Good afternoon everyone. Thank you so much for joining us. My name is Charlotte and I have the pleasure of presenting today's webinar.
Nutrition in the perioperative period. How better consideration of nutrition can optimise patient outcomes. So firstly, I'd like to say a big thank you to Accord Animal Health for sponsoring today's session and for making this webinar possible.
We also have Chris from Accord Animal Health with us today, who's going to say a few words shortly. But first of all, I'd now like to say a bit about our speaker today. Mike Davies, who graduated from the Royal Veterinary College and university in London in 1976.
He owned his own veterinary practise for over 10 years and held academic roles at the universities of London, Nottingham including directing the Beaumont Animal Hospital. Mike holds postgraduate qualifications in radiology, orthopaedics, and clinical nutrition. He has a special interest in geriatrics and has published widely, including books on geriatric veterinary medicine and mineral-related clinical sites.
He is an RCBS specialist in small animal clinical nutrition and is working as an independent consultant and is also the managing director of Proveet Limited. So he certainly has a wealth of experience and knowledge for us to absorb today. I wish to let you all know that today's session will be recorded and available on playback, and you will receive a certificate for today's attendance also for your CPD.
Please use the Q&A box for any questions you may have or our speakers throughout the presentation, and at the end of the session, we will see if we can answer any of these questions you may have. If we run out of time with the questions submitted, we will email out any responses to you in the next few days. So, with no further ado, I'd now like to hand over to Chris from Accord Animal Health to start today's session.
Thank you, Chris. Thank you, Charlotte. Thank you, the webinar vet, and thank you for Mike, for today.
Yeah, so I'm Chris. I'm a technical and marketing lead for Acord Animal Health. I'm just going to take up a few minutes of your time before I pass over to Mike.
Promise it'll be short. Just to tell you a little bit about Accord Animal Health, who we are, and a product that we've recently launched that is relevant for the topic of discussion for today. Hopefully, some of you will be aware of the Cod Animal Health.
We launched a few years ago, but our first products didn't come until LVS last year. I'm gonna say a bit about our products shortly, but first of all, just a few words about our cod animal health and, and who we are. So, we're a division of Accord Healthcare, which is part of the INTAS Group.
So it's a large global player in the human pharmaceutical market. We're one of the major suppliers to the NHS and to hospitals worldwide. We are not new to animal health.
We, with ITAS is the largest companion animal pharmaceutical company in India, and we're the 2nd largest animal health company overall in India. We also manufacture for other animal pharmaceutical companies globally, so the only new thing really is we're supplying our own label products in the UK and other countries outside of India. So, Accord Animal Health, we are, there's less than 10 of us.
We're quite a small team, but those of us that work for Acord Animal Health, we've got decades of experience between us, working for other animal health, companies within the UK. So we have a good understanding of, what you guys need, I'm going to come on to, our current product portfolio. It's very small, and there are huge plans for expansion.
We've only got a few products at the minute. All our current products are over the counter. We have more of these kind of products to come.
We've got a full range of nutraceutical products which are coming later in the year. We also have our first medicines coming later in the year, some of which are going to be made in one of our UK manufacturing facilities down in Barnstable. So we've got a very large pipeline in, in future years, starting off with generics, but with novel innovative products coming further down the line as well.
The first product we launched at LVS was the Vinacord Chows, which are dental chews designed to give daily to dogs to help maintain oral health. They contain naturally occurring Ata xanthin from algae and ercoidin from seaweed. They're lowering in calories, which is really important, as we know how much of a problem of obesity is in pets.
The last thing we want to do is give something to improve oral health, which has a negative impact on the overall health of our patients. Coming soon we've got Purnaoxx, which is a green lip muscle-based joint supplement. It comes in a paste formulation to make it easy to give to dogs.
And finally have multi-chord, which we launched only a few weeks back and is relevant to today's. So multicord is an essential vitamin and amino acid supplement. It's an oral liquid.
It comes in a bottle with a dosing syringe. It's got a myriad of uses wherever a patient has a need for additional vitamins and amino acids. So working dogs, those with additional needs due to recovery from illness and so on.
Being in the Market in other countries for a while, but said it's only been available in the UK for a few weeks. But we already have some good feedback. One area where people have found it particularly useful is in, in applicant pets, where people have found, giving it to hospitalised animals that aren't eating so well, it's been useful as a bridge to get them eating again.
It's really easy to get, really palatable, and, I hope you'll, be willing to give it a go. If you'd like to hear more about, our products and our, existing and forthcoming, please, follow us on LinkedIn and Instagram. And have a look at our website.
But I've also got contact details if you want to contact us with, with any questions as well. And we have, a launch promotion for our initial product Multi-chord. It's buy one, get one free.
This is in addition to any rebates that, set up for any groups that you're working for. Products available from wholesalers now, and if you'd like to take part in the promotion, contact my, key account manager colleague Gemma. Her email address is here.
My email address is there as well if you'd like to any questions. That's all for me and, over to Mike. Thank you very much.
Right, thank, thank you very much, Chris, and thank you for called sponsoring my presentation today. As you've heard, I've got a, an interesting career. I'm a, a, a specialist in swal clinical nutrition, with a, a special interest in geriatrics.
And I've got quite a lot to get through, so I'm gonna go quite quickly. I'm gonna have to take questions at the end. And if any of you want references for anything I'm saying, I can always send them after the presentation.
