Transcript Video Targeted Temperature Management After Cardiac Arrest: 2026 Updates Hi, everyone. My name is Doctor Benjamin Abella. I'm the chair of Emergency medicine at the Mount Sinai Health System in New York City. I'm also a practicing emergency physician. But why I'm with you today is I've had a 25 year career in research and education around cardiac arrest and post-arrest care. It's been a lifelong passion of mine. And I'm here to share with you some thoughts around post-cardiac arrest care. As you all know, uh, cardiac arrest has a very high mortality rate, and many people after initial resuscitation have very complicated disease processes and courses in the hospital. And uh one of the key things that we do for these patients is something called targeted temperature management or TTM. But there remains a lot of confusion in the field, quite frankly, about how to use TTM, when to use TTM, and, and what does the evidence show. And that's what today's lecture is going to be about. We're going to focus on the clinical evidence around TTM. You won't see any basic science slides, nothing from the animal lab, except for one slide that I'll go through quickly. Um, it's all going to be clinical, actionable information that hopefully you can find helpful for you and your hospital. And as far as disclosures, I've received research funding from a number of sources, as well as on our area. It's important to point out that I have no equity role whatsoever in Beckton Dixon, and uh uh I, I, I have no financial incentives to be talking to you today, except that I care deeply about targeted temperature management and uh uh I want to make sure that we do right by all of our patients. So, what we're going to cover is the most recent updates to the American Heart Association guidelines around post-arrest care, and then we're going to go through the evidence behind that, temperature uh management itself, with regard to timing and also duration, but then also talk about what should we be doing based on the newest evidence. And I always like to start with a case that does two things. One, it frames the conversation, but two, it reminds us that patients are really where this all begins, the best care for our patients. And so, I wanna share with you a vignette of a fairly typical cardiac arrest story. You've all perhaps had stories like this in your clinical practice. 57-year-old male uh experiences cardiac arrest and is brought in by an ambulance to an emergency department. Now, per the ambulance service, per EMS, the patient collapsed at home. His wife was a witness, and she actually did bystander CPR, which you all know is an important predictor of survival from cardiac arrest, if bystander CPR is provided. So, this means this is a patient that, that we have a fighting chance to, to work with them and get them back to life and health. Uh, there were no symptoms before they collapsed, and they were found in ventricular fibrillation. Now the patient's remained pulseless, uh, and we go through ACLS, give epinephrine, and so forth. Eventually, a pulse is obtained, and we call that ROSC, return of spontaneous circulation, for those who don't know the term. And after ROSC, the patient's, uh, comatose, um, which is also very common after a prolonged resuscitation course, an initial head CT is performed as it should be done for most patients initially after cardiac arrest, and there's no blood. So that's good. The, the main reason for an initial head CT is not to assess the brain, not to make prognostic determinations, but rather to see was there trauma? Did the patient fall and hit their head and crack their skull, or was there blood, uh, subdural hematoma or intracranial bleeding? And there was not in this case. An ECG is also performed as it should be for almost all post-tress patients, and, and there's no STEMI, there's no ST segment elevation myocardial infarction. So the patient is sent to the ICU. So that's a fairly typical case that you might see of out of hospital cardiac arrest, and a very serious one. This patient is likely to have a difficult hospital course with uh critical illness. And so, this is really the domain of where targeted temperature management has played a role for a number of decades, and we're going to walk through some of that, but in its simplest form, the notion is that when you have patients after cardiac arrest, there is this massive inflammatory and dysfunctional storm that strikes the patient, we call that post-cardiac rest syndrome. Uh, we don't have enough time today to go through all the reasons why this occurs, but the general notion is that if you can manage patients' temperature, and in the old thinking, lower patients' temperature, keep them cool for a while, and then rewarm them. You could achieve homeostasis, that a lot of the inflammatory and prothrombotic and other changes settle down, and patients can do better than they would if you hadn't controlled their temperature. Another version of this