ICU Nutrition: Evidence to Practice (2019)

INTRO: Welcome to Clinical Nutrition Notes, a podcast where we speak with guest experts and opinion leaders about the art and science of clinical nutrition, brought to you by Nestlé Health Science Canada. This podcast is intended for healthcare professionals for education purposes. I'm your host, Cindy Steel, Medical Affairs Manager with Nestlé Health Science.

Today, we will be speaking with Michele ApSimon to get a dietitian’s perspective on putting evidence into practice in the nutrition management of ICU patients. Michele ApSimon is a registered dietitian working in critical care at the Hamilton General Hospital in Hamilton Ontario. She has a degree in life sciences from Queen's University and a master's in nutritional sciences from the University of Guelph. At Hamilton Health Sciences. Michele has been involved in many research initiatives including the International Nutrition Survey as well as a recent prospective review looking at protein intakes in ICU patients. Michele has been a guest speaker at many conferences and webinars including ASPEN Clinical Nutrition Week and is a published author, most recently in Current Opinions in Clinical Nutrition and Metabolic Care.

In this third podcast in our series on critical care nutrition, we are bringing our conversation back to the bedside. As a dietitian working on a large medical surgical ICU, we are interested in Michele's perspective on how the evolving literature related to glucose control and protein in critical care has an impact on her practice.

Steel: Thank you for joining us, Michele.

ApSimon: Thank you for having me.

Steel: To set the stage, can you briefly describe the ICU setting where you work?

ApSimon: Sure, the ICU I work in is a 50-bed trauma, medical, surgical, cardiac ICU, in a teaching hospital in Hamilton, Ontario. It’s divided into three separate ICUs that are cared for and rounded on by three separate teams twice a day. About 70 percent of our patients are enterally fed, and we have a 1.5 dietitians that cover this unit.

Steel: Sounds busy. Thank you for that. One of the newer ICU nutrition concepts which has emerged, relates to protein, with more attention to meeting protein needs and less emphasis on meeting energy needs, particularly during that first week of critical illness. Can you review, briefly, what the current North American recommendations are with respect to protein and energy delivery for ICU patients?

ApSimon: I can, sure. There are many different guidelines out there. The Canadian and American guidelines, most recent ones, for feeding critically ill patients recommend around 20 to 30 cals per kilo, in the non-obese patients, and anywhere from around 1.2 to 2.0 grams per kilo of protein. In obese patients, the recommendations vary based on the obesity classification. So, the ASPEN guidelines recommend that patients with a BMI of 30 to 50 should receive around a 11 to 14 cals per kilo but the protein provision of 2.0 to 2.5 grams per kilo of ideal body weight.

And the reason behind feeding a patient a hypocaloric and high-protein regimen, is that the provision of additional calories worsens hyperglycemia and it results in further accumulation of fat mass and increases the potential for over feeding, without really a significant gain in net protein.

In 2016 we had the international protein summit and it gathered experts in clinical nutrition and protein metabolism together to determine the impact of high-dose protein administration on clinical outcomes in critically ill patients. And the recommendations from the summit include a range of protein intakes from a minimum of 1.2 up to around 2.5 grams per kilo per day, especially in trauma, obese, burns, continuous dialysis, and elderly patients.

The type of protein – whey, soy, and casein – were recommended, really, as a higher-quality protein, whereas collagen was not recommended due to its low quality. High-quality protein is important; it’s known to affect nutrient-sensing pathways, which can stimulate anabolism or new protein synthesis.

So, if you consider that protein loss or catabolism is part of the metabolic process in all critically ill patients, and that the magnitude of this protein loss is associated with increased morbidity and mortality, then achieving protein goals in the first week of admission to the ICU, we think, should take precedence over meeting energy goals. High-protein, hypocaloric feeding seems to be evolving as the best strategy during the initial phase of critical illness to avoid this over feeding, improved insulin sensitivity and maintain your body protein homeostasis, especially in our high nutrition-risk patients.

Steel: That’s great, thank you. Thanks for summarizing that too. So, considering these sorts of recommendations or your goals around hypocaloric and high-protein feeds, do you believe clinicians are faced with a challenge when aiming to meet those or put those in practice?

ApSimon: Yes, absolutely. The challenge to meeting, basically, these goals are that many enteral feeds are lower in protein, so to provide patients with high protein and lower energy, one would have to provide a feed at a lower rate than goal rate and then top up the energy and protein with some modular protein supplement. Unfortunately, any time you add extra work to the feeding regimen, especially around here, it can contribute to decreased compliance. So, added supplements take more time to find, mix, and then give to the patients. If the supplements aren’t properly mixed, they can clog the tube. If supplements aren’t conveniently stored, they won't be given.

We recently conducted a five-day retrospective review of 40 patients in our ICU. We reviewed 20 patients who received traditional enteral feeds and then 20 patients who received a very high-protein feed. And the primary objective was to assess the protein intake and percent daily protein needs met. Protein intake mean, for the first five days of ICU stay in these patients, was about 1.5 grams per kilo per day in this very high-protein group, and 1.1 grams per kilo per day in the traditional enteral group. But of interest, in this group of patients, daily caloric intake was 17 cals per kilo for the high-protein group and 19 cals per kilo for the traditional group – so less for the high-protein group.

