Solid Organ Injury Management: Update Course 2017

Um, we're going to talk about pediatric, um, solid organ injury today, and I'd like to start by, by presenting a case, and this is a fairly challenging case, and it's one of my favorite teaching cases. Um, 16 year old male is involved in a motor vehicle collision as a front seat passenger, and he's T-boned on his side of the car, and there's a prolonged extrication, uh, that you can see the images of the, of the car accident itself. He's on, he's, uh. At the scene, moaning, his Glasgow coma scale is less than 8. He's intubated and then transported. Um, the, uh, he arrives in the ambulance. They're having problems with the airway. They extubate him just prior to pulling up to the, to the, uh, ambulance bay. And, um, this, you know, once, once he gets into our trauma bay, we work on the ABCs and so he's being bag masked, uh, ventilated, um, he's immediately, uh, intubated with an endotracheal tube. His, uh, chest, uh, rises asymmetric. He has, uh, diminished, uh, absent breath sounds on the right. He's got massive crepitus on the right. His sats are 83%. His vital signs are terrible. His tech, his heart rate's 123. His blood pressure's 74/50. He is pale. He's cool. He's got. Central pulses that are OK, but he doesn't have a good cap refill and he's in shock. And so I guess the next question is what do you do next? So Um, and I think we have the opportunity to poll. We're gonna put that poll up right now. OK, so let's get, I ask a question before we, yeah, OK, David, go ahead. You bet. Can I challenge you on the order of intubation versus chest tube placement, so. Um, you know, uh, you know, for years, the answer is yeah, absolutely. I mean for years, um, we've been taught, you know, airway breathing circulation, and then, uh, ATLS, um, later said, you know, we should worry some of that that active bleeding while we're getting that airway. Um, you can definitely make a case that, uh, that this patient, uh, in the field maybe should not have been intubated. You could, uh, make a case that, um, you know, that, that airway and breathing. Um, you know, maybe should be reversed, um, but the, but the reality is, um, in multi-system trauma you got different people working on the airway than you do on the chest tube. So, so Wolf can. A, B, C, or D? You want to defer to wit? Now of course you're gonna go right to the operating room, right, David? Isn't that why you're presenting all this? I say B. You say B, yeah, I say B. You say B. So I'd say OK, what about here? But wait a minute, time out. Maybe I missed something. Does the patient already have a chest tube? Not yet, so. I would argue you either need to needle the chest or put in a chest tube if you're set up to do it. I would put in a chest tube. Yeah, that was gonna be my answer, but so I'd say none of the above. It would be my answer. Yeah, well, you are correct. Well, I was gonna say, but so that's, that's, you know, in these trauma questions, that's one of the fallacies of these multiple choice things, right? Because you're doing things simultaneously and that's why it's always hard, but I'd say yes, you need a chest tube, but that. Patient needs an IV too. How's that? Yeah, absolutely. So, um, so you're, you're absolutely right. This patient needs a chest tube, and I, and I think that, um, that, that when you, when you think about a multi-system, uh, patient who is both hypotensive and has airway problems, you need to think about breathing and circulation at the same time. This patient, um, when the chest tube goes in, what you get out is 600 cc's of blood under high pressure. And um and so you think you're putting a chest tube in for air and, and you get a massive rush of uh of blood. Um, we were able to capture about 300 mLs of that into an auto transfusion uh trap and the SATs came up to to 90%. So now his blood pressure is 70/30 and his heart rate's still 120 and his shock index is still elevated and I think that um that uh the shock index was originally proposed in the 1950s. It kind of fell out of favor and now it's become um more uh more in favor again. I think there are a lot of reasons for that, but a normal shock index is, is really um less than 1 or less than 0.9. And uh there's some adjustments for kids now and what it does is it allows you, um, if you're not, uh, comfortable, if you're not seeing kids on a regular basis to know, uh, to help know if a child's in shock or not, um, without knowing what their normalized blood pressure is, and I think that's the biggest advantage. So this patient's shock index is 1.7, so it's pretty elevated. He's got diffuse pallor. His abdomen is distended, and he's got no obvious deformities to, to his extremities. So he's been given 20 per kilo