So, I'm not quite sure why. Right, there are a lot of books published on nutrition in the cat and dog, and the one on the left here is the National Research Council latest publication from 2006, Nutrient Requirements of Dogs and Cats. And then there are a myriad of other books that are available that you can look at.
And but if you have a look through these, you won't find very much at all about perioperative period. And the thing to remember is that all of these publications, including FEDA guidelines, are all geared around normal healthy animals, not animals with diseases, illnesses, or undergoing major procedures such as surgery. And so a lot of the information isn't really readily available in published veterinary papers either.
We're relying a lot on human publications and the human experience and then applying it to our veterinary patients. So, the first thing to say is, how do you manage your patients currently if they're going to go to surgery? I mean, hopefully most of you will be doing a clinical history, which can be done obviously by a vet or by a veterinary nurse.
Also a physical examination, and then there is immediately a difference. A lot of practises rely on nurses to do the the physical exam. But of course nurses can't do a lot of things that vets can.
They can't auscultate the chest. They can't palpate the abdomen. They can't look in the eyes and detect changes there.
And so physical examination is best done by a vet, although a lot of it can be done by nurses. Again, practises often do blood screening, but we shouldn't rely too heavily on them. Because really we should be using the history and the physical exam to pick up problems that we then would investigate further with a blood test.
But it is true that if you do a pre-anesthetic blood screen in about 1% of cases, in other words, 1 in 100, you will pick up abnormalities which are not found from the history and the physical exam. And then other cheap and cheerful tests can easily be done like urinalysis, particularly when we're giving drugs to older animals which may have impaired renal function, and they're going to be relying on the kidneys to excrete that drug. But most importantly in terms of this presentation is we should be doing nutritional assessments and doing a thorough nutritional assessment as well, not just ask the owner what do you feed the dog, but examining the animal, the cat or dog, to determine its nutritional status.
Well, what did I get? Well, as a student, I got very little about perioperative nutrition. We were taught to starve animals before they had an anaesthetic, and then we were taught nil by mouth during the post-operative period until we could hear gastrointestinal activity going on.
But this dogma has now been totally reversed because of extensive scientific evidence that nutritional status needs to be optimised before and as soon as possible after surgery. So a question I'm often asked is, can an animal be fed right up to the time of induction with an anaesthetic? And the answer to that is still no, and the reason is if there's food in the stomach when you induce anaesthesia, you can get passive regurgitation or even vomiting and inhalation, which obviously is not desirable.
The stomach does need to be empty before you er do an anaesthetic induction. But one of the issues is, when do we know that the stomach is definitely empty in an animal apart from trying to palpate it? Well, you don't, and it does depend on gastric emptying time in that individual.
And that can depend on gastrointestinal function, but also on what meal the animal has had, because if you feed a high fat meal, that will actually delay gastric emptying. So in other words, the stomach will become empty in different time scales after feeding in different individuals. But the, the general advice is to starve on the morning of an anaesthetic unless the animal has delayed gastric emptying.
Now there are some things we could be looking for and should be looking for if we're doing things like blood screening. So we know for example that if an animal has low serum albumin that really increases the risk of postoperative wound infection. And we know if an animal's on an inadequate protein calorie intake, it's, that's also associated with poor postoperative wound healing.
And in a Cochrane systematic review in humans, they found that the administration of immune moderating nutritional supplements did actually help in the postoperative period by reducing complication rates. Now human systematic reviews have also shown that early enteral feeding, that is providing food into the gastrointestinal tract within 24 hours of surgery, significantly reduces postoperative hospitalisation period by up to 2 days compared to patients not fed until there was evidence of bowel activity. And other randomised control trials have shown other benefits such as reduced wound infection rates, the development of pneumonia, which is a big issue in elderly human patients, and also reduced mortality rates.
So there are lots of benefits being shown about nutrition around the time of surgery. So the primary nutritional goals in the preoperative period are to evaluate the patient thoroughly for pre-existing malnutrition, to treat and correct any malnutrition to optimise surgical readiness. We want to minimise starvation in that pre-operative period, and we want to prevent post-operative malnutrition and support anabolism rather than catabolism to ensure adequate recovery.
So when we subject an animal to a general anaesthetic and to a surgical procedure, we are inducing what's called surgical stress. This is rather similar to stress starvation and it parallels the extent of injury which is going on in the animal, and this is characterised by changes in hormones, haematological parameters, metabolic and immunological changes. And these changes are clinically manifested as salt and water retention to maintain plasma volume, increased cardiac output through increased cardiac rates, and increased oxygen consumption by increased respiratory rates aimed at maintaining systemic delivery of nutrients and oxygen-rich blood to tissues.
At the same time, with this type of surgical stress, we get mobilisation of energy reserves, so that's glycogen, adipose and lean body muscle mass to maintain energy processes, repair tissues, and synthesise the proteins that are necessary, well, for healing but also for immune responses. So the nutritional consequences of surgical stress are similar to non-simple starvation, and they are hyperglycemia, which results because of peripheral and central insulin resistance and whole body protein metabolism, which will result in time to breakdown of lean body muscle mass in particular muscle. And lean muscle mass mobilisation releases amino acids into the circulation, which can then be preferentially taken up by the liver to allow synthesis of acute phase proteins, and we also get production of glucose from non-carbohydrate sources via gluconiogenesis, and that is breaking down and utilising amino acids.
