A 2021 randomized trial reported that successful intubation on the first attempt was 80.4% with use of a bougie and 83.0% with use of an endotracheal tube with stylet, a difference that was not statistically significant.
In this video, Jonathan D. Casey, MD, of Vanderbilt University Medical Center in Nashville, Tennessee, Stacy A. Trent, MD, of the University of Colorado School of Medicine in Aurora, and Brian E. Driver, MD, of Hennepin County Medical Center in Minneapolis, Minnesota, present findings from the BOUGIE Trial at a Critical Care Reviews livestream presentation (CCR20) on December 8, 2021.
An oral editorial from Sheila N. Myatra, MD, of Tata Memorial Hospital in Mumbai, India; a BOUGIE Team reply to the oral editorial; a Q&A session; and a panel discussion follow.
Click the Related Article link for full trial details.
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This transcript is auto generated and unedited.
Hey, thanks Rob. Thanks for having us and for inviting us. Again, I'm Jonathan Casey and I am a pulmonary critical care specialist at Vanderbilt University Medical Center. And today, we're going to tell you the results of the bougie or stylet in patients undergoing intubation emergently, the bougie trial, which was conducted by the Pragmatic Critical Care Research Group. We have no disclosures or conflicts of interest relevant to this talk. So, why are we talking about emergency airway management? Well, it's extremely common, in the US alone, 1.6 million patients are intubated each year, and despite the frequency of the procedure, complications occur frequently. Severe hypoxemia occurs in 25% of patients, cardiovascular collapse occurs in 20%, and cardiac arrest occurs in 4% of ICU intubations. Further failure to intubate on the first attempt occurs in up to 20% of intubations in the ED and ICU, is associated with these severe complications.
Further, the manner in which emergency airway management is conducted varies significantly between different providers, different specialties and different regions. Shown here are two of the devices commonly used to facilitate tracheal intubation. On the left is the bougie device, and on the right is an endotracheal tube with stylet. When performing intubation with an endotracheal tube with stylet, a malleable metal rod is placed inside endotracheal tube. The endotracheal tube with stylet is then placed into the airway with the stylet being removed after tube placement. When performing intubation with a bougie, this long thin plastic rod is placed directly into the trachea, and the endotracheal tube is then passed over the bougie, and then the bougie is then removed, the so-called Seldinger technique. Historically, most emergency tracheal intubations in the United States have been performed using an endotracheal tube with stylet, and the bougie has been reserved for cases of anticipated difficulty, or following a first attempt failure. As evidence of this in a large registry of intubations performed in U.S. emergency departments, the use of a bougie on the first attempt was reported only 3% of intubations.
However, several recent observational studies have suggested that routine use of a bougie in the first attempt might increase the incidence of a successful intubation. Only one prior trial is compared use of a bougie and a stylet during emergency tracheal intubation. This trial was the bougie use in emergency airway management, the BEAM trial. The BEAM trial was conducted by Brian Driver and Matthew Prekker, shown here at right. It was a single center trial conducted the Hennepin County Medical Center emergency department from 2016 to 2017. It randomized patients to use of a bougie, or use of a stylet on the first attempt at intubation. The primary outcome was intubation on the first attempt, and data was collected by an independent observer.
The BEAM trial randomized 757 patients, of whom 380 had difficult airway characteristics. Shown at bottom left is the primary outcome of the trial, in which bougie increased intubation of the first attempt, which occurred in 98% of patients in the bougie arm and 87% in stylet arm. A difference that was significant with a P value less than 0.001. This relationship was similar among those with difficult airway characteristics. Shown at right is the Kaplan-Meier curve of time to successful intubation. The bougie group shown in yellow and the intertracheal tube with stylet group is shown in blue. And the Y axis is the percent of patient successfully intubated, on the X axis its time. As you can see in the BEAM trial, not only was bougie use associated with an increase in successful intubation on the first attempt, it was also shown associated with a shorter duration of intubation, with the P value of 0.02.
So, why is a multi-center validation trial needed? The results of the BEAM trial have already been incorporated into expert opinions and many national guidelines. However, the concerns have been raised regarding the generalizability of being. In addition to being a single center trial, the trial was conducted in a setting where providers were used to routinely using bougie on their first attempt and had less familiarity with intertracheal tube with stylet. Therefore, the pragmatic critical care research group partnered with the leads of the BEAM trial, Brian Driver and Matt Prekker, to plan this follow up validation study.
The Pragmatic Critical Care Research Group is a clinical trial network based in the U.S. It enrolls patients in the EDs and ICUs of 19 medical centers. And the network is composed of investigators who represent all the specialties that perform emergency airway management, including emergency medicine, anesthesiology, and critical care. And the network specializes in pragmatic trials comparing the effectiveness of common emergency interventions like, use of a bougie and use of a stylet. And I want to thank Rob, for inviting us to present results today, and I'm going to turn it over to Stacy Trent from Denver Health, to go through the methods of the trial.
Thank you, Jon. As he said, my name is Stacy Trent, and I'm an emergency physician at Denver Health Medical Center in Denver, Colorado. And I'm going to discuss the methods we used for the bougie trial. The bougie trial was designed as a multicenter randomized pragmatic trial comparing two standard approaches to tracheal intubation. Either the bougie or the endotracheal tube or stylet. The study was performed in 15 sites in the United States, including seven emergency departments and eight intensive care units. Patients were included, if they were undergoing an emergent intubation in a participating unit of an adult hospital. They had to be medically sedated or unconscious during the intubation, and the intubator had to be using a non-hyperangulated laryngoscope blade on first attempt. Either direct or video laryngoscopes were allowed, but the blade could not be hyperangulated.
Because this study was performed under a waiver of informed consent, our exclusions primarily focused on situations, where there was a lack of equipoise is in relation to either approach. If an intubating provider felt that either a bougie or a stylet was required or conversely contraindicated, then the patient was excluded. Additionally, if the providers felt that the intubation was too emergent to perform the randomization procedures, then the patient was excluded.
Providers were blinded to group allocation, prior to randomization. If a patient was eligible for the study, the intubator was asked to choose their laryngoscope before randomization, to prevent group allocation from modifying the type of laryngoscope used. Patients were then randomized one to one and stratified blocks. But once the randomization envelope was opened, providers were no longer blinded to group allocation. Data collection occurred in three steps. First during intubation, a trained independent observer collected data on vital signs, as well as the number of attempts at intubation. Immediately after intubation, the intubator documented the characteristics of the intubation, as well as their prior experience with intubation, as well as with use of the bougie. And lastly, research personnel collected data on clinical outcomes, as they became available during hospitalization or at time of discharge.
Our primary outcome was successful intubation on first attempt. In an intubation where a stylet was used first, this meant that the laryngoscope blade entered the mouth once, followed by a single insertion of an endotracheal tube loaded with a stylet. If an intubation occurred with the bougie first, this similarly meant that the laryngoscope blade entered the mouth once, followed by a single insertion of a bougie, and a single insertion of an endotracheal tube over that bougie. Our sole pre-specified secondary outcome, was incidents of severe hypoxemia, defined as an oxygen saturation, less than 80% between time of induction, and two minutes after intubation.
This study was powered to find a 6% absolute difference between the bougie and stylet groups. Assuming an 84% first attempt success in the stylet group. Using these assumptions, we calculated that we would need 1050 patients to find the 6% absolute difference. And we plan to enroll just over 1100 patients to account for potential missing data. We performed an intention to treat analysis for the primary outcome, and calculated an absolute risk difference between the two approaches. In addition, we analyzed the primary outcome using a generalized linear mixed effect model, to account for correlation within study sites and to adjust for potential confounders between groups. I'm going to pass it over to Dr. Brian Driver, the lead author on this study from Hennepin County Medical Center, will present our results.
Thank you, Stacy. As Stacy mentioned, my name is Brian Driver. I'm one of the lead investigators for the bougie trial, which commenced in April 2019 and concluded in February 2021. There was a pause between March and August 2020, due to the COVID 19 pandemic. In this trial, we screened 1,558 patients in the 15 participating units. We excluded 81 patients most commonly, with 77 patients being excluded because the operator preferred to use a hyperangulated laryngoscope. We additionally excluded 371 patients, most of whom were excluded because they met one or more exclusion criterion, 282 underwent intubation, two urgently to complete trial procedures. And of note 29 patients were excluded because the operator preferred to use a bougie or stylet. This left a randomized cohort of 1,106 patients. After we excluded two patients in each group, because they were discovered to be prisoners after enrollment, this left 556 patients in the bougie group and 546 patients in the stylet group.
