Hi, my name is Louise Southwood, and I am an emergency clinician at New Bolton centre, which is the large animal hospital of the University of Pennsylvania. Today I'm gonna discuss with you improving the outcomes of horses with colic and asking the question, can we do better? So in this lecture, we'll go through some of the current expectations following colic surgery and understand the importance of early referral for horses, particularly with a strangulating obstruction.

Importantly, we'll go through how to identify the clinical features that are absolutely key for early identification of horses with an intestinal strangulation. We'll also address some of the challenges or roadblocks with improving the outcome of these patients, and then briefly discuss the vital role of primary care veterinarians in referral and a successful management of a horse with colic. If time permits, we'll go through some of the research that we are currently doing at our hospital to try to better understand recurrent colic as it pertains particularly to large intestinal diseases.

Historically, the expectations following coiac surgery were that all horses died following colic surgery, and that's an actual quote from a very prominent orthopaedic surgeon. Success was historically defined as survival to hospital discharge. Today, the expectations are and should be high, with good to excellent long-term survival, and not just survival to hospital discharge, and the horse not having problems with recurrent colic.

We expect that they should be able to return to their athletic function. And if it's a pregnant brood mare, she should be able to maintain her pregnancy and develop a healthy fall. So where are we with meeting these expectations and what do we need to do to continue to improve them and even exceed current expectations?

Shown here is a survival curve from our hospital, and this is from several years ago, the cases were collected from 2005 to 2010. These are horses undergoing small intestinal resection and anastomosis. So, to start with survival to discharge, and I just want to note that this excludes horses with salmonellosis.

During this time period, we were still having a high number of cases with salmonella. It was sort of just at the tail end of our, salmonella outbreak, and we do not have, this problem anymore, fortunately. But at that time, including horses with salmonellosis, JJ or J Junogenostomy, the short-term survival was 89%.

Jjuno ileostomy or JI was 88%, and J. Juno's ticostomy or JC was 87%. So a good to excellent survival rate, and I would say today, it might even be a little bit higher than that.

So for horses surviving to hospital discharge, subsequent survival to 1 year, which is marked with a blue arrow, was 99% for ostomy, which is this, solid line, which is the solid line here. 9 97% for J. Junogenostomy, 100% for J.

Juno ileostomy, which is the, the dash line, and 83% for J. Juno Ccostomy, which is, which is the dotted line here. Only 5 horses were euthanized due to colic in the first year.

Four of these 5 horses had a Derenousycostomy performed and one of these had a degeneroussostomy actually performed during a repeat celiotomy. The 5th horse, also had a repeat celiotomy following a J Juno agenostomy. Therefore, all the horses that were euthanized in the 1st year, either had a G.

Junocicostomy or a repeat celiotomy. We also hope to update these numbers in the near future. However, they do show that horses can have an excellent long-term outcome following so colic surgery.

So importantly, you know, recurrent colic, some degree of colic post discharge was observed in 31% of horses, so about a third. 24% of horses undergoing DejunoJostomy, 19% of horses undergoing dejuno ileostomy, and actually 50% of horses undergoing Jino Ccostomy. And that was one of our initial hypotheses was that horses undergoing, De Junoscostomy were the ones that would have more problems with colic, following, hospital discharge.

Most importantly, most of these colic episodes were very transient, and this has been previously reported as well, so it might be 11 colic episode, in that 1st 1 to 2 months after colic surgery that usually responds to, Fleix and melamine. I'm gonna say at this point, a vital, a vital, aspect of our clinical management of these cases is the early diagnosis of intestinal strangulation by the owner and the primary care veterinarian, and then early referral and early surgical intervention. The importance of early, referral and surgery has been highlighted by some of the clinical research by Doctor David Friedman, and this has shown, I'll describe this in a minute by this paper by Doctor Meredith Rudnick.

Dr. Freeman, and his, co-authors have demonstrated, that horses that are referred sufficiently early to not require a resection have better long-term outcomes than horses, requiring either a Jjuno Giostomy or a Gino Ccostomy. The survival curve shown here represents horses recovering from colic surgery, and it actually excludes horses that were euthanized on the table, so these are the horses that completed the surgical procedure.

Horses not requiring a resection are shown in black, and so that's the higher curve. Those undergoing genostomy are shown in blue, which is here, and those undergoing Jaiyostomy here. So, similar to our results, the Jajuno yostomy did, have a tendency to have, a lower survival than the other cases.

However, it was, it was still good. of note is with this survival curve is they have included death due to any reason and not just colic. So for example, if a horse is euthanized because of a lameness or a fracture, this is still included as a death.

In this. The arrows, however, at the top of the graph here show horses that were dyed or euthanized due to colic, and the colour code is similar, to that for the, the line part of the graph. So there were 8 horses in this.

There were 8 horses euthanized due to colic, and all of them were euthanized after approximately 2 years. The important thing is you can see here, once again, the horses that were referred and underwent surgery sufficiently early to not require a resection had a significantly higher long-term outcome than horses requiring a Ginoticostomy. So the take home message from the data presented here is that horses can do really well following colic surgery, even surgery for a strangulating obstruction, and that early referral and surgery decreases complications and improves long-term survival.

We're gonna discuss later in this lecture updates on how to identify horses with an intestinal strangulation and criteria that might prompt referral and further diagnostic test. This study also reported on survival of older horses, so greater or equal to 16 years of age, and in this figure that they're shown in the red. And keep in mind that this includes death from any reason and not just colics.

So greater than 16 years of age is shown in the red and less than 16 years of age are shown in the blue. Not surprising, all the horses did not live as young as long as their younger counterparts. Yet only 4 older horses.

And 4 younger horses died due to colic as shown by these arrows here. Suggesting that geriatric horses, so even these older horses, can do very well after colic surgery for a long time. We actually, found a similar thing, geriatric horses, so this is 16 years or older, which is once again shown in the red.