Now, there are no systematic reviews that I can find on postoperative nutrition in veterinary patients. But there is one study that demonstrated that early feeding reduced the hospitalisation period for critical care case dogs which had septic peritonitis. And in other studies, including one in dogs following bowel resection, they showed that supplementation with glu glutamine, and if you remember, glutamine is a non-essential amino acid but can become conditionally essential when rejuvenation of the alimentary tract, the villi in the in the intestinal tract are necessary.
And they found that supplementation with glutamine postoperatively can significantly improve nitrogen balance, which is really important to maintain health and avoid protein metabolism. Now, you may not be aware of the European Society of Clinical Nutrition and Metabolism, ESPN, but they've published guidelines to help formulate something called the enhanced recovery and surgery concept, and this is what this is doing is looking at what we can do in humans, primarily to improve recovery after surgery. And what the the guidelines say is that early oral feeding is the preferred mode of nutrition for surgical patients, not intravenous nutrition, and avoidance of any nutritional therapy bears the risk of underfeeding during the postoperative period, which is very negative.
And because malnutrition and underfeeding are risk factors for postoperative complications, early enteral feeding is especially relevant for any patients undergoing surgery which is recognised to have a nutritional risk, especially if they're gonna be undergoing upper gastrointestinal surgery. And from a metabolic and nutritional point of view, the key aspects of perioperative care which are included in the ESPN guidelines include the following integration of nutrition into the overall management of the patient, avoidance of long periods of preoperative fasting, re-establishment of oral feeding as early as possible after surgery. To start nutritional therapy as early as possible and as soon as nutritional risk is apparent.
To control any metabolic issues, for example, in in inappropriate blood glucose concentrations, to reduce factors which can exacerbate stress related metabolism or impaired gastrointestinal function, and early mobilisation, that is physical mobilisation, to facilitate protein synthesis and normal muscle function. Now there's another group called the EAS Society, and this group are the Enhanced Recovery after Surgery Society, and what they've done is they've published guidelines which include nutrition for all sorts of post-surgical situations, including, gastrointestinal surgery, cancer surgery. Bladder cancer, bladder surgery, even neurological surgery.
So if any of you are interested as surgeons in current recommendations of this group, then I would urge you to visit their their website which is erassociety.org, and there are a whole group of guidelines that they've published which all include nutrition as well as other guidelines on postoperative management. Now the WSAVA on their website have a lot of very useful bits of information regarding nutrition, including how to conduct a nutritional assessment of a patient.
And I would urge you to go and look at them. Now sometimes we're presented with animals, which are, when we do our nutritional questioning will become clear straight away that they could have an issue. So any animal being fed raw foods are potentially carrying very serious infectious diseases like salmonella, E.
Coli, and so on. And even if they're apparently healthy, they shed those pathogens into the environment. And this means that any animal being fed raw coming to to your surgery are a risk for your hospital environments and also for other patients in the hospital as well as you and your staff.
So my my strong recommendation is that you correct any diet before you subject these animals to elective surgery. That you screen and treat them for any infections that they may be carrying, and if possible or necessary, delay and avoid elective surgery until any infectious risk is removed. They should then be bury a nurse on your premises, kept in isolation, and obviously, if possible, try and educate your clients to avoid feeding raw exclusively because of these risks.
Now, generally speaking, maintaining protein status is really good, and historically, we've always described biologic value, the quality of a protein, which is a measure of its digestibility and also the amino acid content of it and generally speaking, if you look at the biologic value of different ingredients for protein, you'll find that animal derived sources are better biologic value, in other words, higher quality than cereal and other plant-based sources. So the way biologic value works is that egg is given a perfect score of 100. And then you rank other food sources to that.
So you can see in this chart that liver and beef are higher than soybean meal and other other plants like wheat and maize. However, the soybean meal is actually not that far behind the animal derived proteins, and there's been a, a paper published recently which has shown that if you swap out meat-based. For plant-based protein that actually there's very little difference on total protein digestibility.
So that's a bit of a surprise for most of us. And the other thing is that these days we have access to hydrolyzed proteins which are very digestible and basically pre-digested proteins which are ideal for treating patients in the postoperative period. Now there are other specific nutrients that we should be considering.
Copper is one of those. It's important to maintain a really good copper status because copper deficiency can affect CNS function because it's involved in lots of processed me. Processes as well as cardiac function and actually copper deficiency can lead to changes in the vascular system, including connective tissue composition and tensile strength in blood vessels, which can lead to aneurysms and so on.
And it's a bit of concern because in 2017 when I was at Nottingham University, we analysed a lot of pet foods to see if they complied with FEDA guidelines. And we found that 20% of the wet foods we analysed didn't, which were labelled as complete, did not comply with FEF guidelines for copper. So that's a bit of concern because that means as many as 1 in 5 dogs or cats being fed wet foods may not have sufficient copper going into the systems.
Now it's also important to maintain blood albumin and globulin within normal reference ranges, and there's a study that was done in healthy beagles where they were undergoing bowel resection, and following bowel resection they were fed by a gastrostomy tube and they were either fed electrolytes alone or they were fed a monomeric diet which we'll talk about shortly. And basically what they found was that the the dogs said the monomeric diet had 12 grammes of globulin in the blood compared to 5.3 grammes of globulin in when they were just being given electrolytes.