This table shows some patient characteristics for both groups. The median age was similar in both groups at 58 years. The body mass index was again similar between groups 26 and 27. You can see the indications for intubation shown there. A little bit more than 60% of intubations occurred in the emergency department, with the remainder occurring in the intensive care unit. And slightly more than 40% of patients had one or more difficult airway characteristics, which included obesity, cervical immobilization, body fluids in the mouth, which obscured the glottic view and facial trauma. Because the effect of the bougie or stylet might depend on the operator or details of the intubation procedure, we collected detailed data on these, and some key variables are shown here.
So, the median number of prior intubations for operators in the trial was 60 in both groups. And the median number of prior intubations using a bougie was 10. As you can see, a little bit more than 60% of patients in both groups were intubated by a resident physician, with most of the remainder being intubated by a fellow physician. The vast majority of patients received both a sedative and neuromuscular blocking agent before intubation, and a Macintosh shaped video laryngoscope was used in about three quarters of patients in both groups, with most of the remainder on being intubated with direct laryngoscope.
Shown here is the receipt of the trial interventions, showing high protocol compliance in both groups. 98.6% of patients in the bougie group received a bougie on the first attempt, and 97.3% of patients in the stylet group received a stylet on the first attempt. Crossovers were uncommon, and there were eight patients received neither device in the first attempt, and were intubated on second or subsequent attempts.
So, in this trial that lasted about two years, enrolled a little over 1100 patients, with a primary outcome of successful intubation on the first attempt, defined as a single insertion of the blade, and single insertion of the device, the primary outcome occurred in 447 patients in the bougie group, which is 80.4%, and 453 patients in the skylight group, which is 83.0%. This corresponds to an absolute risk difference of minus 2.6%, with a 95% confidence interval that spans zero, and a non-significant P value. And a secondary analysis of the primary outcome, which accounted for study site and pre-specified baseline co-variants, the adjusted odds ratio for success with the bougie compared to the stylet was 0.88, with a 95% confidence interval that spanned one.
Now, because the bougie might not be more successful in all patients, but might be more successful in certain subgroups, we perform this pre-specified subgroup analysis, taking into account intubation location, diagnosis of trauma, direct versus video laryngoscope, grade of glottic view, the presence of difficult airway characteristics, and the operator's prior intubation experience dichotomized at the median value of 60. The force plot shows point estimates for the odds ratio with the line, demonstrating the 95% confidence interval. Values to the left of the line favors stylet and values to the right of line favor bougie. As you can see, there was no subgroup with a significant difference between groups.
This graph shows more detail on operator experience and intubation success. So, the Y and X shows successful intubation on the first attempt, which is the primary outcome. The X axis shows the operators total prior intubation experience, with the histogram showing the number of trial intubations at that level of intubator experience. As you can see, the bougie and stylet were not significantly different for operators with little intubation experience, or for operators with more substantial intubation experience. This graph is similar with the same Y axis of the primary outcome, but the X axis instead now shows the operator's prior number of bougie intubations. Again, the histogram shows the number of trial intubations at that experience level, and there was no difference between bougie or stylet with limited bougie experience, or more substantial bougie experience. Although, as you can see, most trial enrollments occurred for operators with limited bougie experience.
We collected data on other secondary and exploratory outcomes. The pre-specified secondary outcome of severe hypoxemia, occurred in 11% of patients in the bougie group and 8.8% of patients in the stylet group, with a 95% confidence of all that crossed zero. We also collected safety outcomes, which is especially relevant, because it is thought by some, that the bougie frequently causes mechanical injury to the upper airway and trachea. We noted 1.8% of patients in each group to sustain an intubation complication. Notably there were zero patients in the bougie group who suffered injury to the oral, glottic or thoracic structures. There was a new pneumothorax present within 48 hours in 2.5% of patients in the bougie group, and 2.7% of patients in the stylet group. So, these results run slightly contrary to the notion that the bougie frequently causes trauma. Although, it should be noted that these outcomes were not adequately powered.
The bougie is a two step process, compared to the intertracheal tube and stylet, which is a one step process. So, we measure the time between induction and successful tube placement. The median value for the stylet group was 112. The median value for bougie was 124 seconds. With a difference of 12 seconds, that was statistically significant, which is similar to previously published work. The clinical significance of this is unclear, especially as outcomes did not differ. Finally, here are some data that show more patient centered outcomes. Looking at cardiovascular collapse within one hour, and death before 28 days, there is a slight difference between groups that is statistically significant in favoring bougie. However, we believe these differences are most likely to be attributable to chance, as similar first attempt success should not lead to differential outcomes.
So in summary, we conducted a 1,102 patient trial, with very high protocol compliance and rigorous methods. In this trial, use of the bougie did not result in higher first attempt success compared to the tube and stylet. This trial has some great strengths, including its multicenter conduct, high quality randomization concealment, collection of trial endpoints by independent observers, and high rates of protocol compliance with no loss to follow up for the primary outcome. There's some important limitations. We did exclude some urgent intubation procedures, and we excluded 29 patients for whom the operator deemed the bougie or stylet to be specifically indicated. Although, this number of patients is small and is unlikely to substantially alter the trial results. Also, many operators had limited prior bougie experience, and some operators had limited prior intubation experience. So, the results of the trial will not generalize to all operators. And we started only the first attempt. So, these data do not inform management after failed first attempts.
So, thinking about how to best put these results in context and accurately interpret them. I think, it's worthwhile to compare the BEAM trial to the bougie trial. So, me and my colleagues at Hennepin County led the BEAM trial and published it in 2018. And just to give a little background on what our single center is like at Hennepin, it's a little unique, and that it's an emergency department where all intubations are performed just by emergency physicians. And the third year residents are maybe 99% of the time performing intubation rather than a first year, second year resident or an attending. And another thing that's a little bit unique about Hennepin is that for the past 20 years, bougie use has been pretty routine, occurring in more than 80% of first attempts, and some data we published several years ago. So, it's a unique center where residents have limited intubation experience for the first two years, then intubate a lot and most commonly intubate with the bougie.
So, here is some key trial characteristics between the two studies, and we can see how they're similar and how they're different. So, obviously BEAM occurred in one ED, the bougie trial occurred in 15 centers. As I noted in the BEAM trial, bougie use is very common, whereas in the bougie trial, 14 or 15 sites either rarely or sometimes use a bougie, on the first attempt before the trial began. Prior intubating experience was modest in both trials, with about 20 intubation procedures in BEAM, and 60 intubation procedures in bougie, with most operators being residents or fellows. The number of unique operators was 51 in BEAM, and 322 in bougie. And I think, a key difference is a number of enrollments per operator, which was eight in BEAM, and just one in bougie, meaning that for half of all patients enrolled in bougie, the operator intubated just one time and didn't contribute to further enrollments.
The indication of altered mental status was similar between trials. Video laryngoscope use was 99% in BEAM and 75% in bougie. One or more difficult airway characteristics was slightly higher in BEAM, and an incomplete glottic view is slightly more prevalent in bougie. There's one other key difference between the trials is that, the primary outcome in BEAM was really just considered laryngoscope blade insertion, and you could insert the tube or bougie more than once, and still have it count as first attempt success. Whereas, in bougie, we refined this and added that the attempt was only going to be considered successful, if the bougie or stylet was also inserted just a single time.
This was meant to capture the highest quality intubation, with the lowest chance of complications occurring. But we want to make an apples to apples comparison. So, looking at the primary outcomes for these two trials, when you use the BEAM definition, which considers just blade insertions, and that's shown here in this table, and BEAM 97.9 with bougie compared to 87.2 with a stylet, and 87.6 with a bougie, and 88.6 with a stylet. So, that's the apples to apples comparison, showing a big difference in BEAM, but not much difference in bougie.
And so, with all these thoughts in mind and differences in trial in mind, how can we best explain the difference between the two trials? And while the patients were slightly different, we included ICU patients in this trial, and they have a little bit higher rate of acute respiratory failure. I don't think there's a strong signal in the data to suggest that the difference in patients, drove the difference in trial results. Especially, because there was no signal of benefit in any patient subgroup. The operators in both trials were trainees being supervised. They both had modest intubation experience. The only key difference really being that in BEAM, they got to contribute more intubations and perhaps learn over time. Whereas in bougie, at least half of the intubations occurred for an operator who intubated just one patient in the trial, and didn't have the opportunity to learn as much.
And obviously I think, the biggest difference between the trials is the intubation system or context. At Hennepin bougie use was present for decades. The respiratory therapists, physicians, residents kind of have this baked in culture to use the bougie. Whereas, in the bougie trial, most centers did not routinely use it, and could not be as familiar with the bougie as if they used it more routinely. What did we learn here? And I think, one thing we definitely learned is that if you hand someone a bougie, who normally uses a tube and stylet, you're unlikely to improve first attempt success. At least over the time period, a number of attempts studied in this trial.
