Are double lumen endotracheal tubes superior to bronchial blockers?

Welcome back to Depth of Anesthesia. This is a podcast that critically explores our clinical practices. I'm David Hao, and I'm an anesthesiologist at the Massachusetts General Hospital. This episode is actually a product of the very exciting Depth of Anesthesia podcast selective that we've been running for our residents for about a year now. A big thank you to Dr. Dan Sidow Kinefka and the academic leadership here in our department for supporting our efforts.

And another big thank you to Dan for actually his thoughtful input on this episode and for joining us today. Our first guest today is Dr. Andy Siemens. Andy is a PGY1 in our anesthesia residency here, and he's a graduate of the Oregon Health and Science University. Dr. Siemens, welcome to the show. Thanks, David.

It's great to be here. And our second guest is Dr. Nick Kumar. Nick is also a PGY1 or anesthesia residency, and he's a graduate of the Ohio State University College of Medicine. Nick, thanks for taking the time to be here. Thank you so much, David.

And our final guest is Dr. Dan Saddawi-Konefka. Dan is the residency program director here at MGH and is a regular contributor to our podcast. Dan, welcome back. Always a pleasure. So before we get started, I just want to say that I'm super proud of the work that Nick and Andy have done.

Aside from the literature review and the episode prep. Um they also presented this topic at a department-wide case conference. This is definitely no small fee considering they were barely a few months into residency at that point. So a big shout out to them and I'm looking forward to putting this um in a podcast format for everyone to listen to So we'll start with our case today, which is that of a sixty year old man who's presenting for leftover lobectomy for non small cell lung cancer. He has a past medical history, relevant for mild tobacco use, but is otherwise healthy and has an excellent functional status.

His preoperative FEV one and DLCO are in the ninety to one hundred percent range, and when discussing options for lung isolation, the residents suggest using a left sided double lumen tube, because they feel that it may be overall better and easier. What are some of the claims in this case? Yeah, I think one of the primary claims here is that double-limin tubes are superior to bronchial blockers for routine thoracic procedures that would require one-lung ventilation, such as this one. We can break down that primary claim into these three smaller ones, the first one being double lumen tubes can be placed faster than bronchioblockers. And we'll discuss various aspects of this, including what time to placement means and whether or not there's going to be a need for fiber optic confirmation of placement and how that builds into the overall time for placement The second subclaim being that double-lumen tubes offer more effective or higher quality lung isolation.

And that could mean different things for different uh people in the case, for the anesthesiologists versus the surgeons. And then finally, the third subclaim, double lumen tubes are equivalent with respect to adverse effects in terms of airway trauma and subjective sensations of sore throat after the case. So here now are two questions for our listeners to think about. What's the level of your agreement with the claim that double lumin tubes are superior to bronchial blockers for routine thoracic procedures requiring one-lung ventilation? And what is the level of evidence for what you believe?

Andy and Nick, I'm a bit curious about how you guys actually got interested in exploring this topic. Yeah, I I got interested in this topic uh actually when I was working as an ancedio technician um before medical school. And seeing all the devices that anesthesiologists use and you know going through medical school and airway management is one of the keys of what anesthesiologists do. And discussing these uh devices really is a convergence of anatomy, physiology, and the technical skills of an anesthesiologist. So I'll start out by just giving our listeners a sense of how we'll be structuring this episode.

In the past 30 years or so, there's been actually a number of studies comparing bronchial blockers to double lumin tubes. The studies are fairly different in terms of patient population and design, but in general they look at somewhat similar metrics, things like time to placement, uh quality of lung isolation. This is usually some subjective scoring by surgeons. Need for readjustment or repositioning and uh complications, things like airway injury or hoarseness and sore throat. Uh so conveniently there was a systematic review in 2015 that aggregated findings from all these studies and We'll reference this review throughout the episode.

Uh as we get started with exploring the first claim, we'll take some extra time to discuss some of the limitations of this review. And many of the limitations we'll discuss carry forward to our discussion of the other claims. So we might not explicitly discuss them for each subsequent claim. Uh what I'll say about this review is that heterogeneity is is quite high. And and the the authors of the review actually comment repeatedly on how much variability there is from paper to paper, uh especially in terms of the outcome measurements.

