Hello, and welcome to this session of Current Concepts in Pediatric Critical Care for SCCM 2022, the SMART course. My name is Sharon Irving, and I will present for you today the 2017 Nutrition Guidelines. I have two disclosures to put forth for you. One is University of Pennsylvania. We have some funding that is non-salary supported from the Penn Center for Nutritional Science. And then we have some funding from the Children's Hospital of Philadelphia from the Nutrition Research Affinity Group. We have three primary goals or objectives for this presentation. Initially, we'll describe the newest recommendations for the provision of nutrition in critically ill children. Second, we'll summarize the evidence behind the nutrition guidelines and how they came to be. And third, we'll highlight areas where future research is still needed for these guidelines and future guidelines. So a little background to get us started with where the guidelines came from. In 2009, the initial and the first guidelines for pediatric critical care were published. And then in 2017, a consensus of a multidisciplinary task was formed through a collaboration with the American Society for Parenteral and Enteral Nutrition and the Society for Critical Care Medicine. This task force reviewed the literature and was able to do an analysis and pull together the most current literature at that time that addressed these guidelines for pediatric critical care nutrition therapy. The task force consisted of doctors, nurses, dieticians, pharmacists, and other stakeholders and were charged with putting together a new set of guidelines. The 2017 guidelines are the ones that are currently in use. So a little background. These guidelines for 2017 are presented as a series of eight questions. The questions are fairly common among health care providers when they are faced with and having discussions about giving nutrition therapy to children in the pediatric intensive care unit. The recommendations of these guidelines are targeted to children between the ages of one month and 18 years and those children who will have an ICU stay of at least two to three days. It is not meant for those children that will have a very short ICU stay. Now there are some populations that are excluded from the guidelines and those include neonates and those children with burn injuries. The guidelines are not intended to cover those children. The major objectives of the guidelines are to offer basic recommendations for nutrition therapy in the critically ill pediatric patient and also to supplement and enhance but not replace professional training and clinical acumen of the health care team that are caring for these children. So we'll use a case scenario to review the recommendations and see how they are applied in practice. Our case is a 14-year-old boy with a history of acute lymphoblastic leukemia. He is status post a hematopoietic cell transplantation and he's admitted to your ICU with fever and hypertension. He has methicillin-resistant staphylococcus aureus bacteremia and presents in septic shock. He's resuscitated successfully but then develops acute respiratory distress syndrome requiring intubation, mechanical ventilation, neuromuscular blockade or paralysis and that is all necessary to facilitate his care. Now it's clear that this child is at risk for metabolic changes, challenges and nutritional deterioration. Why is this patient's nutritional status important? Why do we care? Well, we care because we know malnutrition is present in pediatric patients when they present to the ICU and we don't know exactly what that prevalence is but studies suggest that as high as 60% of the children who present to the ICU are in a suboptimal or malnourished nutritional state. And why do we not have better data on this? Because it wasn't until 2013 that we have clear definitions of malnutrition. And what we also know is that those children who present who are malnourished have increased risk of infection, they have an increased length of stay, they have longer ventilation times and they are at increased risk for mortality. Now the thing to keep in mind with this as well is that malnutrition is at both ends of the spectrum. So it is in those children that we think of as the very small and in a poor nutritional state who are underweight but it's also present in the overweight, the obese and the morbidly obese child. Studies suggest that the overweight child also has an increased use of resources and they too have longer days of mechanical ventilation although they may not have the same rates of mortality. Either way, suboptimal nutrition and malnutrition for the ICU patient causes challenges. So we've identified why nutritional support and therapy is important in the ICU. The next question comes, how do we do it? So we do it by having a team of clinicians with knowledge of both pediatric critical care and knowledge of pediatric nutrition. A vital member of that team is your dedicated dietician. That team together will engage to determine what the nutritional support should be. Your team will not only administer nutrition according to the guidelines but they will also help to identify those patients who are most at risk for nutritional deficiencies and they will also help to assess the patient for a suboptimal nutritional status or malnutrition. They can establish nutritional intake goals and help with the prescription of what that nutritional therapy should be meeting the individual patient's needs. The team can also collaboratively monitor how the patient is doing in response to the prescription and the delivery of nutrition therapy. They will also monitor how the patient reacts to that and look at health and clinical status changes as they occur. So the next step, now we need to conduct a detailed nutritional assessment and the entire team plays a role in this with the dietician helping with a focused nutritional physical examination. This