is that up to 50% of all patients after a rest can get fevers. It's part of this pathophysiology. A pro-inflammatory state, people get fevers, fevers are very bad for the injured brain. And so controlling temperature may involve lowering it, it may involve, at the very least, using a device to prevent fever, and we'll get into that in much more detail. So, I'd like to start with the bottom line. That way, if you don't have the time or attention to get through the rest of this lecture, I'm giving you the, the punchline upfront. The punchline upfront is despite all of the controversy around TTM, all of the debates, what I can tell you is the synthesis of all the current evidence is that precise temperature control after Carre is essential, endorsed by HA guidelines, endorsed by the data. So, don't think that just because there's confusion around what temperature. or when to use it, that does not mean we abandon TTM. TTM is certainly still part of care, essential care following cardiac arrest, and that's because many patients get fever. There's strong evidence from multiple sources that if you don't use a device and you don't do target temperature management, many people have fevers and have worsened brain injury from it. Now for most patients, 36 °C is probably the best target temperature supported by evidence. However, I believe, as do many others in the field, that 33 °C may be appropriate for some patients, and we will get into the details. That's the source, I think of a lot of the confusion. But if you're going to do one thing for all patients, and do it in a way that's consistent with the evidence, you could do target temperature management for all post-stress patients at 36. It's safe, it's effective, it prevents fever, and it's evidence-based. Now, 33, however, may benefit some patients, and we'll get into the details on that later. So that is this whole lecture in one slide, but, uh, but now the rest will all be the commentary and the details on this. So, first, for those who don't know, the American Heart Association comes out with guidelines every 5 years that govern both CPR slash AED use, that is to say, all the initial resuscitation, but also post-arrest care, what we do after we get patients back. And I show you here the after part, um, uh, part 11, which focus on post-arrest care. And um this is updated every five years. Sometimes there are updates between the guideline years. There was a partial update in 2023. I, I hope they don't do that too often because I think it also adds to the confusion actually. Uh, but, but know that currently the quote unquote law of the land regarding guidelines is the 2025 AHA guidelines. And this is an excerpt from that, where they clearly say that if a patient is resuscitated, and it does, is not following commands, or you're not sure if they're following commands, what do I mean by that? Cooling is not indicated, TTM is not indicated if a patient has a Glasgow motor score of 6. That is to say, practically, if you say to the patient, hey sir, can you squeeze my hand, and they do it, or can you open your eyes and they do it, and you're pretty sure they're following your commands, their brain is going to be OK, and they don't need temperature management. The vast majority of post-tress patients do not follow commands, or it's not clear if they do. They may not have spontaneous movement, they might be moving or trying to, you know, pull their tube out, um, but, but if they're not doing something volitionally that you've asked, so that means you're unsure, they need temperature management, you see their deliberate strategy for temperature control. Now, they make things confusing because they give this large range, and you see 32 to 37.5. That does not mean you can allow the temperature to oscillate around in this range. You pick a temperature and you stick with it, but we're, the, the details we're gonna get to later in this lecture will talk a bit more about how we make that selection. But deliberate temperature control is 100% within the HA guidelines, and something all hospitals need to do. Now, where's the evidence for this? Where, where does this come from? And what temperature to choose? And that's gonna occupy the bulk of the rest of this lecture. So, first, where this all came from, was initial randomized controlled trials. That looked at post-arrest care, tested whether 33 °C, whether cooling people to 33, which is around 9091 °F, whether that would improve outcomes after cardiac arrest, and three trials showed an improvement in survival with neurologic recovery, that is to say, not just survival, but survival with a brain recovery. When people were called to 33, and, and one of these studies, the biggest of them, HACCA, hypothermia after cardiac arrest trial, looked 6 months later, and they found that if you were alive initially, you were all but one patient lived 6 months with intact brains. So this is an important take home point for all of us. If, We can get people