Good morning everyone, my name's Janine Berta. I'm a clinical nutrition supervisor at Stanford HealthCare. Stanford's a level one trauma center and I've been providing medical nutrition therapy to trauma patients since 2015. I have no disclosures. So what I would like to accomplish with you all today is to review the metabolic response to trauma to understand the framework of the nutrition care process that all dieticians are utilizing. To evaluate the current guidelines and literature as they apply to trauma patients with obesity and to understand the practical challenges with providing nutrition in an ICU. What I would like to point out is that the scope of this talk is gonna focus on the first two weeks of critical illness. Anything beyond that phase is known as the chronic critical illness phase and feeding strategies at that point generally shift to feeding for rehabilitation. So focusing on really aggressive, high calorie, high protein provision. So the metabolic response to acute stress is broken up into three phases. The ebb phase is in terms of trauma happening in the field in the first day or so in the ICU. The flow phase is two days to weeks post-insult which is generally when the ICU dietician would be involved. And the anabolic phase is looking at weeks to months post-insult when a patient hopefully is at home or rehab or a skilled nursing facility by then. So looking more closely at the flow phase, the initial insult creates some changes in the metabolic pathways that are driven towards energy consumption and wound healing. And all of those alterations in the multiple metabolic pathways culminate in overall altered macronutrient metabolism, hyperglycemia, breakdown of lean body mass and fat catabolism. The latter two of which are diagnostic criteria for malnutrition. And it's a dietician's primary goal to prevent malnutrition due to the poorer outcomes and higher economic burden of patients who are malnourished. So the goals of medical nutrition therapy are to provide individualized nutrition interventions to promote healing, recovery and health. And again, to identify and treat malnutrition and prevent it where it's able. Trauma patients generally come in in a well-nourished state because they were out living life when their unexpected trauma occurred. So the vast majority of trauma patients present well-nourished. This is a population that we really can prevent malnutrition in. And so how does a dietician do this? Dieticians work based off of a standard framework called the nutrition care process. The steps of this can be summarized by the acronym ADIME. So first we assess the nutritional status and the individualized needs. We move on to diagnose the nutrition problem. We implement individualized interventions. And then we monitor and evaluate the outcomes of those interventions. So essentially we're reassessing the patient, starting the process over, and adjusting our interventions as needed. And we keep doing that until the nutritional problem is resolved. So before we dive into the literature that looks at nutrition for trauma and obese patients, I'd like to share with you all the lens that I wear when I'm interpreting nutrition literature. So first is the inherent bias that sicker patients are harder to feed. So when I'm reading a paper and I'm trying to decide how it's gonna apply to my clinical practice, that bias is always in my mind. Robust nutrition methodology can be difficult to implement in a clinical setting depending on what the experimental design is looking at. So for example, it's not possible to blind parenteral nutrition versus enteral nutrition in a clinical setting. However, if you're comparing one enteral formula to another enteral formula, it's entirely feasible to blind that. And I would say necessary for a robust methodology. If anybody here has ever taken a food frequency questionnaire or tried to fill out a food diary, assessment of PO intake is highly subjective. And so that's always in the back of my mind as well. Third is that nutrition is difficult to isolate from other clinical conditions and interventions. Nutrition is provided universally to all patients. And so to do a robust analysis, isolating nutrition to evaluate it in terms of things like mortality and length of stay, it requires extremely large sample sizes in the tens of thousands. So as such, the right outcomes to evaluate the efficacy of nutrition interventions are largely unknown. And if you have an interest in nutrition and you're diving into the literature for nutrition, I highly recommend this publication by Fetter Place and colleagues. This publication discusses why things like the outcomes we like to look at, mortality, length of stay, days on the vent, things like that are not the right outcomes to evaluate the efficacy of nutrition interventions. And really we should be looking at outcomes that are more related to a patient's functionality. Did they discharge home? Did they maintain their weight? And those kinds of interventions. We are still exploring what those correct outcomes are, but this is a good framework to start with. So now that I've told you that mortality and length of stay are the wrong outcomes to look at, we're gonna dive into the literature that looks at exactly those outcomes because that's what we've got. So this is the 2021 ASPEN Guidelines. It's an update to