Great, thanks again for the privilege of the podium here and to talk about something that's a little bit off the beaten path, it's something I think all of us interact with quite frequently, sometimes maybe take for granted and kind of important to understand what we're really gonna be doing operationally when we talk about using aircraft, in particular helicopters. Really don't have any disclosures related directly to this other than some Department of Defense funding in the past for this type of work. So we've come a long ways in 50 years. We were, you know, hearses and very early transports in the 70s is when we really started using the helicopter based on our, really our experience in the Korean War is really what helped proliferate this. And early reports were encouraging. We were seeing things in the literature such as, you know, maybe up to 14, 15% of patients are benefiting because we're getting them to trauma care. And this is really about trauma, really a heavy focus on trauma in terms of the use of the helicopter. But evolving from a hearse to a helicopter in a very short time. And this is just an overview of kind of modern capabilities that we have today. And I think the things to point out here are the speed. These are pretty fast aircraft, but they're also really expensive, really expensive. This one here, the Augusta Westland Leonardo 139, AW139. So what we have in Maryland, that's an 11 to sometimes up to $13 million helicopter that can cost quite a bit to put in the air, upwards of nine, sometimes $10,000 an hour just to fly that. Huge, it's huge. You can do ECMO, you can do things in the back of it. You can actually put people on ventilators and do a lot of critical care. But this technology, at least the technology of the vehicle itself is very expensive and something to consider with all of us. The other thing that really has to come, has to be discussed when you're starting to talk about helicopters is the safety. And I think, you know, many of us have been unfortunately involved with some of these either investigations or people we knew on these helicopters that died. This is our helicopter in Maryland, 2008. Very successful, high volume program, great helicopter, but with one pilot under the weather, trying to come in at Andrews Air Force Base, try to duck under the clouds. This unfortunately killed four people, including a volunteer EMT. And there was one survivor who was severely injured, but also killed two state troopers on board. So really tragic, even in a state like Maryland where try to be as safe as we can. But this was also a mission where the patient did not need to be, the two patients did not need to be flown. They really did not need to be flown. They were not critically injured. They had minor injuries. So this is something we have to be very cognizant of. And as a result of this and other, you know, reviews, there's been a lot of literature out there that looks at when we use this modality, this transportation, it's not just the transportation, it's the transportation and all that comes with it. We're delivering critical care. We're using the helicopter to bridge the gap. And we'll talk about that at the end and how it can be an equalizer. But there's a lot of studies that show when we don't have patients that are that severely injured, at least for trauma, and the same would apply for medical, that overuse and over triage is what we're going to wind up with more safety problems. There's one, it's a little dated now, but one of my mentors, Sue Baker from Johns Hopkins, published a paper where average pilot or paramedic flying 20 hours a week over a 20 year career had a 37% chance of being in a fatal crash. Now, we've done a lot of things in the last decade and a half to improve safety to pilots. We have a lot more technology aboard these helicopters, better criteria, which we'll talk about in terms of triaging patients, but that's a pretty profound statistic. I mean, that's right up there with fishermen on ice boats in Alaska. Other really hazardous professions where high mortality rates. So something that really needs to be looked at. Just another summary table of a lot of studies that we're against. All of these studies though were really case studies, cohorts without adjustment. And so this literature is very limited historically by the lack of a rigorous methodology. And then here, even here in Arizona, I remember when I was here years ago, we had a couple of crashes, really just tragic. I mean, these helicopters land on, they're not landing at airports, they're landing in fields. This case, trying to land in the desert at night, oftentimes bad weather. So there's a lot of factors that go against safety when we talk about this. So that's hence the importance of using this resource appropriately. So really that's my research interest, a little different than your standard intensivist or anesthesiologist for sure, but really trying to cultivate a versatile and really robust research methodology to really look at this, to determine when and if we should be using the helicopter and again, all that comes with it. And so just real quickly, I'll go through two pieces of literature that we have put out there. One is just a structured review to really compare ground versus helicopter transport for adults with major traumatic injuries. It's