Hello, my name is Louise Southwood, and I am an emergency clinician at New Bolton centre, which is the large animal hospital for the University of Pennsylvania. I'm gonna talk to you about rapid classification of the equine patient with abdominal pain, and really what I'm gonna tell you about is some tools to use to try and differentiate if you're in primary care. Does the animal, can the animal be treated on the farm or does it need to be referred in for further evaluation and treatment?

And if the animals in the hospital. I surgery indicated, or should we be able to manage this patient, medically? So just, you know, a little bit of background and just sort of set the stage a little bit.

It's really important to keep in mind that most horses with colic are going to be able to be managed medically. About 75% of horses with colic are gonna respond to a single dose of medication, and some of those respond to no medication, some of them just spontaneously get better. If there's no response to treatment, and I'll go into detail with this in a little bit more in the next several slides, if there's no response to treatment, that's when referral is indicated.

And by indicator I mean you start that conversation with the owner about whether a referral is an option for their horse or an option for them, and their, their interest level. And it's probably about 10 to 20% of horses with colic that end up requiring actual referral, and remember it's referral for further evaluation and treatment, not necessarily referral for surgery. So early referral is critical, it's, it's absolutely important especially for horses with strangulating obstructions, and I'm gonna talk a little bit about how to differentiate or some ways to differentiate a horse with a strangulation, from a horse with maybe a simple obstruction.

Earlier you get them to the referral hospital, the healthier they are, the more cardiovascular stable they are, the better the survival, the healthier their bowel is, when, ultimately we take them to surgery and so the fewer complications they're likely to have. And like I already alluded to, just remember they're not necessarily being referred for surgery, they're being referred for closer monitoring, potentially for the diagnostic tests such as a transabdominal ultrasound, peritoneal fluid analysis, maybe some blood work, and intravenous fluids if it's deemed necessary. And probably, at least in our hospital, I think this is probably similar to other hospitals, about 50% of the horses that are referred are going to, require surgery.

And obviously the decision to go to surgery is a big part of the owner, the owner's willingness and ability to have their horse undergo surgery. So, general indications for referral, I'm gonna go into each of these in a little bit more detail, abdominal pain, shock, tachycardia, nasogastric reflux, any sort of evidence of intestinal obstruction or complete obstruction, and we'll discuss a little bit about how how patient peractum findings can help with this decision making. So probably the biggest, the biggest, clinical finding or clinical feature that's gonna help with the decision of whether to refer the horse or management on the farm is if the horse has abdominal pain.

The horse's abdominal pain is persistent. And or severe, you really don't have a choice, you know, but to refer it or euthanasia, unfortunately. And just as a guideline, and this is obviously a guideline, everybody does it a little bit different.

If you give an animal a dose of flonexamegamin. And then they're still painful and you give them a dose of xylozine and buolphenol, and they're persistently painful through that referrals indicated. And some people like to use the xylozinebutopinal first instead of Floiximaggloin.

And then so you could say a second dose of xylozine butorphenol, and especially if they've had a dose of domidine, and that, and they're painful through that, that to me is very much an indication for referral and likely surgery. Some animals are going to be temporarily responsive to analgesic drugs, but the pain recurs, and that is also an indication of referral as well, and so the impacts, sel and colonic impactions will look like that. The other thing is geriatric horses and draught breeds, it's really, really important to keep in mind that these animals are quite stoic.

And if they, even if they're responding temporarily to any medication, and if they get painful again, I would be thinking about a referral in those cases as well, cause they're not necessarily as demonstrative, of their signs of pain as other breeds or causes of other stigmaments. And we'll talk a little bit more about geriatric horses under strangulation, but they're a lot more likely than, you know, a mature or a young horse to actually have a strangulation. So the other, the other indication for referral that's not necessarily on an emergency basis is those horses with chronic recurrent pain.

And the types of lesions we see with that is internallithiasis, intermittent displacements, gastric ulceration, Plasia, adhesions can always, can often cause this chronic recurrent pain, and they're usually are referred, not necessarily like I said on an emergency basis, but for more diagnostic tests and radiography, sonography. Some lab work, peritoneal fluid analysis, and if we still can't get the diagnosis, or even if we do get the diagnosis, for example, a lithiasis, exploratory, laparotomy, or sometimes we'll do, if we, we think it's some sort of inflammatory bowel disease or something like that, we will, go ahead and we can do laparoscopy, to look for, to get some biopsies. So there's options there, so they usually refer not so much on an emergency basis or there sometimes it is but more on an elective basis.