out the door with a working brain, they can do very well. And indeed, we have many cardiac arrest survivors from our cohorts who've gone on for years, uh, and gone on to meaningful lives, seen their kids graduate college, etc. etc. because we got them to a state where they walked out of the hospital. Now, those 3 randomized trials that I show you here, all looked at shockable rhythm arrest. So the question came about, what about PEA racist, what about non-shockable rhythm arrests? And this study that came out of France, a multi-center trial, looked at that very question. They enrolled patients after out of hospital cardiac arrest who had PEA or asystolic arrest. These are sicker patients, um, and indeed, uh, uh, when you have patients in asystole, not many survive, but their theory was maybe the sicker patients need this more aggressive therapy. So the survival might be lower, uh, you might see people that you might not otherwise do so. And indeed that's what they found. There was a statistically significant improvement in survival after PERA systolic cardiac arrest. If you cooled to 33, and they looked at CPC scores, cerebral performance category scores, so this is basically brain recovery. So brain recovery was better if you cooled people to 33. Well, that would have been, would have been a very simple, nice story, and we'd all be cooling the 33, had it not been for two trials, both from the same group in Scandinavia, that poked at this and said, is this, is this really true? They started with the premise that we know that temperature control is important, we know that avoiding fever is important, but do we really need to lower temperature, or is precise temperature control to avoid fever sufficient? And the first trial that they did was in 2013 of 33 °C versus 36 as target temperatures. Following cardiac arrest, and they use devices with precise temperature control for both arms of the study, 33 and 36. Here's their, their cohort, and I just wanna, whoops, I just want to point out that this cohort is one that we might not expect TTM to make a big difference for. Why do I say that? Most of the patients got bystander CPR. Most of the Patients had a witnessed to rest, and most of the patients had a fairly modest lactate elevation. Some of you may know, the higher the lactate generally correlates with a longer resuscitation and a sicker patient with a longer, more difficult post-arrest course. And so, If you had shown me these characteristics of patients, I'd say, ah, I don't know if cooling's even necessary on a lot of them. I do precise temperature control, but I, I don't know if the extra cooling will really be to advantage. And that's actually what they found. They found no difference in survival at 33 or 36. So this was the first uh controversy that came up. Do we need to cool at 33? Maybe 36 is sufficient. Well, then they did a follow-up study, a big randomized controlled trial, and these are the investigators, their pictures here, or at least two of them, where they said, OK, if 36 was the same, what about 37? Why, why even cool at all? Why not just manage them at true neurothermia? And they did a somewhat complex study, before I jump ahead, where the Intervention was temperature management, but they, they then did two forms. One was to 33, 1 was you didn't have to use a device unless the patient got above 37.8, and then you had to use a device. So it's a tricky control group because patients got two different therapies, either nothing, if their patient just stayed within normal range, or if there a certain amount of fever, they got a device and were kept under 37.8. That sounds complicated, it is, but they were basically testing whether you needed to cool. And what they found again was at 6 months, exactly the same. Whether you cooled to 33 or you managed at 37, it was the same. Now, many people took from this, that TTM has been debunked, it's been disproven, that you don't need to cool at all, and many hospitals abandoned TTM. But remember, half of patients get fevers, we know that fevers are bad for the injured brain, and guess what, at many hospitals, survival worsened, neurologic outcomes worsened. So, if you take one thing away from this, it's that TTM is recommended in the guidelines, and we should do it regardless of the controversy of the selection of temperature. And now I want to make the point that this is a much more complicated story than this controversy would have you think. And, and I want to suggest there are reasons why we should be careful about cooling everyone at 36, because there may be some sick patients, as you saw in that prior French study, who might benefit from lower temperatures. And I'm going to go through this in 4 slides. This is like a menu of what's coming next, but we'll just, we'll just get right into it. I promised you one laboratory slide, this is it. And it's only to make one point. Hundreds of studies have looked at post-arrest cooling in animal models, rats, mice, pigs. I