So Even though we'll start with the conclusions of this review, we'll definitely take our time to dive into the individual studies to give us a more nuanced approach to actually understanding the evidence that underlies these claims. So uh Nick, can you tell us a little bit more about this review, what their findings were uh in terms of our first claim that double lumen tubes can be placed faster than bronchial blockers? Absolutely, David. So this is a uh 13 RCT uh systematic review that was done in the University of Edinburgh in the United Kingdom Like I mentioned, it includes uh thirteen randomized controlled studies, uh comprehensive of seven hundred and ninety-one patients, and the sample sizes of these included studies range from twenty-eight to hundred and twenty patients each. uh comparing bronchioblockers to double lumen tubes.

The inclusion criteria for the systematic review were randomized controlled trials comparing the use of at least one Bronchioblocker model and double lumen tube for lung isolation during thoracic surgery in adult patients. And the outcomes were to compare the efficacy and adverse effects of these two device types. The systematic review pulled data for outcomes including the time to positioning of the device, the frequency of malpositioning intraoperatively, and the quality of lung collapse as scored by the surgeon subjectively. Um as well as the incidence of airway injury or trauma, including s uh sore throat and hoarseness, as rated by patients posed operatively. So Nick, just to get this straight, 13 RCTs, about 800 patients total, and they're going to be looking at how long it takes to position, how often it's malpositioned.

How effective it was quality wise and was there any airway injury or trauma. Is that right? That's right. Awesome. Okay, so what did they find?

So the primary outcome of the systematic review was time to placement, and they found that bronchioblockers took more time to placement compared to double lumen tubes by 51 seconds. They also found that bronchioblockers were more likely to become displaced during the surgery. They also found that there was no significant difference in time to lung collapse or the quality of lung collapse is rated by the surgeons as excellent, fair, or poor. Double lumen tubes were associated with a greater incidence of sore throat Raserated by patients as well as hoarseness, and double lumen tubes cause significantly more airway injuries than bronchibloggers So just to get this straight, bronchioblockers were slower. Uh they were more likely to be incorrectly positioned, although the quality was once they were well placed the same, and double lumin tubes were had a higher incidence of sore throat and airway trauma.

Now how did they assess for airway trauma again? That's a really good question. So there were three studies in the s systematic review that specifically looked at airway injuries. And what the investigators did is they used a bronchoscope to evaluate the airway after the case to evaluate for any airway injuries. So that would be what, like redness or tears or that sort of thing?

That's right. Yeah. So hematomas, uh bleeding, things like that. And Nick, as we alluded to prior, there's a there's a couple of limitations with this systematic review. Any worth pointing out?

Absolutely. So there were quite a few limitations to the systematic review. The first one from the fact that although this in the systematic review includes 13 studies. They all have fairly small sample sizes, which introduces a risk for type 2 statistical error. There's also varying degrees of experience from the device operators, from residents to experienced seasoned clinicians, attending physicians.

And there was also an unequal distribution of men and women between the two interventional groups. That's really important because men have larger airways. So as a result that these devices could be more easily placed with less less risk for injury. And then probably the biggest limitation is the smattering of devices that were can included in the systematic review. So this is the various types of bronchioblockers, the arnt, the Fuji Yun event, the EasyBlocker, the Cohen. um among others, um compared to both left-sided and right-sided double lumen tubes.

So not necessarily comparing apples to apples. Alright, so if I were to summarize, it sounds like the systematic review has some limitations, including study heterogeneity, potential for error due to small study population sizes. and fairly broad oversimplification of device types. But what they found were that bronchial blockers were slower to place by about 51 seconds and were more likely to be positioned incorrectly. And double lumen tubes were found to be associated with more aerial injury, uh sore throat, and hoarseness. That's a very good summary, yes, David?

Diving a bit further into our first subclaim here, which is that double lubin tubes can be placed faster than bronchial blockers. Dan, I'm wondering how we think about 51 seconds in a clinical context. Yeah, it's a really good point. If you think about fifty-one seconds in the context of the entire OR time, it becomes relatively insignificant But when you're taking care of someone's airway on induction, 51 seconds almost an entire minute might make might make a difference in terms of hypoxia or in terms of sometimes you know, preventing contamination of a healthy lung if we're if we're isolating in the in the case of uh um bleeding or um infection So uh I think it depends a little bit on the context of the patient in front of you, but it could actually be pretty meaningful.