I think, it's still unknown what happens if somebody like an individual intubator, or a system starts using a uniform bougie first approach, and whether that can improve first attempt success or not. And I think, that's an area for future study. So, in conclusion, among critically ill adults, undergoing tracheal intubation, use of a bougie did not significantly increase the incidence of successful intubation on the first attempt, compared with use of endotracheal tube in stylet. And I'm pleased to report that this manuscript was accepted in JAMA and is available online today. And I really want to thank all of my co-investigators and collaborators. This was an unfunded study, a labor of love, and I really appreciate all of their hard work, and all the credit goes to all the hard work they put into this trial. So, thank you. Thank you to Rob for hosting us in Critical Care Reviews.
Brian, thank you very much. Many congratulations to you, Jon, Stacy, and of course, Matt. A fantastic achievement and...
Matt, a fantastic, fantastic achievement. And I have to say a little bit unexpected. We ran a poll earlier today on Twitter. Small numbers, but about 70% of respondents expected operators using a Bougie to have superior outcomes. So a little bit unexpected. I certainly primarily use a Bougie. Okay. We will cross now to Mumbai and to Sheila Myatra for an editorial. It is well after 1:00 AM in India. So Sheila, thank you so much for staying up to join us for this, and for preparing this editorial. Over to you.
Thank you very much. I'm going to be presenting the editorial for the Bougie trial. First of all, I'd like to congratulate Brian Driver and the entire team. Jonathan Casey and Matt Sumler and Stacy Trent, and the entire team for the publication in JAMA. And I'd like to thank Rob Sweeney and Critical Care Reviews for giving me this opportunity to present this editorial. At the outset I'd like to say that I do not have any conflict of interest for this trial. I'm going to give you my perspective, and my editorial will cover a bit of the background related to this trial to put this in perspective, my comments on the methods, results, and also the implications for practice and where trials in future direction will take us. So just to give you some background, if you look at the major studies that have looked at complications of tracheal intubation in critically ill patients, and these are series which are either national series or single center studies, the complications with airway managed tracheal intubation in critically ill patients are much higher in critically ill patients as compared to in the intensive care unit.
And this is well-known, and you are all aware of the INTUBE study that's just published in JAMA. And I was very fortunate to be working with Vincenzo Russotto and Jacomo Balani in this trial. And this trial looked at was published in March, 2021. This looked at intubation practices and adverse intubation events in critically ill patients from 29 studies. So it was a prospective study that looked at global real world practices. And what were the key findings? In this study that looked at close to 3000 patients from 197 sites in almost 29 countries, they found a very high frequency of and related adverse events. Cardiovascular instability was the highest among the complications, followed by severe hypoxemia and cardiac arrest. And it was one of the first studies that showed a mortality difference in patients who had peri-intubation adverse effects events.
And they suggested that future trials should focus on interventions to limit complications. Definitely one of them is to limit intubation attempts. And here you can see that cardiovascular stability was the highest among all the complications, followed by severe hypoxemia and other complications. Now, one of the findings of the INTUBE study was that patients, if you compare the number of attempts, first attempts, second versus third attempts, even between the first and second attempt, there was a difference and repeated intubation attempts were associated with severe hypoxemia and cardiac arrest. And these resulted in worse outcomes. So definitely we know that the complication rates are high and these are associated with worse outcomes. So we do need to improve our first attempt intubation success. And why are these differences seen in between patients who are critically ill and non critically ill in the operating room?
In my mind, there are three fundamental differences. One is related to the environmental factors in the ICU, in the emergency department, complex environment, not controlled conditions. Second is the operator factors that has already been alluded to. Various levels of skills, not skilled anesthesiologists who are routinely doing all the intubations and are highly trained. And the third most important are the patient related factors. Now patients who are critically ill have what we call the physiologically difficult airway, and in addition to this, they might also have an anatomically difficult airway that might make tracheal intubation difficult. Now, in addition to the airway management itself, where we are worried about the anatomy, they often have an imbalance between oxygen consumption and delivery for various reasons, as you are aware, and this physiologically difficult airway can increase the risk of complications during tracheal intubation in the intensive care unit.
So if you look at the routine procedure of tracheal intubation that we follow, these patients who are critically ill, because of their critical illness and the presence of hypoxia, hypertension, right ventricular failure, perhaps metabolic acidoses and various other condition. These increase the risk of complications during tracheal intubation in the intensive care unit. So they have what we call a physiologically difficult airway, which increases the risk of hypoxia, hypertension, and other complications which increases the morbidity and mortality. And in addition to this, if they also have an anatomically difficult airway, this can further increase the risk of complications. This is why aiming to have a first pass intubation success becomes extremely important in these patients as compared to those in the operating room. The BEAM study has already been alluded to, and this came from Brian Driver's group, where they looked at the effect of the Bougie versus endotracheal tube and stylet on first attempt intubation success among patients with difficult airways undergoing emergency intubation.
So this was the first randomized control trial that was comparing the two groups. And if you look at the primary endpoint where they looked at patients which had at least one difficult intubation characteristics, it was significantly better for patients who were intubated using the Bougie at first attempt, as compared to patients with endotracheal tube and stylet. And you can see quite a high first pass intubation success in this group. And has already been discussed, this was a single center study, and it looked at only patients in the emergency department, but what was most important was this was a group that was highly skilled and experienced with the use of Bougie and did not have much experience with the use of a stylet. So we had this trial that was already there that showed that Bougie was better, but of course there were these limitations. So we were not sure as to which one was better to use to improve first pass success.
And then we have the STYLETO trial that was recently published from the group of Samir Jaber, and they looked at the effect of the use of endotracheal tube and stylet versus the endotracheal tube on first pass intubation success. And this was a randomized control trial of close to a thousand patients. And this only looked at patients in whom direct laryngoscopy was performed. They didn't look at videolaryngoscopy. And the interesting finding was that in patients in whom they use a tracheal tube and stylet upfront, versus not using, just doing a routine intubation, there was a significant difference, a superiority with the use of a tracheal tube and stylet in the first pass success. 78% versus 71% without any difference in complications.
So where does that really leave us? So it left us with many unanswered questions. For me as a person who's intubating patients in the ICU, I look at INTUBE study and it definitely showed us that repeated attempts at intubation are associated with severe hypoxia, cardiac arrest, and can increase morbidity and mortality. The BEAM study showed us that the use of Bougie compared with endotracheal tube and stylet results in significantly higher first attempt intubation success among patients undergoing emergency tracheal intubation. But again, as already been spoken, this was from a very experienced group, single center study performed only in the emergency department. So it didn't give us the generalizability of the study was really questionable. So it didn't give us different answers. And then we have the STYLETO study that has shown us that the systematic or routine use of a stylet for tracheal intubation in critically ill patients results in significantly high first attempt intubation success.
So this is what we already know, and what we really didn't know was would it be a Bougie or a stylet that would increase incidents of successful intubation on first attempt? And I think this is what the Bougie trial has helped us answer. And this was a very important question to be answered in the clinical setting, that in critically ill patients undergo tracheal intubation, does the use of Bougie increase the incidence of successful intubation on first attempt compared to the use of a tracheal tube with the stylet? And you've already listened to the results that were presented by Brian Driver. Close to 1100 patients, critically ill patients and successful first intubation success was 80% versus 83%. And there was no difference, and there was no statistical significance in the results of this study.
Now, when I look at the two trials, the Bougie trial and the BEAM trial, both of them compare the use of the first pass intubation success using either the endotracheal tube with a stylet or using the Bougie. But as already been discussed, this was a multicenter trial, the Bougie trial, whereas BEAM was a single center trial. Emergency department patients only used, whereas here it was all critically ill patients, emergency department and ICU. And I think what is most important is that in the BEAM trial, it was very experienced operators with the use of Bougie. Whereas in the Bougie trial, you had a mixed group of experienced, inexperienced people who had done... Not only with intubations, but also with the use of Bougie. And I think this is what really made the difference between the two studies. Now, when I look at the methods of the study, and I must say, I must congratulate the authors for the very robust trial that was done, multicenter parallel group, very pragmatic, randomized control trial.
One thing that surprised me was this trial was approved with waiver of informed consent. And that was a little surprising to me because if you look at Bougie and using a stylet, this is not a standard of care and it was not used in all the centers as routine practice. So I was a little surprised that there was a waiver of informed consent, and not only that there was no deferred consent taken. So this was a little surprising to me. The trial sites, it was a multicentered trial and definitely a mixed population. So more generalizability of the results, very good randomization methods. And what I like most is the trial interventions. It was very pragmatic because the trial group only assigned determined whether the Bougie or a tracheal tube with the stylet was used during first attempt at intubation. Whereas all other aspects of the procedure were deferred to the operator. So indeed a very pragmatic trial to follow. The data collection, the way they handled the missing data was all very well done, and the sample size calculations.