So by feeding a monomeric diet, the globulin levels were twice as high as they were by just giving electrolytes alone. So there are lots of potential consequences of malnutrition, and obviously in a postoperative period where it's important to have normal tissue synthesis and repair and amino acids and carbohydrates are used locally for collagen and ground substance synthesis. Now the amino acids have to be provided by the diet or they have to break down body proteins to release them.
And carbohydrates are not an essential nutrients, and carbohydrates can be synthesised from other nutrients that are in the diet. So as well as the amino acids and carbohydrates for tissue synthesis and repair, adequate energy intake is needed for fibroblasts to be able to produce RNA and DNA and ATP for protein anabolism, and also for migration of fibroblasts and endothelium epithelial cells into the wound sites, and the liver needs, of course, energy to build new proteins including fiberectin. Bone marrow needs nutrients to make platelets, red cells and leukocytes, and of course cardiovascular performance is essential to be able to optimise oxygen and nutrient supply to tissues during the healing process.
And what they found is that people who are fed perioperatively have a 91% increase in protein synthesis and a 10% increase in degradation of proteins. So they have a net synthesis of proteins. Whereas people who were fasted during the perioperative period only had 50% increase in protein synthesis and a 79% increase in degradation, so people who are fasted perioperatively have a net loss of protein, which is obviously not desirable.
OK, so nutritional status is really important for normal healing, but also for drug efficacy and safety. So when we think about drug metabolism, we've got to consider transportation of drugs, that's usually in the blood and often combined with a protein like albumin. We've got metabolism, which usually takes place in the liver but also takes place in other tissues such as muscle.
And then we've got excretion of the drug, usually via the kidneys into urine, but also via the liver into bile, and we've got, depending on whether the drug is water soluble or lipid soluble, we've got different distributions in tissues across the body. So what's been found is if nutritional support is provided, and that can be either enter or parenteral, but if it's supported without or with little lipid component, in other words, no fat. What happens is you get decreased hepatic P450 activity, and that is responsible for metabolism of drugs and as a result of decreased P450 activity, we get decreased drug clearance rates.
Also, protein calorie deficiency decreases lived by a transformation of drugs, the concentration of serum proteins for transporting the blood, and also renal blood flow or GFR, which reduces excretion. So basically what we're saying here is that individual drug efficacy may be increased or decreased depending on the specific pharmacokinetics and pharmacodynamics of that drug. And there's been an interesting Cochrane review.
For those of you who don't know, the Cochrane Library is a resource which only looks at systematic reviews of randomised controlled trials, and it's a fantastic resource. And what they've done is conduct a review of 540. Patients undergoing preoperative nutritional therapy in gastrointestinal surgery where they were given immune enhancing nutrition supplements and what they found was giving these supplements significantly reduced postoperative complications.
So in other words, modifying nutritional intake prior to surgery can have a big impact on post-surgical outcomes. Now one of the scourges of the pet world is obesity, and obesity can have a major effect on drug efficacy and safety. So in other words, to reduce body weight before elective surgery is highly desirable because of the benefits that could have on drug metabolisms.
So general anaesthetic agents that are used in anaesthesia are lipid soluble because they have to cross the blood brain barrier, and they may accumulate in adipose tissue and thereby delay recovery. So for opioids and especially if they're administered intramuscularly, it may be preferable to give a dose according to the patient's actual weight rather than their optimum weight, so that after redistribution into fat, an effective plasma, an effective site concentration can be achieved and maintained. And during prolonged administration of inhalation agents, which may often occur in obese patients, the blood solubility of the agents becomes less important than their fat solubility for influencing recovery from anaesthesia.
So obesity can have a major effect on postoperative recovery. And the potential for prolonged recoveries is greatest when halothane, but also other, inhalation agents like sevofluorine and even isofluorine are used, and, and increased circulating free fatty acids, triglycerides and cholesterol compete with acidic anaesthetic agents for protein binding with albumin. Thereby increasing free and active drug concentrations, in contrasts, the increased alpha one acid glycoprotein concentration found in obese states can increase the binding of basic drugs like ketamine, opioids, and local anaesthetics and thereby reduce their free active concentrations.
So obesity can have a significant effect on drug efficacy and safety and also a significant effect on wound healing. Now there are several reasons why this this may be the case. We know that obese patients are in a chronic inflammatory state, and we also know that they are more likely to develop wound infections and get wound dehiscants.
And some of the factors are increased surgical time because often obese patients take longer for surgery to be performed, but also local tissue hypoxia, and in humans they've tried to increase the levels of oxygen, oxygen tension in the tissues by administering oxygen pre, during, and post-surgery. But they have been unable to do so. So there is something about the obese state that results in hypoxia in tissues which then increase the risk of infection and also poor wound healing.
So, just a word of warning, when, when if you read human texts, when they talk about enteral feeding, that does not necessarily mean oral feeding because they're often talking about feeding direct into the small intestine. And early enteral feeding it turns out is really very important. So in one study where they were looking at burns injuries in people, what they found was that if there was no food going into the dunum for 24 hours after burn injuries, there was a 50% decrease in gjunal mucosal mass and thickness, and this was due to atrophy.