I think that's a very valid point, Dan. It does sound like this is uh a very context-dependent number. One of the other aspects of heterogeneity that's reflected in the nine papers included in the analysis for time to placement that I think is worth commenting on is the variability in how the outcomes were measured. Andy, any thoughts about this? Yeah, I think that's a great point, David.

I think some of the notable things here are that there's disparities in the start and end points used amongst the studies in terms of when they were measuring device placement Uh for example, were they measuring at the start of laryngoscopy to one lung isolation, or perhaps they were measuring from the time that the tube was passed the vocal cords to the point of satisfactory placement of the device? Another discrepancy here is the level of training amongst the anesthesiologist within the procedures. Yeah, I think those are all important considerations when we think about time to placement. Not all studies are looking at the same time intervals, and it's going to be important to be cognizant of what exactly is being measured Another issue I want to touch on is that of fiber optic bronchoscopy.

Here at MGH it's standard practice to use bronchoscopy to confirm placement for both double lumin tubes and bronchial blockers. But some clinicians, depending on the institution, will claim that double lumen tubes may not require bronchoscopy for confirmation, and this could reflect in additional time savings. Andy, any literature looking at this? Yeah, I'm really glad you brought that up. I actually came across a study that was published by Klein et al. in 1998 that looked just at this.

So in this study, they looked at 200 patients who were undergoing thoracic surgery. 40 of the patients were women, 160 of the patients were men, and age range of 14 years to 78 years. And the thoracic surgeries that they were undergoing was predominantly lung surgery in 187 of the patients. And then 13 of the patients were undergoing esophageal surgery. And within this cohort, there were 70 patients who had a left-sided thoracotomy, 114 patients who had a right-sided thoracotomy, and 16 patients who had a median sternotomy The methods of this paper is they specifically had double luminance tubes placed blindly, so without fiber optic bronchoscopy. confirmation. And then positioning was confirmed by the anesthesiologist using auscultation after selective clamping of the bronchial and tracheal limbs.

And then they had a second anesthesiologist who was blinded to the initial intubation who would come in and perform a fiber optic bronchoscopy to confirm the complacement of the tube. and to correct any malpositioning. And then later on in the case, a second bronchoscopy was also performed with correction of two positioning as needed once the thoracotomy was done. Or once the strenotomy was done. And that's correcting for positioning, repositioning of the patient as we transition to the lateral decubitus position, or with neck hyperextension for strenotomy And just some of the definitions within the paper, they defined malpositioning as if the tube had to be moved in or out by more than half a centimeter. in order to correct its position.

And then critical malpositioning was if the left endobronchial limb was compromising. the left upper or lower lobe bronchus, so allowing no clear view of those bronchi. Or if the right endobronchial limb was allowing no clear view of the right upper lobe main bronchus. Then the final aspect of critical malpositioning was if the endobronchial cuff was misplaced such that more than half of it was within the trachea. Andy, I just want to make sure I understand the methods and do a little recap for our listeners. So it sounds like a double lumen tube was placed blindly and then confirmed by auscultation.

After that, a second blinded anesthesiologist performs bronchoscopy to confirm placement and correct any malposition scene. And then finally, after positioning for surgery, a second bronch was performed to again correct the tube position if necessary. Is that right? Yeah, you got it, David. Okay.

Awesome. What were their findings? So the results of this study, what they found was that via auscultation alone Malposition was detected in 28 of the 200 patients. And then when they looked at these patients with bronchoscopy, the most common reason for malpositioning was intubation of the wrong main stem bronchus. And that was in 13 of those 28 patients.

And then as a cohort altogether They found that fiber optic bronchoscopy detected malpositioning in 79 additional patients, so 79 more patients than just the 28 who were detected via auscultation. The most common malpositioning was distal malpositioning when 52 of the patients, and then in 18 of the patients, the tube was actually too proximal. Critical malpositioning was found in 25 of these 79 patients. And then post-positioning, so either after going into the lateral decubitous position for thoracotomy or neck hyperextension for sternotomy, bronchoscopy revealed malpositioning in 93 patients. All right, so we have a study of 200 patients where auscultation alone for placement identified 28 patients who had a malposition double lumen tube. and then fiber optic assessment picked up an additional seventy nine patients who had malposition of the tube.

