Dr Soeyland - Aortic Compression (7/19/2022)

Oh, yeah, go ahead, Joseph.

Sorry, I was muted. Double muted. Applications are open for fams credentialing. That'll close in August. Also, check your inbox if you're an NMSP member. There is a letter to National Registry from NMSP on their standing on credentialing.

Oh, that's great. Okay, well, we appreciate that. Very good. Okay, thank you for that update. All right, so without any further ado, we've been very, very fortunate to have Tom Soyland come join us. It's very late. It's 1am it's cold. He's in Australia. How did I get in touch with him? I read just an incredible paper that he had on the junctional tourniquet. It's kind of a nice, beautiful review of many papers, and it's one area that a lot of people ask me about all the time. And when I saw it, I contacted him and he was very kind enough to say, absolutely. And here he is. So, Tom, can you give us a little bit of introduction of who you are, where you work, and then we're really excited to hear about your discussion today.

Absolutely. Thanks very much, guys, and good morning. I think I'm just a day ahead of you now, so. So welcome to the future.

Please feel free to interrupt with questions as I go. I'm never quite sure what people know or what they've heard about this topic, so if there's anything that's not clear, just interrupt.

And first just want to say thanks for the opportunity to talk about this research paper. I'm not an experienced researcher and this is just a literature review, so it's not really research as such. And it was pretty stalked when it was accepted for publication and even more stoked if anyone is actually reading it.

I don't have any conflicts of interest.

Other than an interest in the topic and also just want to sort of declare that I'm not a trauma specialist as such. There is limited trauma in Australia compared to the States and other places, so.

I'm just a regular ed doctor that has sort of stumbled up on this interest.

My name might be a little bit confusing, so I'm originally from Norway.

And I've ended up in Australia, where I've done all my medical training and I'm currently working as an emergency department staff specialist in a little town called Port Macquarie. And I'm also a staff specialist in pre hospital and retrieval medicine, as we would call it, which I think you guys called ems.

Just in case the geography isn't immediately clear.

I'm in New South Wales at the moment.

You can probably see Sydney here and Newcastle where the retrieval service I work for is operating is a little bit north of Sydney, the second largest city in New South Wales. But they have the second largest trauma center in Australia. There. There are other larger cities in Sydney. Sorry, there are other larger cities in Australia but in the bigger cities they often have multiple trauma centers, whereas Newcastle has one trauma center that covers a large area of the state and therefore becomes a big center.

And it's a pretty nice town to live and work in.

And the Hunter retrieval service that I do work for have a pretty substantial capability. We have Augusta, Westland or now Leonardo helicopters139.

Or we work in road vehicles. There's a mix of teams, usually a doctor paramedic team for all the pre hospital stuff. But we can also work doctor and nurse for inter hospital transfers. We can intubate, we have video laryngoscopy, we can do chest tubes, we carry packed red cells and extended life plasma for blood product transfusions.

And we are part of a sort of governmentally organized statewide network of similar services. So all the pre hospital services in the state have to.

Achieve standards similar to this to be, to be allowed to operate.

And we do everything from roadside trauma search and rescue.

Winching over water, over land and pretty sort of night and day capability.

And like I mentioned, we cover quite a large area. So again, if you can see on the map, Sydney is south of us. They have multiple services that sort of COVID a small area. And then we cover this huge reach going north up towards a place called Coffs harbor which is sort of normally our northern limit. And a round trip there to come back to the trauma center is around about 700k which is about the length of Florida according to Google. So we have, we have pretty long jobs compared to many other pre hospital services.

And I'm here today, like we mentioned in introduction to talk about external aortic compression.

A paper that was accepted in Annals last year.

My interest in this topic started back in 2016 when I was new to the retrieval service. I was a registrar or a trainee. I was studying for my fellowship exams, I think board exams for you guys. And there was one of these devices sitting in one of the offices and I sort of fiddled with it and found out what it was, that it was the abdominal and junctional tourniquet.

And I couldn't quite understand why we didn't have it on the helicopter. Did a little bit of sort of searching around. Among other papers, I came across this one from 2013 by Matthew Duma over in the States. And it's a pretty remarkable case report of himself being out, you know, outside work as a civilian. When he comes across a. A guy that's been shot multiple times.

And he can see the blood, you know, coming out of multiple wounds. The guy loses consciousness and in desperation he applies abdominal external aortic compression. The guy has reduction in the hemorrhage and he regains consciousness. And then there's this stepwise description where every time they release the pressure, the guy goes unconscious. And every time they reapply it properly, the guy comes back. He eventually dies in hospital when they stop providing pressure. And.