the 2016 ASPEN Guidelines and it's sought to answer five specific questions. The first two questions are looking at appropriate calorie dose and protein dose in the first week of ICU stay. So the appropriate recommended calorie dose for the first week of critical illness is 12 to 25 calories per kilogram. This is less than what you would consider normal metabolic, which is 25 to 30 kcal per kilogram. The second question remains largely unanswered. The second question looking at the appropriate protein dose for patients in the ICU. We don't have the answer to this yet. However, we anticipate more information coming out with the publication of the highly anticipated effort trial. So we're all on the edge of our seats for that paper to drop. Now, how do these recommendations apply to obese trauma patients? These two questions were looking at MICU and SICU patients specifically. A tiny, tiny fraction of the population was a trauma patient, but they were not specifically obese. This paper is a really good summary of the different guidelines for caring for a critically ill obese patient. And this is Table 1 from that paper, which summarizes the different nutrition recommendations. At Stanford, we focus pretty heavily on the Aspen Guidelines. And the Aspen Guidelines in terms of calorie provision recommends indirect calorimetry whenever it's available and feasible. In the absence of indirect calorimetry, there are simple weight-based equations that you can use based off of the patient's BMI. So for patients with a BMI of 30 to 50, they recommend shooting for 11 to 14 calories per kilogram of actual body weight. And for patients with a BMI over 50, shooting for 20 to 25 calories per kilogram of ideal body weight. And for protein, the BMI ranges are a little bit different. For patients with a BMI of 30 to 40, doing 2 grams per kilogram of ideal body weight. And for patients with a BMI over 40, doing 2 1⁄2 grams per kilogram of ideal body weight. This is known, this combination of calorie and protein provision is known as hypocaloric high-protein feeding. If you take the time to deep dive into this table and read all the fine print, what you will find is that there's generally a lack of consensus over how to estimate nutrient needs for obese patients, what weight to use. And so really we're still left with many questions. So now switching gears, looking at nutrient needs specific to trauma, much of what we know comes from the 90s. So these are the three just sample studies from the 90s that performed indirect calorimetry in trauma patients within the first week of ICU stay. And some of those ICU studies were repeated during the first week at varying frequencies. The mean injury severity score for these three studies was in the mid 30s. And the patients were not specifically obese. These are the findings from those three studies. And in summary, what they found was an overall increased caloric expenditure of 28 to 48 kcal per kilogram per day. So much of the sentiment that trauma patients are hypermetabolic is rooted in this history. So let's fast forward into the current era. This is a very recent article by Byerly and her colleagues, and they performed continuous indirect calorimetry on 55 trauma patients starting within 48 hours of ICU admission until ICU day 14. So exactly the timeframe that we're talking about today. Their patients, however, were not specifically obese. And they were the first to apply group-based trajectory modeling to indirect calorimetry results. And from that, they were able to identify four metabolic phenotypes, and some were hypermetabolic and some were not. Now there were some limitations to this study. They did allow for concurrent CRRT while doing the indirect calorimetry studies. If you run the two at the same time, you can't interpret the results of the indirect calorimetry directly because CRRT introduces another area of gas exchange that you're not capturing in the indirect calorimetry. Their sample size was unfortunately limited. Their institution in the middle of their study changed some of their procedural workflows, and which effectively eliminated the continuous indirect calorimetry equipment. They did exclude incarcerated patients whose physiology should be just like the rest of ours. I presume they had good reason for doing so. Now despite these limitations and how novel this modeling approach is to indirect calorimetry, I really do appreciate these findings because it resonates with my clinical practice. So in keeping with the theme of all the speakers up here, there really isn't any literature on providing nutrition specifically to obese trauma patients. So instead, I'm just going to summarize for you my anecdotal experience with indirect calorimetry. It's been my practice to get an indirect calorimetry study on all trauma patients two to three times a week for the first two weeks whenever patients were eligible for those studies. Generally speaking, I expect a trauma patient's metabolic curve to look like this purple line. Now this is fully anecdotal. I don't have a IC baseline on any of my trauma patients. But what I expect to see is I expect the metabolic rate to peak anywhere from three to seven days post insult and then gradually taper off, but level out higher than what I would expect their metabolic baseline to be. Now if I were to categorize metabolic phenotypes