of crystalloid prior to arrival, and almost all of our patients these days have gotten some or too much fluid um at the at the time. So what do we do next? Do we give them another 20 per kilo? Do we give them pack cells? Do we give them FFP? Um, do we allow for a hypotensive resuscitation? So I'll open that one up. Let's start with Dan. I'd give him A and B at a minimum. Any thoughts here? If you guys have a thought, give you raise your hand. All right, Ian, start with a B and consider calling massive transfusion resusci. Yeah, yep, OK. All right, so massive, massive transfusion protocol. Nobody went for hypotensive resuscitation in this patient with a head injury, so, um, which is, which is really interesting because ATLS certainly, um, it showed up in this edition of ATLS kind of much to my, much to my shock, um, as an AT ATLS instructor, um, I'm not sure that's what I would do. Um, he in fact got transfused 2 units of Paxels and one of FFP, um, and his blood pressure stayed 70/30, and the massive transfusion protocol was activated and, and you, you're, if you're gonna use a massive transfusion protocol, you have to do it when, once you've decided that that patient is, is bleeding massively. You can't wait until you hit a certain threshold. You need to activate it as soon as you can if you're gonna make a difference. Um, and then we gave him, uh, 300 mLs of his own autologous blood that we captured from, from that chest. Um, whether you wanted it or not, um, he did get a, a chest X-ray while all this is going on, and, uh, what you see on this, on this chest X-ray. I didn't ask if you wanted it. I just get it, gave it to you. Now that is a cool pointer. Yeah, thank you, Todd. You know, uh, uh, Todd is known for his technology. So, um, the chest tube is in place. The lung appears to be up. We don't see a whole lot of blood left in there. We evacuated most of it, and the pelvis is relatively unremarkable, which is its contribution to this patient's care. David, is the, is there still blood coming out of the chest tube, or is it slowed down? So it's slowed down, but there's a, but there's a continuous air leak. So I've got a lot of air with the lungs up, and that's part of the reason that we that we rushed to get the chest X-ray because we do have a massive air leak. I think you presented on a really cool case of a of a bronchial injury that was, uh, that was missed if I recall many years ago. So, um, so what now? So you've got a patient whose blood pressure is 70 and, um, you know, and has been given a fair amount of blood at this point. So do you want to go to the CT scanner and CT his brain? You want to take him to the CT scanner and scan his and pan scan him? Do you want to do a fast or do you want to do none of that and just go to the OR? Let me, before, before we start quizzing people, I will tell you that this is probably the most difficult thing that pediatric surgeons face is having to make the clinical decision of what to do in the absence of data. So most of the time in pediatric surgery we have a CT scan. We have, we have stuff, and now we're having to say, all right, well this patient's unstable. Are we gonna take him to the CT scanner and risk an arrest in the CT, um. What do you want to do? Well, the problem, uh, with going to the OR right now is where do you make an incision? Yeah, absolutely. So you need more data. You got a lot of blood coming out of the chest. You hadn't hit 1500 from the chest tube yet, but you've any have extended abdomen, and you've got a distended abdomen. So because of that, I'd probably do B. Realizing that there's risk involved with whatever choice you make and it and if you do be it's vitally important that there are experienced surgeons. Uh, in the CT scanner in the CT scanner, uh, area to, you know, watch the patient as the scan's being done and that you can get it promptly and you can continue to resuscitate him while you're doing that because clearly the patient's still in shock if his pressure is still 70 and yeah, I, I would say, I would say the answer to this question is gonna depend on your local resources. Good answer. Just so you know, David, let me tell you, so the, the virtual audience, the answers are all over the place. So, uh, pretty much everyone answered every one of those. What I, I do want to see is there anyone here. That uses fast, so I was going to raise that because it's a particular It's an interesting topic for me. I am, I'll confess up front, I'm an anti-fast person because I think we spend a lot of time doing it, but it doesn't really frequently help us. The potential for help is when you have hypotension and you don't know where the where the site of blood loss is. This kid has blood coming from the chest, so you know that