Coming to the outcomes. Now, this is very interesting, the primary outcome. Now, most of the time when we talk about first attempt, what do we mean by first attempt intubation success? We mean putting a laryngoscope blade in and out is usually concerned as one attempt. Irrespective of the number of times the tube or a Bougie or a stylet is put in or out. So what this group did is they looked at successful intubation on attempt and define it as a single insertion of not only the laryngoscope blade in the mouth, and either a single insertion of Bougie into the mouth. So not only the insertion of the blade, but also the insertion of the tube or the stylet. So I think this was a more rigorous method that they used. The secondary methods outcomes, of course, where they looked at the incidence of severe hypoxemia, which was saturation going less than 80% up to two minutes after intubation. And they looked at various exploratory outcomes as well.
This part I liked very much, was the sensitivity analysis that they looked at, and this explained the robustness of the trial. They excluded the intubations that were performed with the hyperangulated blade, counting the crossovers as failures, including only patients where there was complete observer data. Excluding cases in which the operator had less than 10 total prior intubations. Excluding cases where the operator had less than five total prior intubations using a Bougie, and also defining successful intubation on first attempt as intubation with one insertion of the laryngoscope blade. So this was a definition that was used in the BEAM trial, and they also did a repeat sensitivity analysis with this definition. So I think this made it a very robust trial. And I must say that the methodology that was used and the statistical analysis was very robust in this trial.
Now coming to the additional statistical analysis. And I won't go into that. It was all well done, looking for adjustments of baseline covariates, and the second model that was used for video laryngoscope adjusted analysis. But what was interesting to see is that they started off, the hypothesis was that by using a Bougie, they would increase the first pass success from 84% by 6%. So that would be 90%. But if you see at the end with the results, it was quite the reverse. The first pass success reduced to 80%. And also during the interim analysis, they performed the interim analysis when they completed 553 patients looking at serious adverse effects and also to compare the incidence of successful intubation. And if you look at the numbers, there was actually a trend towards a better result with the Bougie compared to the stylet when you do the interim analysis.
However, at the end of the trial, there was really no difference. And that was really good that the trial proceeded until the end of the entire study was completed, because the results were quite the opposite at the end of the study. Looking at the primary outcome, successful intubation on first attempt occurred in 80% versus 83% in the stylet group, and there was no difference between the two groups. And a successful intubation on first attempt did not significantly differ between groups with the adjusted analysis and the multiple sensitivity analysis also was performed, and the odds of successful intubation on the first attempt also did not differ significantly.
With the secondary outcome in the Bougie group, the saturation, there were more desaturation patients in the Bougie versus the stylet group. However, this was not significantly. Now, one of the things with the exploratory outcome which I found interesting was the time to intubation. And when you use a Bougie, it's a two step procedure. First, you put the Bougie and then you railroad pass the tube over it. Whereas when you use a stylet, you preload the tube with the stylet, and then you do a tracheal intubation. For some reason, the BEAM study, as one would've expected, did not show any difference between the groups in terms of timing. And this may be because this was a very experienced group who was routinely using a Bougie for tracheal intubation. So I was happy to see this difference in timing, but this is what one would expect in this kind of a pragmatic trial. So it was 124 seconds for the use with the Bougie and only 112 seconds, and this was significantly different.
The other thing which has already been spoken about cardiovascular collapse within an hour ventilator-free days, ICU free days, was higher in the patients with stylet group. And this could not... Maybe this was just a chance finding, and this could not really be explained. I was interested in the videolaryngoscopy versus the direct laryngoscopy findings. Like if you look at the BEAM study, there was a high usage of videolaryngoscopy, but for some reason, the screen was only used in half of the... It wasn't really used like a video laryngoscopy. The STYLETO trial, of course, only used direct laryngoscopy, but the Bougie trial almost close to 75% of the patient, they used videolaryngoscopy.
Now the benefit of the stylet, and if you look at only patients with direct Lao, the benefit of the stylet seems to be greater when direct laryngoscopy was used compared to videolaryngoscopy. And this is pretty much in line with the STYLETO trial. So perhaps a trial with direct laryngoscopy comparing these two interventions may show a difference. And this is something that we have to think of. Another thing that concerns me is the hyper-angulated, of course, were excluded. And this was a good thing that they did. Nevertheless, when you use the Bougie, a Bougie is a floppy structure, unless you pre shape as was done in some of the cases. So when you use a Bougie, when you use a videolaryngoscope for intubation, there are two steps, you get an excellent view, but the challenge is really for passing the tube. So in that sense, a stylet, which is already pre shaped, maybe more successful. So whether this Bougie will really help when you're using hyper-angluated videolaryngoscope is something that needs to be seen, because these were done in patients which had at least one difficult intubation characteristic.
What was interesting is that the drugs that were used, higher use of and Etomidate Ketamine Propofol was only using 13%. If you look at the tube study, it was almost 41% usage, and this is real world practices. And perhaps explaining why there was such a high incidence of hypertension. Even neuromuscular blockade was... Most of the patients got neuromuscular blockade. And these are conditions are very important for increasing your first attempt intubation success and decreasing the complications. There was higher use of videolaryngoscopy, and even if you look at the per-intubation oxygenation, there was higher use of high-flow bag mass ventilation, and per-intubation practices were greater or much higher than what was seen in the global practices. And this may reflect the tracheal intubation practices in the United States, or even considering that there were university hospitals that were involved in these.
Of course the limitations have already been spoken about. Urgent intubations were excluded and they didn't include hyperangulated blades. The results may not apply to those with extensive experience with intubation and the use of Bougie. And I agree with Brian when he says that perhaps people who have extensive experience with this, the Bougie, as was shown in the BEAM study, show better results when there's a higher sample. No blinding, and of course you cannot define the role of a Bougie after a failed first intubation. This has not been seen. But these, I would not consider them as big in limitations because these are inherent limitations of such trials.
So I would like to say that what we know so far is definitely that repeated intubations are associated with severe hypoxia, cardiac arrest and other complications, and the systematic use of a stylet or a Bougie may improve first pass incubation success. What we didn't know was which one was better, and definitely this large, well-conducted, pragmatic trial among critically ill adults undergoing tracheal intubation has shown us that either Bougie or an endotracheal tube with a stylet may be used to increase first pass intubation success, as a Bougie was not shown to be superior.
Just some things for future trials. My concern with most of these trials is that they use a primary outcome of first pass intubation success. Looking at the high risk of complications in critically ill patients, I think it's important, just looking at first pass intubation success has no meaning. We need to have a composite endpoint of first pass intubation success along with complication, without complications. And I think that is a more meaningful outcome to look at for trials. And of course, as we're using more and more of videolaryngoscopes, we need to see whether there are any differences between the Bougie and the stylet with the use of hyper-angulated videolaryngoscope, especially because we are looking at patients with at least one difficult integration characteristics. Thank you very much for your attention. And once again, I congratulate the group for this excellent trial and publication in JAMA.
Sheila, thank you very much. Superb editorial, lots of things to pick up there. We'll turn to Matt Sumler. Maybe we'll start with you. And I certainly saw your reaction when Sheila mentioned the issue about consent. Maybe we'll start with that.
Yeah. So I appreciate you, Sheila. Thank you for that editorial, and Rob, thank you for having us. I'm Matt Sumler from Vanderbilt University, I'm chair of the steering committee for the group that ran this trial, the pragmatic critical care research group. I think there were several great points in that editorial, and Brian I'll let you take on several of them, but I'll start with the one invited by Rob, that conducting this type of comparative effectiveness research is important. These are devices that are used all day, every day in our practice for the 5 million patients who are intubated each year, and knowing which of them is better is important. And each country has different regulatory structures that permit that sort of comparative effectiveness research. So in the United States, we have the code of federal regulations that has a set of key criteria that have to be met for research to be conducted under a waiver of informed consent. And importantly, in the United States, we don't strictly have a deferred consent option that exists in many other countries.