that I have seen, I could break it down into three categories. The vast majority of patients are going to continue to fall into that hypermetabolic phase. So before I get the results of an indirect calorimetry study I still have to come up with something. So I start with 30 to 35 kcals per kilogram. This is very common. Elderly patients who have less severe traumas like ground level falls and females tend to fall on the lower end of that range while males tend to fall on the higher end of that range. I have seen what I'm calling hypometabolism which I'm defining as less than 25 kcals per kilogram. And that is rare and unexpected. And I've also seen what I'm calling ultra-hypermetabolism, defining that as anything greater than 5,000 calories a day and that's less rare than hypometabolism and it's always a young male. Now speaking specifically about obese trauma patients I can tell you with great confidence that hypocaloric feeding in this patient population is wrong. I have seen the greatest variance between the results of an indirect calorimetry study and these predictive equations. So if you're at an institution that doesn't have indirect calorimetry I would anecdotally advise you to start at 30 to 35 kcals per kilogram of ideal body weight and continue to assess the nutritional status and the clinical progression of the patient and adjust as needed. So now that we've determined calorie and protein needs let's move into the practical aspects of providing artificial nutrition. So I don't have time for a deep dive on all of the considerations that I'm making as a dietician for these patients but the three main things that I want to talk about today are immune modulating enteral formulas which are formulas that are enriched with any combination or amount of arginine, glutamine, fish oil and other antioxidants. There's not really any robust literature on the antioxidant content. Most meta-analyses looking at immune modulating formulas are looking at the amount and combination of arginine, glutamine and fish oil and then volume-based tube feeding and parenteral nutrition when needed. So the Aspen and Society for Critical Care Medicine 2016 guidelines does specifically address trauma and traumatic brain injury. And for both of these populations early enteral nutrition still applies. For TBIs, actually for both, we still have a weak recommendation that immune modulating formulas should be used in these populations. And for TBIs this recommendation was based off of one small study. For trauma patients in general, they based this recommendation off of this meta-analysis. This was a meta-analysis that looked at studies which compared immune modulating formulas to isocaloric and isonatrogenous standard formulas. And they broke their analysis down by MICU, SICU and trauma patients. So what I'm showing you is the results from their trauma subset. This forest plot shows you that immune modulating formulas don't really have any mortality benefit compared to standard formulas. But they do have a slight benefit for the prevention of new infections and a slight benefit for decreasing the length of stay compared to standard formulas. And all of these forest plots have significant heterogeneity in their data. Now the Aspen recommendation for using immune modulating formulas is very specific. It calls out formulas containing arginine and fish oil. And that recommendation likely comes from this sub-analysis from the same meta-analysis which does show a mortality benefit in trauma patients for immune modulating formulas that contain both arginine and fish oil. So the takeaway here is that not all immune modulating formulas are created equal. If you have one on your formulary, you should take a very close look at what is in that formula. Moving on to volume-based tube feeding. This is just kind of a snapshot of how we operationalize volume-based tube feeding at my institution. But the core principle of volume-based tube feeding is that you're tube feeding a patient with a goal daily volume in mind and allowing the bedside nurse to adjust the rate of feeding throughout the day to make up for pauses and delays in enteral nutrition. There's many different ways to operationalize this and volume-based tube feeding protocols are recommended by the 2016 Aspen and Society for Critical Care Medicine Guidelines and also the 2022 Aspen Consensus Statement on enteral nutrition indications. Now, even with volume-based tube feeding, if you have a patient who's going to the OR every day or every other day, volume-based tube feeding may not be enough to make up for that amount of holding. So for trauma patients in particular who are going through those frequent procedures, parenteral nutrition may be indicated. So in trauma patients specifically, parenteral nutrition is indicated when you can't get enteral access due to their injuries, if the GI tract is non-functional or when enteral nutrition is grossly inadequate. Now, there's a very strong and pervasive sentiment that parenteral nutrition is dangerous, that it increases infection risk, and that is incorrect. That was laid to rest in the 2021 Aspen Guidelines. So this is question three and four from the Aspen Guidelines. On the surface, they do seem to contradict each other, but this gets back to the lens with which we need to interpret nutrition literature. So the first question