has all these other injuries. So I'm not again, even in this case, but I will tell you that in our institution everybody gets a fast, but it's done more as a teaching effort so that when a patient comes in that you need to know how to do it, you do it, but having just had a trauma. Review from the ACS last week, one of the pushes from the adult person was you need to do. Everybody should have fast and you should have quality control metrics for it, and I struggle with what is the utility of FAST in a pediatric patient population. Have we excluded the possibility of A tamponon cardiac tamponon just based on the X-ray because that's the to me this patient is the ideal patient for fast. You know you've got blood in the right chest. You don't know if this is what's going on in the belly. You suspect it's bleeding. And you have to make sure there's not a cardiac injury. Is that fair? Yeah, I agree. I, I, if I were going to do a fast exam on a trauma patient, this would be the patient would this patient, I think I agree with you for the most part, Dan, because we, you know, you go down to the trauma band, it's usually our in our institution, it's the ED docs that are exactly, and I, I, I move it out of the way so you can't get to it. Hide the machine, but there are instances when it's good, and I, I'll tell you the best folks at doing fast in our institution are the 4th year general surgery residents because they're doing it all the time in adult patients. That being said, this patient, you know, you asked where to make the incision, you know, that blood in the chest could be coming from the belly. Could be a diaphragmatic injury with blood coming up from the belly. It may not be so bad in the chest. And again, you know, even if you have a CT scan, it's like if once the patient, if the patient's unstable enough and you need to, they know, you know they need to go to the OR, you could, you, you go to the OR and you're ready to just do sort of the, the big trauma whack, right? You know, if you have to, you know, you prep everything and you know I, I would, I'd probably if the descended abdomen, if the fast is positive, you might start in the belly, pack it off, and if you need to go to the chest, then you just go to the chest. I think you guys raised some absolutely amazing points. So to, um, to Doctor Ivan Alman's point, the, the, the fast, um, for stable patients really has not turned out to be very useful, and the, um, Cuperman's group with Pcar recently published a, I'm gonna interrupt you. Can you explain to the virtual audience what fast is? Oh, fair enough. Um, well, they're different versions of the words, but basically focused, uh, abdom, uh, focused assessment of sonography and trauma, I think is the one that's currently being used. And what it is is a is an ultrasound done by the, um, by the surgeon on an injured trauma patient to look at four specific areas. So, um. There are 3 areas in the abdomen and 1 in the in the pericardial sac. It's done very quickly, hence the name FAST. It's not looking for organ injury. It is only looking for hemoperitoneum or pericardial tamponade or pericardial effusion. And so that's what FAST is. It's a, it's a very focused, uh, look for blood in the abdomen or blood in the pericardial sac. And if I could just make a comment. Generally while all the resuscitation is being done somebody is doing a fast, uh, whether or not you, the surgeon have ordered it or want it or not so generally it's, it's being done and, and in many ways this would be as has been expressed a really good case for it to be done in so I think the challenge that. That we've been challenged on appropriately is how accurate is it for people who don't do it all the time or who do it when um when they're not ready. I, I mean, I, I think the point about a pericardial tamponade is a really good one in this kid and again to your point about what's, what's the environment you're in, you're in, if you could get a cardiac echo while you're doing the resuscitation, that's what we would do with our in-house, uh, trauma cardiologist. So, um, I, I, um, I do think that FAST is losing its appeal in stable patients. The study that was published by the Pecar Group, which is the emergency room physicians, really, really kind of showed that that FAST doesn't help you in stable patients because it misses too many injuries. But I think that that it's exactly what we said, which is it's in the unstable patient it's it's it's, it's a it's a replacement for DPL for those of you that have enough or have enough gray hair or not enough hair to remember that the diagnostic peritoneal lavage. The thing is though that we'll never be good at fast for unstable patients unless it's done in stable patients and so it's