So, I think this study not only showed that we can provide more protein with this new feed, but we've also changed our practice, and now we provide less energy to these patients at the start of their ICU stay.

Steel: I think that's probably fairly common when you make the comment about the more steps it takes, the less or the lower the compliance gets when you're dealing with enteral feeding for sure. So, thank you for that. And now, I'd like to switch gears a little bit and turn to the topic of blood glucose management. Can you talk about traditionally how has blood glucose been managed in your ICU?

ApSimon: Traditionally in our ICU, treatment of blood glucose has been reactive, so we have a sliding scale. So, we provide fast-acting insulin after we get a high blood glucose, which just promotes variable blood glucose in our patients, and we know that it's not good for outcome. So, we're starting to add longer-acting insulin to our protocols, but change is slow, and in our blood sugars, in this ICU, are often anywhere between 10 and 20 range, which is unfortunately pretty high.

Steel: In his new 2018 publication in JPEN, Dr. Todd Rice describes what some may consider a new approach to nutrition as therapy, one that uses a specialized enteral nutrition formula to help manage blood glucose in the ICU. He has described this study as a key turning point in ICU nutrition research. So, how do you see the role of a whey-based, high-protein, low-carb enteral formula to help manage blood glucose in your ICU?

ApSimon: We know that the critical illness worsens insulin sensitivity, and that resistance hyperglycemia is associated with the severity of critical illness outcome – something we know, and we're trying to translate that to all of our docs. And we also know from previous studies like the NICE-SUGAR trial that the optimal glucose range is not too tight – it's less than ten – because stricter glucose protocols increase these hypoglycemic events, which then increase mortality.

So, our patients are at risk if we use too much insulin. So, if we are providing too much glucose then a good strategy would be to decrease the dextrose load for our patients, which is what we are doing with this lower carbohydrate, high-protein feed. So, we utilize that feed not only for obese patients, but we utilize it in our brittle diabetics to provide less glucose.

Steel: So, given what we've been talking about with respect to the evolution in nutrition as therapy in the ICU, what are the biggest practice changes you have made in the past couple of years?

ApSimon: That’s a good question. I guess when I started many eons ago, we were very rigid about providing the exact amount of protein. You know there was a number, like say 0.8 to 1.2 grams per kilo body weight. And we now know that when we don't provide enough protein our body takes the amino acids it needs for wound healing or immune regulation and to maintain your splanchnic proteins, it takes that from your skeletal muscle. So, I would say that now we're comfortable with giving anywhere from 1.5 to 2.5 grams per kilo per day. So, that's one of the biggest practice changes.

The second one is feeding our patients less in the first five days of ICU. There was a point where we figured, well, if we can start a goal rate, why not? And that practice has changed, so now, you know, we're aware that the stress insulin resistance and over-feeding often causes hyperglycemia. So instead of just increasing the feeds and hoping that added insulin will eventually regulate the blood sugar, we now pay attention to the amount of carbohydrate we provide our patients. So, we often use the lower carbohydrate, high-protein feeds in patients, like I said before, with diabetes or insulin resistance, or who have uncontrolled blood sugar.

So, we no longer just use it to feed, you know, a particular obese population. And not only has our practice changed with enteral feeds, but in our patients receiving parenteral nutrition, we also start with a much lower glucose load than in past years. So, I think those are the two biggest changes.

Steel: It's really interesting to hear how much practice has changed in the last decade but also in the last couple of years, I find. And we really are witnessing nutrition being considered as therapy for ICU patients, and it's going to be interesting to see how this aspect of nutrition management continues to evolve over the next couple of years.

I think these are exciting times to be a critical care dietitian.

ApSimon: They are.

Steel: Before we sign off. I would like to take a minute to ask you one last question, so our listeners can get to know you a little more. Can you tell us how you first became interested in the field of nutrition?

ApSimon: It's a good question. Well, I finished my degree in life sciences and decided to pursue a master's in nutritional sciences thinking it would tie in my science from my undergrad and the real world. Unfortunately, I worked with rats for a few years – so that didn't quite tie in the real world – looking at nutritional deficiencies in tumour formation. And this work, while interesting, led me to believe that I would probably end up in rat hell, but more importantly that working with humans would be more fulfilling for me. So, I followed my gut, completed my internship and then I was in the right place at the right time and landed a job in the ICU. That was 20 years ago.

Steel: Well we're really glad you decided to switch to humans. Thank you for sharing that Michele.

ApSimon: You're welcome.

Steel: And on that note, I will conclude this podcast. I'd like to thank Michele ApSimon for joining us and thank you to all of our listeners.

CLOSING: This concludes our episode of the Clinical Nutrition Notes podcast, to listen to more podcasts or to subscribe to Clinical Nutrition notes, visit our website at NestleHealthScience.ca.

For the Nestlé Health Science podcast team, I'm Cindy Steel.