Hello, we're back. Uh, this is the 3rd episode of our intestinal rehabilitation podcast. Again, we are joined by Doctors Michael Helmrath and Paul Wales from the Cincinnati Children's Hospital Intestinal Rehabilitation Program. I'm Ellen and Cisco. I'm Rod Gerardo, and we are research residents at Cincinnati Children's. So, today, to continue this series, we're talking about enteral autonomy. And if you're like me, and you're like a general surgery resident, You're probably thinking, what does that even mean? Because I, I think a lot of these concepts are very abstract to me. So, I think that the best way for us to learn about what enter autonomy is, we have to first take a step back and we have to ask another question that I don't fully understand, which is, what is adaptation? The word adaptation is to develop and to strengthen function. Initially, the understanding adaptation is that it's a natural process that occurs in all infants once they, you know, are being developed in utero and over the first few years of life, or it can occur at later times in older children as a regenerative response to the damage. That was Dr. Michael Helmath, and he is the former director of the intestinal rehabilitation program at Cincinnati Children's Hospital Medical Center. And it generally takes time, and that time is measured in. Months and years and not weeks and days, but the one thing that it requires in all situations is enteral nutrition. As we're talking about adaptation, we need to think about what the gut needs in order to grow and adapt, and one of those things is energy and how do we get energy from nutrition. And so a lot of what we're going to talk about today is how to provide nutrition to these infants, and it requires a lot of creativity. Especially in these really complex patients. So consider the patient who is diagnosed with short gut syndrome. That remaining bowel, that residual intestine goes through this process of adaptation and where the bowel is trying to compensate to reestablish function, to absorb enough nutrients and fluids to maintain survival. That was Dr. Paul Wales. He is the new director of the intestinal rehabilitation program at Cincinnati Children's Hospital Medical Center, and the process is driven by The presence of intraluminal nutrients and their interaction with both gut secretions, you know, pancreatic biliary secretions, as well as the impact on the relationship with trophic gut peptides. So that sort of milieu sort of drives the adaptive response. So over the course of adaptation, there are structural changes too, like mucosal hypertrophy, which would include increased villous length, increased blood supply through angiogenesis. and bowel dilation. In the case of younger children, gut lengthening. What all of those things have in common is that they increase surface area for absorption absorption of nutrients, right? And then on the functional side, there's a change in motility. Motility tends to slow down to allow more contact time, as well as individual enterocytes are sort of an up-regulation of transporters to move nutrients across the, the, the enterocytes. So, each, each cell is working harder, if you will, to try to, to, Function better and our job as a team is to try to promote that the best we can. So that is adaptation, but we still can't jump to autonomy yet, not without talking about anatomy. The GI tract, typically the duodenum, is a portion first off the intestine where we really sense our caloric intake, our sugars are monitored, secretions of hepatobiliary secretions are there. Iron is taken up there, and it's a profound. Endocrine engine that recognizes the initiation of a meal. The jejunum is largely a source of secretion of a large amount of fluid that's needed to digest in a washing machine way. It just randomly sloshes back and forth. And then next we have ileum. You start to see differences in secretion of different hormones that would start to include the incretins, GLP-2 and 1 and PYY. So these signals. Recognize if there's too much liquid in the distal bowel and the first part of the colon, they tell the jejunum, hey, it's time to slow things down. And those profound things stop gastric emptying and slow down motility, and they are very much integrated. The fact that distal ileum can take up bile is really important because it sends a signal to the liver, which is the metabolic engine that helps regulate the whole metabolism of the baby or the patient. Finally, the colon, specifically the right colon. Taught that this is where fluid is reabsorbed. But that's not totally true, apparently. It, in fact, in, in our patients is a source of energy uptake when allowed to see things like free fatty acids, and that requires the presence of bacteria. And so over time, the adaption that occurs in the place like the colon doesn't occur in most patients because you don't need to reclaim energy from your colon because it's not there. It's already been reclaimed before that. All required. time, but it also is highly influenced on the things that we can do, which is the type of formulas we give H2 blockers, antibiotics, all these things affect it. At any time you get sick and you change motility, which