And what they found was if they've introduced nutrients into the intestinal tract early this atrophy could be prevented. So what we're gonna try and do with our, with feeding our surgical patients is to ensure minimum daily requirements and energy and all the essential nutrients are going to be met. And we can partly do this by using higher quality ingredients because quite often animals don't want to eat a large amount of food, so the higher the quality ingredients, the higher digestibility, the more bioavailable they are, the less food the animal has to consume, which is the benefit.
Now, now, generally speaking then, if an animal's well fed in the postprandial period after eating, the exogenous nutrients are gonna be used for metabolic needs, and it spurs the animal's stored glycogen, adipose tissue and muscle protein. Once metabolic needs are met, any surplus that's present from feeding replenishes stores of glycogen and protein, and then any surplus can be converted into adipose tissue. And, and generally then in the, in a fed state when blue glucose is high, the liver can take up that glucose as a net import of glucose and traps it via glucokinase and insulin.
OK, so we're going to consider feeding an animal in the post-operative period, and then we, the first question is how much energy does this animal require? Is it higher or lower because of its clinical condition and how best to provide it? Generally speaking, in our animals we're going to provide energy as fat because 1 gramme of fat provides 2.2 times as much energy as 1 gramme of protein or carbohydrates.
So unless the animal has a fat metabolism problem or has a disease like pancreatitis where we want to be careful about fat. We're going to go fat first. The second choice is going to be protein because proteins obviously contain essential amino acids, and they're essential for tissue healing and growth and so on.
So the second choice is always going to be protein and carbohydrates, although carbohydrates provide energy, they don't provide any essential nutrition. Because the carbohydrates the animal needs otherwise can be synthesised from other things, so carbohydrate is always going to be our third choice for energy supply. And then we've also got to consider whether this animal requires more vitamins or minerals depending on its clinical situation.
We've got to calculate the approximate energy requirements to meet its needs and avoid overfeeding because that can cause metabolic and mechanical complications. And the aim is to get the daily requirement of the animal through its tube. And obviously if we look at this.
Which has got a nasogastric tube in place. You can see the ball of the tube is quite narrow, which means that this will have an effect on the rate at which we can administer nutrients and how long it might take to get the daily requirement into the patient. Now in terms of calculating resting energy requirements, there are a number of formulas that we can use.
My students always used to like the 1st 1, 30 times body weight in kilogrammes plus 70, because you don't need to use a calculator, but there are other ways of doing it. I just want to point out that these are not exact science energy calculations. These, these only give you an approx.
Often requirements, apologies for that, an approximate requirement for an individual animal and between individual animals of the same breed and size, there can be as much as 50% difference in actual energy requirements. So these are only giving you a general guideline, not absolute figures to rely on. And then what you can do is you can refer to the WSAVA guidelines, which give you an RER depending on the size of animal.
Generally speaking, animals that are in the postoperative period require less energy than animals that are in a normal state, and it's even animals with critical disease usually require less energy, but there are certain situations like multiple fractures or severe infections where the energy requirement might be higher than normal and then you've got to make sure they get that. So the importance of early feeding is to replenish any nutrient deficiency that's present in the animal to meet those energy and nutrient requirements for tissue healing and immune defence mechanisms and to ensure normal drug metabolism supported. Now eating is normal and should occur in animals that have undergone surgery because usually they've been starved for a period first and they should be hungry.
So any animal that's in pain will refuse to eat, so eating is a good indicator that analgesia is adequate in the patient. Now, there is a condition called refeeding syndrome, which has been clearly demonstrated in people, which is, if, if a person has not eaten for a long period and then is given a large meal, the metabolic changes that can occur, including changes in phosphate, magnesium, potassium, can result in fatal pulmonary or cardiovascular changes which can actually kill the patient. So the recommendation is if an animal has been starved for any length of time, in other words, it may be a major trauma patient before it goes to surgery, that we should start feeding at 25% of the RER initially and then gradually increase up to normal RER a day over a 5 day period.
So nutrients that are important for wound healing include proteins and specific amino acids, polyunsatid fatty acids, some vitamins, some minerals and trace elements, magnesium, copper, zinc, and iron, and then any deficiency of these can result in impaired healing, increased risk of infection, and wound breakdown. Now I don't know how many of you still feed what's called a bland diet, but I was always taught to feed chicken and rice, and I know lots of practises still do this. But if you look at this chart, this is showing you a 100% of requirements, and if you feed enough meat to meet 100% of calorie requirement, which is the first bar on the left.
You'll see this is the effect on other nutrients, so you'll be providing 5 times as much protein as the animal requires, which is no surprise, but of these essential nutrients in this chart, the only other two which meet requirements are potassium and magnesium, and that's because they're intracellular. All the other essential nutrients on this chart are not provided by meat by all meat diets. And so this is a totally deficient diet.
It contains no calcium, and even if there were a trace of calcium there, it's totally negated by the high amount of phosphorus that's present. But please note, an all meat diet does not provide the minimum requirement. For phosphorus either.
But if you're feeding chicken and rice, what does the rice consist of? Well, boiled rice consists of almost entirely water and carbohydrate, with very few other essential nutrients. So you can see a little bit of sodium.
A little bit of calcium, but that's totally negated by twice as much phosphorus and then just small amounts of iron and copper and manganese. And if you look at the essential vitamins, no vitamin A, no vitamin C, no vitamin D, a little bit of vitamin A, only a trace of hyperflavin. No vitamin B6, B12.