assessment should be done within 48 hours of the PICU admission and it should include things like the child's diet history, what are their anthropometrics or their anthropometry measurements, what's their functional status at presentation, what are the components of this nutrition focused physical examination that need to be highlighted. This reassessment should happen weekly so that you can see exactly how the child is responding. Are they hitting these nutritional goals and are the prescriptions helping with what you are trying to accomplish? So in addition to the general physical exam, the nutrition focused physical exam will assess the muscle and fat mass of the child. They will look at their skin, their hair, their nails, eyes and orbital regions, their oropharynx, their dentition. Do they have the use or the necessity to use medical feeding devices? Are there ostomies present? Is there presence of any medical devices? When you follow some of their muscle and fat mass measurements, this gives you some idea of how they are doing overall in terms of their nutritional status when you look at those because when you look at areas such as the triceps and the subscapular, these denote subcutaneous fat stores. The mid-upper arm circumference is demonstrative of both muscle and fat mass. So following these measurements over time can provide information on fat stores and muscle accretion for these patients and or muscle loss. So a complete nutritional assessment is much easier to perform in an ICU that is well resourced. But what do we do in low resource settings and when we don't have all the tools that we think we need? So to date, there is no validated screening tool for use in the pediatric ICU patient. So therefore, the current guidelines do not recommend any one tool to assess these patients. Why is there no screening, no good screening tool? Because the metabolic changes that occur and that are altered and the point of nutritional deterioration that we know can happen very quickly in the ICU, the tools are not able to keep up with that at that point in time. So again, the guidelines do not recommend the use of any single screening tool. However, what we can use is anthropometrics or anthropometry measurement. Their weight, their weight for AHZ scores, their height or their length, their BMI for AHZ scores, their head circumference, and then some of the measurements that I just mentioned in terms of triceps and subscapular. So let's go back to our patient. On assessment, we have a 14-year-old male. His diet history is poor. He drinks lots of sugary drinks, eats very few vegetables, and eats out three to four times a week. Prior to admission, his functional status was typical or normal. His nutrition-focused physical exam reveals an obese teenager. He's lying in bed. He's sedated. He's neuromuscularly blocked or paralyzed and mechanically ventilated. On this initial assessment, there are no areas of muscle or fat loss that are seen. He does, however, have 2 plus pitting edema bilaterally on both his lower extremities. His anthropometry measurements reveal a weight of 98 kilos or 216 pounds. His height is 175 centimeters or about 5 foot 9 inches. His BMI is in the 99th percentile, and his Z-score is plus 2.24. His ideal body weight is about 65 kilos or 143 pounds. We need to determine the energy needs of our patient, so we should use indirect calorimetry to calculate his energy needs and formulate a nutrition prescription. Indirect calorimetry works by measuring the oxygen that is consumed and the CO2 that is produced or eliminated. It takes these numbers, plugs it into what we call the Weir equation that is presented here, and the result gives us a metabolic rate in the form of kilocals for a day. It also gives you a respiratory quotient. However, the respiratory quotient can range anywhere from 0.65 up to 1.3. These specific values are associated with lipid metabolism, protein metabolism, or carbohydrate metabolism. The respiratory quotient is not recommended to use as much in the PICU patient because it can really alter what your macronutrient prescriptions are, and you run the risk of not providing what the patient needs. And that is because the metabolic needs of a pediatric ICU patient changes daily, if not hourly, and their metabolic rates can change all the time. That is not to say you change your prescription every time your rate changes, but it tells you the range in which you're in. We have found that indirect calorimetry is more accurate in assessing those energy needs compared to predictive equations. It can also help you to identify both hyper and hypometabolism, which can be difficult to detect in a patient. However, these are common occurrences. This is why we say, and the guidelines will tell you, that indirect calorimetry is the better method to determine energy needs in these patients. So even though we know that indirect calorimetry is the better method to identify metabolic needs, there are pitfalls. It does require specialized equipment and personnel who are well-trained to be able to do these tests accurately. And sometimes when that equipment is available, everybody wants in on it, and so you share it, and that means it may be difficult to have it available because they are an expensive piece of equipment. And to have the trained personnel available to use to perform the tests can be challenging when you're trying to meet all kinds of staffing needs in your ICU. There are also some limitations in terms of the technology. It can be used in patients who are intubated, and that makes it easy to obtain your oxygen measurements and CO2 production through the ventilator. However, alterations that can occur with these measurements can throw them off. For instance, if you have a leak, that can throw off what your values look like. It also cannot be used in some of our specialized ventilatory modes, such as high-frequency oscillatory ventilation, or