And our mature horses are shown in the blue. So this was 4 to 16 years, this was, Sorry, this is basically 4 to 15 years, and this, line here is 16 years or over, or older. And we, we showed a similar thing.

Basically, we showed here in this graph that older horses die sooner than younger horses. However, When we only included death due to colic, the survival curves were similar and so this is really not different to the data presented by, you know, Doctor Rudnick and Doctor Freeman. So, basically, horses can do well with colic surgery.

Older horses. Horses older than 16 can also do well with colic surgery, and have a good long term outcome. So I said we also have high expectations for athletic performance as well.

So generally speaking, if a horse survives colic surgery, the expectation is that having undergone colic surgery should not preclude them from returning to their, intended use and performing at the level. Affected. And that's assuming that those expectations are realistic.

So, for example, a claimer horse or horse racing at the claiming level is not necessarily going to become a winning stakes horse after college surgery, but they might. Previous studies, Have reported over 80% of horses that over 80% of horses returned to work at the same or higher level after colic surgery. Clinical variables, in this study by Davis, that were associated with a delay or a decision not to return to work, included unrelated problems, so hospitalisation for problems such as musculoskeletal or respiratory disease, laminitis, was also a reason, incisional hernia and diarrhoea.

Unfortunately, laminitis is a relatively uncommon complication after colic surgery with less than 1% of horses, developing laminitis. However, you can see how that might impact return to performance. Horses can also perform very well with an incisional hernia, and you can see this picture here, was a show jumping horse, and, she did very well, with her hernia.

Horses, while horses developing moderate severe diarrhoea, or colitis, they may have a prolonged rehabilitation due to factors such as weight loss, just generalised ability, postoperative colic, for example, horses with salmonellosis. We actually found that horses, Developing salmonella after cardiac surgery, we had the same percentage of horses that did not develop, salmonella returned to work and performed successfully. So even though diarrhoea, for example, may delay, return to work, just because of all the other factors associated, they're still capable of returning to work and can do very well, at their, expected career.

So owners and trainers of racehorses often claim that horses were never the same, after college surgery. And so, and, and a lot of horses were euthanized because, you know, they're not going to be a racehorse. In order to address this problem, our group at New Bolton centre, and actually Completely at the same time, but a completely separate study out of California compared racing performance of horses following colic surgery to their cohorts from the race two horses selected from the race prior to them having colic surgery.

Both horses actually had surprisingly similar results, with over 75% of horses that raced prior to surgery, racing after surgery. And interestingly, as a side, in our study, it was actually horses with large colon lesions that tended not to return to racing. Unfortunately, the reasons for not returning to racing.

More likely multifactorial, and were not investigated specifically, and this is just due to challenges with telephone style follow-up, and horses changing ownership, it was hard to get that information, so we just used their racing performance. Clinical variables that were associated with not returning to racing were admission heart rate and blood lactate concentration. And these are variables that are generally associated with disease severity as well as colic duration.

So, 4 horses that did return to racing after college surgery, and this is in both studies, and I'll go through our study first, and then I'll go through the study out of California. They had similar earnings and racing careers compared to their cohorts. And those cohorts, as I said, were selected from the race prior to surgery.

So in this, graph here, the earnings are shown on the Y axis, and each quarter after colic surgery is shown on the X axis. The cases are in blue, and the controls, so the control cohorts are shown in red. So basically what you can see other than the period of convalescence after colic surgery, there was no significant difference between cases and controls with earnings, with quarterly earnings, other than this convalescence period.

So this second graph looks at the number of starts, with number of starts on the Y axis, quarters post-op on the X-axis, cases are once again in blue, controls are in red, and you can see the only quarters that the number of starts was significantly different, is shown here, in quarter 1 and 2, while they're convalescing and somewhat randomly 6, and we didn't have a great explanation for quarter 6. Similarly, the study in California compared earnings and races per 6 month period, so similar to ours we did quarterly, they did 6 month period between horses undergoing colic surgery and their cohorts. The graph on the left shows the earnings per 6 months, and the graph on the right here shows the starts, number of starts per 6 months.

The surgical cohort is the solid line, and the reference cohort is the dotted line, and you can clearly see, with these graphs, there's no difference, except for the period, of convalescence, included here at 0 to 6 months. So that was very similar to our results. And horses, undergoing colic surgery also had, similar earnings per start as shown here, and a similar, career, longevity, as, as shown in the graph on the right.

Therefore, based on these two studies, and there's also been some other studies as well earlier that horses can race very, very successfully after colic surgery. So pregnancy outcome is also a common question that owners and managers, with horses needing colic surgery, they want to know. And this was a great study out of Kentucky.

They reported a 67% live falls registered, from in the thoroughbred database after surgery, the Mayhead surgery while, she was pregnant. Variables associated with failure to register a fall, a fall from a pregnancy after colic surgery were very early gestation, so less than 40 days, and this falls less for less than 40 days pregnant, the pregnancy outcome was less than 50%, and then it was almost 70% for mas greater than 40 days. Older mayors, had, a lower chance of registering a life fall, which obviously may have confounding variables there, and also colic duration of greater than 5 hours, similarly had, an overall lower falling rate.

And this once again highlights one, that means it can carry a pregnancy to term after colic surgery, except maybe if it's in the early, period. And then if the colic duration is prolonged, once again, prompting, you know, emphasising the importance of early referral, the chance of the fall surviving is also, or the foetus surviving is also lower. And we had similar results.

Our results showed that a very early, in a study I'm gonna talk about next, but it had very, early pregnancy, had a, had a lower, full survival rate compared to ones that were sort of mid, gestation as well. So this is our study done at New Bolton centre. We looked at mare survival, mare survival, recurrent colic, and risks for a negative pregnancy outcome of pregnant brood mares presenting for colic.

So this included both medical and surgical cases. So if they came in for colic, They were included in the study. And the other thing that we wanted to do, and we noticed that, you know, the mortality of mares, with colic, was somewhat higher than our average population.