is asking whether or not parenteral versus enteral nutrition creates any difference in clinical outcomes. So the meta-analysis that was done for this recommendation was done in just under 5,000 patients. And the design of those trials, of those randomized controlled trials that, there were two, two randomized controlled trials, those trials were designed to answer exactly this question. So they were looking at patients who were all appropriate for enteral nutrition, but randomized those patients to receive either parenteral or enteral nutrition. And what they found is that they're equally safe. So there is no greater infection risk for parenteral nutrition when compared to enteral nutrition. The takeaway is, if you need to provide parenteral nutrition, you can do so safely. Now, question number four discusses whether or not providing supplemental parenteral nutrition provides any benefit to patients in terms of the outcomes that they were looking at. Now, again, this gets back to that lens. What outcomes were they looking at with these patients? They were looking at things like incidence of bacteremia and mortality and length of stay. This question did not ask if you provide supplemental parenteral nutrition to a patient who's being underfed through enteral nutrition. Does that help maintain weight? Does it help prevent malnutrition? Does it help them to discharge home? That question remains unanswered in the literature. It is my practice to provide parenteral nutrition when enteral nutrition is inadequate, even in the first week in the name of maintaining functional outcomes and preventing malnutrition. And finally, I leave you with my practical tips and tips for working around all the challenges that we encounter in the ICU with feeding trauma patients. But much of this applies to the ICU population in general. So first, frequent operations and procedures interrupt enteral feeding. We know that. We have to anticipate it. And so we do that by aiming high on our nutrition provision. So I know at my institution that if I aim for 100, I'm going to get to 60 in the first week. I know that through internal audits. And this is generally true in the literature as well. And so in order to combat that, I am utilizing volume-based tube feeding. Again, it's an aggressive feeding protocol. So I'm doing that for any patient that it's appropriate for and that can tolerate it. And when both of those interventions continue to fall short, we're starting supplemental lipids or TPN. Hemodynamic instability is something that you can see in any ICU population. There's a ton of literature on this right now seeking to clarify when it is safe to enterally feed a patient on what dose and combination of pressors. The general guidance is you can start enteral nutrition when the maps are greater than 60 with a stable or decreasing pressor dose with one to two agents. Or you can consider using the vasopressor dose equivalent score, which I've referenced for you down there in the corner. And when your patient is too hemodynamically unstable to feed, use early TPN. For trauma patients in particular, it can be difficult to obtain enteral access if they have a facial trauma. So if they have an OG tube, it's okay to use that. You can ask your ENT colleagues for assistance with placing nasoenteric tubes or place them during surgery. Consider early PEG for patients that it might be appropriate in. And if all else fails, use TPN. Propofol and clovidipine are calorie-containing drips. And on high doses, we can overfeed a patient with propofol and clovidipine without providing any other nutrients. No protein, no micronutrients, no carbohydrates. And so when patients are on high doses of these medications, we are using a lot of protein modulars or we're using low-calorie, high-protein formulas. With these medications, you definitely want to be monitoring the patient's triglycerides as they are suspended in IV lipids. With trauma patients, assessment information is not always available, particularly diet and weight history. And so dieticians need to know, am I feeding a malnourished patient or am I feeding a well-nourished patient? And a trained dietician can glean that information pretty confidently based off of just a nutrition-focused physical exam. And then finally, the overzealous discontinuation of artificial nutrition in favor of volitional PO intake. Do not assume that just because your patient is extubated and can swallow, that they will eat adequately. People who are sick and injured don't have robust appetites. They're not in their home settings. People in the hospital generally are not eating adequately. So a dietician can help you assess the actual PO intake of a patient and come up with a transition plan to gradually wean a patient off of tube feeding when a patient is starting to meet their needs by mouth. The last thing that you wanna do is pull a feeding tube out only to have to put it back in, because now your patient's awake. They're not gonna like that. Takeaways are that indirect calorimetry is a dietician's best friend. Feed aggressively in your trauma population. Do not use hypocaloric feeding for your obese patients. And do not be afraid of parenteral nutrition. Thank you for your time. Thank you.

metabolic response

nutrition care process

trauma patients

medical nutrition therapy

malnutrition

nutrient needs