kind of a vicious cycle. But it's, I, I, I mean, I think it's more at least our, and this is fresh experience for me in having cases reviewed where the FA was reported as negative and the CT scan is positive. So unless you have a mechanism for actually training people to use it so that they do it right, you can't just whip it on there and say, well, oh this is negative, we're not gonna do anything about it anyway, and that's the end of it. There has to be a loop for people to actually learn how to use it and the other. Point that at least sometimes you see is they, they, uh, the emergency room physicians allow the least experienced person to, to do it for a quote training purposes, whereas in a setting like this you really want the most experienced person to be doing it and let the least experienced person train on stable patients. I agree completely. David's got about 10 minutes left, so I want him to get through the rest so we haven't gotten to the operating room yet. So this patient is unstable. The fast is floridly positive. We did a fast exam. There's a continuous, uh, air leak from the right chest tube, and his blood pressure drops to 50. Now when you say the fastest positive, you're talking about from the abdomen Matt is abdominal, yeah, sorry, let me go back with this fancy you may want to just point that out for the oh yeah audience I'm sorry to use that fancy pointer there OK, so this is the liver, this is the kidney, and that is that black area is blood in there and so you've got a, a pretty good looking um. Uh, pretty good looking amount of blood in there and the pericardial window was normal, was no, yeah, it was negative, yeah, and it was extremely difficult because there was crepitus everywhere. So to the OR, yep. So what, so what now? So you've got a head injury, you've got a lung injury, you got no CT scan. Uh, this patient has received 40 per kilo of blood products and the systolic blood pressure is 50. So I assume you're on your way to the OR. You can do an ED thoracotomy, OK, um, you can stay in play, more lines, more blood, straight to the PICU, straight to the OR, or the OR via CT scanner. The CT scan is about 40 ft away, or you can do a reboa, a resuscitative endovascular balloon occlusion of the aorta. Which I will tell you and with our adult colleagues that's probably, uh, that's probably what they would do. So we are not set up to do that. So I would suggest we would go to the operating room. OK. What does the audience say, Todd, uh, first of all, I never heard of that. Can you give 30 seconds, 10 seconds? So I guess you wouldn't do that either. Oh goodness, um, so is it not worth getting into right now? Uh, if I had more time, yeah, um, the, in one sentence in, in one sentence, um, you put a femoral or. Arterial line in and then put a catheter up into the aorta and you you insufflate it and you basically occlude the aorta to stop all the blood flow or most of the blood flow to the lower half of the body and it buys you time to, to, uh, you know, it's like cross clamping the aorta effectively. All right, OK So the, uh, audience, let's see, 77% said straight to OR. I think that's a good decision. We'll get back to that. So, um, guidelines for management of, uh, of, of pediatric trauma have changed, and it, it really kind of started, um, with McVeigh's article in 2008 where, where they talked about throwing out the grade book and, um, and this is what the atomic, uh, guideline is, is built on, and we're not gonna have a chance to, to go over the atomic guideline in detail, but basically it divides patients into stable patients and unstable patients and it says, you know, for stable patients you really don't need to be, uh, in the hospital for a long time. The, uh, you can, you can basically transfuse them so their hemoglobin is greater than 7, and when they stop bleeding they can go home and then, uh, Sean Saint Peter and his group, uh, with, uh, with Witt, I think you're probably an author on, on the, on the prospective study which also validated an abbreviated period of bed rest, um, really said patients can go home much more quickly if they're stable from the get-go. In patients that are unstable, um, it, if you don't respond to Pax cells and, and fluids, you need to go to the OR, and I think that that really that's the situation that we're looking at in this patient, um, and if you do respond, um, then you get the chance to go to the PICU and see if you'll stop bleeding in the PICU. The problem is that um we have a hard time as pediatric surgeons defining what's stable and what's unstable and so um we found that young children with head injury are often hypotensive even if they're not bleeding and that some children who are are bleeding are not hypotensive. And