And so we wanted to look at reasons for death or euthanasia, to identify, ways that we can improve the outcome for these mares. So approximately, as you can see from the flow chart, approximately half these mares were surgically managed and half of them. Were medically managed.

The reasons for euthanasia at admission. For the two horses was that surgery was recommended and declined. For both these horses, intra-op death or euthanasia for the 12 horses, euthanized or died in surgery, or recovery died in surgery here.

Was, poor bowel viability and a poor prognosis, severe haemorrhage, severe peritoneal contamination, and cardiovascular arrest under general anaesthesia. The tumours that were euthanized in recovery, were euthanized due to a tibial fracture, and one of which had a bilateral tibial fracture. So that's a problem and that's especially in older mares as well.

We see that a little bit more. In hospital regions for euthanasia and 15 mayors, was declining condition, and that was not specified, gastrointestinal rupture, and uterine prolapse. So survival for to hospital discharge in the study including all the mares, was 70%.

So, 19 mayors were euthanized following hospital discharge, and the reason for euthanasia in 9 of these mayors was colic. And then other reasons were neoplasia, a rectal tear, sudden death, so no known cause, musculoskeletal reasons, perippatuan haemorrhage, and sadly, one farm, was reducing the size of their farm. And so, unfortunately, they were reducing farm expenses, and 1 may have required euthanasia for that.

Variables associated with brood mare non-survival were similar to other studies with high lactate, high PCV associated with non-survival, so that's shown here. So the odds of a high hypolactatemia and a high pa cell volume increased by about threefold. And the other thing is, and this is, .

Not surprising because these variables, high lactate and high PCV are tend to be associated with this disease severity. And the degree of shock, and also increased with increased colic duration. Similarly, compared to medically managed mares, mares with intestinal strangulation, so small intestinal strangulation here or large intestinal strangulation had significantly higher non-survival.

Compared to miss that were managed medically. An important concept, you know, when we're going through this, to get across to owners is that horses with intestinal strangulation, when we're talking medical versus surgical treatment is, it's not a choice per se. And that the longer we manage these horses with strangulating intestinal obstruction medically, the more injury to the bowel that affects prognosis.

And so I think when we're communicating, we have to make it clear that we suspect a strangulating obstruction. And that the really the only option is surgical intervention so that owners don't elect to manage their horse medically for a period of time before undergoing surgery. Interestingly, this, these are variables associated with mares having recurrent colic, and interestingly thoroughbred breed, was associated with more recurrent colic, and also, and that was the odds ratio was 5.

And, older mayors were less likely to have problems with recurrent colic than younger mayors. And that's likely, you know, to con to be confounded by, you know, potentially them living longer or not being, rebred. So looking at pregnancy outcome, variables as associated with a negative pregnancy outcome with small intestinal, strangulating obstruction.

So not surprisingly, these meds are likely to be sicker. Signs of systemic inflammation or SERS, which is the combination of fever, tachycardia, tachypnea, and leukopenia or leukocytosis during hospitalisation and diarrhoea. This is an important finding.

It was a little bit of a surprise to us that altranoist, any sort of, altranoist type of administration was protective against losing the pregnancy. So I think that's an important variable. We do use it a lot.

Actually, Olmes, currently presenting for colic, end up receiving some form of altranogest. So we can potentially improve mare and pregnancy outcome by surgically correcting mares with a small intestinal strangulation, for example, early, prior to the mare developing ums or systemic inflammatory response and prior to the bowel becoming irreversibly injured, which once again emphasises the importance of early recognition of disease. So, recalling that the paper by Rudnick and Freeman, this is their graphic again that I've already showed you, reported improved survival of horses undergoing surgery for small intestine strangulation that did not require a resection.

And that they were referred sufficiently early that the affected bowel was not irreversibly injured. Or strangul lesion. Of note is that horses undergoing resection of non-viable bowel and, and, and then anastomosis.

They also did, they also did quite well. And I, you know, when we're going through this, I don't wanna, say, oh, if it needs a resection, we should euthanize it. That's an important concept, to grasp as well.

So, Doctor Freeman's done other work looking at this, and this is in a similar study. He concluded that the favourable post-operative course in these horses provides strong evidence that early referral could avoid the need for a resection and improve survival. However, even if a horse does require a section and anastomosis, they can still do very, very well.

However, we still want to get them to surgery, as early as possible, because it becomes critical that that bowel or add to the anastomosis is healthy and functional. So if that bowel has prolonged distention for a long period of time, even just several hours, so a longer duration of colic, or, and this is another thing to keep in mind, or administration of enteral fluids when they have a small intestinal, strangulating obstruction, that actually causes ischemia and reperfusion injury to that Red segment of bowel. That we expect to, that's gonna stay in the abdomen, and that's gonna kinda lead up to the site where we're doing our anastomosis.

And so we need that bowel to be really healthy to prevent complications associated with postoperative reflux or postoperative ileus and also adhesion formation. The other thing is, not only is distension a problem, and that's actually been demonstrated, very well by these papers by, Doctor Robin Dabaaa, where she showed that this intraluminal distention, and particularly if you have to decompress it, after, damages the serosa, damages the intestine, and sets that horse up for problems with, postoperative ileus and adhesions. So the other thing is when it's really distended like that, not only is just the distention causing damage, the other thing is it takes a long time to decompress all that bowel at surgery.

And so once again, you know, there's probably gonna be some distention, but shorter duration of colic and not giving these horses if you suspect a strangulation, not giving these horses enter fluids, is going to improve the sur viability of this bowel. So, we said, hopefully I've convinced you early referral is really important. How do we accomplish this?

How do we recognise these horses with intestinal strangulation? And how do we get them to surgery sooner? And I'm going to go into that over the next, the next few slide in the, in a few slides.

One of the first and foremost things is client communication and education. Caregivers, who are sort of on the front line of looking at these horses need to know what to look for, with their horse. And this is particularly so in older horses, and know, when to call their primary veterinarian, right away.