a Cochran review. And as you know, with Cochran, you have to re-review it every several years. So it gets updated at least for the first couple of years, but this really just included exactly that, adults traumatically injured. And you can see right away, there's a risk of bias that's detected. These are not studies that are randomized control. It's really very difficult to do that. It's really never been done honestly with this literature. So you're talking about observational trials that are probably underpowered with a lot of issues with internal and external validity. When you put it all together in this busy forest plot, you've wind up with an effect estimate that's really smacked down the middle, not statistically significant in either direction. But if you start to look at studies that do adjust for injury severity and other factors, mainly injury severity, because that's important. And the sicker and more injured the patient is, the more likely they may be to benefit from this. You do see a very consistent effect estimate, which oftentimes in most studies has been statistically significant in favor of the helicopter and all that comes with it. We'll talk about that at the end quickly from an epidemiologic standpoint. One thing that's of interest, I think, to our profession as intensivists is transfers. Because this is something, again, we take for granted. Yeah, bring the patient, maybe we're on the consult and we're accepting the patient into our unit. And how are we gonna get them there? Are we gonna drive them? Are we gonna fly them? There's just no guidance, no great guidance for this other than the fact that time dependence and crew expertise are often the two factors that you have to make in helping with this decision. I can say out of the Cochran Review, four studies we looked at pre-planned did show survival benefits, but lots of methodologic issues with this. But different methodologies, kind of methodologies all over the place. But did show an overall signal of benefit, perhaps with this review, but understudied. Majority available evidence does support a benefit, but the quality of existing data is fairly poor. At least historically, it's been poor. And really, this really begs for more advanced methods. So to do that, this is another study in another layer, and this has been replicated, but I'll show you the original one here. And I think everybody understands and appreciates when you get a data set nowadays, it's really easy to put that into statistical package and hit the regression button. Anybody can do it, it's really easy. You can get an odds ratio, a confidence interval, put it in a table and try to publish it. But what about the diagnostics for this? What about checking the model? Is it the right model? Have you picked the right variables? There's a lot that goes into this methodologically to do this the right way. And so that's what we tried to do, again, with trying to address the deficits we saw in that Cochrane review. So looking at this with a very large database, the National Trauma Database, and over 200,000 patients, and using propensity scores as the main mechanism. And propensity scores, I won't review all of this in detail for the time, but really what we're looking at here is trying to compare apples to apples, oranges to oranges in some way statistically, based on the known variables that you have. And so in this case, we did have a lot of known variables and could calculate a propensity score and match that up so that we could see similar injury severities for ground versus helicopter patients, and look for an observed difference. So again, over 200,000 patients. Other statistical methods are required. You have to control for clustering. So general estimating equations in addition to propensity score matching. So a lot of sophisticated methods here to really look at this. And just the busy table one that shows injury severity, pretty banged up population. Fortunately, this got cut off, but you can see level two. So what you see here is just interesting. The effect estimate flips. It goes from an unadjusted effect estimate, odds ratio that does not show any benefit, to one that when you actually control, and we did this three different ways, control for injury severity, there is an effect estimate that's in the positive direction for the helicopter. And so that's really what we showed here with this is that reversal. So in concluding this, in severely injured trauma patients, there does seem to be evidence for effect. You're really looking at injury severity scores greater than 15 and injury severity score is not calculated at the time of injury. As you know, it's all done after the fact. And so how do we do this a little bit better? We'll show, I'll show you one way we could possibly do this in a second. The number needed to treat was something that we had to calculate. We're asked to calculate for this. And it turned out it was about 65 patients you'd have to fly to save one life. And at the time, the flights were about 5,000. They're a lot more expensive now. So really we're looking at a cost of well over $300,000 to save one life. We just look at the cost of the helicopter, the crew, that aspect of their critical care. It's a lot of money. And it is a lot of money. And we have to be cognizant of this for sure. But