So I think those key criteria are important. So the first one is impracticability. Is obtaining written informed consent prior to the research practicable? And an emergency tracheal intubation, like in the Bougie trial, where 70% of the patients had decreased level of consciousness or coma, and of the remaining 30, half were delirious and many didn't LAR, it's not practicable to do written informed consent and enroll a representative patient population. So that's the first criteria. The second criteria is that performing the research introduces no more than minimal increased risks compared to the risks the patients would already be experiencing. And so comparing two devices that are used commonly during tracheal intubation in the United States, including used commonly at the sites that they're being studied, with some of the sites saying they always use a Bougie, some less frequently, predominantly stylet, and many using a Bougie sometimes, but not other times. This trial was foot felt to both be impracticable to obtain written informed consent prior to enrollment, and to pose minimal incremental risk compared to the risks of clinical care outside of the context of research.
So that's how it met those key criteria. And then I think information for patients is something that we provide, often after enrollment in these studies, and that includes Bougie. So I think that's the very short version of something that we've obviously thought a lot about. And because I think it's vitally important that we do this research and we know what's best, and at least in the United States, that's the mechanism under which we're conducting this research. So I'll stop there because I think, Brian, there are important questions that Sheila raised about use of videolaryngoscopes, and particularly hyperangulate blades that you might want to get to.
Yes. Thanks, Matt. And thank you, Sheila, for the editorial. I appreciate all your insights there. I think, as you pointed out, one big difference in this trial, to my knowledge hasn't been used before, is the primary outcome differed. It wasn't just blade insertion, but blade insertion plus a single tube or single Bougie insertion. And actually, when we ran the data after the trial, it did show that patients who had a single blade and single device insertion had a slightly lower complication rate than folks who had two blade insertions or one blade insertion and two device insertions. And so I think it's our contention that that might be the highest quality way to represent first attempt success. And I think your point about that might be meaningless if the patient has a complication, but you got success. And I think that's a very good point.
I think one thing we ran into when we were designing the trial that so many of the patients either are already meeting a complication criterion at the time of enrollment, or are near it, and whether you can attribute that to the intubation procedure or not, and that was a little tricky. But I think it's a really good point because that's, of course, what we strive for is first attempt success without any complications. So I think it's a really good point.
And dovetailing into the issue of video and direct laryngoscopy. Obviously this was a pragmatic trial and most folks chose to use video, and it is hard to say what the results would've been if everyone used direct like the STYLETO trial. There was only about 300 patients in the Bougie trial who had direct laryngoscopy, and perhaps if there was 1100, maybe the results would be different. Although we didn't see that in the subgroup analysis. But I think it is pretty clear that we enrolled enough people who had VL to have a pretty adequately powered subgroup that shows that the Bougie didn't help when VL was used.
... Powered subgroup that shows that the Bougie didn't help when BL was used, at least in these operators and systems. And we did kick around the idea of hyper angulate because some centers have intubators that use the Bougie with hyper angulate, but just in talking with other airway practitioners, it's just technically more difficult and we didn't want to muddy the waters. I think it's something that the people who do it, I'd love to see their data to see what the success is like and their techniques are like. So again, thank you Sheila, for that editorial.
Brian, thanks very much. Jonathan Benger, I think you we're going to come in and make a comment about the consent issue.
Yeah. I just want to add to Matt's comments there. I mean, in Europe, similarly, I think we are developing consent models that allow us to do this kind of high quality research in critically ill and injured patients. And it's absolutely essential that we do that. There are, of course, important ethical safeguards, I think around equipoise and kind of demonstrated equipoise between the techniques that are understudy. Very strong kind of patient and public support and advocacy. So that one has a public group that understands the need for the research and supports those processes. An important safeguards about the way that the trials are conducted and delivered. But over the last 10 years, we've seen the sea change. I think in the way that these trials can be delivered. And I think that there is actually a risk in Roberts, for example, is written on how the consent ritual can actually slow down care and it can actually cause harm.
And so we need to think very hard about how to design studies that will deliver these kinds of results. I always want to talk about differed consent because differed consent is a phrase that gets used a lot, but clearly by the time patients have recovered, they cannot not be in the trial. So we need to be careful about our phraseologies. They are inevitably in the trial; they have inevitably received the intervention. And so they could actually only consent to either continue in the trial as it were in terms of data collection or not because we can't kind of pretend that they aren't on the trial or operate a time machine to change what's already happened. And indeed, we need to be slightly careful because if you let people withdraw from studies like this retrospectively, then there's a risk that we will introduce bias because a patient who has died will not be able to withdraw, but a patient who has survived will be able to withdraw and then one could create a situation where survivors preferentially withdraw, disappear from the study.
And in fact, a treatment that is beneficial in terms of survival appears to be harmful. So this study is exemplary in achieving very high primary outcome rates for all patients who enrolled. And we need to ensure that the mechanisms that we put in place to conduct research do exactly that. And obviously we need to adhere to strong, ethical stay safeguards, but it is possible to design studies I think that are ethical. That are effective, and that have extremely high ascertainment of the primary outcome to ensure that no bias is occurring as a result of differential dropout, either voluntarily or involuntarily in patients that are enrolled.
Jonathan, thank you very much. An excellent point. We will move on now to the questions from our viewers. My colleague, Chris Nott has been scowering Twitter and looking at our chat function as well, a slightly easier hashtag to follow tonight, Chris.
Thanks, Rob. So yeah, bit of shock out there about the results, some Bougie fans, other stylet fans out there. Certainly some chat around the use of video laryngoscopy, as we've already mentioned in 75% of patients and maybe some comments that video laryngoscopy maybe isn't available in third world countries or even in some other departments. Could you comment on that?
I'd be happy to take a comment on that, which is, I think, and I'm laughing, looking at John and Brian, because we discussed this all of the time. It is my view that we have in places where it's available, adopted video laryngoscopy more universally than the evidence supports. And I think it is our responsibility in the same way that we've generated evidence around Bougie versus stylet to generate the same sort of level of evidence around video versus direct laryngoscopy. And, of course, we have an expert on the call who in Jean-Baptiste, who has provided the best evidence we have so far, but we're very interested in adding to that evidence base. And I think if your hospital doesn't have access to a video laryngoscopy, it's a very important question because they are not inexpensive.
Whether a video laryngoscopy improves first past success prevents complications. And so I think that question, although there are a lot of strong, almost religious feelings around this that I don't want to step on the toes of. I think it needs an evidence-based answer of this level of quality. And so I think I put my foot down on the scale of equipoise here and that we need to be doing further work on that question.
Thanks. So moving on to the people who were doing intubations, and there's a variety of people in the trial, ED physicians, anesthesia critical care, and you've mentioned that they had a median of around 60 intubations, so they were deemed confident. So the question is with experienced operators in intubation, does it really matter what technique you use?
I can take this one. I think for people who are achieving very high levels of success, I certainly wouldn't quibble with whatever technique they use. I just want to see the patient successfully intubated. And if you're very experienced, it probably is less relevant. Although, you in a formally use an endotracheal and stylet every single time and you don't have the confidence with the Bougie, you might run into some glottic views that make it challenging. But for your garden variety intubation, it probably is less important.
And maybe could follow that up with a question around the intubators in this trial seem to have less experience with a bougie. And do you think that had an influence on the outcomes? And can we follow that up with the fact that then if they failed with a stylet, they seemed to move to a bougie as a rescue therapy when they didn't have as much of the experience. Could you comment on that?
Yeah, so I think it's hard to parse out whether it's the limited bougie experience or whether it's the fact that the system has limited experience. Whether it's operator or system, I think it's hard to separate the two and then as far as the devices used after first attempt failure. Yeah. So in the stylet group, there were 93 failed first attempts and half of those transitioned to the bougie, whereas a quarter of the bougie failures transitioned to the tube. So it was a little bit more common. And for the bougie fans out there that you could definitely kind of grab onto that and use that as an argument. But I don't know if that's compelling enough as the sole reason, as the sole convincing reason that a bougie first strategy is best. I think you have to maybe find other evidence to support it as well.
Okay. Thanks. Moving on to the sort of the difficulty of intubation, you'd mentioned that the rate of characteristic of difficult intubations was similar in both groups around 40% for the characteristics, but when you looked at it that only correlated to around a seven or 8% grade three or four Cormack-Lehane view. We tend to reach for these devices when we think it's going to be a difficult intubation. So were there actually enough difficult intubations in the trial to show a difference?
Going to take a stab at that, Brian. Defining what a difficult intubation is in a way that's reproducible and prospective is tricky. What we can say is, was the rate of failure what we expected it to be, right? So we estimated that 84% of patients would fail in the stylet group, the control group, I'm sorry, 84% would be successful. 20. The inverse of that would be failure. So 84% success was what was estimated 83% was what was observed. So we saw exactly what was expected and very similar to what was observed in beam and prior trials. So I think this is representative and as expected. What's a difficult intubation into whom I think is hard enough to define that we've tried to stay a little bit out of that quagmire.