Or if they really suspect a strangulation, the horse is really painful, just to talk to the referring vet. And transport their horse to a surgical facility, as soon as possible. The other thing is, owners should have a plan ahead of time as to whether or not, they will pur pursue surgery, on a particular horse and how much they are willing to spend to save that horse's life.

A lot of times, owners are unsure, and that just adds to the duration between onset of colic or onset of strangulation and surgical intervention. So having an emergency plan in place, including which hospital, the address of the hospital they're taking it to, and having a trailer available, that's another sort of a time, another sort of area where colic duration becomes prolonged if they don't have a trailer or access to a trailer, and that can all save time. I just wanted to add this, it's a little, we've mostly talked about small intestinal strangulations.

There are also large colon strangulation, so large colon vulgars. It's particularly critical type of colic. These horses can have irreversible colonic damage, even after about 3 or 4 hours.

And unlike the small intestine where we can actually often resect the affected bowel. Large colon vules typically includes the entire large colon, and often it's strangulated in an area where, you know, it's, it's not particularly easy to, do a resection cause we'd be doing our anastomosis in affected bowel. This study, I thought, this was an excellent study once again out of, out of Kentucky.

And I just want to focus on colic duration prior to admission. And you can see that the survival or the, the, the survivors went down when you went from less than 2 hours, duration down to greater. Than 4 hours duration.

And their hospital is in a somewhat unique position that they can get horses really early. But you can see that any delay in identification of a strangulation, and, referral and surgical management is going to, decrease, decrease the survival. So how, how do I identify early strangulating obstruction?

So horses with large colon strangulation, or large colon volvulus, usually it's quite obvious. These patients are severely painful, and they are usually markedly have a markedly distended abdomen. And while gildings can also get large colonvolvulus, Postpartum brood mares appear to be particularly predisposed, especially during that 1 to 3 month period, after falling.

Any geriatric course presenting with colic, a strangulating obstruction, should be suspected, and the way we approach this in our hospital, should be suspected, and we do everything we can to rule out a strangulating obstruction in a geriatric course. The other confounding thing is geriatric horses. Tend to be more stoic than just mature horses, and, should be, really carefully examined for evidence of unobserved colic and the more subtle signs of pain, which we're gonna talk about in the next slide.

The other types of the other types of horses that we need to. Be careful with our draught breeds. And they can be particularly challenging cause they also tend to be extremely stoic.

And any clinical signs, such as even persistent mild colic, which might be just lying down in their stool, mild to moderate tachycardia, so even a heart rate in the high 40s, low 50s, I'd be concerned about more serious disease in these horses. So these two horses, presented for Karlik at New Bolton centre, and neither of these horses were showing classic signs of Carlik, i.e.

Pawing, kicking at their abdomen, trying to lie down and roll, neither of them showed those signs. Of note, I wanted to point this out, so some, and these are some of the clinical features that I look for for for identification of intestinal strangulation. You can see they've got these very small abrasions on the side of their head.

And these, these are things that I look for, in any, any horse presenting for colic. And these are some of the signs of, that the horse had pain, that made more classic signs of colic, i.e., lying down, rolling, etc.

That, may indicate that more severe pain than what they are demonstrating at the time of presentation or at the time that you are looking at the horse. Both horses also have this sort of dull, demeanour and a vacant expression. They're really not paying attention to their surroundings.

And in particular, this horse on the right has this open door. He's in a stall, has this open door, and his head's not out the window looking at what's going on. It's just standing there at the window, but not really out the window.

And he's really not paying attention. And then you can also I see this horse, on the left has this nostril flare. So I pay a lot of attention to to toynia, nostril flare, and also this, crinkle that they get, in the, at the side of the naries just here as well.

So, so sort of the grimace, their facial expressions. I think this can be very, very important and often missed, sign of, colic. Ultrasonographic evaluation, if you have it available to you in the field, can also be really helpful.

So, this is a point of care ultrasound. This is just done with a, a point of care machine, not a very big or fancy machine. And you can see a combination, we've got this dilated loop of small intestine here.

And then we have this smaller loop that has a very, very thick, wall. Here, so this, this sort of combination you can see other dilated loops down here, and so, This is to me, with the abrasions, the nostril flare, I believe this horse was a geriatric horse. We find these, you know, distended small intestine that gave us an indication to perform peritoneal fluid analysis.

And this horse's peritoneal fluid, with serious sanguinous. Unfortunately, so we, tentatively diagnose him with an intestinal strangulation. Unfortunately, unfortunately, this, whole surgery was not an option, so we ended up having to, euthanize him.

Similarly, surgery was declined in this horse, you know, we did put this horse in a stall for a while and, and watched him, you know, to make sure, That, you know, euthanasia was indicated. On point of care ultrasound, we did not see any dilated small intestine. However, we got our ultrasound service to look at him a little bit more closely with their machine.

And what they did see is this one dilated and thick and loose of intestine on the left side of the abdomen adjacent to the spleen. This horse eventually Became painful, and we were able to do a postmortem on this horse. And he had a very small loop of bowel, trapped through his gastrosplenic ligaments.

So here's the spleen here, here's the spleen on the ultrasound, and this is the loop of bowel, that we were looking at. And this horse, if the owners were able to go to surgery, would have had a good prognosis, after a section, of the affected bowel. So this is an area that's really important to me.

Early identification, of course, is with a strangulating obstruction. And so we've looked at this, clinically, and I'm gonna show you the results of our study, in, the next 4 slides. So this, first slide, and another thing to note is when, Excuse me, when we're examining a horse for colic at our hospital, we do not routinely perform peritoneal fluid analysis on, all the cases.

We only perform peritoneal fluid analysis on horses where we're concerned about a strangulation, but we want to, try and rule in or out, a strangulation and make the decision to go to surgery versus manage the horse medically. So in this study we were primarily looking at peritoneal fluid, so we only included horses in which peritoneal fluid, peritoneal fluid analysis was performed. So horses that were either really obviously a medical colleague, they weren't painful, they were passing manure, were not included in this study.