So the other big indication for referral is if the animal is showing any signs of shock, it's time to refer them in and like in most instances, it's ideal to refer them in well before they're showing any signs of shock, and I talk a little bit about shock, in the lecture of early assessment, assessing the emergency patient. So I'm not gonna go into a lot of detail here, but basically, it's when it's inadequate oxygen delivery to the cells, they can't produce enough ATP and you start going into cell death, which is your multiple organ dysfunction. And so we want to see these animals earlier.

So, anytime hypovolemic shock, endotoxemic shock, are the two most common, we see here, with colics, but occasionally we see an animal with hemorrhagic shock as well, and I spoke a little bit about that with lacerations. However, animals with colic, they can have haemorrhage into the peritoneal cavity for various reasons and present for colic as well. So anytime you've got any signs of shock, it's an indication for referral.

So we're talking tachycardia, injected mucous membranes, prolonged capillary refill time, and prolonged jugular refill time, cool extremities, consider referral for resuscitation. So tachycardia, I talked a bit, quite a bit about this in a, in another lecture. Anytime you have a heart rate, you know, if the tachycardia is persistent, even if it's in the 50s, it's probably an indication for a referral and especially if it's over 60.

The other thing is if you start treating an animal with colic, and you go out to look at them the first time and the heart rate's 40 beats per minute, you go ahead, maybe give them some analgesia, and then you get called out again, they're uncomfortable and now their heart rates, for example, 56 beats per minute. So that animal's not getting better, it's actually getting worse, and so that's an indication for a referral to, I already talked about pain and shock and you're gonna find the tachycardia sort of enveloped in the signs of pain and evidence of shock as well. Any, time you've got any indication of a severe disease or failure to respond to medical treatment, tachycardia can be an indication of that, and, it's time to refer them in.

So the heart rate's really important. Nasogastric reflux. This is generally not 100%, but generally an indication of small intestinal disease.

And the two most common that we see or the two most common categories that we see in our areas, proximal Nits or ileus and mechanical or strangulating obstruction. And the thing with the presence of reflux, surgery is often necessary. If it's a strangulating obstruction, but it's strangulating lipoma here, the sooner you can get that close to surgery.

The better, generally speaking, the better the prognosis, the fewer the complications. And my goal is with horses with strangulating obstructions, I like to get them into surgery before I need to resect bowel. So if I can transect the lipoma stalk and the bowel becomes pink and healthy again, obviously not the case in the one shown in the picture here.

However, that is my goal, so you wanna get them into surgery, but even if surgery isn't necessary, so we think it's a proximal enteritis, and we don't see a lot of ileal impactions in our area, but if you live in the southeastern United States or areas where you see a lot of ileal impactions, then those indications, for referral is for, often IV fluids. They need, fluid and electrolyte replacement, especially if they have a large volume. Of reflux, so anytime you get reflux, be starting to begin to have a conversation with the owner, about referral.

And then anytime you've got evidence of an intestinal obstruction, to a complete obstruction, I'd be starting to have a discussion about referral. Whether it is a strangulating obstruction or not, more aggressive therapy is likely, to be needed. And then, and so what does a complete obstruction look like?

Those horses. With reflux, it's, in the case of proximal anneuritis, it's a functional obstruction, so it's inflammation of the bowel, you know, it's not moving, it's secretary, it's producing a lot of fluid. They really need IV fluids, but I also mentioned reflux can be an indication of a complete small intestinal obstruction.

So, consider a referral for them. Anytime you've got abdominal distention or worsening abdominal distention, maybe when you first went out to look at the animal, they didn't look that distended, or maybe it was mild gas distention. However, as you've been treating it, the animals become more and more distended, that's an indication for a referral and actually potentially surgery.

Absent forboygy is definitely an indication for referral. It is interesting, it's somewhat of a subjective clinical finding. However, there was a study done surveying veterinarians in primary care practise, and they found that the clinical finding in primary care practise, so, you know, vets in the field that was most likely associated with eventually the need for surgery was absent bribe.