um um Mark uh Wan talked about the fact that you have to individualize the care and, and you do so the bleeding actually may be due to concurrent injury. So what's the contribution to an unstable pelvic fracture which teenagers get, um, young, younger kids tend to be fairly protected from that, but older, older teenagers do get unstable pelvic fractures and can bleed. They can have um external bleeding that contributes. They can have a lung injury which they're bleeding from, which contributes, and, uh, femoral, uh, femoral bleeding. So you really have to put it all in context. And so the truth is that an algorithm is, as good as it is, is never gonna be able to completely define what you do and, um, and who needs to go to the OR. And so as we see here, you know, the algorithm says leave spleen, take spleen. It's not quite that simple, so. Um, you have to look at the relative contributions of the, of the injuries to the patient and then make your decision. Um You have to balance that with the fact that hypotension due to solid organ injury is ominous. There's a good chance that a patient who has a solid organ injury and is hypotensive is going to die, and, um, and they're at a significant risk of failing non-operative management. Is that persistent hypotension because patients not uncommonly come in hypotensive respond to initial fluid resuscitation so it's interesting. So um in little kids, so younger kids that are not of the teenage, if they are hypotensive or they have a blood pressure less than 50, that is a. Really ominous sign there, there's, they, they really are at high risk. Teenagers and adults, adult patients get hypotensive. You give them blood and they bounce back, and a lot of times you can even manage those patients non-operatively. So there's, there's definitely a break point, and we don't know where that break point is where the, where the two different cohorts of patients behave differently. So this is an older kid and it may not be as ominous, but if you've got a 10-year-old who's hypotensive, it's, it's a pretty bad sign or their blood pressure cuff is an adult cuff. Can I ask a quick question about blood pressure. So, you know, in adults with head injury, we really worry about second hits or whatever. Is there a role for vasoactive medications in that I'm going to the OR but it's gonna take me 20 minutes to get there? That that is an absolute great question. There's some really neat studies showing that the ideal blood pressure for a patient with a head injury is much higher than we thought it was. It turns out that the Cushing's reflexes may actually be protective. Hard to imagine that. Um, you, there's a, if your blood pressure is 150 or 160 after, after a head injury, you're much more likely to have a good outcome than if your blood pressure is 90 or 120. And so, and that's adult data. So, so yeah, maybe, but right now, no. So in, in this. Patient with a Glasgow Coma scale of 8, I suspect our neurosurgeons would be putting in a monitoring device while we're in the OR getting ready to go. They'll be up at the head of the bed and they'll put it in and then we'll manage our resuscitation based on cerebral perfusion pressure, not necessarily an absolute blood pressure. It's always tough, um, when, uh, you know, when you have a patient who's in shock, their GCS is gonna be low whether, whether, whether they have a head injury or not, and it's hard to, it, you know, it's a judgment call as to what the relative contribution is but yeah, having a monitoring is very helpful if you're, if, if you can't follow a clinical exam. Alright, we got about 3 minutes left, so we'll stop interrupting you, OK, um, so, um, so this patient has, has reached the, the, the, the end point at which, uh, non-operative management can no longer be recommended, and, um, I'm gonna have to skip all the stuff about the atomic guidelines and we're gonna go straight to, um, uh. To what happened to this patient. So The bottom line in in the study where we actually prospectively validated the atomic guideline is that it works really well and you'll have to read about that in the upcoming publication as soon as it gets uh accepted um the. It's in revision. It's in revision. Um, we'll speak to the editor. Uh, I, I don't think we got this one. He may, he may be seeing it though. Um You asked about, and I'm gonna cover this briefly, you asked about whether or not it's sustained hypotension or um or not, and one of the things that happened is that when we started this um this algorithm, um, if you responded, then you were considered a responder and what happened was we had a patient who 8 months into the study had a fall, had a 60 ft fall from from height. He was climbing. And he was, he stabilized after