ECMO, or a patient on dialysis, because all of this changes, and the produced CO2 is different than what it is on a child who is mechanically ventilated and not using some of those other technologies. In the very small patients, it's also difficult to use indirect telemetry because their tidal volumes are smaller, and there are certain tidal volumes that need to be hit for the machine to be able to measure them accurately. So while we know that it is an excellent technology to be used, there are limitations to it that we must also be aware of. So we've used indirect telemetry on our patient, and the resting energy expenditure is 2,075 kcal per day, and his respiratory quotient is 0.7. We've spent some time talking about indirect telemetry, and I've identified for you why it is the method of choice to determine energy needs. But not everybody has access, and not everybody has a cart to use to do those measurements. So what do you do? You use predictive equations. The two most common ones are the Schofield and the Food and Agricultural Organization of the United Nations slash World Health Organization slash United Nations University equation, both of which are shown here. These equations differ based on a patient's gender and age. When you calculate energy expenditure using these equations, the guidelines do not recommend that you throw in a stress factor. And that is because there tends to be more hypometabolism in PICU patients, often because of some of the things that we do to them. We decrease their work of breathing, and we decrease their activity through sedation and such. So their metabolic needs may be very different than what those stress factors would owe themselves to. The guidelines also recommend against using the Harris-Benedict or the recommended daily allowance equation. These equations were developed for healthy children, and so they are likely to overpredict what the energy needs are of an ICU patient. Either way, whichever equation you use, the guidelines recommend that you monitor for overfeeding and underfeeding in your patients, because either case can cause complications. So this is what these equations would look like for our patient with the correct values plugged in. The results, as you can see, are relatively close to each other. The Schofield equation gives an energy expenditure of 2,348 calories per day, and the WHO gives 2,366 calories per day. But it's close to 300 different than what indirect calimetry predicted for our patient or gave us for our patient. So now we have what the energy prescription should be for our patient, and we can calculate the goal energy intake that we want him to get over time. So data shows that if you can provide and deliver at least two-thirds of the prescribed daily energy target by the end of the first week, these patients have been shown to have lower mortality rates, decreased ICU stays, and overall better outcomes. So when we apply this two-thirds to our patient using his indirect calimetry kilocal estimation, we get about 1,400 kilocals per day by the end of the first week. So we've identified what the energy needs are for our patient. What about protein? The current guidelines recommend 1.5 grams per kilo per day of protein in the ICU patient. This is higher than what previous recommendations were. If your patient is obese, you should probably use be using an ideal body weight. And so for our patient at 65 kilos, that's about 98 grams of protein per day. You also want to aim to provide protein early in the course of illness as best you can. Because this higher protein intake has been associated with a positive nitrogen balance and that in turn has been associated with better outcomes. So higher doses of protein earlier in the course of illness has been associated with improved outcomes. These recommendations of the 1.5 grams per kilo per day are higher than the RDA values for protein intake. So again, the RDA should not be used when you are prescribing protein for your ICU patients. So let's do a brief summary of goals for our patient. The total goals based on indirect calimetry for energy is 2,075 kilocalories per day with a delivery of approximately 1,400 kilocalories per day by the end of the first week. And our protein goals are about 98 grams per day. We've determined what we need to give and now it's time to think about how we're going to give it. So enteral nutrition is the preferred method of nutrition delivery in the ICU patient. Enteral nutrition has been associated with lower mortality in this population, but importantly, it also helps to strengthen the mucosal GI barrier in the GI tract. And that means there's less risk or you decrease the risk of bacterial translocation and you support or you enhance the immune function. However, enteral nutrition, while it has all the benefits that I've just described, is often interrupted. Sometimes interrupted needlessly. And so when you do all those interruptions, you are not able to provide the energy and the protein target that you have identified that your patient needs. So we have to think about those interruptions and see if they are avoidable or unavoidable. For instance, the notion that a child cannot be fed when they're on ECMO or vasoactive medications or pressors is we're finding out that that's just not true. And there are studies that are showing success in feeding those patient populations. We don't have strong evidence that says exactly when to stop enteral feeding and so therefore it's often stopped prematurely because we don't have evidence that tells us when you can feed through and when you cannot feed through. So we need to use clinical judgment, clinical acumen, comfort level, and the patient's clinical status to avoid interruptions as much as we possibly can. When we think about what is the best way to reach these target goals that we have now established, data shows and the evidence shows that the use of algorithms or pathways