is a huge underlying issue. We had a topic which is autonomy, internal autonomy. Up until very recently, there actually was no standardized definition for that. Um, like most things in intestinal failure, there's really Poor definitions for outcomes that we all talk about. Eral autonomy would mean that the patient has had improved gut function such that they are no longer dependent on that intravenous support. We are promoting adaptation and we're using the tools that we'll discuss a little bit later, optimize absorptive capacity of the gut. But as we all know, TPN comes with some known long-term complications. So, You know, Lyme infections, liver disease, throm vascular thrombo, all that kind of stuff so that we give this patient the best chance to reach its potential. That's where a lot of the advances have taken place in the last 1520 years is that in the old days, we lost patients as a result of complications such as liver disease before they were able to reach that adaptive potential. So we're way better now at managing those things. OK, so let's circle back here. What again is the new definition of enteral autonomy? So the current Aspen guidelines that just came out with standardized definitions, the independence of uh parental support for 12 weeks and with maintenance of adequate growth and hydration during that time period. Because it's one thing to turn off parenteral support, but, you know, you're not really off TPN or off parental support unless you can actually grow off TPN. It's a mistake to stop it and, uh, you know, pull the line out. Um, healthy growth is the underlying. Driver, not time off TPN. You'll get there. But what people don't recognize is the last thing you need to come off a TPN is fluid. And so without hydration, the baby won't grow. And so accepting an underhydrated child is one that will not efficiently absorb the nutrition the way they need to. They'll lose energy and essentially they'll decrease their plane and whatnot in compensation for it. So the, the next question. I think is kind of twofold. One is how has enteral autonomy changed over time, like the definition of it changed over time. But then on top of that, how does enteral autonomy in the child change over time? Looking at the last decade or so of clinical outcomes, and there has been an evolution over time. There is one paper by Squires, who was the first author, and it was a paper from the PIFCO Group, which is the Pediatric Intestinal Failure Consortium, and it Published in 2012. And of course, here again, we have some articles that we're referencing, they're all going to be linked below in the media player. Basically, 50% of patients achieved dental autonomy over 56 years, 25% died and 25% got transplanted. So that represents sort of the outcome of management from back then. And if you look since then, there's been several papers, especially in the last 56 years, which have shown that overall the proportion of patients that have achieved dental autonomy. Has increased between, depending on who you read, anywhere between 60 to 80%. A higher proportion of patients are surviving to sort of have the ability to read gen autonomy. Over the years, as we've improved care for these patients, we have seen improvements in survival and expectations for the patients, the families, the surgery team, they're going to start to change as well. And this leads to improvements in care for the babies. It's easy to Feed a child a very elemental diet, but to continue on that elemental diet is not to challenge the child. Using cyclic antibiotics may seem to make sense, but it also comes at a cost. One of the biggest advantages of having Paul join here is one, the ability to look back in time and compare different strategies to really identify the data that supports the practice and not the opinions. The truth is it's only as good as you collect the data and without. A standardized data approach, the field is not going to move as fast forward as I or Paul wanted to. So we talked previously about anatomy. So let's kind of go back a step again and then revisit anatomy and specifically how the anatomy can impact the capacity for adaptation. Small bowel length always comes up as a variable of uh that's independently significant, uh, which is kind of. Intuitive, the majority of actions taking place as far as digestion of uh nutrients and uh absorption of fluids. There's more to the absorptive and adaptive equation than just length of the intestine. Like you mentioned previously, anatomy and which part of the intestine we're in plays a big role too. You know, the ileum has a much greater capacity to adapt than the jejunum does. So, if someone who's got predominant ileal anatomy as their remnant anatomy, they're gonna do better than someone with predominant jejunal anatomy. OK, let's talk about some numbers here. A full-term baby is born with approximately 160 centimeters of small bowel. When you're 5 years old, you have about 425 centimeters of small bowel, and the rate of growth on the curve is steepest between 35 weeks gestation to about 6 months postnatal. OK, so let's do the math. 80 centimeters of small bowel is about 50% of the small intestine in a term baby, but if we