A final interesting point from the study, malpositioning was as common after repositioning as it was after intubation. So I'm certainly getting the sense that bronchoscopy is vital as a confirmation tool, uh at least by the definitions of malposition and critical malposition used in the study. Dan, any other thoughts? No, I think I think Andy did a nice job summarizing and I I think it just really shows the limitations of what we can do by by just clinical signs, feeling chest movement, auscultation. Uh fiber optic uh bronchoscopy for positioning has a very important role.

Awesome. So Uh assuming that bronchoscopy is used for confirmation with both techniques, do we have any studies that look a bit closer to our first claim, which is that double lumen tubes can be placed faster than bronchial blockers? Yeah, it's a good question, David. There was a recent study that was published by Reese et al. that compared placement times of the EasyBlocker versus double lumen tubes. Before I dive into this study, Dan, do you mind chatting a little bit about what exactly the EasyBlocker is and how it differs from routine bronchial blockers?

Sure thing. So bronchioblockers by themselves are one a single lumen uh very very skinny uh long-ridge tube with a balloon at the end. Oftentimes they have a loop that can come out of the lumen that you can use to lasso your fiber optic to push it into the correct side Then you inflate the balloon, open the channel, and the lung slowly comes down. Easy blockers are a little bit different. It's a semi-rigid catheter still, but it has two distal extensions with two inflatable cuffs and uh central lumen.

And the idea is it forms a little Y at the end, and that Y you push it in and that sort of anchors on the carina. So now you have one extension into the left main stem, one extension into the right main stem. And you can look with uh fiber optic uh and just inflate one of the cuffs or the other one to isolate either the left or the the right lung. That's the easy blocker. Thanks, Dan.

That's super helpful. So for this study, 80 patients who are undergoing a lactive thoracic surgery that would require one-lung ventilation were randomly assigned in a one-to-one fashion to either a double lumen tube or an easy blocker. Some notable exclusions in this study. There were patients who were undergoing non-elective surgeries, patients who were pregnant, patients who were already scheduled to have a rapid sequence intubation. Or patients who had a contraindication to a double lumen tube insertion for one-lug ventilation were all excluded from the study.

As I mentioned, patients were randomly assigned in a one-to-one fashion. And notably relevant to some of the limitations we talked in the meta-analysis. In this study, all the anesthesiologists were, quote, experienced anesthesiologists. And there were only four anesthesiologists who were included or used for the study. The primary endpoint of the study was the time to successful run-lung ventilation.

And how they defined that was from the time required to prepare the device all the way until a lung isolation was achieved. And then they specifically for this study kind of broke that up and were able to analyze different chunks of those time in combination. So they looked at preparation time of the double lumen tube versus the easy blocker, time to successful intubation, time for placement of the easy blocker or double lumen tube, and one-lung ventilation And then time to confirm tube placement with fibroscopic bronchoscopy. The secondary endpoints of this study was quality of lung collapse the number of attempts it took for intubation, malpositioning of the tubes, and then any intubation related injuries that were noted after the surgery.

Hey Andy, do you mind just clarifying the time intervals? Yeah, sure thing. So they looked at preparation time of the easy blocker or the double lumin tube. They looked at time to successful intubation They looked at time for placement of the Easy blocker or double lumen tube in order to achieve one-lung ventilation, and then they assessed time for confirmation with fiber optic bronchoscopy. So now getting to the results.

One notable thing is that within this study there was more male patients than female patients So within the double lumen tube group, 25 patients were male to 13 females. And then within the EasyBlocker group, 23 patients were male to just 13 females With regards to the primary endpoint or the total time to achieve one-lung ventilation, what they found was that the easy blocker was faster than the double lumen tube by an order of about 60 seconds. So it took 234 seconds to achieve one-lung ventilation with the EasyBlocker and 298 seconds with the double lemon tube But then notably by breaking down those times into various segments, what they found was that the time gap between the two devices was really all attributed to different preparation times So, if we were to exclude preparation times, what we find is that for the double lumen tube, it takes about 140 seconds, and for the easy blocker, it takes 165 seconds So if we just ignore the time that it takes to prepare the device, there's really not a difference.