or protocols really help to optimize nutrient delivery. Why? They give instruction for the initiation and advancement of feeds. They help you to avoid unnecessary interruptions. They provide guidance on the management of common issues that come up with feeding. It standardizes interruption time. So a lot of protocols will give you some ideas about how long you should hold a feed for a particular issue. For instance, gastric distention. There are protocols that will say just withhold it for an hour and restart again or give you a specified time frame. Many protocols also help to define feeding intolerance because that is also a challenge in feeding the ICU pediatric patient. How do we define intolerance? When do we say they're not tolerating that feed? In addition, use of a feeding algorithm or protocol or a guideline helps to standardize the approach that your entire team will have to the provision and initiation and advancement of nutritional therapy for the ICU team so that you can reach those target energy and protein goals that have been prescribed. Another question that often comes up when providing feeds to the ICU patient is does it matter if they're gastric or small bowel feeds? The gastric route is preferred. Although, there's not a lot of strong evidence showing that gastric route is better. Post-pyloric feeds however or transpyloric feeds can be associated with delays in feeding initiation because you have to get the tube post-pyloric and sometimes that requires a specialized tube or specialized study. They have to go to interventional radiology or you need providers that are skilled in getting those tubes past the pylorus at the bedside. Studies do not show that there is a reduced risk of aspiration with post-pyloric feeds because remember even though you're feeding post-pylorically there are still gastric juices that are being produced and so there is not a reduced risk of aspiration. We still want feeds initiated early in the course of treatment. So within the first 24 to 48 hours of the ICU admission once your patient is stable feeds should be initiated unless completely contraindicated. Initiating feeds within these two days has been associated with higher survival and better outcomes in our PICU patients. So feed early feed the stomach. So I said there's not a lot of strong evidence about feeding the gut. Well a study that was just published in 2021, remember these are the 2017 guidelines, so to update them or to update evidence for these guidelines. A study that was just published in 2021 which was called the continuous versus bolus multicenter randomized effectiveness trial or COBO looked at 147 participants across seven clinical sites. All of these children were mechanically ventilated within 24 hours of PICU admission and they had an expected duration of at least 48 hours for mechanical ventilation and longer for their PICU stay. They were divided into bolus or intermittent gastric feeds versus continuous gastric feeds by participating center assignments. So the centers were assigned as to whether they were going to be a continuous feed center or bolus feed center. 72 in the bolus feeding group and 75 were in the continuous feeding group and there was a standardized feeding algorithm for each arm of the study. So if you were a bolus or continuous, there was a standardized algorithm that needed to be followed if you were in the study. So what did they find? They found that the time to goal feeds was shorter in the bolus feeding group compared to the continuous feeding group with a hazard ratio of 1.5 and a p-value of 0.04 with a confidence interval of 1.02 to 2.33. In addition, the median percent of attained target energy bolus feeding had 0.78 versus continuous feeding. So the bolus feeding group attained their energy target sooner than the continuous feeding group. The bolus feeding group also attained their protein delivery target sooner than the continuous feeding group. There was no incidence of ventilator-associated infections in either group. So that gives us more evidence to say we can feed gastrically and if you feed gastrically you can do it in a bolus or intermittent fashion, which is much more physiologic than a continuous feed. So more study needs to happen and in larger groups and in different populations, but this study at least lays the groundwork to look at this question closer. So back to our patient. So our goals were here of 2,075 kilocalories and 98 grams of protein and if we're using 1440 mls per day of a 1.5 kilocalories per ml formula, which he's old enough to use an adult formula, that would give him about 60 mls per hour for a continuous delivery or somewhere in the neighborhood of 240 mls every four hours if we go with bolus feeds for him. Overall this will give him about 2,160 kilocalories and the 98 grams of protein that we know he needs. And if you look at that, that kilocalories breaks down to 22 kilocalories per kilo per day and we know in the adult population they give around 20, between 20 and 30, most often around 25 to 28 kilocalories per kilo per day and they're having good outcomes with providing that amount of energy. The initiation and advancement for this, if you're doing continuous feeds, would start at 20 mls an hour and advance by 20 mls every two hours until you hit your goal of 60 mls per hour. If you do bolus feeds, you could start with a smaller amount than the 240 that was mentioned. You could start with 30 mls every feed and then increase incrementally until you hit to the point and watching all along the way that this patient is tolerating these volumes. There's not a lot of data that looks at the optimal time. So there are several options that you can consider in terms of do you advance every two hours, every three hours, every four hours, every six hours. It depends on the comfort level. It depends on your patient's clinical status and continual monitoring. You may start out slower and