only show you three examples here. In the vast majority of these studies, it's a large literature, the deeper you cool, and the longer you cool, the better the outcomes. So there's a strong dose effect relationship in the animal lab with cooling post-re. So this was why. This was such a surprising result in the humans that that it didn't seem to matter as much. With the animals, cooling makes a huge difference, strong, strong biologic evidence why this should work. And then when you look at the, the studies, the actual, the clinical trials, the balance of evidence suggests that cooling deeper may benefit. Yes, there are two RCTs that show no benefit, but there are no RCTs that show harm. So, if you like a sort of a sports analogy in the, in the wins loss column in the standings for a team, it would have to be a soccer or maybe a football team, not baseball, because they don't have ties. It's 3 wins, 0 losses, and 2 ties. So now when you have a patient coming in and you have a family saying, do everything you can for my loved one, please. And you know, there's 3 trials showing a benefit to 33. There are no trials showing harm to 33, and 2 trials that say, uh, maybe 33 helps, maybe it doesn't. It, it's pretty hard to deny the patient the therapy in my mind, but that is what's happening in some hospitals. So, I, I, I think we have to be pretty careful here about leaving TTM and especially leaving 33 for some patients. So, here, here all is lined up. Um, I just have this as a reference. I'm not gonna go through this in great detail, but just to show you that the trials done have mixed results. But then in the real world, when hospitals switched from 33 to 36, some found that their outcomes worsened. This is one such example out of Melbourne, Australia, when they switched from 33 to 36 as a target temperature post arrest, they had fewer survivors, and they went back to 33. Now, You remember from my first slide, if you do one temperature for all patients, 36 is acceptable. This is a cautionary note though, that maybe we shouldn't do one thing for all patients. We don't use the same dopamine dose for all patients. We don't use the same sedative dose for all patients. Why should we use the same TTM dose for all patients? Another example, this is from Seattle, where they also switched to 36, and they found worse favorable neurologic outcomes when they switched to 36. So this is a complicated story, and I'm not here to scare you with complexity. I'm here to say, we may 1 dose may not be right for all patients. Now, this study, I think, really brought it home. This was a very well done study out of Pittsburgh, where in the UPMC system, University of Pittsburgh Medical Center system, they have many hospitals and they have many critical care docs, and some over time believed that 33 was the best temperature, some believed that 36 was the best temperature. So they said, OK, great, natural experiment. Let's see who survives better at one or the other temperature. But in this case, we're gonna group the patients by how sick they are. After all, you remember, I said, maybe sicker patients benefit more from lower temperature. They, they asked that question, and they used a scale called the PCAC Pittsburgh Cardiac Rest Category Scale. It's, it's a scale that they invented that is, um, basically puts people into one of 4 categories. Uh, 4 is very, very sick, dense coma, cardiovascular instability. PCC 1 is waking up a little bit. Moving, following commands, uh, and, and 23 are intermediate. And what they found was very, uh, interesting, but also I think a little predictable. They found that patients who were less sick post-arrest, didn't matter. They actually were fine at 36. Patients who were more injured, sicker patients, some instability, they did better with more aggressive therapy when cooled to 33. And this was a large, well-done, statistically controlled study, and, and so this suggested to many of us, you know, this is absolutely consistent with the French study I showed you earlier, this is absolutely consistent with the animal literature, sicker, and with general critical care principles, by the way, that sicker people need more aggressive therapy. And so, again, a cautionary tale that some patients may benefit from 33, we just aren't sure how to prospectively identify them. This is another version of the study I just showed you, this from Japan, where they categorized patients by how sick they were, and they found there's a sweet spot. If you were not very sick, it didn't matter if you did 33 or 36. If you were super sick, most everyone died, and it didn't really matter, 33 or 36. But there was this moderate injury category. They used a system called the RCAS score. It's a a scoring system for our sick there, it includes lactate, includes whether people got bystander CPR or not. Again, not clinically used by many, but, but sort of useful, at least for research purposes, and they found there was this group of patients that