And similarly, horses with a large colon vullus that were extremely painful, markedly distended, that went straight to surgery, were not included in the study. So it was just that horses in that grey zone where we weren't sure what was the right decision to make regarding surgery for the owner, and the horse. So this first slide is horses, just any horse coming in for colic, having peritoneal fluid analysis performed, and this first table is our minimum database information.

So the horse comes in, we've got a history, we've got physical exam findings, and we do point of care, blood work. And so the key variables associated significantly. Associated with a strangulating obstruction on multivariable analysis where the horse's age, abdominal pain, rectal temperature, abdominal palpation per rectum, either small intestinal distention or not small intestinal distention, and blood glucose on a point of care metre.

So, I'm going through these the odds ratios, so for every 1 year increase in age, the odds of the horse having an intestinal strangulation increased by 7%. Horses with marked abdominal pain compared to horses that did not have marked abdominal pain, the odds ratio was 5. But as the rectal temperature increased, the odds that that horse had an intestinal strangulation actually decreased.

Horses with small intestine identified on palpation, small intestinal distention identified on palpation per rectum had a five-fold increase in having an intestinal strangulation. And for every 1 millimole per litre increase in blood glucose, the odds of the horse having an intestinal strangulation increased by 23%. I want a couple of points I want to make from this, is colic duration, actually improves the model with a shorter colic duration.

Leading to a higher odds of having a strangulating obstruction, and it was significant. However, the, it really, because we don't have that data reliably on a lot of our, colic cases in a retrospect for a retrospective study, we had to remove it because the numbers got really small when we included it in the model. I also want to highlight, at this point here, abdominal palpation per rectum is not super sensitive for identifying dilated small intestine.

And I wanted to put a, you know, word of caution here. A lot of times these horses will just have what you feel like is a vacuum packed, usually left ventral colon or large colon on the left. And that to me, becomes a sign that the horse may have, you know, an obstruction in the small intestine because that, colon becomes vacuum packed when, the, the fluidy contents of the, of the digestive tract are sequestered up in the stomach and small intestine, so the colon dries out.

And also there's massive absorption of fluid, from the colon into the systemic circulation. So, looking at this model, the area under the curve of the receiver operator characteristic was high, which generally, suggests it's got a reasonable accuracy. We actually focused on a high sensitivity, so identifying horses that might have a strangulation.

So the sensitivity, the cutoff was designed such that the sensitivity was high. and, sacrificed, the specificity. So we had a high sensitivity, and a reasonable accuracy, with this, with this model.

But the key thing is, higher age, pain, lower rectal temperature, any identification of small intestine and higher blood glucose suggests a strangulating obstruction. With this, these, the next 3 tables are gonna be fairly similar, with this one, we added peritoneal fluid analysis. And so abdominal pain, marked abdominal pain, was significantly associated with strangulation, lower rectal temperature, er sangguidous peritoneal fluid.

You can see that's very, very, very high odds that the horse has an intestinal strangulation. And other studies have also reported that strangulating, that era sanguinous peritoneal fluid almost has a 100% specificity, for a strangulating obstruction. This is where it got interesting with peritoneal compared to blood lactate.

So peritoneal fluid lactate concentration alone did not, was not associated with the model, was not associated with a strangulating obstruction. However, as the difference between peritoneal and blood lactate increased, So for every millimole per litre increase in the difference between peritone and blood lactate, the odds of a strangulating obstruction increased. And at the same time in this model, so look at these two calculations.

Together, as the ratio between peritoneal and blood lactate concentration actually decreased the odds of strangulation increased. So, for example, if you have a blood lactate of 2 and a peritoneal fluid lactate of 1, the difference is 1, but the ratio is 2. Rather than if you have a a blood lactate of say 8 and a peritoneal fluid lactate of 2, the ratio is still the same.

However, the difference is much larger. And hence that's why those two variables were included as described in the model. So because this study involved a lot of horses with small intestinal strangulation, we looked at this them separately, so this was for using a minimum database to look at early identification of horses with small intestinal strangulating obstruction.

So age, was still, That's significant and included in the multivariable model. Abdominal pain was, broken down into three categories, none, mild to moderate, or we included dull with that, and then marked, which it also included horses with muscle fasciculations and excessive sweating. So abdominal pain was, the degree of abdominal pain was significantly associated with a strangulating obstruction.

Absent buriggy was also associated with strangulation, and this has been shown in other studies, even though it's somewhat subjective, to be associated with the need for surgery. This is one interesting thing that I really want to highlight the lower volume of reflux, so the less reflux. The higher odds of an intestinal strangulation.

And this is because strangulating obstructions tend to affect the distal ginum and ileum. And so if you, so it has to, you know, be colic duration has to be sufficiently long such that all that fluid builds up to lead to gastric distention. This is something like proximal anitis or o duodenitiss proximal jginitis, those horses that's some more.

Or, the more orate part of the bowel affected, and so they're more likely to have large volumes of reflux. So the less reflux or absence of reflux, the more likely to have an intestinal strangulation. And obviously colic duration, is a an important component, of that.

However, once again, we couldn't include it in the model just because we didn't, we had too many missing data points for that. And, blood lactate concentration. So for every millimole per litre increase in lactate, the odds ratio for a strangulating obstruction increased by 56%.

So remember, this is only for horses with a small intestinal strangulating obstruction. And the area under the curve, was 0.92, which is excellent discrimination.

And for this we have a high sensitivity and a high specificity. I didn't introduce this earlier, this bootstrap procedure. This is just a P value, and usually we use Pers less than 0.2, to decide whether the, model passes bootstrap validation, and What that means is, so what bootstrap validation does is it excludes data points and produces several iterations of the model using different populations, and if it doesn't pass the model, it means that that model may only be applicable to the study population.

Versus if it does pass the bootstrap model, the model is more likely to be applicable to other other populations because it's not really driven by just a couple of cases. So all these models that I presented to you have passed the bootstrap validation. So this is including peritoneal fluid which Once again, the relationship between blood and peritoneal fluid, lactic concentration was, quite complex, reflux volume, remains significant once we included peritoneal fluid.