increase because your patient is tolerating them well or the opposite. You may start out a little faster and need to decrease and watch how your patient is tolerating. The overall point is that using an algorithm helps our patients to meet their goals. So, what do we do if our patient is not tolerating their feeds? You followed the algorithm, the feeds were started and each time you attempted to advance, there's been many interruptions due to abdominal distention and emesis and so there is the perception that this patient is not tolerating their feeds. Right now, at the time of your assessment, he's only receiving about 40% of his nutritional goals. So then the question comes up, should we add parenteral nutrition to his regimen? I will also say that make sure that the tolerance or intolerance is true. Be sure that your patients are on stool regimens. Be sure that the delivery is appropriate, that there's not air in their stomach. There's all of these kinds of things that we still need to be sure that we are monitoring for our patients. When should we add parenteral nutrition? So, under these current guidelines, the use of parenteral nutrition is not recommended within the first 24 hours of PICU admission. During this time frame, it is believed that the use of parenteral nutrition may actually increase the risk of new infection and therefore have the patient with a longer length of stay and due to the complications that can occur. The guidelines do, however, recommend the use of parenteral nutrition for patients who are unable to have any enteral nutrition within that first week of ICU admission. So, not in the first 24 hours or so, but if it is very clear that your patient will not be able to tolerate any enteral nutrition in that first week of the ICU admission, then it is recommended to start parenteral nutrition around day three of the ICU admission. You want to make sure that your patient is as stable as possible during that time frame and provide the parenteral nutrition and again talking about protein because you want to decrease the negative nitrogen balance and support a positive nitrogen balance because that has been associated with improved outcomes. The benefit of supplemental parenteral nutrition is really unclear. So, these guidelines say that you can hold supplemental parenteral nutrition for about a week for patients who are not severely malnourished because in the instance of our patient, they are still receiving about 40% of his nutrition. Now, the goal is 60% and he's at 40%. So, it may take a couple of more days to get him to that 60%, but there's not a need at this point in time to add parenteral nutrition to him. So, we're eight days into this. What does our patient look like? He's still intubated, no longer under neuromuscular blockade or sedated, tolerating goal feeds at this point, has had a repeat indirect calimetry done and his energy expenditure is now 2200 kilocalories per day with an RQ of 0.8. And his nutrition-focused physical exam is noted for a pressure sore. So, you're rounding and you have an astute medical student who says, what about using an arginine-containing formula to promote wound healing? So, you and the team ponder that question for just a minute. Would this patient benefit from an immunonutrition-based formula? The short answer is that under the current guidelines, there is no recommendation for immunonutrition in pediatric patients. Why is that? There's so little data regarding benefits of immunonutrition in our population. Even the studies that exist in the adult populations, the results are mixed. Many of the studies are not looking at a single component in the formulas. It's often multiple components and they will focus on a combination of things such as omega-3 fatty acids and fiber. They add to that some arginine and glutamine. There may be minerals mixed in the formula or they're looking at minerals as well in terms of selenium and zinc and copper, which we know do promote wound healing. A lot of these studies are also underpowered. So again, it's difficult to know if there was really a benefit because of the small sample sizes. There are some studies that have possibly shown some benefits and others have tended towards increased mortality. So again, the results are mixed. The data is unclear. And so for those reasons, we do not recommend that immunonutrition be used in PICU patients. So in our patient, to answer your medical student, we would not start this patient on an immunonutrition formula due to the mixed results in the adult populations and the lack of data in pediatric populations. So over the course of this session, we have reviewed the 2017 nutrition guidelines for PICU patients. So to summarize, proper nutrition impacts outcomes in our PICU patients. A thorough nutrition assessment is warranted for each and every patient that is admitted to the PICU within 48 hours of that admission. Within that, it is especially important for those patients who are baseline malnutrition or who are at increased risk for a nutritional deterioration. And remember, malnutrition is both the very small, suboptimal, undernourished child, as well as the child who appears to be overnourished, who is overweight, obese, or morbidly obese. Both have malnutrition. Energy expenditure, whenever possible, should be measured by indirect calorimetry. Gold protein intake in PICU patients is 1.5 grams per kilo per day at a minimum. Enteral nutrition is preferred over parenteral nutrition, and evidence is emerging that the gastric route on an intermittent bolus feed schedule is well tolerated. Parenteral nutrition should be avoided within 24 hours of the PICU admission. Immunonutrition is not recommended in children. So thank you very much for your attention.

Nutrition Guidelines

critically ill children

pediatric intensive care unit

malnutrition

enteral nutrition

energy and protein requirements

indirect calorimetry

immunonutrition