And if anything, what we see is that the double lumen tube is able to achieve one-lung ventilation actually faster than the EasyBlocker. So I think that I think that that makes a lot of sense, especially with the meta -analysis that Nick was talking about before. In that study it was time to placement, and I think it was fifty-one seconds faster for the double lumen two group And here, if you look just at the at the big headline, it's oh double limit tubes take longer. But that's when you account for the time it takes to set them up, which is important. But uh the other thing that we were talking about before is the time when it occurs makes makes a big difference.

Uh time after you make your patient apnec and uh you want to secure the airway may be much more important than time that you spend uh without as much uh uh hustle uh before you induce the patient. Does that sound fair, Andy? Yeah, I think that's a great point, Dan. I think A lot of anesthesia is preparation and we can prepare these things before when the patients are stable. And so that critical airway time when there's more opportunity for instability.

There's less differences between the groups. And just like you said, if anything the double them in tube is faster, as we see in this study. And then just to comment on some of the secondary endpoints of this study The double lumen tube was correctly positioned in 71% of the patients compared to just 44% of patients in the Easy Blocker group And then inadequate lung collapse was noted in five of the patients who underwent the EasyBlocker. And then going forward in this group, they were actually not able to have successful repositioning. And so these patients ended up getting converted into a double lumen tube group.

Got it. So it sounds like in this study of about 74 patients, the total time to obtain one-lung ventilation initially seemed slower in the EasyBlocker group when you took in all elements of device placement, including PrEP. But when prep time was actually excluded, the time to placement was not statistically different. Dan, any thoughts about the study in terms of strengths, weaknesses? Yeah, for sure.

So right off the bat, I think uh I really liked how they define the time periods so that we know exactly what they're measuring in terms of time to placement and one-lung ventilation. I hadn't seen that in a lot of studies prior, and I think it's particularly useful. And I think we shouldn't completely ignore the prep time. If if you get an emergent case and you don't have the time to prep, it's you should probably take that into account Uh the the weaknesses um so uh obviously the operator is not blinded uh to uh to which is which is uh being placed. But that's fine.

That makes it, I think, r reasonably generalizable. And there was a decent attrition rate, 7.5% AD patients initially, so that there may be some bias that's introduced through that. Perfect. Thank you, Dan. Um, so let's move on to the second claim, which is that double lumin tubes are superior to bronchial blockers in terms of the quality of lung isolation.

Any thoughts about that, Andy or Nick? Yeah, I think it's important to step back and consider what metrics are being used to define quality lung isolation What a surgeon might consider high quality of lung isolation may differ from what an anesthesiologist may define as high quality From a surgical perspective, the researchers of these studies tend to assess a subjective evaluation from the surgical field um as rated by a surgeon. And this rating may differ if the patient is undergoing an open open thoracotomy versus a minimally invasive video assisted thoracoscopy. Likewise, from an anesthesia standpoint, an important metric might be the need for a device adjustment following patient repositioning and throughout the surgical case Like we talked about with the Clayton and Smith meta-analysis from earlier, of those 13 trials that were included, eight of those actually reported on quality lung collapse as evaluated by a surgeon's subjective rating as either excellent, fair, or poor.

There were 617 patients in the double lumen tube group and 864 patients in the beta uh bronchiobalger group, but the meta-analysis revealed that there was no significant difference in the quality of lung collapse between these two groups with p-values of 0.11, 0.6, and 0.54 for excellent, fair, and poor respectively. All right, so that touches a little bit more on the surgical side of things, which is the subjective evaluation of the surgical field. Andy, what can you tell me about the anesthesiologist perspective in terms of device stability? And the need for intraoperative repositioning? Yeah, sure.

I think that's a great question. When reviewing the literature, I'd come across a lot of older trials. That in general had supported the stability of double lumen tubes versus bronchial blockers from the perspective of the anesthesiologist. And that's generally just looking at the need for intraoperative repositioning whether that's after initial intubation or after repositioning of the patient. But the interesting caveat here was that a lot of these studies I mentioned were older and so they were looking at the more traditional bronchial blockers.

And I think due to their design of just sitting in one main stem bronchus, it wasn't entirely surprising to me that they would require more repositioning events, as intuitively they just have less stability. And so I was particularly curious about the stability of the Easy Blocker versus the double limin tube, because I think their design more closely mimics each other in the sense that both of them have that more or less Y shape at the end that allows them to have some localization within each main stem I was able to find one prospective, single standard study that did look at stability of an EasyBlocker versus a double lumen tube, and from the perspective of the anesthesiologist.