Matthew has since sort of published several research studies on this principle.

And then as I started looking around, I realized that external aortic compression is actually very well described, especially in the obstetric literature, and that there were a smattering of other types of.

Applications of the technique. And we started together with Alan Garner, who's a more senior clinician than I. We started just collecting articles of interest and eventually work towards this review that we had published.

And just to cover the basics, the. The premise of external aortic compression is that you, with manual pressure or a device or whatever, can essentially completely occlude the abdominal aorta in the area similar to zone three riboa. You have to push against the lumbar lordosis, so you can't really get as effective compression, at least more proximal, and that it will then cause occlusion of distal flow and increased systemic vascular resistance, so you can increase blood pressure and perfusion of proximal organs.

And the hypothesis is that it might then improve chances of ROSC in traumatic cardiac arrest, and it should be able to achieve hemostasis in pelvic and junctional hemorrhage distal to your occlusion area.

I guess ROSC in traumatic cardiac arrest can be a little bit of a misnomer in that, you know, often it's more a low flow state. But you can perhaps hypothesis generate that you can improve hemodynamics in traumatic cardiac arrest situations.

Just a little bit of background, I guess, of how I see trauma care at the moment. And if you have any objections or other thoughts, please let me know. But.

In general, there's been huge advances in trauma care recent decades. We have increased car safety, we have reduced interpersonal violence, believe it or not. We have much more sophisticated trauma systems in the western and developed world with very skilled pre hospital and emergency department providers. Now concepts such as damage control, resuscitation, Surgery seem to have made a difference.

But head injury and exsanguination still remain some of the leading causes of acute death in trauma.

There are still problems that we are sort of trying to solve, head injuries I think, and there's not. No one has any great new concepts or ideas that are going to make a huge difference there yet.

And non compressible truncal hemorrhage.

Is always difficult to treat even in the emergency department, you know, outside the operating room and to some extent even in the operating room, obviously it's hard to treat.

And traumatic cardiac arrests, you know, have still very poor prognosis because there's a multitude of possible coexisting pathologies going on. Inflammation in especially blunt trauma remains difficult and poorly understood. And to some extent we're hitting the point now where a lot of the low hanging fruit have been sorted, such as limb tourniquets, etc and be able to transfuse blood in many situations. And so we're probably having to put in a lot more effort in to get some improvement.

And my sort of looking out from where I work there seems to be sort of two streams at the moment. There is a tendency towards more aggressive care, you know, looking at ECMO and riboa in in many trauma situations. But at the same time a little bit of a less is more trend with smaller chest tubes and you know, don't do things you don't need to do, just move the patient to definitive care.

And harking back to what I said about our area of responsibility, some people still refuse to live in metropolitan areas and it's obviously very hard to bring the same level of care to someone who lives rural or remote as you can to someone who lives in downtown Sydney or downtown Miami.

So our paper basically had as a goal to just summarize, sorry.

The current literature on external aortic compression so that we could decide whether we were going to start carrying this tourniquet and in which situations we should think about using it. So before we did the review as such, we already had a fair grasp of the literature so we, we knew some of the problems and issues we would come across. And so we chose a scoping review.

Which is poorly defined I guess, but it's just a review that isn't too systematic and your goal is not to do maths, it's just have a look across the whole literature. And we knew that a lot of it would be animal stuff and that there wouldn't be a lot of randomized control trials to cohort together.

So we did A literature search. I won't talk about all these sort of tables and figures in detail. I've just got them in here to show the content of the paper, I guess. And we ended up with roughly 25, 27 papers.

We excluded papers that were looking at, you know, surgical techniques of occluding the aorta or when it was done in theater with say a laparotomy.

And we excluded where it was applied to medical arrests, things like abdominal counter pulsations and that sort of thing.

And initially we, we sort of wanted to look at hemostasis. But I guess what the papers almost invariably look at is actually distal flow, sort of just subtleties there. In, in the actual outcome, you're not looking at blood coming out of a wound, generally looking at the flow in distal arteries as a surrogate for whether it could stop bleeding.

And under that sort of heading we found a total of six papers. Nine were human and seven were swine models. There were a couple of very large obstetric studies and a smattering of sort of healthy volunteers where they take soldiers or medical students or other able bodies and they apply external aortic compression and then measure distal flow with ultrasound. And again, I won't go into much details with these slides.