Sure. Were there any factors that favored either bougie or stylet in the trial, High BMIs, or?
Nothing that we could detect in our subgroups. They were pretty similar across the board. All slightly favoring stylet, but none that were statistically significant.
Okay. Thanks. Just moving on then to the complication rates. So desaturation rates were fairly low in this trial. No difference between the groups, this stylet trial had a bit of a difference in desaturations in respiratory failure patients. There were a round, a third of the patients in this trial. Was there any difference between the bougie and the stylet and patients that are maybe at higher risk of desaturation?
I don't think we parse the data to that degree. I think it's an excellent question. And we can certainly look that up for the future, but we don't have that data currently.
Okay. Thank you. There are a few comments. You sort of maybe already addressed this about the rates of cardiovascular collapse. Any ideas, why that occurred and if it's by chance, why look at it?
We hypothesized that maybe patients are just reassured when they see the blue bougie coming towards them and they just spontaneously heal. No, but in real reality, we tried to come up with any explanation for this. And we had nothing we're grasp at straws. I have to imagine it's just due to chance. We did want to measure it in case there was a difference between groups or say bougie's better, but it led to more hypoxia and worse cardiovascular collapse. Of course, then the improvement in success wouldn't have been worth it. So that's why we measured it in the first place. But as much as people like to think that blue bougie is healing. I'm not sure that's the case.
I would jump in there to say that two things. One, when measuring these exploratory outcomes, we try and keep the understanding that there's a lot of testing going on and they are exploratory. The second is that I think we have to thank Sheila and her co-authors for INTUBE. We've spent the last 10 years being criticized for our complication rates being so high. So it's now nice to hear that our complication rates aren't that high, because we have some actual context on real world practice. Turns out, this is just a hard, dangerous procedure when patients are critically ill. So thank you for that context.
Fantastic. Chris I might come back in here if that's okay. It's time to move into the panel discussion. Jean-Baptiste and George are waiting patiently. Jean-Baptiste I might start with you perhaps you could give us your initial impressions on this trial, please.
First of all, congratulations because probably the major last randomized trial in the airway field. So I have just two major comments because I think now we know that stylet is better than no device and the bougie is better than no device. I think if you use currently one device, the bougie or the stylet, you must still use the same, because there is no reason to change or to switch for one to the other with the results. And there are probably some practice difference from Europe and the US, because I can see that the non [inaudible] mask was used in more than half of the patient and the [inaudible] was used in more than one third of the patient.
So probably it's because maybe Brian Driver work on that some years ago. But I think it's not the quite same thing. And if you look at the data in STYLETO trial probably maybe it explains the difference in the rate of hypoxemia and the other one is that the huge question is expect the truth of the operators because when you look at all three are done in the same field.
If I can show you this one, I don't know if it works; you see that the first success is almost the same in all three done in the last year, between 65 to 80%. And the only one who is not in the same range, it was the beam results, but with very high rate of experts. So probably we need to work more, even more because we have probably the same rate of success and last thing, but it wasn't where in the presentation, it's probably there was a several way to use bougie. So I understand that you still use in the same way, the force on the side as a [inaudible] , but maybe the other one, it can be faster or it can be easier. And so maybe can I have your input on that?
Yes. Thank you, Jean-Baptiste, for the comment. I think it's a reasonable conclusion that if whatever you're using no need to switch, because certainly needs something either a stylet or a bougie. And then, as far as a comment of how to use the bougie, I got to say at Hennepin. We've always just inserted the naked bougie and then a tube over it. And we've had good success with that. Anecdotally I've heard, other people use different methods with high success, but I haven't seen that published. So for now, I think I would stick with the recommendation to use the naked bougie, unless you're a sole operator somewhere and you don't have an assistant, but that's not necessarily evidence based. It's just because there's a lack of evidence for the other techniques. Just anecdotal evidence. But thank you for that question.
George, I'm just going to come to you now. Firstly, for your thoughts on the trial. And secondly, if you could maybe comment about the use of bougie. Particular question, I'll ask you when we come to this too. Firstly, your initial comments please.
Yeah. I thought it was a poorly done, weak study and I'm just waiting for some real good evidence. That'll come down the pipe here. I can see both Brian and Matt laughing, and thank goodness. And I'm looking to you Rob to laugh also. But yeah, my first is what's already been said, is congratulations on an amazing piece of work. I have a lot of notes and I'm probably just going to go freestyle, but I might comment on the last piece. I don't agree with the fact that this trial says that there's no value in switching from one device to the other. And that's, again, we didn't talk about the type of view that is achieved now. Really, the bougie was born out of use with a grade three view where it's an epiglottis only type of view and you're using that Coude tip tip to tuck under that, right.
And so if you're going to say, if you've got a grade three view and you're going to say that a blind placement of an endotracheal tube underneath the epiglottis in a grade three is equivalent to either feeling clicks or meeting holdup. I don't think that's a fair thing to say. So there is definitely, I think, a value to switch from one to the other, as long as you understand the anatomic context for which you're going to do that. The real difference in the beam trial. And again, I haven't seen the breakdown and this was commented on the discussion and addressed it very well. There was no real difference in grade one views and grade threes, weren't that common. And the big difference was in grade two views. And the hypothesis was is that the approaching larger endotracheal tube obscures the view as it enters the glottic inlet.
And that's the real message. And if you look at the breakdown in that cohort, that was the major effect of the beam trial, right? Because you couldn't say it because the numbers in grade threes weren't that high and grade four, I always, this is so of a bit of a facetious comment, but if you have a grade four, the only thing you should put down is a gastric tube. Because I think the most common thing is that, you've got a big four blade and you're in the esophagus and people don't necessarily view that. And I think that this is one of the things we need to move to. The fact that we are using video laryngoscopy is that we need to... The impressive feature about this study and the beam trial. And then the precursor to the other Hennepin trial is that they had good observable evidence of the number of attempts, right?
Either from a camera in the room or somebody there observing it as opposed to a retrospective self-reported how many times I put the blade in the mouth. The recurring definition of first pass success, or an attempt. I think that this is a brave and a very appropriate thing to do. The real reason why people didn't want to do blade in plus device in whether it's tube or bougie is it's too hard to document, right? And when somebody's in there, retrospectively set up, put my blade in, I want this, whatever, or I crossed the lips, et cetera. How do you record that? And so the only way to reconcile this is that if we do video laryngoscopy, we need to record this, right? We need to record on the screen. It needs to be part of the chart because this is where we're going to learn. Why it didn't make a difference, right? In this situation.
So, what's our approach? That's the standard we should be moving towards, right? There's all kinds of benefit to use video. And some people think I use video as my primary approach period, but let's use video for additional quality assurance and learning how we can do this. What the driver study and again, I apologize for using the etal here, or the beam study told us is what things can be. And that's the big message here, right? What it can be. A 98% first pass success, 96 in those with difficult characteristics, whatever, but a 98 first pass success with objective observations of this actually being a number, right? This is something that we need to aspire to.
And the fact that we don't do it often enough, then that's our problem, right? That shouldn't be the patient's problem. That's our problem, right? And so you do need to be experienced. And we've been saying since our circa 1996 slides here, 3, 2, 1. Three things to do with two hands on first attempt, right? Your hand goes from crossing mouth opening. It goes to the ox, put to additionally, raise the head. It goes around; it does ELM and the hand goes out to here to a bougie that's placed. And our difficult airway drill is to do that all in under 30 seconds, right? And, again, I think in the beam trial; the time was significantly shorter there than it was here. And that's a system thing, right? Again, I'm going to naked bougie believer because I never have to look away from the screen or in the mouth, right?
Because our team knows and has practiced accordingly to do that. To me, the message here is not that they're equivalent. The message is, is that we have to be better, and the bougie is not a heat-seeking missile. Okay. It is an adjunct to optimize laryngoscopy, right? The other last thing I'm going to say, Rob, is this, so you need to know device, because there's a difference between what type of mac blade you used. And this hasn't been, we've talked about this, but a c-mac is different than a GlideScope mac blade, was different than a Mcgrath mac. And we've studied this from a cadaveric point of view and it's significant, clinically significant. And if I have time, I'll explain what I mean by that.
Fantastic George, thank you. And not only are the blades different, there was a paper came out on anesthesia just a couple of days ago and it suggested that bougies are also different and there are different rates of first pass with different types of bougies. George, I was going to ask you quickly, just one point about the bougie before I move on to Jonathan. In the manuscript, it stated that this stylet should be performed with the bend at the tip, but there was no mention of doing similarly with the bougie. Should that have happened?