Within this study, there were 163 patients who were scheduled to undergo thoracic surgery requiring one-lung ventilation. Some notable exclusion criteria for this study is that they excluded any patients who had a history of difficult airways on intubation They excluded patients who had distorted lower airway anatomy that was visualized on any imaging that had been obtained prior to the procedure. Patients with a BMI greater than 39 were excluded. And then any surgery that would require specifically a right-sided double lumen tube was excluded. As in this study specifically, they were looking at the use of left-sided double lumen tubes versus easy blockers.

And just for some context here, the majority of the cases in this study, 156 out of 163, were robotically assisted thoroscopic procedures. So wedge resections, lobectomies, decortications. mediastinal mass resections, those types of cases. Patients were randomly assigned to receive either a left-sided double lumen tube or an Easy blocker for either right or left-sided thoracic cases. The primary outcome of the study was any episode of malpositioning or loss of isolation requiring blocker or double lumen tube repositioning during surgical manipulation or During one-lung ventilation. Loss of lung isolation was assessed visually by the surgical team, or from the perspective of the anesthesiologist, if there was a significant change in ventilation requirements.

And in either of these instances, this would trigger a position check with fibroscopic bronchoscopy. Secondary outcomes of this study Was quality of lung isolation assessed by the surgeons? And this was an isolation score of one to three. So a score of one by the surgeons was suggestive of poor Positioning that substantially impacted surgical conditions. A score of two was acceptable positioning that mildly affected surgical conditions And a score of three was good isolation with good surgical conditions.

And I just want to note that by nature of where this study was conducted, Unfortunately, the surgeons were not blinded to what device was used as hospital protocols dictated that the surgeons had to be present for intubation. So I think it's an important caveat here that when surgeons are giving their mean isolation score of 1, 2, 3, being poor, adequate, or acceptable. Sorry. I think it's an important caveat to note that when surgeons are giving their isolation scores of one, two, or three for being poor, acceptable, or good, they knew whether or not the patients had received the easy blocker or the double lumen tube. Alright, so to get this straight, we're looking at randomized patients to left double lumen tube or easy blockers.

For either side thoracic cases. And they're looking at any episodes of malposition. And they're also looking at quality of lung isolation as assessed by surgeons with the caveat that the surgeons are not blinded. Does that sound right? You got it.

What'd they find? Yeah, it's interesting. So when looking at left-sided versus right-sided cases, they actually found some discrepancies For left-sided cases, the authors didn't find any significant difference in the rate of repositionings per hour or the prevalence of at least one repositioning event per case This wasn't the case for right-sided cases. In right-sided cases, the authors found that the double limit tube was more stable. than the EasyBlocker, as noted by a statistically significant increase in the rate of repositionings per hour for the EasyBlocker versus the double lemon tube. Just for some context here, so for the EasyBlocker group, there was about one repositioning event for every two and a half hours of OR time.

Versus in the double lumen tube group, there was one repositioning event for every 10 hours of OR time. So a notable discrepancy there for right-sided cases And then when looking at this from the perspective of the surgeon in terms of those mean isolation scores, what they found was that the initial isolation was statistically better for the double lumen tube. than the EasyBlocker for both right-sided and left-sided cases. And that on the whole, throughout the case, the double lumen tube was significantly better in left-sided cases But there was no significant differences noted from the perspective of the surgeon throughout the case for right-sided cases. All right, so it sounds like in this study the most significant result was that for right-sided cases the easy blocker was less stable overall. with increased rates of repositioning relative to a left sided double lumen tube, but this was not observed in left sided cases And presumably this is due to the more proximal takeoff of the right upper lobe relative to the carina and the potential inability of the balloon to completely occlude the right upper lobe takeoff.

I will also point out that other studies have looked at the stability of easy blockers versus double lumen tubes, but in general they're secondary metrics and The studies are not powered appropriately to capture differences. This is the first study designed to capture this, and it's also the first study to look specifically at right versus left-sided cases. Andy, in terms of limitations, we definitely have a couple. Surgeons were not blinded to which device was used, thereby potentially biasing their isolation grading. And another limitation is that only left-sided double lumin tubes were used, so any potential extrapolation to right-sided double lumen tubes should be made very carefully.