I would submit to you that there are other things we do in critical care that have similar costs. And we wouldn't hesitate to do a lot of these things such as liver transplants. These are just adjusted. You know, the amount that the patient's actually charged versus billed, you know as well as I, we always bill for a heck of a lot more than we collect. But you know, these are also other things such as open heart surgery that really have large costs as well. You know, there's no National Institute for Trauma. We just have it as the number one cause of death under age 45 So I would argue that it does fall into this spectrum of costs, although we still do have to watch and make sure we're using it smartly. Two other populations that may be of interest to us as intensivists. And you heard a lot, you heard some great reviews. One great review there about stroke already today. And you'll hear a lot more about that at the Congress. But you know, what about stroke patients who can't get to a place where they can do a mechanical thrombectomy? Well, what about those patients? Well, they looked at this in a systematic review and they showed that when they use the helicopter to bridge that gap, they actually see an odds ratio of improved survival, improved neurologically favorable survival. So this is really a promising research in the realm of stroke. What about acute myocardial infarction? In Denmark, large population over 16,000 patients where they looked at helicopter to ensure they could get to a PCI within less than 120 minutes because they don't have PCI centers everywhere across the street necessarily. So by using that, they did demonstrate that they could narrow that gap, that time gap and use the helicopter as an equalizer. And that's where I stand with this. I think when you talk about in particular the helicopter, some systems that may be fixed wing air transport, the idea is really you're not necessarily gonna always improve outcomes, but you want them to have equivalent outcomes, not necessarily improved. You want them to have the same outcomes if they're injured as though they were injured five miles from the hospital versus 50 miles from the hospital. That's the idea is you're bringing critical care to the patient too as an equalizer. And that's the way I think, at least that's the way I think about using this technology. Now to finish up, there's a lot of factors here, tons of factors that we have to consider. And there's lots of different ways we can study it. This is a DAG from the epidemiological folks that might be interested in this. Really the helicopter, even ground EMS is a mediator. It's not directly, sometimes it's directly related to a life save, but oftentimes it's a mediator. There's some element in that causal pathway to an outcome, hopefully a favorable outcome where this can be a mediator. How to use this, how to operationally use this. Last two slides here. We have really good criteria that establish when we should bring patients to trauma center expeditiously. They were careful with these guidelines, which are not written that long ago. There's a whole list of things here that really highlight the need to get to a trauma center and get good trauma critical care. A lot of them are consistent with common sense, but when you start to get into these yellow criteria, maybe do we really need a helicopter for yellow criteria? Maybe, maybe it depends on your system and the constraints of your system, but you don't necessarily have to fly the patient. I remember when I was a young paramedic, I had a young lady who got hit with a Frisbee. She got knocked out for like 30 seconds. By protocol, we had to fly her. So I had to call a helicopter. It's crazy. That's the kind of stuff we need to get rid of because that introduces a lot of extra hazards that we just don't need. So one way, and finally, final comment I would make here is that there is a good score by Josh Brown and colleagues at Pittsburgh. They've really done a lot of great work in this area. I really think this is a validated score. It's been validated over 200,000 patients, I believe, in the Pennsylvania Trauma Registry. So it's a validated score. When you hit two of these points, yeah, you should consider helicopter transport unless you're literally right within 30 minutes of a trauma center. So this is a validated scoring system for trauma patients that can be used. We need the same type of methodology for transfers. They're just much more heterogeneous. They're harder to study, but we do need similar things. But I think this is really one of the best things out there in terms of making prudent decisions about using this. So in conclusion, we have a majority of well-designed research that does show a role, but only for patients that are really, truly injured severely. And we really do need to use the proper methods to control for all the different variables that are inherent in this type of work, especially when we can't do a randomized control trial. And then really thinking about helicopter emergency medical services as an equalizer, an equalizer in terms of our critical care continuum. So once again, thank you very much for the opportunity to speak about this today. Appreciate it very much. Thank you.

helicopter transport

trauma care

Injury Severity Score

critical care

medical outcomes