But if you see the second from the top there, the obstetric cases, you have one had 120 patients from an Egyptian sort of semi randomized trial in postpartum hemorrhage.

And a few decent series with, you know, 20 something healthy volunteers. And essentially the outcome is that in almost all situations distal flow is either severely reduced or completely stopped. So almost without fail you can preclude the flow.

Obese patients or obese healthy volunteers seem to be slightly harder to achieve this in.

And then when we looked for papers on traumatic arrest, we found four papers and one swine, four human papers and one swine model. One of them had, one of our co authors was a co author on that one as well, which is a, an actual pre hospital case series with 19 patients. They had a ROSC and about 22% of those patients.

One survived to organ donation, but none survived till discharge. And there were some other case series basically.

And you can see here we've sort of grouped this slightly differently. We've looked at where they used to devise such as the junctional tourniquet or where they just used hands or legs, sort of manual compression.

And there is a case report from Afghanistan where they used the device and had a survival to discharge in an individual with a severe lower limb blast. Injuries, he was really unwell and they basically used the aortic occlusion to get him to.

Blood resuscitation and then to theta.

Physiological changes. We also found a lot of papers, most of them looking at.

Animal studies. And here the tables basically sort of just jumbled together with humans and animals.

And essentially we've just looked at whatever physiological parameters we could find.

And in most cases there seems to be an increase in heart rate.

In almost all. So 14 out of 15 papers they reported sustained increase in blood pressure and proximal to the occlusion.

Not really much change in cardiac output, but the systemic vascular resistance goes up, which again stands to reason mechanistically there is some negative effects on ventilation because you will obviously displace abdominal contents and increase the abdominal pressure.

And.

You have increased pressures, reduced volumes and increased rate to look at that. And you do tend to get an increase in end tidal carbon dioxide when you look at applying it, for instance, in traumatic cardiac arrest.

One of the main.

Issues we want to look screen for were complications.

And very little there in terms of human data.

Pain was looked at in many of the volunteer studies and some of the postpartum hemorrhage papers.

With quite variable severity of pain.

In some of the postpartum papers there is probably a bit of contamination with patients that may have had a spinal or an epidural anesthetic.

And there seemed to be an association as well with increased BMI causing more discomfort, both in a healthy volunteer paper and in one of the obstetric papers. Release syndrome is just basically post release hypotension.

And one of the papers that I've.

Was actually on humans way back in the 50s, I think aortic occlusion was used as a way of.

Targeting chemotherapy.

And they would essentially try and occlude the legs so that you could get higher concentration of very toxic substances in the torso. And there was one paper with very good physiological data on these poor patients that underwent that, that technique. And they all had hypotension after release.

Vomiting was seen in some of the postpartum patients and leg numbness and tingling were also seen in some of the obstetric cases. But they all had resolution of those symptoms.

When you go to animal studies.

Not so good again. Hypertension on release is quite common. Respiratory arrest happened in some of the many swine that have been sacrificed to this technique. And you have other metabolic disturbances like hyperkalemia, a drop in ph, release of creatinine kinase, myoglobulin, and in some animal Cases, again, actual internal organ injury. These are all swine models. And it's obviously a little bit hard to know whether this would be the same for humans, but essentially there seems to be severe problems if you go beyond 60 to 90 minutes of occlusion.

Just a little bit of sort of random bits and bobs that came out of the paper. It is, it is a very interesting topic again because.

It covers so many different fields and there were some very sort of interesting.

Papers in there. One of our favorites was. We haven't included it in the review because it didn't fulfill the criteria, but There's a. From 1911. So, you know, 110 years ago there was a letter to the editor of a British medical journal where they basically said this technique always works for postpartum hemorrhage. And all you need to do is apply a couple of fingers of pressure to the abdomen of the patient and you can just feel how much blood is going through the aorta and you can release as much as you want to the distal organs. I don't think that would work very well on our current sort of obesity afflicted population.

It does appear from some healthy volunteer studies that the best way to do this technique is using a knee so that you can apply your whole body weight, whereas using the fist is sort of second best. And the device is also. There's a couple of different devices seem to work relatively well.

There is one case report where this was applied for abdominal aneurysm rupture. A Japanese case report where again they give. I think there was a lady in her 80s or 90s who came into the emergency.

With typical symptoms, was found to have abdominal aortic rupture, decompensated and they applied aortic compression. They sort of got her to theater where during transfer someone released a pressure and she immediately decompensated. They reapplied the pressure and she stabilized. And they basically prepped the patient with the fist pressure in situ and went sort of straight for laparotomy and managed to save her.