actually did better at 33, who were moderately sick. A third example of this, this time they looked at EEG and they found that people, and I'm not gonna walk you through all this, but people who showed moderate brain injury on EEG and brain recording, did better at 33. So, 36, totally acceptable if you do one temperature for everybody, but I would argue that think twice if someone's really showing problems, myoclonic jerks and EEG, dense coma, cardiovascular instability, uh, myocardial depression, they may benefit from a deeper temperature of 33 following cardiac arrest. Now, other folks have looked at other aspects of this, like the timing of TTM because this is a question we get often, when do you have to start this therapy. So they looked at in, in, in a large trial and did a data analysis of how long it took to get TTM going, sort of door to balloon time, but door to TTM time. And what they found was the earlier you do the cooling, the better the outcome. So, so we do think this needs to be started relatively soon. And in fact, one objection that's been raised about the two Scandinavian studies that found no benefit to cooling, is they got to cooling people kind of late. And it may be the case that you need to get cooling started really soon, in the first hour or two, or the injury is baked in, and it just doesn't matter anymore. So, that's at least one objection, theoretical that's been raised about those studies, but the earlier you get to this, the better for patient outcomes. Another important question I get asked a lot is, what about longer cooling? Should we cool for more than 24 hours? This study tested that and randomized post-res patients to 24 versus 48 hours of cooling, and they found no difference in outcomes, didn't matter, but there was a trend towards lower mortality in the 48 hour group. So that's interesting, and one wonders if they had many more patients in their study, would this have been significant, and all of us would now be doing 48 hours of TTM. Well, to a certain extent, that is the genesis of a large national study that's recently finished called the ICECAP trial. And the ICECAP trial is a national study at many, many hospitals that is looking at duration of TTM. We expect those results to come out sometime in 2026 or 2007, probably 2027, uh, so stay tuned for that as well. Now, a little regulatory note, it's important to mention that the Joint Commission, also known as JACO, um, although I think now the Joint Commission or JC is, is the current more preferred lingo, um, Joint Commission who comes through and accredits all of our hospitals on a regular basis. Has, as of 2022, included post-arrest care as one of their criteria. So they, it is fair game for them to ask, do you have protocols, do you have a temperature selected for your protocols? Do you review post-arrest care? So, we can't shove this under the rug. In theory, it could come up. And I just put up here again, as a reference, the specific criteria that they list. I'm not gonna read it, but, but certainly, you can, you can grab it and then look at it or, or find the article online. So, this is something that hospitals should care about. OK. So, some questions that come up often, um, are, uh, what to do, uh, for strategy, you know, how do, how do we, how do we do all this? And I would say, well, first importantly, you need a device. In my experience, and many's experiences, fever is too common, and you just can't get there with cold fans or, or, you know, ice bags. It, it's too imprecise and it makes things very difficult. So, device-driven TTM is important if the patient is not waking up. As we talked about, most people should be temp managed at 36, and maybe more injured patients. Again, we, we, unfortunately, in 2026, we don't know how best to define this perspectively, but I would suggest anyone with a lactate that's really high, if I was going to pick a number, I'd say over 10. Anyone who had a longer cardiac arrest episode, I'd say longer than 20 minutes, and showing some evidence of shock, I personally would recommend 33. Now, the evidence, as I said before, is mixed on this, but, but many in the field sort of would support that. And this is a review article that I, I recommend if you, if you like this, you can check it out, where they sort of summarize this, where they say, look, um, uh, people who, it may not matter, consistent with the skin study are people with witnessed arrest, bystander CPR and a clear cardiac cause. But the ones who might benefit from deeper cooling, unwitnessed arrest, no bystander CPR, and this is many, many patients, or people with non-shockable rhythms. Now, there's been some newer work, certainly that's been done in this area, and part of my goal today is to share with you some of the newer studies that have come out. This is a, a, a newer study that's actually looked at in-hospital cardiac arrest because the question that comes up often is, should we be doing this for in-hospital arrest? I would