So, a chicken and rice diet is totally inappropriate and should not be fed for any length of time following, major surgery if you want optimum recovery. OK, so let's talk about assisted feeding techniques, to round off this presentation. First of all, we need to do a full history physical exam, including a nutritional assessments.
We need to try and ensure energy and essential nutrient intake, which is really important for normal and optimum case management. We're going to use the nutritional assessment guidelines which are published by WSAVA. And there are other things they also provide if you go to the website, body condition score charts, muscle conditions score charts, and so on.
And then, how important is nutrition? Well, it's important to triage first and do any life saving actions before we look at nutrition. So obviously hemostasis, providing oxygen, fluids, electrolytes, antibiotics and blood transfusions if necessary, all come before nutrition.
But then nutrition is important and it's important to avoid deficiency or toxicity. That, so that we can get good wound healing, a good immune response, and we don't alter drug pharmacokinetics and so on. Now the WSAVA made these recommendations.
They say if an animal has not been eating sufficiently or is anorectic for 1 or 2 days, write down feeding instructions, monitor food intake. And clinical condition. After 3 to 4 days, nutritional support might be likely.
Consider feeding tube placement if the animal is undergoing anaesthesia, and then after 5 days, definitely nutritional support is needed. Well, I disagree with this because we know that just 2 days or 3 days of not having any zinc intake will result in zinc deficiency signs, and so I would suggest placing tubes much earlier. And introducing nutritional support certainly by 3 days if the animal is not eating at all.
Now when we're tube feeding, tubes must be flushed with water every every day after every feeding session to make sure they don't get blocked. E port tubes are easier to manage than blind ended tubes, which food can accumulate in. If you're creating a stoma, it's important to look after that stoma.
It needs to be examined every day, cleaned if necessary with antiseptic after every feed, monitored for signs of pain or inflammation. And it's prudent to use antibiotics sometimes if necessary. Any bandages need to be checked and cleaned and and changed if necessary on a daily basis.
What we do for every patient is we review the feeding that the animal's been getting, we ensure nutritional intake to meet energy requirements first, then the essential nutrient requirements. We're gonna avoid or minimise nutrients which could be detrimental for that patient, and we're gonna increase intake of nutrients which may be beneficial for that patient. And that means there can be variation between what different individuals require.
So we need to specify what type of food we're gonna give, how much based on its RAR, the route of administration and how frequently. The first thing to say is there's no single food that will meet all animals' specific needs, so we must select the food based on that individual's unique requirements. Any animal that's not eaten for 6 or 7 days should have a high fat diet to provide energy unless it's got a disease such as pancreatitis.
But if it's less than that, you can just get away with an ordinary diet, with carbohydrate fat protein balance. Tubes smaller than French gauge e are suitable for liquid foods, but you need wider board foods, tubes, sorry, for foods that have got a a non-liquid consistency. So first of all, we'll talk about monomeric elemental diets.
These are already hydrolyzed, so there aren't whole proteins. It contains free amino acids which are small chain peptides, dipeptides, tripeptides. You've got fats which are mixed medium and long chain fatty acids.
You've got carbohydrates which are simple sugars, mono dye, or trisaccharides, and these are quite osmo have quite a high osmolarity. But they're suitable for all tubes, including geojunal tubes or J tubes. Now these are human products, they're suitable for dogs unless the dog has a protein losing disease, but they are far too low in protein content for cats, and they provide insufficient other essential nutrients that cats require, for example, of acheddonic acid, arginine and taurine, so they cannot be used for long-term feeding to cats.
Beyond that we've got something called polymeric diets, and these are the vast majority that are used commonly in veterinary practise. These contain proteins as large peptides usually based on whey or casein. The carbohydrates are usually corn starch or syrups.
They contain medium chain triglycerides or vegetable oils, and these, these foods require normal gastrointestinal function to be able to be utilised. So, these diets can often called convalescent diets, they can be diluted further with water, and some of these diets, claim to meet AO or for the feeding feeding guidelines. Being liquid, they have a low energy density, 1 to 1.25 kilocalories per mL.
So you've got to feed quite a lot of these to medium and large breed dogs, to get the energy requirements into them. And I just quick mention liquid milk replacers are inappropriate because they're too high in osmolarity and they have a low energy density. So my preferred way of tube feeding is blended foods, because you can take a complete food which is complete and has been formulated to meet needs of animals with specific disease conditions.
And wet foods obviously are easier to administer, but they can be further diluted with water and you can add water across dry foods to help make them get through the tube. And for me these are the ideal solution because they provide the correct balance of nutrients to the energy density and foods with naturally small particle size facilitate tube feeding. So basically, if the gut works we're gonna use it, ideally voluntary intake, but if not assisted feeding.
And if the gastrointestinal tract is not functional because of obstruction, intractable vomiting, acute pancreatitis, or trauma, then we need to consider parental nutrition, which can be short-term through peripheral veins, but long term needs a central vein, to be canniulated. OK, what about voluntary intake? Well, despite what owners say, the, the evidence is if you put a cat or dog in a kennel for 3 days, it will eat whatever you give it at the end of that period.
So whenever possible, we want to use the oral roots. We know that er palatability or acceptability can be increased by warming food and by increasing moisture content, so adding warm food to a diet can help improve acceptability. We can add aromatic substances, but you've got to be careful because many of them are really high in salt.