There is one case report from Australia pre hospitally for a ruptured ectopic where an Australian team found a sort of semi conscious, no palpable output, patient thought to possibly have an ectopic. They applied this technique and essentially got her stabilized, moved to hospital and she survived to discharge.

A couple of or one paper looking at trying to apply this technique during or in a moving car. I think that was Matthew Duma who looked at that and it's like cpr, very hard to do during transport. And there's probably a role for a device in that setting, such as the ajt.

There's another paper where they looked at applying abdominal compression or aortic compression to compensate for.

Hypotension during induction in elective anesthesia. An elderly patient. And we could only. It was a Chinese paper, we could only get the abstract, but it appeared to have a stabilizing effect and obviously only pretty brief.

Intervention, so not a prolonged occlusion.

Similarly, there are human studies again from this Egyptian center that have done a fair bit of external aortic compression in postpartum hemorrhage where they have occlusion for up to 150 minutes with no apparent significant pain or long term ischemic issues, but where there was some ongoing femoral flow.

During the application of a spring loaded device.

I just thought I'd mention mast suits. People who remember them often ask about it.

For those that don't know what they are, they were sort of pneumatic devices that were very fashionable I think in around about the 80s and 90s in pre hospital care where you could basically inflate. I've never used them. Well, you could basically inflate a garment that would provide pressure to your whole lower limbs and lower pelvis.

With similar ideas of increasing systemic resistance and working as a sort of auto transfusion and to some extent a hemostatic device. And they had very initially promising results, but then was found to probably cause more harm than good.

And I can't in any way argue that that will never happen with external aortic compression. But they are fundamentally different ways of trying to solve this problem where aortic compression is obviously very targeted.

Intervention.

And I just also wanted to mention release syndrome management. In some ways, prolonged external aortic compression is probably similar to a crush injury for someone who's been trapped in an earthquake or something along those lines. And so if anyone is thinking about applying this, you need to have a plan for where and how it should be released. And theoretically there might be benefit in similar preparations as you would do for a crush syndrome or release syndrome where you use calcium, you use intravenous fluids and so on to stabilize the heart and, and protect from all the metabolites that will come north when you release the compression.

So where to from here with what the review sort of reveals.

In our service? Obviously this, this review doesn't, it's not evidence, it's not, doesn't prove anything, but it I guess indicates that yes, it can probably cause or, or help with Hemostasis, and it might help physiological parameters in traumatic arrest, but with the risk of ischemia, we've sort of said that for us, we're going to limit the use of this technique to traumatic arrest management. For now. There has been variable uptake among my colleagues. I think it's fair to say that some are believers and some are not. And also in some of the TCA cases we've had, they just forget about this option, among lots of other options.

We advocate that in that setting, people use just manual compression first because the device costs hundreds of dollars. And in the patient population with very poor outcomes, there's no point using the device as a. As a given. And then if you do find that you get some result, some improvement, and you start to think about moving the patient, then you can apply the tourniquet that we carry. Now.

We know that we have it as a last ditch in. In pelvic hemorrhage, anecdotally, in our service, we go out, we pick up patients who have an isolated pelvic injury. They're conscious, they're doing all right, they get loaded in the helicopter. We're flying for an hour, an hour and a half, and by the time the helicopter lands, the patient is. Has died despite us transfusing all our blood products and so on. And in that situation, there is probably a role to apply aortic compression to bridge to definitive care.

We don't see a lot of postpartum hemorrhage patients. They generally get managed okay in our regional hospitals. But in theory, we could get deployed to such cases in rural and remote areas. And we know then that we have that up our sleeve.

We're hoping for some prospective data, as in, we're hoping to do some prospective research ourselves, but we're small, and again, the severe cases, we're never going to be able to, in our service or in our network, generate any kind of definitive prospective data set. And the other thing I'm very curious about is any potential for this technique in medical arrest where there isn't a lot of literature, but there is some literature to show that the physiological effects could be beneficial without having.

Grams of adrenaline in the circulation when you do get rosc.

So I just thought I'd mention as well that while we deal with traumatic cardiac arrests, we apply something called a hot drill. And I don't know how well known it is outside Australia.

But it's a way of sort of triaging your resources a little bit. So external hemorrhage control is the first order. So if there's any kind of obvious squirter, you apply a limb tourniquet or direct pressure or whatever and often the road crews will have done that before we even get anywhere. And then you oxygenate and the emphasis is to not intubate unless you, you have to, to not tie up resources there. If you, if it's easy to do then we do that. But it's not, it's not about intubating, it's about oxygenating.