That's correct. Thanks for making that point, David. Great. So let's head into our final claim, which is that double loop and tubes are equivalent with respect to adverse effects. uh specifically things like sore throat, hoarseness, and airway trauma. Nick, any studies that help uh shed some light in this area?

Yes, absolutely. There was actually a very good study published in anesthesiology by Maurice et al. in 2013 comparing the incidence of airway injuries. Due to the double lumen tube versus the easy blocker. So in this study of a hundred patients, of which ninety-eight of them were included in the analysis, um These patients were randomized on a one-to -one uh ratio to the double lumen tube versus the easy blogger group Um and what was really interesting in this study is after the patients were uh were induced, uh an LMA was placed And then an unblinded pulmonologist performed bron fiber optic bronchoscopy to evaluate the airway before actual airway intubation to classify any pre-existing injuries. The anesthesiologist would then come in and place a double lumen tube or an easy blocker, depending on what the randomization protocol for that patient was.

And then once those devices were placed the pulmonologist would confirm placement of of those devices once again. And at the end of the surgery, the device was removed, the LMA was reinserted, and the pulmonologist would once again take a look with the fiber optic scope and classify any injuries uh that would that could be found along the bronchus, the carina, and the trachea This study was also unique in the sense that the anesthesiologists performing the intubations and device placements were all classified as experienced in both of these techniques and there were only four anesthesiologists performing the intubations across all hundred patients. Um the surgeons were absent and and blinded uh for the study as well.

And although the primary outcome was the incidence of malposition detected by bronchoscopy after initial insertion I think the study did a really good job at highlighting the difference of where these injuries occur along the airway and the difference between uh the two devices. Going into the results, the patients in the double-lumen tube group had a higher incidence of post-operative tracheal hematoma, tracheal redness, and bronchial hematoma compared to the EasyBlocker group. Nick, I'm just gonna jump in here and comment on uh some of the other results. There were actually no differences in injuries at the vocal cord in Maine Corina. Uh there were more lesions at the tracheal and bronchial levels in the double lumen tube group, but no greater main carina hematoma in the Easy blocker group, uh despite the design characteristic of uh sitting on the carina.

Dan any thoughts about the results of the study? So they found an increased incidence of sore throat, which to be honest, doesn't really surprise me. If you look at the external diameter of a the smaller tubes, double-lumen tubes we tend to use Uh 35, it's going to be on the order of 12 to 13 millimeters, and a lot of times we're using a 37, 39, 41, which gets up to close to 15 millimeters for the external diameter. Compare that to our single-lumin endotracheal tubes. When was the last time you placed a 9-5 endotracheal tube?

That's how large you'd have to place in order to get 13 mLs for your external diameter So that makes sense to me. And and I think we probably have seen enough evidence now that we just have to accept the sore throat as a cost of doing business if you're planning to do a double lumen tube. Maybe there's some techniques to minimize that But I'm not aware of them. The one thing about this study though that does give me a little bit of pause is I think there probably are techniques to minimize the the carinal and tracheal injury. They they say that they push the they advance the double lumen tubes until slight resistance was encountered.

Um I've been taught from my mentors, and it's always been my practice, that if you push the double lumen tube until you feel resistance, you pushed it too far So uh my typical practice is to fall short of that, you know, 28, 27, something like that in men versus women, and then place it uh exactly where I want it with the use of a fiber optic. So I I worry that uh maybe the uh fibroscopic findings that they're finding with their pulmonologists doing the bronx afterwards Maybe those are just a result of the placement technique rather than something that is a must occur with the double lumen tube group. So I I find that to be one shortcoming of this trial in the methods.

Did that make sense Yes, that makes sense. And that's a really good pickup um in the method section on how they described how they placed these devices and uh seemingly different institutions and maybe across um different training programs and different practices, uh how these devices are placed is a significant confounder in how these s very studies are done and ha when they went assess sore throat and uh airway injury. Another area I want to touch on is that of cost. Dan, any thoughts about how to consider the cost of each device in in this greater discussion? Yeah, I think I think you know healthcare costs are rising.

I don't know necessarily that the single cost of a device that we use in the OR is what's gonna tip the scales, but I think it is incumbent upon us to to consider that in in all of the things that we we do in medicine. In particular, if we reach aqua poison benefit to patient, then for sure we should consider cost. But even short of that, I think I think it we owe it to our patients to consider the cost benefit of these things. Andy, Nick, do you have cost data on the devices, double tubes versus bronchioblockers? Yeah, so I do have some comments on the cost.