Blood and lacate concentration also remained significant, however, the interesting thing is, once we included peritoneal fluid, lactate concentration, The, for every millimole. So in this model, and I stress that this is in the model, so you have to take into consideration all these variables. You can't use any one of these variables, with these odds ratios independently.

So it's with the model. So, increasing reflux, more likely, less likely to have a strangulating obstruction. Increasing blood lactate concentration in this model was less likely to have a strangulation.

Siro sanguinous fluid once again, highly significant. And also here the perit as the peritoneal fluid lactate, so just lactate by itself, increased the odds of an intestinal strangulation also increased. We did have to exclude abdominal pain from this model because with that in this model, it did not pass bootstrap.

So once we removed it, you can see this model did pass bootstrap validation, with an excellent area under the curve, for the receiver operator characteristic and a high sensitivity and a really high, a reasonably high specificity as well. So kind of to summary, I, I, presented, you know, several variables, that, help us decide whether a horse, is more likely, you know, to have an intestinal strangulation. And first of all, the first step is, do we do peritoneal fluid analysis.

The second step is, once we have that data, do we, Do we need to go to surgery? And I included the reference, for that data on the first slide. So, therefore, to review, a strangulating obstruction is likely in horses that are moderately to severely painful, not surprising.

Or I will include that persistently painful. If they remain painful through a dose of, Flenex and melament and a dose of xylazine with or without buorphenol, referral should be discussed, with the owner or caregiver. So horses that are sufficiently painful to requiredomidine or a painful after domidine also likely have have a surgical and often a strangulating lesion.

So keep in mind, and we weren't really able to capture that in our study. Well, just because of taking the history, tends to be, you know, it's, it's, it's, it's not consistent. We don't have consistent, means of collecting that data reliably, but also taking into consideration the analgesia that the horses had.

So, so other things, like when the horse presents to you, they may not be particularly painful. And this is an example of this horse. He came into us, unfortunately, he was, had been caring all night.

The owners did not observe him. They were devastated when they found him in the morning. And you can notice his abrasions.

He also had, abrasions on his tubercoccy in his legs. And you can also notice his nostril flare, with the grimace, with the, the crinkles at the side of his nose, and he also has a grimace as well. This horse wasn't particularly tachycardic, and we took this horse to surgery, and, he had most of his, bowel, strangulated, and we ended up having to euthanize him on the table because he had insufficient bowel left to perform an anastomosis.

So keep in mind that tachycardia, even, you know, sort of mild to moderate tachycardia, so in the high 40s, low 50s, can be an indication for surgery. So strangulated, like I've mentioned before, strangulation, strangulating obstructions will always be suspected in any older horse. So in their teens or older, presenting for college.

And we've shown that in a couple of, geriatric courses, you know, a couple of our studies on geriatric horses, and also in the data that I just presented to you, age, definitely was associated. With, a strangulating obstruction. And just keep in mind as well, with some of these older horses, pedunculated lipomas can also cause strangulation of the small or descending colon.

And these horses can present similarly, except they often have colonic distention, you know, rather than, distended small intestine. And in about, I, I'm guessing about half the cases, most of the cases you can in, in that instance with the strangulation of the descending colon, you can actually, feel the small colon distention and you can distinguish the small colon from the, small intestine by palpating the anti-mesenteric band and you can also palpate the, the sort of thicker, mesenteric band as well. And then occasionally, the actual stalk of the lipoma can be palpated wrapped around the small colon or the small colon, distal small colon cranial rectum.

So, Identification of dilated loops of small intestine on palpation or sonographically should raise concerns about a small intestinal strangulation. OK. And we did not include ultrasound findings in our study, because when we looked at that retrospectively, during that time period, we weren't.

Reliably using ultrasound, but we are using it a lot, a lot more, more recently, and looking for a dilated small intestine, looking for dilated and thick and small intestine, and also looking at increase in, peritoneal fluid, as observed sonographically, as well, is also suggestive of, a, strangulating obstruction. OK, so looking for those dilated small intestine. .

And so in in in our population, and we're looking at this in conjunction with the above signs, also less or no reflux, and this is in our study population, and it's because those strangulations occur at the more ahoid part, . Of the gastrointestinal tract. So these are some of the things that I look at more subtly, to try and help make decisions, for these horses.

So I've just got a couple of cases to present. The first case is a 22-year old Arabian mare. The first thing to note is her age.

She presented to us for a few colic, so 4 hours duration, very short duration. And the referring veterinarian had given her fleix and melamine, xylazine bulophenol, and like I mentioned before, domidine as well. So anytime I've got a horse that's been painful enough to requiredomidine.

I am suspicious of a strangulation. Here's another key thing. The horse was down on the trailer at presentation.

So once again, being down on the trailer and we can't really capture this retrospectively, but that's another, sign that I look at. If the horse's kwaiki, and they're down on the trailer, they're usually really painful. I'd mentioned, in our data analysis of horses with small intestinal strangulations, we look for muscle vesiculation.

This was actually quite tachycchotic. She had decreased to absent bulbaricy. On palpation per ectum, she had distended small intestine, and she had no reflux.

We, like I mentioned, we do point of care blood work. Her blood glucose was quite high, as was her, blood lactate. So honestly, with these, her age, having given deteridine, being down on a trailer, absentor barymidysten a small intestine with no reflux, and a high blood glucose and a blood lactate, we really didn't need to do any other diagnostics, with this horse.

We just took her straight to surgery. And she had a strangulating pedunculated lipoma. It affected about 10 metres, of her distal degenum and ileum, so that's about 30 ft, it's a lot, because the referring that got her to us early, she did not require a suction.

she was, you know, we had her on 80 microbials for 48 hours. We're only using 24 hours now. She had fellinicamagglobin, IV lidocaine, IV fluids, for a couple of days, and she was discharged from the hospital on full feed at 5 days after surgery.