suggest the HA guidelines are for everybody out of hospital and in hospital arrest, but in hospital arrest, patients are tricky. Uh, they're, they're in the hospital for a reason. They're sick, many are in the ICU, many are septic. That is to say, the causes of cardiac arrest out of the hospital. stemi-opioids are different than the causes of in-hospital arrest, sepsis, acute hypoxic respiratory um um uh acute respiratory failure, etc. etc. So, differences both in and out of the hospital with regard to etiology and physiology. Uh, but that said, and I'll just show you their conclusion here, that there is a decreased risk of brain disability as they framed it, when patients were cooled, when patients were managed with TTM from the in-hospital side. So there may be some reason also to be careful with this from the in-hospital side as well. There's just fewer uh pieces of evidence supporting it. Well, here was, is a, is a large cohort evaluation, also recently published from 24 hospitals. Again, looking at temperature control after in-hospital cardiac arrest, and what their data were less clear, but certainly, uh, they didn't find harm with uh uh an aggressive temperature control strategy. Uh, but, but they, they did not see a statistically significant survival or outcomes difference. So, Inhospital rest, I, I'm not sure what to tell you except that 36 is very safe, and the AHA guidelines would suggest we at least do 36 for all patients after arrest. Harder for me to argue for 33 from the in-hospital side. Now, a question I get asked often is what about kids? And, and this is a newer study looking at that, there's only one RCT, one randomized trial. Published to date looking at pediatric cardiac arrest and it was neutral, 33 versus 37, it found no difference. So it's harder to know what to do. However, however, what has been shown multiple times is that you need a temperature device. The question is, can you avoid fever if you just do something that is non- temperature controlled, that is a, not closed loop with a thermometer into the device? And the answer is it's hard. People get fever more often, it's harder to manage. So, and there's certainly strong evidence for neonatal arrest. It's a condition called hypoxic ischemic encephalopathy, HIE. That there's basically brain injury in the newborn, and temperature control is well established there. So, any neonatologists watching this, TTM deeper TTM is indicated in that one, condition of neonatal uh injury. Now, if you like a good debate, um, I had, we uh set up a pro-con debate in the literature between myself and a, a Finnish friend of mine, Marcus Skvas, and, uh, uh, Marcus argued against. Cooling, the 33 and argued pro-cooling. So, it lays out all the evidence and why one might be good, and you can make up your own mind because there's no clear conclusion in the literature, uh, but, but we sort of lay out here some of the key reasons for cooling more deeply and against cooling more deeply, but it might be a fun read if you want to check it out and you like a good food fight in the literature. So in summary, the most important thing I can leave you with, cardiac arrest is not hopeless. We must not give up on these patients. There are long-term survivors and we can have more. Families are very grateful when their loved one makes a recovery from cardiac arrest. Fever avoidance is essential, and it's really hard to do that without device-driven TTM. So, if I have one bias is that, you know, I did this well before there were devices, and it was very hard to do with cold fluids and ice bags and warmer, you know, those sort of blower devices. For some patients, TTM to 33 may be important, and I think particularly the more injured ones and more studies will need to be done with that. But if you're going to choose one temperature for everyone because you like to keep things simple at your hospital, it would not be wrong to choose 36 for all patients. It's safe, it's very close to natural physiologic temperature, and it's supported by all the evidence. Also, it's important to get on this promptly. You can't do TTM like a day into this. It's got to be served within the first few hours. Uh, now, if you don't get there within the first few hours, you should still do it, but a lot of the benefit may be mitigated by that time delay. So sometimes we'll receive transfers from other hospitals 2 days in, and, and we don't do TTM if they haven't started it because uh there's just no uh potential benefit from that. So, I thank you for your attention. And um I just want to point out my research team. I always like to thank the people who supported work that we've done and work in this field. This is our center, the Center for Resuscitation of Science and Innovation at Mount Sinai, where we are, are doing a number of uh studies pertaining to cardiac arrest and post-arrest care and uh we're thrilled to be contributing to the conversation. So, with that, I, I thank you very much. Created by