And I will preface this that the trials that have reported costs are trials that are a little bit dated from the 90s or early 2000s. Um and that some of the newer studies that we looked at weren't necessarily reporting costs of double lumen tube versus bronchial blockers. But from the studies that we've been able to see We do see on average that double lemon tubes are cheaper than bronchial blockers on the order of $75 from a double lemon tube versus $130 for a bronchial blocker. Though again, I will just highlight the significant caveat here being that these studies were published in the 90s and early 2000s, and so certainly the cost of these devices has changed over the years.

And now throughout this talk, we've talked a little bit about the EasyBlocker. And the EasyBlocker didn't exist when those studies were published, so that wasn't a reference point in their trials. Great, thanks Andy. Uh so we'll wrap this episode up by returning to our case. As a quick reminder, the case is that of a 60-year-old man presenting for left upper lobectomy with preoperative FEV1 and DLCO in the 90 to 100% range.

The resident again suggests that a left-sided double lubin tube is preferred because they feel it's overall better and easier. So I'll let Dan take it away here to wrap up the episode. Andy, Nick, thank you guys very much. This was a I know a lot of work went into all of the lit review to to dig into this question. Overall, what I'm sort of taking away here is that the double lumen tubes probably come up with a cost of uh increased sore throat.

But they may afford benefits such as speed for placement and less need for repositioning. And I and I know I'm taking a lot of data that you guys looked at and really summarizing it, but it seems like that's where the tendencies were. And I think that's great. I think, you know, from a practical standpoint, even had they looked equivalent or questioning, you know, is the sore throat worth it? There are other pros and cons that don't seem to be discussed in the in the literature but are worthwhile mentioning to listeners.

So for example, with a with a double lumen tube you can uh you can suction a lot easier on the non-ventilated lung. You also have the option of delivering clinically significant CPEP much more easily And uh lastly, it's it's not that infrequent that I'm assisting with the surgical identification of a bronchus by putting my bronchoscope into the non-ventilated lung, say just uh putting the down the the middle lobe or something so that they can confirm the anatomy on their end by looking at the light of my fiber optic scope. All of those things would not be possible with a bronchioblocker, and that's something that you've got to take into account. At the same time, the bronchioblockers have some particular advantages that may make them the right choice independent of these other considerations in some situations.

So for example, if you have someone with a difficult airway and you can't navigate a double lumen tube, or if you have someone with a tracheostomy that you do not want to remove. . You're not going to be able to get a double lumen tube in in there. You could, however, navigate that with a bronchial blocker. Bronchial blockers also allow you to do low bar isolation So you could actually even put an easy blocker or a single channel bronchioblocker into a particular lobe and just take down that one lobe if say hypoxia for taking down the entire lung would be too much. And lastly, if uh if you're planning to take a patient uh to their post-operative destination, intubate it.

Using a bronchial blocker avoids the need to re-intubate the patient at the end of the case. You can just leave the single lumen tube in place, assuming that most postoperative destinations wouldn't be as comfortable with a double lumen tube. So though the literature is rich and gives us a lot of information about quality of placement, sore throat trauma, need for repositioning. There still are some operative considerations where we we've got to think beyond what's available in the literature to see what's most appropriate in the case that we have in front of us. Dan, thanks so much for such a masterful summary.

I know our listeners will greatly appreciate not only the review of the evidence we chatted about today, but also some of the clinical considerations that you added in there. I want to thank you for taking the time to join the show today and for all the work you've done in supporting Andy and Nick throughout this project. Absolutely a pleasure. And finally, a big thank you to Andy and Nick for all your work throughout this podcast elective. You guys should be really proud of the work that you've done.

My pleasure. It was a good experience. Thanks, David, for having me on. To our listeners, thank you so much for taking the time to join us today. The podcast elective here at MGH is off to a flying start, and we have multiple episodes in the queue waiting to be recorded.

As always, if you enjoy the work that we do here, please rate us on Apple Podcasts. But more importantly, share this content with your colleagues and have those thought-provoking conversations. Our mission is to improve the quality of the work that we do, and I thank you for taking the time to join us. As always, stay hungry and keep asking questions. So it's a very small , it's a place to face value, it's a very small , it's a very small , it's a very small