And she was, this is a picture of her at home, you know, she's on. She's on turnout, so she's at least a month after colleague surgery, she was doing well. So I think this case highlights the importance of early referral and surgical intervention being critical, for these horses with intestinal strangulation.

And the other thing is, we try, we'll talk about this on the last few slides, but only do diagnostic tests if it's really gonna change what you do. The next case is a 14 year old, Missouri fox trotter mayor. She had a 24 hour history of colic, and, the referring vet was treating her for a large colon inaction.

OK? On admission, she wasn't particularly, painful. She had a heart rate of, 52 beats per minute, but she had a respiratory rate of 40 breaths per minute.

So that's quite tipni. She also had a mild increase in her rectal temperature and she had barboymy. On rectal palpation, we also felt what the referring veterinarian, had felt, and that was, I'm gonna say a mild large colon impaction or probably better described as a vacuum packed colon.

So the colon. Firm digester in it, but it wasn't enlarged. So the impactions are usually quite large versus these vacuum-packed colons, tend to be, tend to be, a more of a normal size, somewhat quite small as well.

She had no reflux. So we ran our minimum database blood work on her, you know, thinking, you know, she was, she was tachycardic, tachynic, you know, that made us concerned. But when we got this data, minimum database blood work back, we got very concerned about an intestinal strangulation.

She had a high lactate. She also had a high, creatinine concentration, also suggesting, assuming it's pre-renal, maybe renal from receiving Flenexamaggleline. She had a very high, markedly high blood glucose, and she also had a low chloride, so she had a hypochlorinic metabolic, alkalosis, which also suggests to me that she has, what we call an upper GI obstruction, and she's sequestering chloride in her upper GI tract.

So, you know, she came in as an imp impaction, but there were several things with her clinical exam and her minimum database that made us think this is not an impaction. So that prompted us to do a brief ultrasound and we saw multiple loops of distended small intestine. So then that prompted us to do peritoneal fluid analysis, and it was serous sanguinous with a high cell count, total protein, and lactate concentration.

So we did take this course to surgery and found an epiloic frame and entrapment. It affected 5 metres of. And she required a resection and adrenal ileostomy.

This was did reflux after surgery and ultimately responded to erythromycin. I just have to put a note in here now. We don't typically use erythromycin anymore, for treatment of ileus, because of antimicrobial stewardship.

And she was discharged 11 days after hospital. We did get 3 months follow up on her and she was doing well at that time. So the key points, what I want you to take home from this is that physical exam and some of that minimum database sort of lab work, can prompt you to do additional diagnostic tests.

Like, if there's something not quite right and it doesn't make sense based on putting all your clinical findings together, do further diagnostics, and that may be, you know, an ultrasound exam, that may be peritoneal fluid analysis, to come to, a, a diagnosis. So this next one is a 15 year old quarter horse gelding. He presented for acute colic of unknown duration.

Once again, he had had determine by the primary care veterinarian. He, on admission, he was dull. He showed those mild signs of colic, basically just stretching and occasionally he'd kick at his abdomen, but you had to watch pretty closely to see these signs.

He was mildly tachycardic. He had decreased to absent vulvargy. On palpation per rectum, we identified dilated loops of small intestine, and he had a small volume of reflux.

So we ran a point of care blood work, and even though, his PCV total solids and lactate were, you know, not, not terribly exciting, his blood glucose was also high, not as high as some of the others. So based on the age of this horse, the fact that he had, ditomidine, we could palpate dilated loops of small intestine, which only, with only a small volume of reflux, and that blood glucose, we decided to just go straight ahead and do peritoneal fluid analysis. And, he had, er sanguinous peritoneal fluid, with a lactate of 2.5 millimo per litre.

So the lactate wasn't super high, but identification of serous sanguinous peritoneal fluid, once again, like I said, is pretty specific, for the need for surgery and a strangulating obstruction. So we did take him to surgery. He was a little bit interesting.

He had, strangulation of his distal jaurum and ileum in a meso duodenal rent. It affected about 1 metre of bowel, but because we got him early, he did not need a resection. So he was, discharged.

At 6 days after hospital. And, you know, he's bill, this is, these are prices that I've included from 2016. So they're old.

And in our hospital at the moment, these horses would probably, he would probably have a bill around $8000.80 to $10,000 as well. So peritoneal flu fluid colour and point of care measurements can be really useful in determining the need for laparotomy.

So the last case I wanna talk to you about a 7 year old quarter horse gelding. So he's younger than some of the others. He had an acute colic and then he was dull.

The referring ve, obtained 8 litres of reflux. At presentation, he was in no signs of pain. He had a normal heart rate.

His capillary refill time was prolonged, and that's probably cause he's just reflux 8 litres. So he's probably a little, little dehydrated, hema concentrated. Palpation, we could palpate duodenal distention as the duodenum passes around the base of the secum.

However, Excuse me, we, could not palpate small intestinal distension distention. We obtained 8 litres of reflux. You know, his lab work, I'm not surprising, his lactate and creatinine was slightly increased.

His blood glucose was quite high. So that made us concerned. His sodium and chloride were low, and he had band neutrophils.

We usually don't run a white count, on these horses, but we did on him. And band neutrophils are pretty Pretty uncommon, at least in our study population, for, for, strangulation. We did peritoneal fluid analysis, and it was red tinged with a really high cell count, a really high lactate, and a high total, total protein.

So at this point, we were thinking maybe he did. Need surgery. However, the horse was not painful, no signs, no evidence of pain, no abrasions, no vesicular muscle fasciculations, not sweating.

And so we did do an abdominal ultrasound and there were no abnormalities detected on ultrasound. So no distended other than the duodenum, no distention on palpation per rectum. And no distention on ultrasound.

So we actually pursued medical management, at least for a while, in this horse, getting ready to sort of take the surgery if anything changed. And so we managed him medically and he had an excellent outcome, and was discharged within 96 hours. So we thought maybe he had an idiopathic peritonitis, or duodenitis proximal ginitis.