Yeah. So excellent question. It comes back to what I was going to say. So again and first of all, you're right, a bougie out of the pack. Is there all kinds of difference? I think you guys use SunMed. Those are the ones that we use, right? And so they have memory, right? So, and then the memories measured in seconds lost to return due to whatever. So we talk about out of the package straight, we talk about a pillow bend or a deliberate bend, and those are three things in three different situations that you use. So out of the package bougie with a 30 degree, coude tip is meant for a direct laryngoscope or again, a c-mac which will behave, and we did a study where it was again, blinded versus looking in the mouth versus on the screen.
And it was blinded. And we looked at the GlideScope mac blade. We looked at the c-mac and there was no difference in the c-mac group, but there was a difference in the GlideScope and it's up to between six and 12%. And we said that wasn't clinically significant. If I was to go back and change it, I would change that at is clinically significant. If you are using and I was getting these messages during COVID because we were coming out with guidelines saying, you need to use a mac with a bougie. And I was getting all kinds of Twitter when I was on Twitter and stuff saying we're having problems with it. And again, my hypothesis is usually when that's going, it's going posterior. Okay. And it's going posterior because with the GlideScope mac blade, there's about a 10 degree difference in terms of it working as a see around the corner device and with the McGrath Mac, it's even more than that, right?
And so, an out of the package bougie, which is straight, other than the coude tip, will often not be able to manage that difference. And it will be clinically significant if you have a grade 2B view that now is a grade three review, right? So it is something. And what I say is you need to be used to what your device; what's on the screen and what's in the mouth and there's equivalence there from a c-mac point of view. But I would suspect that, again, I don't know if the numbers are enough and it certainly wouldn't be powered enough to do that if you're using a GlideScope Mac blade...
And it certainly wouldn't be powered enough to do that. If you're using a GlideScope Mac blade or using a McGRATH Mac that the potential bougie failures are going to be. That's a hypothesis that I have is that the potential failures in that grew. You require a pillow bend and what a pillow bend is somebody you're coming out and you're just going on the pillow like this, and it will just give you a slight bend. And we do that routinely now so you don't have to think about what device you're using. That's different than doing a deliberate bend where there's a hyperangulated bend, where we get somebody to hold it there and release it just as you're getting it. And the problem with that is you are going to hit, you're going to hit actually, you're going to go into the cricothyroid membrane. You get hung up on the anterior portion, superior to the cricoid ring. That's usually easily manageable. And then there's the steerable stuff that I won't get into. All right. I've been blabbing. I'll shut up.
Thanks George. Jonathan, in your AIRWAYS-2 trial, you had paramedics intubating in the pre-hospital environment. So there would've been an amount of training required cause presumably they're not doing a huge amount of pre-hospital intubations. This study was also undertaken in a large number of operators who were relatively inexperienced, 50% had 10 intubations or less with a bougie. From the AIRWAYS-2 trial, what lessons did you learn about the training and set up of the design that might be relevant to our interpretation of this trial?
Thank you. And some great points from other colleagues on the panel. And can I just also convey my congratulations to the team. This can be a bit disheartening 'cause we end up talking about kind of minor stuff when we can lose sight of just what's been achieved here and the quality of the research and how that takes us forward. I think you're right, that paramedics in our study were occasional intubators and that had a significant impact on the success rates that we were seeing. We endeavor to standardize intubation using a bougie. So that a bougie was mandated for any intubation, regardless of the view, because our view is that that improves the first past success rate and that did help, I believe, but it still didn't achieve as high a success rate as we would've liked to have seen.
I mean, I think what I would say is that in some respects this study could be interpreted as being a study that shows that if you take a group of relatively inexperienced operators and you ask them to stop using a stylet and start using a bougie, then for the first intubation, after they're asked to do that, so their first ever intubation with a bougie, they're no worse than they were with the stylet. And then if that's true, then what happens after they've done 20 intubations with a bougie? Well, maybe after they've done 20 intubations with a bougie, you get to the BEAM kind of results. And I think it was Brian that was talking about systems. So certainly in pre-hospital care in the UK, we're building pre-hospital intubation systems that are extremely clear about what we expect people to do, heavily protocolized.
I work in a system where we always use a bougie and that's just what we always do and there's no discussion. The team know exactly what's going to happen. Choice is not really an option for our operators. And I think that what would be really interesting would be a follow on would be to keep going longitudinally in centers and say what happens to the first part intubation success rate over time where those centers embed around a system that uses the bougie routinely. And particularly some of the tips that George is discussing, some of the finer points of use.
I'm biased, I've worked in a system where we have used intubating bougies for a very long time and we very rarely use stylets. And so there is, I think a way of looking at this trial, which is to say that in fact, because of the population, because the low number of intubations done per person recruiting, and because in general, people weren't that familiar with the bougie beforehand, the equivalence is actually quite impressive and it's quite attributed to just how good bougies are, and let's see where people are in 10 or 20, 30 intubations later.
So Jonathan, can I ask, do you think that these results then maybe downplay the usefulness, for want of a better term, of a bougie? Do you think the bougie was maybe biased against, just in the setting that it's been used?
I really hesitant to criticize just a well conducted trial, but I think one of the potential limitations of the study is that if you look at the practice beforehand, which was eloquently demonstrated in the presentation, in general, it's generalization. But what we're saying is these are a bunch of intubators who generally, routinely would choose a stylet. And they'd only use a bougie perhaps in a difficult situation or under certain selected circumstances. That's in keeping I think with lot of North American practice and it's actually quite impressive. If I go to my emergency department tomorrow and said, look, guys, stop using bougie first, everyone's going to put a stylet down the tube. I would expect bad results for the first few intubations for each operator because they would be unfamiliar with the expectation, they'd get the angles wrong on the stylet.
They wouldn't know how to deal with the particular view that they were looking at. And so in reality if bougies perform as well as the stylet in a less experienced group of intubators who are using these less frequently than actually the message might be that you just need to keep going. And I say let's keep going for a year and then see where we are, whether the higher volume use. Because BEAM suggests that in the center where the bougie's routinely used, where there's a high volume of intubations using the bougie and the staff are familiar and trained, the first pass intubation success rates significantly higher.
Brian, I'm going to turn to you. From reading the manuscript, I think you visited every center to deliver training and try and get the clinicians up to speed. Is that right?
No, I hope we didn't miswrite that, but no. So just the site principal investigator conducted training for individuals at the site. Would've loved to have flown out and met everybody but as an unfunded study, would've been coming out of my own pocket. So no, we were all site PIs.
Brian visited virtually through a very nice video that he prepared on best practices in use of bougie that was viewed by all sites and is available online. So those interested in knowing the best practices in use of a bougie straight from the horse's mouth, Brian is on YouTube demonstrating that. And that was what we used to disseminate to the trial sites.
Fantastic. It would've been a lot of trial sites and a lot of people to train up. So I have a question now for Jean-Baptiste, your compatriot Samir Jaber did the STYLETO trial. It showed that the use of a stylet was superior to no stylet in intubating critically ill patients. So have been now reached the point that we should be using one or the other, and we can maybe choose whichever we're more familiar, more comfortable with?
I think it's always difficult to discuss superiority trial as a non-priority result because if you under care use a stylet I think you must stay with the stylet, but the BEAM trial has a huge impact. In fact, I think in France, but worldwide, there is a lot of people who now use the bougie as the first device. And as George Kovacs said the bougie is a safety and the second line. So why don't use the second line as the first line, but it's the same question about the video laryngoscope. If you use your laryngoscope when you face difficult intubation, why you didn't use it the first time, but is there a difficulty as regarding to hyperangulating of your laryngoscope and tongues [inaudible] care of your laryngoscope?
I think we didn't have this problem with the bougie. So I'm still convinced that maybe the bougie is better. Even we can see this in the BOUGIE trial and I will stick with the bougie. And the major thing is I think that we still think about BOUGIE trial as experts in airway, but the large proportion of intubation performed with non-experts. So what is the better device for non-experts is the main question of your whole trial.
Super. Sheila, I'm going to turn to you. This trial was undertaken in 15 centers in the US. Will this be generalizable outside the USA? How similar is this to your working environment in Mumbai?
Right, so again, this was university centers. I just want to allude to the results of the INTUBE study. Only 17% of people globally were using the visual laryngoscope. And this wasn't a difference between the developing world and the developed world, even in the developed world, there was no difference. 17% is really low so this is what is real life practice. And if you look at the preference between stylet and bougie, two third prefer to use a stylet, only one third prefer to use a bougie. So really there is a wide variation in the preferences and I completely agree that it depends on which device you are experienced with. So this is not the question of the experienced operator. Perhaps if you have a person who's experienced with both devices, as most of you are, there won't be any difference. What we really need is a study which can be globally applicable and generalizable.