transfusion. He went to the CT scanner. He had a liver injury, a spleen injury, a pelvic fracture, a traumatic brain injury, a pulmonary contusion, a tibial fracture, and some compression fractures. He got hypotensive in the CT scanner, and they, and it's not exactly clear when he got 8 units of blood, but he got a lot of blood. And since he had stabilized, they took him to the PICU, and then he went on to fail non-operative management and undergo a splenectomy and then died of bleeding. And um and really recurrent hypotension you've given that patient blood and they're hypotensive again that's really bad and in kids that that really needs to fail and so the algorithm was was was modified 8 months into the study to basically say that recurrent hypotension or lack of a sustained response to Pax cells, you've failed on operative management. So, um, the guideline basically guided, uh, effectively guided, uh, care for 1,007 kids, um, except for that one, and with the modification could have guided care for over 1000 kids, um. Um A lot of things have spun off out of the study, including the fact that shock does not necessarily mean low blood pressure, and only about half of kids that are that are in shock um are hypotensive. The shock index was pretty well validated, and now we're going to conclude the case before Todd kicks me off the panel. Um, we got no CT. We took him to the OR. It's about 200 yards, um, because we have some construction going on at our hospital, and, uh, as often happens, and, uh, en route is a really dangerous time. His chest tube had to be on water seal. Um, his systolic blood pressure was 50 when we left. We hung blood. We took a cooler of blood products and we, uh, took some vasopressors with us in the back just in case because of that head injury. Those vasopressors did stay in the bag the entire time. When we rolled up to the OR after that trip, his blood pressure was 100 and his heart rate was down to 100. He was profused. His chest tube was placed to suction, and we saw that he had a continuous air leak and his blood had finished en route and had not gotten any more blood. So again, we, we're, we're in the operating room. We're not sure what instrument to use. Um, I, I personally like that instrument, um, and, um, you know, and we've had about 100, about 1 L from the right chest and no imaging. And what operation do you do? Um, but at this point the chest tube isn't continuing to, to, uh, to bleed, and we have an air leak, and after 20 minutes, um, I don't let him transfer the patient onto the OR bed because he's, because he's profuse. He looks like a different patient than the one that we left. And after 20 minutes he's not hypotension. We don't give him any more blood products, and at this point he becomes a responder. So what we've got is we've got bleeding from two separate chest, two separate cavities. We've got some abdominal bleeding. We've got chest bleeding, and we think that we've got the abdominal, the, the chest bleeding under control. And we left the OR without operating so I think that's a really good move since the patient's um hemodynamics have changed in a short period of time to just sit there and watch the patient, uh, and then try to figure out what's next as opposed to just everybody, you know, getting 6 people to grab the patient, put him on the operating table, then start prepping somewhere. Yeah, it's, it's hard, you know, pediatric trauma is easy until it's not. And that's, I mean, you know, and that's one of the things that we saw in the study is that we have a tremendous number of uninjured kids, and when you have a kid who's, who's really injured, you, you have to treat that kid different different so I might have you waited. You waited, you said 20 minutes, yeah, once we got there, yeah. So did you, was there anything magic about 20 versus 60, or, or you just thought that was long enough? I just thought it was long enough. I, I can't tell you why. Um, I really, I really wanted to know what was going on. I really wanted to see CT scan. Did he have? Still have a massive, massive air leak, and did you consider bronking him before you left? He, so he had, it was, it was a very large air leak. It wasn't a massive air air leak like you'd associate with a bronchial disruption, but it certainly was much bigger than what we would expect. Um, we scanned him. We did a pan scan, um, uh, maybe PTSD of the, of the, you know, of the trauma director at the time, um, and this is what a CT scan looked like. With a chest tube in, one of the things you'll notice here is that. He's got a pretty bad, bad injury to the lung. This is either contusion, um, and or, and or blood in this area. The lung is relatively re-expanded. And then his abdominal CT shows that