We generally do bilateral finger thoracostomies for tension or to rule out tension. And then we have the option of tourniquet and here meaning abdominal tourniquet because limb tourniquets come under hemorrhage control.

And then we transfuse and meaning by that that we don't necessarily transfuse all of them because it is a pressure resource. And part of the point of having a doctor pre hospitally is to make a high level decision as to whether you spend that resource or not, depending on what you think the likely outcomes could be. And then lastly, we have limited training and ability to deal with, you know, pericardial tamponade. We have, we have the option of doing a, a resuscitative thoracotomy but we don't actually carry specific gear for it, so we don't carry rib spreaders and so forth.

I have N equals 2 experience applying this in in two motorcycle traumas, traumatic cardiac arrest and in both cases we had unequivocal physiological response. None of them survived to discharge. One of them got to the point where we applied the tourniquet and we had him on the stretcher. We had police cars arriving with more blood because we had spent all our blood and I actually thought we were going to get away and then he just suddenly arrested and was unrecoverable.

So I think with the little data we have we can sort of somewhat support our hypotheses. But the remaining questions are whether it will make clinical differences or whether most of these patients are going to be so injured that applying a technique like this will never actually make any sort of statistical difference. It'll be hard to identify the right group of patients where this is the right.

But it might be the poor man's riboa in pre hospital and rural settings. I think at least here, and I'm guessing in the States as well, there's no way you're ever going to be able to put ribowa capable crew near all of these patients that may benefit from it. And even in bigger centers here in Australia, when they crunch the Numbers. It's rare to have patients that are suitable and therefore maintaining skill and all that sort of stuff is hard. Whereas external compression in some patients, obviously not zone one and two, but in some patients might be more doable.

Again, there are controversial patient groups such as ruptured AAA and ectopic pregnancy and all that sort of stuff, but it's by no means an accepted mechanism. But if you're in a small rural hospital and someone's rupturing their abdominal aorta and the surgeon is 30 minutes away, you know, maybe it has a role.

And lots more needs to be found out in humans about the potential adverse effects, same as it needs to be done for riboa. What is your ischemia time? Is there a role for intermittent or partial application? Can you use ultrasound to monitor dynamically what you're achieving and so on and so forth.

And is there a fundamental difference in a blunt trauma patient, a penetrating pore trauma patient and a postpartum patient in terms of all the other inflammatory mechanisms that are going on that actually are going to play a significant role in this population?

And that's about it.

Wow, Tom, this is really the, the best really overall review of this, of the junctional tourniquets that I've ever heard of, including going into the physiology, some of the parameters. But really what's most striking to me is the outcomes. How.

It appears that these devices aren't the be all and the end all. Even though you have blood on top of it with a device, it seems like it's hard to get really many neuro attack survivors, which is, which is pretty interesting. If I had to poll everyone on this call, I would suppose that many of us don't carry these devices.

I just wonder, and I know I want to get over to Dr. Pepe's webinar, but does anyone on the call are using these devices and that you could talk about your experience with them? Does it corroborate with what Tom is saying? Before we move over to Dr. Pepe's.

Webinar.

I'm looking for hands. I don't see any.

Well, I guess I would just emphasize again that I don't think the focus shouldn't be on the device because I think these patients will be rare and.

That you don't need a device, you just need two hands or a knee.

Yeah.

And.

Not running around looking for a device that someone think might exist, a drawer or, you know, I think doing them manually because they are expensive and you can probably. Well, we know you can achieve the same effect with manual compression.

Yeah, that, that, that's, that's a huge, that's a huge learning point for me as well. Is that how successful you can be with a knee dating back a century? No.

Exactly. And, and again, every time you think you found something new, it's already been done before. And again, this seems to be going more than 100 years back and in obstetric literature.

And yeah, there's, I suspect there's more older stuff that just wasn't available online that we, that we didn't come across, basically. Right.

Well, I could tell you that I'm sure I could speak for everybody. And you're getting a couple of thank yous from our friends out there on the call. Michael Austin Academy. This has been very, very helpful. Your. This talk will go out to a couple hundred people. I'm sure it'll be watched over and again. So, Tom, thank you so much. I know you're probably very tired. Go get some sleep. Thanks for the other webinar, but. And by the way, the same link every week we have another presenter, so feel free to join us or have others join us as well. Okay.

If I'm up.