer. This is an important question.
Providers were not blinded to which device they were using.
Only adult patients were included.
The authors excluded some patients, which may have affected the results (see below).
Background. Optimizing first pass success in laryngoscopy is critically important, as multiple attempts at laryngoscopy are associated with risk of severe hypoxia and cardiac arrest. Historically, the rigid stylet was almost universally used when performing intubation, but more recently the bougie has gained considerable favor as the emerging first-pass introducer of choice. Multiple recent studies seem to suggest the bougie offers higher first-pass success (at least in the hands of an experienced operator) and several commentators in the FOAMed world have promoted the bougie as a more effective tool. Nonetheless, the stylet has retained its adherents. Many providers who strive for high first-pass success have “tried to love the bougie.” While some have found it effective, others have found it challenging to use and have returned to using a traditional stylet.
The Study. The BOUGIE Study looked at 1102 critically ill adults undergoing tracheal intubation in seven emergency departments and eight intensive care units in the US between April 2019, and February 2021. The primary outcome was successful intubation on the first attempt. The secondary outcome was severe hypoxemia, defined as SpO2 less than 80% during the time from induction until 2 minutes after intubation. Successful intubation on the first attempt occurred in 80.4% (447 patients) in the bougie group and in 83.0% (453 patients) in the stylet group. The odds of first pass success did not differ significantly in any of the prespecified subgroups, including among more experienced operators, among patients with difficult airway characteristics, or when a video laryngoscope was used. Severe hypoxia occurred in 11% (58 patients) of the bougie group, compared with 8.8% (46 patients) of the stylet group.
The study also had several interesting “exploratory outcomes.” These outcomes are NOT conclusions of the study as it was not designed to test these outcomes; rather, they are interesting findings that suggest areas for exploration in future research. The median time from induction to tracheal intubation was 124 seconds in the bougie group and 112 seconds in the stylet group. The incidence of airway complications, which included esophageal intubation, injury to airway structures, witnessed aspiration during intubation, and postintubation pneumothorax was not meaningfully different between the groups. Two final findings that are puzzling are a higher incidence of cardiovascular collapse (16.7% vs 12.2%) and of death by day 28 (33.7% vs 27.3%) in the stylet group. These findings are odd given that the stylet had a slight edge in the primary and secondary outcomes. The authors note that “the mechanism by which bougie [versus stylet] would influence these outcomes is unclear and these differences may be attributable to chance.”
It should be noted that the overall first-pass success was 80-83%. Our goal must ultimately be to achieve higher first-pass success (e.g. above 90%). In another often cited study on this topic, first-pass success by providers who had significant experience with the bougie was reported to be much higher, perhaps suggesting that factors other than choice of introducer are at work. In that study (doi:10.1001/jama.2018.6496), conducted in a single academic ED, the rate of successful intubation on the first laryngoscopy attempt was 98% in the bougie group and 87%
in the stylet group. The authors point out differing methodologies that may explain part of the discrepancy.
The study had important limitations, including:
Providers were not blinded to which device they were using. Obviously it would be impossible to blind the providers with regard to which device they were using, but it nonetheless carries the possibility of introducing some bias into the trial.
Only adult patients were included. It is unclear if the results are applicable to pediatric patients.
The trial looked only at first-pass success. It did not address the question of whether, once the first-pass has been unsuccessful, it is beneficial to switch to a different introducer. This is an important question. On the one hand, we often preach that you should “change something” on your second attempt. Providers who routinely start with the stylet will then switch to the bougie for their second attempt. Does that make sense, or should you stick with the tool you are most familiar with and perhaps change other characteristics of your approach (e.g. hyperangulated blade)? Or should a provider remain flexible in the choice of introducer for a second attempt, based on conditions appreciated during the first attempt?
The trial excluded patients in a way that may have biased the results. They excluded patients for whom the urgency of intubation precluded performance of trial procedures, patients intubated using a hyperangulated laryngoscope, and patients for whom use of a bougie was specifically indicated. The authors thus conclude that “the results of the trial may not apply to patients being intubated under specific urgent circumstances (eg, cardiac arrest), patients being intubated with a hyperangulated laryngoscope, or patients known to have abnormal airway anatomy.”
Conclusion. By finding that the bougie and stylet yield equal first-pass success, this study seems to suggest that choice of introducer is not a major factor in first pass success. For providers who train with a stylet and feel comfortable with it can continue to use it without being concerned they are sacrificing an opportunity to improve first pass success. For providers that have trained with the bougie and have achieved success with it, it continues to yield at least as good first pass success as the stylet, and potentially higher success in those who are highly proficient with it. While this study is an important addition to the literature in this area, it is almost certainly not the last word as this topic generates significant attention. Also, as noted above this study leaves unanswered other important questions, including whether to switch introducers for a second attempt and, perhaps most importantly, what steps can we take to increase our first-pass success above the 90 to 95% threshold.