And of course a lot of you will be using appetite stimulants, and there are a number. I'm just going to show you a list from the Merck veterinary manual, you know, prednisolone, diazepam, oxazepam, surfaheptadine, litazapine, and beggerol acetate are some of the ones you could use. Personally, I don't like using them.
I think they kick, they can kickstart an animal that's refusing to eat, but they're only a short term gain. A lot of them have side effects that are undesirable. And they don't really lead to long term improvements in appetite because the underlying reason for impaired appetite has not been addressed.
It's just a medical way of stimulating appetite short term. And my experience is the RER is rarely met by using these ingredients. So I would prefer to go to tube feeding rather than appetite stimulants.
OK, so what's the recommendation we're going to feed warm food to meet RAR for the 1st 24 hours. The feeding rate is slow. We can only administer 5 mLs of food per minute, and for anyone who's ever administered fluids or foods through a tube, a minute is a very long time, so it's very slow administration.
We're going to give the daily requirements in several small meals over the day, not in one big meal or two big feeds. And we've got to remember that gastric capacity is only 5 to 10 mL per kilogramme of body weight, so that's quite small, and we will know if we're feeding too fast because the animal will start gulping, salivating, wretching, vomiting, and if that happens, we need to stop feeding, reduce the amount of meal size by 50%, and then gradually increase it back. So hand feeling, that especially works from owners, that's quite successful.
Force feeding, where we take food and ram it down the throats of an animal, I don't recommend that because there is a high risk of aspiration. Obviously with neonates we can use bottle feeding through a bottle with a teat attached. We can use syringe feeding where we fill the syringe with more liquid or solid food, and we can administer that.
We don't require an anaesthetic or sedation for this, but we have to get it beyond the dorsum of the tongue for the animal to swallow it, and we have to be careful not to administer it too quickly. To avoid aspiration, to give the animal a chance to swallow properly. We can use orogastric tubes.
We pass these to deflate bloat, so they're well tolerated, certainly for a few administrations, and that well tolerated by dogs, and we can get the whole of the daily rations through that that size tube. And again, no anaesthetic is needed, and these tubes can be red rubber or polyvinyl tubing 8 to 24 French gauge. Now, these tubes can be passed into the stomach or distal oesophagus, and the food administrated like a like a drenched through it.
Now, nasal esophageal tubes, for many years we've been taught that we should be placing these tubes into the disc oesophagus and not into the stomach. But I attended a human, clinical nutrition course recently. And it is still the gold standard in people to pass tubes into the stomach, and the gold standard for evaluating positioning is aspiration of acid back up the tube, not imaging because there are too many mistakes being made with imaging.
And they have no increased risk of reflux of acid by placing the tubes into the stomach. And when I came away, I was intrigued by this, and I did a literature search and I found a paper which showed that the rate of side effects of reflux. In our patients is no difference whether you place the tube in the distal oesophagus or into the stomach.
So the dogma that it must be in the distal oesophagus and not in the stomach does not appear to be true, and I no longer, am concerned whether it goes into the stomach or not. Anyway, nasoesophageal gastric feeding tubes are easy to administer. You place them into the ventral meatus of the nose and aim the tube medially towards the medial septum, with a little bit of lubricants or possibly even a local anaesthetic on the end, and then you can feed it through, you measure the tube from the nasop planum, to the last rib.
So they're usually going to be placed for 3 to 7 days. If you're going to want them placed for longer, it's advisable to move the tube from one side to the other about every week, and you can use polyurethane tubes, 6 to 8 French with or without a weighted tip or silicon tubes, and then 8 French generally I find is most suitable for most dogs and 5 French gauge for cats. So cadal oesophagus or stomach by measuring from the nasal planar, as I said to the caudal edge of the last rib.
And no anaesthetics necessary, but there are some issues. If the animal has nasal, oral, or pharyngeal disease or major trauma, it may be inappropriate to give a pass a nasal esophageal tube, and they can be regurgitated back up of the oesophagus, and sometimes they're quite irritant and can be removed by the animal. Interestingly enough, some people remove their nasoesophageal tubes as well.
Complications can include, nosebleeds. And then deliberate removal, so it is advisable to place a Elizabethan collar, and they are contraindicated if the animal's vomiting or has severe respiratory disease. Now beyond the nasal tube, we can use, we used to use pharyngostomy tubes to place cran on to hyode.
We don't do that anymore cos they're too irritant. We now place esophageal tubes. These are easy to place, they can be left in place for weeks and months.
You can use different size tubes from 8 to 19 French gauge. They're placed down the to the from the the the incision, they they're forced down, you bring the tube out through the mouth and push it down to the cord oesophagus or into the stomach. And they are very well tolerated, and you can get a lot of food down them.
Beyond the esophageal tube, we've got gastrostomy tubes. These can be placed at surgery or they can be placed using an endoscope or a percutaneous endoscopically placed tube. And basically these tubes sit inside the stomach and are held against the abdominal wall with a flange, and then you can feed through the abdominal wall straight into the stomach.
And these are really well tolerated as you can see in this dog, and they can be left in situ for a very long time. So, they can be placed intraoperatively or using an endoscope, and they have a mushroom tipped tube, at the end, and they can be left in for even months and years. Some dogs do vomit with bolus feeding, so, some can take a whole meal through the tube in one go, but others might require, slow administration and several small administrations.