consider A 30-week infant, 80 centimeters would be something like 80% of expected gut length. So when we have a baby that has something like gastroschisis or necrotizing enterocolitis in the bowel takes a global hit, we have to consider how old the baby is and at what gestational age they're at. And then the other variable is, uh, well, twofold is the presence or absence of the ileocecal valve, uh, which, you know, I personally don't think the valve as a, as an entity. Is the important factor. Um, people talk about the valve preventing reflux of colonic flora back into the small bowel, and, and there's some truth to that. Most people that lose their ileocecal valve also lose their terminal ileum, and I think that is the bigger factor as far as, uh, adaptive potential. And that last factor to keep in mind, the presence or absence of a colon. The role of the colon really, really takes on heightened. Importance. So we've presented data that shows that if you've got the majority of your small bowel, then it almost doesn't matter how much colon you have, you have a probability of ventral autonomy somewhere between 85 to 100%. And if we lose some small bowel, you know, our small bowel remnant is less than 50% of the expected length, the colon then becomes vitally important because it assumes an increasing role in terms of energy absorption from the Short chain fatty acids as well as fluid and salt absorption to a certain extent. Those are some of the anatomical factors that sort of go into uh whether some, you know, predict someone's ability to adapt. A lot of people think that the small bowel has far less microbiota than the colon, but according to Doctor Helmrath, this is not true. Data that we've generated from the lab, um, looking at microbiota suggests a shift in the microbi. biota to, to one that's more acid producing is an acidotic state. It's obviously one that might be more full of bile because it's not being reclaimed. So basically, the colonization of bacteria in the intestines is also part of the adaptive response. And just seeing something that's different than normal doesn't make it bad, needs to be studied and needs to be taken into context. You know, we think of these diagnoses as being like a global hit to the intestine, but actually each one is unique in how it affects enteral autonomy. So what makes them different? Remember, a kid doesn't acquire, the neck is acquired, so they are born, they start eating. Many of the times they almost can get up to full feeds, and then they have this incident, usually at 2 or 3 weeks of life. They have not been using their gut in utero at that special time. that Paul mentioned that 35 weeks to 6 months is really valuable. Ask yourself, has this child been fed before, because that child's different than the one that's never been fed. The nutritional status of the infant can act as a guide for the timeline of a procedure too. It's really important that when you do a procedure on this child that you understand the 2nd and the 3rd and the 4th step. You, this is a game of chess. You really have to plan ahead. And so the sooner you can feed the child safely and and actually get access to bowel without exposing them to risk, which includes a surgery, the more you're able to take advantage of the adaptive process. The strategies that we've developed in Cincinnati were largely ones that tried to take advantage of the easiest, safest way to use the bowel early without having the need to go right back. The surgery because surgery is not without risk. So we're trying to reduce the number of surgeries that this child is going to undergo by taking advantage of their adaptation. You put kids in harm's way when you go to the operating room, no matter how talented you are. So making sure you balance that and, and optimize that with the ability to do things, I think has led to improved outcomes. That's it. We're out of time. What an episode. We talked about anatomy, biochemistry, micronutrients that, well, we started to, but we're gonna have to get into the therapies next week cause there's just no time this week to cover everything. Come back next week for part two of episode 3 with Doctor Wales and Doctor Helm Rath in his intestinal rehabilitation podcast series. Whether you're listening to this podcast on your way to work or on the way home from work, we know that you're busy taking care of patients, and you probably were so busy that you couldn't go to every pediatric surgery conference that you wanted to this year. But don't worry, we have a webinar coming up for you. It's called The Best of the Best in Pediatric Surgery. Ellen, when is it? Happening on Friday, April 8th in the morning at 9:00 a.m. Eastern Standard Time. So if you want to register, guess what? Registration is free, it's open. There's a link under the media player. Sign up today so that you don't miss the best research from every pediatric surgery conference of the past year. Right here on your phone, on your tablet, on your computer, wherever you are. But until then, I'm Rod and I'm Ellen. We're a research residents at the Cincinnati Children's Hospital, and remember, knowledge should be free.
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