we've got a pretty significant liver injury in this area. We have blood below the diaphragm here. And what we see here is again liver injury and blood. Sorry about that. And you'll notice that this injury actually extends all the way to the to the inferior vena cava which is here. So, so this is an injury that goes from the outside of the liver to the inside of the liver to the inferior vena cava, which is operatively a very difficult um surgery to to to control once you once you get in there and you find it. And there's a good chance that when you lift the liver to see it, you're going to make it worse. So, so David, I wanna um. Wind up, so I'll let you finish up, but then I want to ask you at the end if you could just in one minute summarize the key new concepts that we need to know now from the stuff that you've presented. Fair enough. OK, 22 slides and we'll be done. Um, within the next 24 hours, the patient developed another pneumothorax, um, had 2 more chest tubes placed, massive air leaks, did a bronchoscopy at the bedside for free of a bronchial tear. And um it was difficult due to hypoxia. There was blood in the airway, but there was no major bronchial injury. Um, ultimately we felt like we could not control and he was almost impossible to ventilate. We considered doing a double lumen intubation and ventilating the two sides separately. Decided instead, um, because of his head injury and, and he would get hypotensive when, when the chest tubes would stop draining. Um, we took him to the OR and found a right, uh, uh, lower lobe laceration. Sevo filled the room. Lung would not hold stitches. This looked like a blast defect, um, from the injury, and we did a formal lobectomy. That's what his lung looked like. It was ripped all the way up to the, you know, to pretty significant bronchi. What you can see, um, in this area is that this stuff looks like, um, like it's been pulverized, and that's why it wouldn't hold stitches. Um, afterwards, the patient acted like a different patient. They were very easy to manage, and the patient ultimately did well, was extubated, uh, on day 5, went to rehab, and discharged. Um, total 6 units of, uh, of Paxils, 2 of FFP, 2 of platelets, um, with a high chance of this patient, um, dying, and that's what he looked like when he was done. He gave me permission to use his photo, so good kid. Um Managing multiply injured patients without imaging is extremely difficult. I think that um that 40 units per 40 mL per kilo or 4 units of pack cells is still a really good threshold for failure. Um, for years we had, um, expert opinion that said that 40 per kilo was good, and now we actually start to have some, um, some data from military experience that 40 per kilo was a good threshold, and, and, and we're seeing clinically it was incorporated into the guidelines is now part of the atomic guideline is that that's when you've, that's when you have failed algorithmically, um, management without surgery. Um, if you lose 600 mLs from the chest, maybe we shouldn't be counting that towards, um, towards the 40 mLs per kilo of solid organ injury. The, the, the problem with that is that you can have a, a continuous, uh, some of that blood may be from a ruptured diaphragm, and you may be having abdominal bleeding that comes out through the chest, and that's really hard to know what you got. And as always, luck beats skill. So, um, I think that the, the final thing I'll leave you with is, um, the, the atomic guideline, um, has been published in, in 3 different journals now, so it's, it's, uh, relatively easy to find in the literature. Um, there, it should be, uh, published in a 4th journal, uh, pretty, pretty soon. And um and it's uh it is uh not copyrighted it's uh Creative Commons so it's it's freely available to uh to to uh modify, put your own logos on it you can put your own hospital logo on it for all we care we just want the kids to get uh to get care and people to be managed with the, with the, uh, uh, advantage of an algorithm. Todd, well, that was, uh, obviously there's a lot to discuss here. That was fantastic, and I have a million more questions, and, uh, I know a lot of the other stuff that you've been working on. I know that you have published numerous papers in the past year, so this is just one aspect of it, um. So I, I will ask you, David, there have been a ton of comments and questions. So if, if all of you or if you could look at some of these questions afterwards on your phone or whenever we can help you get a device, if you can answer some of these, I know that, uh, Khalid, uh, you had a lot of questions and comments about imaging, and we'll let, uh David address those, uh, after, after, uh, this break. So, uh, I want, let's go to the next, uh, talk, uh, Ted.