And that's why we need trials like this. And I think the BOUGIE trial has answered this question very nicely. And I'd just like to make two comments. One is about what Jean-Baptiste said about it really depends on what device you're using and what you're familiar with, because that will make a lot of difference to the outcomes. So here are these were university study results. And I think the other thing for first pass intubation success is not just bougie or stylet, it depends on your intubation conditions. Is the patient paralyzed? What are the drugs that they're using? This makes a difference to the complications. So I think in this center, and I alluded to that in my slide, most of the patients were paralyzed. They used Ketamine or Etomidate. In the INTUBE study, half the patients received Propofol.
So it wasn't surprising that the complication rates were high. And this may be the reason why the complication rates are lower. And one comment about what George said, I completely agree with him that video laryngoscopes are not the same, they're a heterogeneous entity. When you're using a Mac blade, it's a different story with a bougie. But when you're using something that is a higher angle on a hyperangulated blade, a bougie may not work because you'll have an excellent view, but you may not be able to use it, the bougie as a naked device. And what I saw in this trial was they had pre-shaped the bougie. Some of the centers had done that.
So if you're doing that, you're doing exactly what a stylet does. You're just using a two step approach. So you're probably using a bougie as a stylet. That's what you're doing. So we have to think about all these things. It's not so simple as just bougie or stylet, but I think the clear message is definitely in this high risk group of patients we should use one of the two devices. And the bougie trial has shown that with the current evidence, there's no difference really between which device you and you should use the one, probably like Jean-Baptiste says, that you're more familiar with.
Matt. A question for you. The secondary outcome was the incidence of hypoxia up to two minutes, I think it was, after intubation yet there was a range of different preoxygenation devices used. Would it have been better to have standardized the type of preoxygenation that was used?
Thank you. Phenomenal question. I think the question of what is the optimal approach to preoxygenation for critically ill adults in the ED and ICU setting is one in which we have a series of piecemeal trials, but not yet the definitive data required to tell us what we should be using for everyone. And Brian and Jon and others are working on answering that question. And particularly, is non-invasive ventilation superior? Not just for those with acute hypoxemic respiratory failure, but for the wide range of patients that are seen in the ED and ICU. And as we saw in the INTUBE study and other, those are standard of care, especially in some ICUs and especially in France, but across the world. That's not a standardized approach yet. And I think, especially with our colleagues in the emergency department, where many patients are being intubated for altered mental status and not acute hypoxemic respiratory failure, we were not at a point where we could protocolize one approach to preoxygenation. But I think with better data, if those show a difference in that setting, we hope to in the future.
George, going to turn back to you. You're a noted airway teacher. I've only just heard the trial results. What impact do you think this will happen? You're teaching other airway teachers around the world.
So it's to aspire to what has been happening at Hennepin and quite frankly, I've been talking about this for quite a while. It's not about the device and we wrote an editorial on this. It's about optimized approach to airway management and that optimized approach includes the mechanical procedural aspect of placing the tube and it's around optimizing the patient's physiology so that we get the real outcome differences that we're looking in terms of patient morbidity mortality. And so we tend to sort of say that is the hyperangulated going to be the answer? Is a video laryngoscopy gonna be the answer? Is bougie going to be the answer? And those aren't the answer. The answer is to look at this as a package. And what Hennepin does have is they have a package, it's a culture, it is a bundle, right?
And to me the BEAM study was about a bundle. It wasn't about the bougie. And if you think about it, the laryngoscopy first pass success rates have been pretty stable. Some people have shown that, right? And 85%, right? Things are plateaued, right? And 85 and getting between 85 and 90, but this was a significant jump, right? And so it was 87, I think, 98 versus 87% in the BEAM trial. So the stylet group was the same as what the practice has been out there for high performance places. And we can improve that if we make it part of our culture and are good at it. The crazy thing is that concert violinists, fighter pilots, professional athletes spend 95% of their time practicing and very little time performing.
And we in medicine spent the vast majority of our time performing, very little time practicing. And that is crazy. The stakes are higher from a human life point of view than a World Cup game. I'm sorry, it is. And that's where our culture needs to change. And we can't necessarily learn at the expense of the patient experience. And we have to find ways in which we have that system bundle approach of what to me it's going to be is that we've got work to do from bougie use and understanding why it didn't, we didn't get the results that we've seen. Yes, they're pragmatic, but more pragmatic means is being practical and saying we can change and do better.
Thanks, George. We'll cross to Denver and Stacy, you were one of the top recruiters for this trial. What was the feeling like on the ground? Did the people who were doing the intubations have a preference for one or the other? Was there an expectation that one or the other would prove more beneficial?
Thanks for that question, Rob. I think there was a lot of excitement on the ground to help inform which of these practices should be our sort of standard of care. I think for us, bougie was used in the more traditional sense. It was a rescue device and not what we would have been using on first attempt. That being said, some providers had moved to using a bougie after seeing the BEAM trial. So there was a fair amount of familiarity with the bougie amongst our group. But overall, I think in our center, we're a very high volume intubating center in the Denver area.
And our residents were taught to intubate kind of unlike what George is speaking about, which I actually agree with, but we provided them with a multitude of different options to intubate so that they could be experienced in different devices and in different approaches so that when they left residency and they entered a new site with a different tool, they could step in and use whatever tools were provided to them. But I think George is right in that a standardized approach is probably the way to go. And that approach that Hennepin uses of a package deal, this is how we intubate. This is what everyone is expecting. I certainly would love to get to that 98% success on first attempt, that is enviable.
It certainly is. And Jon, as one of the main trialists, you must have been very, very impressed with what seems to be a very, very high level of internal validity. The vast majority of patients proceeded with the intervention that they were allocated. So presumably we can say with very high confidence that we have answered the question that this trial has attempted to answer within the confines of the design of the trial.
Yeah. Thank you and thanks for the kind comments and thanks for all the panelists for being here. I think so. I think we sought out to look at, among the investigators who were enrolling at these centers, these were the experience levels they had. The median of 60 intubations represents the average operator at each of these centers and the result of the BEAM trial suggested that asking them to start using a bougie would improve success. And I think Jonathan and others have highlighted some limitations in the interpretation of the study, but I think it does answer the question that simply handing them a bougie and asking them to change their practice does not in and of itself improve first pass success. And I appreciate you pointing out the separation between groups. I think it's a really impressive accomplishment for all of our sites that during this emergency procedure, they're able to enroll patients and deliver an intervention with such high fidelity and deliver such high quality results.
Yeah, super. So we're going to start rounding up. There's only a couple of minutes left, so Jonathan, I'll come back to you. Is there anything else that you'd like to say, any other comments that you haven't had the opportunity to make yet?
No, I mean, it's been a really fascinating discussion and I think we've covered a lot of ground. Just want to reiterate my congratulations to the investigators on, this is exactly the kind of trial that is world leading and that we need to see more of in the future.
Thank you. And George...
You're on mute, George.
Yeah, sorry. Great conversation. Great discussion. I still think there's some unanswered questions and, thank goodness for, again, dedication and volunteer work that's being done. And I need to speak to your academic chairs and make sure that you guys get some protected time that you need, not that that's going to make any difference, but it's amazing. One minor comment that I'm not sure if it was appreciated. We do understand that there's heterogeneity within class blade differences. So not Mac VL blade. There are differences. Most, a lot of them are Mac plus blades and the same thing from a hyperangulated. We've simplified it into three, Mac hyperangulated and channeled and there's considerable variability and you need to understand how your anatomy works and how your blade works and the subtle differences that are there to have the success rates we're looking for. So congratulations. Amazing, amazing work.
Thank you. Jean-Baptiste, a last word from you.
Yeah. Again, congratulations. I think that we will have others from the pragmatic [inaudible] field, so I'll be happy to discuss the future trial again. Thank you.
The future trials, that is indeed a great point to bring us to. So I was looking at some of the major airway trials earlier on, and this group have completed so far BOUGIE, BEAM, PrePARE, Check-UP, FELLOW, and PreVent. It's quite a number of airway trials. So Brian I'll come back to you. What is next?
I think I'll throw that to Matt, just 'cause he's chair of the executive committee. I'll let him answer that one.
So we really appreciate the support of this whole community and we can say simply what's next, which is PrePARE-2, which is a 1000 patient trial of fluid bolus administration versus none to prevent cardiovascular collapse that has completed enrollment and we would be thrilled if Critical Care Reviews would have us back to share those results with everyone sometime in the next couple months.
Oh, that would be fantastic, consider yourselves booked in. With that, we better stop tonight. Otherwise, we will be here for hours because it is just a fantastic discussion.
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