One year, I did get longer follow-up on this whole think he maybe he had neoplasia or something else going on in his abdomen. And at one year, he was doing well. So this is, you know, the take home message was this is we've got to take care with interpreting our findings and put all the information that we've got together.

All the information we've got, look at it together and make sure everything makes sense, and then if you're leaning towards not medically manage leaning towards medical management, I think it's really, really important that you continue to. Monitor that horse really closely and repeat, repeat your tests. We do need more information on peritoneal fluid lactate in peritonitis and enteritis cases and in my experience, it can actually be quite high in these cases.

So that's some, so, so far we've gone through expectations following colic surgery, as far as survival goes, as far as performance goes, and as far as, you know, pregnancy outcome in some of these mares. That present, for colic. So, what are our challenges, you know, we're, we're not at 100%, we're far from 100% with regards to survival.

So what are some of our challenges? And like I mentioned before, early referral and surgery for horses with strangulating obstruction, It is really, really important. And that's gonna require, like I mentioned earlier, client and caregiver education, so that they can recognise that a horse might have an intestinal strangulation early and then need to get their primary care veterinarian out to manage the horse's pain, and evaluate it and or take it to a, a surgical facility.

And, and that's, that's absolutely vital. The other barrier that we have is the expense associated with surgery. And this also ties in with early referral in that if horses are referred early, as I've shown, they may not need an intestinal resection, which is gonna save a lot of money.

For anaesthesia time, surgery fee, just cost of surgery, and then also, decreased complications the earlier they're referred, the less complications they get with things like post-operative ileus, which if they're refluxing large volumes, they can, and that can get very, very expensive in the post-op care. The other thing is, as, veterinarians, we need to be fiscally responsible and really represent our clients and do everything we can to decrease the costs associated with managing colic and colic surgery. And so that, involves, as I've shown you in some of those cases, avoiding unnecessary diagnostics.

So, you know, if a horse is extremely painful, And you palpate dilated loops of small intestine, on per rectum, then you maybe don't need to do ultrasound or peritoneal fluid analysis. So, and also therapeutics, as well, watching how much fluids we're actually giving these cases, reducing the amount of fluids, unnecessary fluids, I should say, similar with an perioperative antimicrobial use, decreasing the duration, making sure we're, we're really only treating the horse, with things that they absolutely need, to improve their outcome. The other thing is I wanted to talk about is owner perception.

And this is still tough, as I alluded to some of the things that prompted the studies, that we've done is the owner's poor perception, of colic surgery. And a lot of owners base their decisions, at least in my experience, of the experience, obviously, that they've had. Previously, but also the experience of, their, their friends, their neighbours.

And there was this interesting study that's published in the Equine Veterinary Journal. It's out of Australia and New Zealand, and they looked at risk factors or factors associated with owners not consenting for colic surgery. So horses housed or managed in, more rural or remote geographical areas, the owners were less likely to consent to surgery.

As the owner age increased, they were less likely to consent to surgery. If the anticipated cost, was high and the estimated prognosis low, They were less likely consent to surgery. And so that's for us, where it comes important.

If we're gonna give an estimate, it has to be, we don't want to underestimate the cost or overestimate the prognosis, but at the same time, we don't want to overestimate or underestimate the prognosis. Either. And for me, a lot of times I give a base estimate and just explain if the horse has a complicated recovery, the cost is gonna go up.

Similar with prognosis, a lot of times, unless it's really extreme, so for example, the lactates 15, the horse's heart rate's over 100. You know, I do not obviously give those owners a good prognosis. But a lot of times I say, look, we can get a better prognosis at surgery.

And then I tell the owners at surgery, you know, give a more, refined, prognosis, for their horse. They also based it on previous experience. So, and then also the use of the horse.

So horses that have a purpose, are more likely, the owners are more likely to consent to surgery versus, horses that are kept at paddock and, and really don't have a purpose. So what's the role of the primary care veterinarian, and I've alluded to this, throughout. Throughout the throughout the paper.

We at referral centres, we don't have that first line, and that rapport with the client that you do if you're their primary care referring veterinarians. So I think it's important to educate clients regarding, colic surgery. Like I mentioned earlier.

Early referral, to a surgical facility is absolutely vital, and I think that's probably the number one thing that has improved outcome of horses undergoing surgery in the last 20 years is early identification that the horse has a surgical lesion and actually getting them to a referral hospital and to surgery earlier. I think that's vital. Like I mentioned in the previous, slide accurate estimates of expense and prognosis.

And I always, communicate positively, and cause that can, you can sway an owner with how you present, the information. You've got to be realistic, but also, you know, present the positives as well. Cause the owner is obviously less likely to do surgery if you tell them that, you know, survival, you know, it's, it's really serious, you know, unfortunately, your horse needs surgery and it's gonna cost you $10,000.

. You know, that's, that owner if I would not do surgery versus if you, you know, explain that, you know, it's gonna cost $8000 to $10,000 and, you know, we'll get a better prognosis in surgery, you may actually save that horse's life. So help clients prepare for an emergency. Know which horse is in a facility, referral and surgery is an option.

Know how much owners are willing to spend, on their horses, have a trailer available, address, know the address of the referral hospital, and manage expectations upon referral so the owner knows what's gonna happen, when their horses, referred. And then, really effectively communicate your clinical findings at the referral hospital cause as, I noted throughout this talk, a lot of information from the history is really, really important for us to know to make the decision for surgery. And so recurrent colic can be a problem.

It is an ongoing area of research in our hospital. We don't have time to go into this, in detail. But things that we're looking at is stereotypic behaviour and recurrent colic, gastric, the relationship between gastric or Ulcerations, inflammatory bowel disease, and recurrent colic.

And then we're also, looking at the microbiota, and this is primarily horses with large colon recurrent colic. So stay tuned as we start together, gather more information on that to, to hopefully improve the lives of these horses. At this point, I'd like to thank you, and if you've got any questions, please do not hesitate to contact me at this, email address.

Thank you.