I, I haven't got time to show you a video of a gastrostomy tube being done, but if you do a literature search, sorry, a Google search, you'll find YouTube, video footage of placing peg tubes. And complications of gastrostomy tubes include wound infection. You can get dehis.
It's quite rare, as well as peritonitis is rare. And if you tighten the purse string sutures around the tube or put too much tension on the, on the flange, then you can get pressing necrosis. But again, this is rare.
Jujunal feeding, this is where we bypass the whole of the upper alimentary tract, including the stomach, and we go straight to the jujunum. This can be done across the abdominal wall, as in the diagram at the at the bottom on the left, and it's very similar to a gastrostomy tube. Placed surgically or it can be passed through another tube.
Now in humans they have very long nasoiunnal tubes, so they pass a nasal tube and it's so long it can pass through the stomach and then on into the dunum. And they feed it through the pyloris using an endoscope, and you can provide elemental foods through straight into the dunum. And this is a traditional way of managing patients with acute pancreatitis.
So J tubes tend to be 5 to 8 French gauge, and then they can be threaded through esophagostomy or gastrostomy tubes and pushed through, and usually they are used with a continuous pump driven system using elemental foods, so that they're given the resting energy requirement over a 24 hour period. Rarely, these tubes can also be passed back by reverse peristalsis back up into the stomach. And finally, just to finish my presentation, we need to just briefly talk about parental feeding.
This is partial parental nutrition or total parental nutrition. This is where the proteins, carbohydrates, and lipids that an an animal requires are administered intravenously. You need aseptic precautions to do this, and however careful you are, the intravenous lines fail within about 48 hours.
You get infection at the site of the cannula. And this is a real problem, and to try to avoid this, you need to have separate lines for fluids and foods going into separate lines intravenously. So basically, or we'll just go back to that one, and just to say that people are trying to develop products that can be utilised in veterinary patients, but it's proving complicated because pretty soon you run out of veins when the cannula gets inflamed and you have to remove it straight away.
Now in humans though, this the art of giving parental nutrition has really improved over the last decade, and instead of having to go to hospital to have your intravenous nutrition, there are now specialist nurses who go around patients' homes administering TP TPN in the home, which is fantastic. OK, just to finish and conclude, nutritional status should be assessed and optimised pre-surgery. Patients can be fed up to the morning of anaesthesia.
Drug choices and doses may need to be altered depending on nutritional status. Enteral feeding should be started as soon as possible after recovery from GA and assisted feeding techniques should be employed if necessary, with tubes of feeding being used and and looked after properly. And thank you very much.
I'm sorry if I've overrun. Thank you, Mike, for presenting today's webinar. What a great informative session on nutrition.
We have had a few questions submitted, so, I think, you know, we can go through with those cause I mean, we've only just gone over anyway. So the first question we have is, what have you found to be a better alternative than chicken and rice, cos obviously we know that this is used quite frequently. OK, so er I always use what the animal is on already.
So if the animal is being fed a proprietary food as its normal ration and it doesn't have any special requirements, I'm happy to feed that because it's less likely to be rejected by the animal when you move to feeding it by the bowl as well. And I that's what I do. If the animal has a disease, like a gastrointestinal disease, having gastrointestinal, then I will use an appropriate therapeutic diet for that particular condition that the animal has.
So that's it, so I will always, I will always feeder the food that the animal normally has and try to get it to voluntary take it. If it won't take the food voluntarily, then I will modify it for administration by tube feeding. No, thank you, and I think that sort of does bring us .
To the similar question as, you know, in the sense of, you know, not putting them off their feed, especially like things like blocked cats, you know, not, not starting them, on their urinary tyre until they get home. So, thank you for that. Another one that we have is, do you have a preferred, starvation period for each life stage for elective surgery or any other guidance on this?
OK, so for all, all animals undergoing surgery. I'm happy for them to be fed, you know, up to last thing at night, not on the morning they're coming in, but up to last thing at night. The exception to that would be if we have an animal that we know has delayed gastric emptying, and there are some out there.
Where it can be 12 hours before they, you know, if they've got gastrointestinal problems. So those, then I would want to starve them a little bit earlier. But other than that, as far as I'm concerned, they can be given food right up to the last thing at night, and they can be given a drink in the morning.
They can be given fluids in the morning. Because the fluids moved out of the stomach very quickly and you know unless you you let it drink a whole bowl full of water and then immediately anaesthetize it and it brings the whole bowl full of water straight back, it's not likely to cause trouble. Yeah.
Perfect. Well, I just wanna say thank you so much again, Mike, and, a, a big thank you to Chris and Accord Animal Health for sponsoring today's webinar, . Obviously, any questions that you guys may have, feel free to obviously contact, Mike, or Accord, in, in regards to I suppose, I suppose one thing I should add actually is is that, there is absolutely no problem about giving nutritional supplements on top of the main ration, because, a lot of these animals have increased requirements over the normal for various reasons.
And if you're giving more, I don't know, amino acids, essential amino acids and things like that, that's not a negative thing. You know, it's giving more to the animal that it can utilise to recover from its, procedure. .
Yes, yes, definitely. Definitely. Obviously, get, get that nutrition in them.
Yeah, that's it. So lovely. Well, thank you again, and, I just would like to say, thank you for joining us at the webinar vet, and we, hope to see you all again soon.
So thank you so much for watching. Thanks very much.