And in some of the clinical studies that we've done as well, abs and bulbargy is definitely an indication of more serious disease, and potentially the need for surgery. So, pay attention, to that, even though it is somewhat subjective and seems to be variable, it is a really important clinical finding. And then the other thing I pay a lot of attention to is faecal output.

If you've got decreased faecal output or no faecal production, then that can be an indication for referral, especially if it's more prolonged. So for example, those horses that you go ahead and do rat palpation on, and there is nothing in the rat, that is very, very, that's an abnormal finding, and I would have, in the back of my head that that animal potentially has a complete obstruction. And probably should be referred in for further evaluation.

So, abdominal palpation perum can also be a very, very useful diagnostic tool. I'm not gonna go through, you know, all the, the importance of restraint, adequate lubrication to prevent rectal tears, and do it safely, so as a veterinarian, you don't get injured. Generally speaking, if an animal's got some Mild tympani or a pelvic flexure impaction and you're comfortable managing it on the farm.

I think that's, I think that's OK to manage it on the farm for, you know, a while to see if the animal responds once again taking into consideration those other clinical findings, that I spoke to you about. The thing is with pelvic flexion and passion, you have to be very, very careful and make sure it's truly a pelvic pelvic flexure impassion and not a vacuum packed left ventral colon associated with sequestration of fluid in the upper GI tract. So sometimes horses with With small intestinal strangulation or small intestinal obstruction, and the fluid that's produced as part of the secretions for digestion can't get through to the colon.

And so the, intestinal contents in the colon get very dried out, and they can feel like an impassionate, but it's not. And the main difference is, is, is those impassions that aren't truly impassionate, it's just kind of Vacuum packs. They're a lot smaller.

They're usually a lot more cranial in the abdomen, versus a true pelvic flexure impaction. they're quite large, they're quite impressive. You put your arm in the rectum and it's like, oh my gosh, that impaction's huge.

So be looking for that, and don't make that, mistake because you will delay referral on a horse, potentially with a strangulating obstruction. So while abdominal palpation perectum findings are very, very important and I'm gonna go through them sequentially, they're not necessarily associated with the need for surgery, in every case, and studies have shown that. So I'm gonna talk a little bit when we talk about individual diseases, about sequel impaction.

If I was in primary care practise, I would probably refer these in. They can be insidious, the horses can not necessarily be painful, they can respond really well to flinic and meg women and Until they rupture and these and I'll talk a little bit more about sequel rupture, but essentially as shown here in this picture from Mueller and Morph out of the University of Georgia, you can see, you feel this big distended viscous and it's usually quite tight on the right side of the abdomen. Small colon impactions, I would probably refer them into and these feel like they actually feel like a big long Chinese dragon in the caudal abdomen.

These can be really, really difficult to resolve medically because the small colon at the, obviously the caal it's. End of the gastrointestinal tract, it's as a oral as you can get, and its job is to resolve water. And so once it's impacted to try and get that really well hydrated, it can be a challenge.

And the bowels are actually often quite inflamed and has poor motility. So a lot of times we end up taking them to surgery as well. Anytime you've got a colonic displacement, more and more we're getting, those horses managed medically.

However, you know, surgery is often indicated, and usually we manage them with, intravenous fluids, and more and more we tend to be using intravenous lidocaine, as an analgesic for these horses to try and help them work through their displacement. And basically what you feel. Palpation per ectum in those cases is for right dorsal displacement is you feel the colon coursing across the abdomen, the caudal abdomen just in front of the pelvic brim, and it's usually quite distended, so quite a bit of colonic distention, and you often, you can see with the displacement here, you can't feel that ventral band of the sum.

And then you've also got your left, so this one here is your right dorsal displacement. You can feel, so the colon basically is displaced between the secum and the right body wall, and then you've got your left dorsal displacement with or without nephrosplenic entrapment. You've got your spleen.

This is the quarter dorsal border of the spleen that you can palpate the quatal pole of the kidney here and then if you can palpate the colon between the The cordo dorsal border of the spleen and the kidney, then you've got a left dorsal displacement with or without nephrosplenic entrapment. And I'm gonna talk a little bit about ultrasonographic diagnosis of that as we go through, but ultrasound can be very useful for diagnosing both of those conditions. Anytime you have severe colonic distention, even though sometimes those horses can resolve, sometimes it can be just gas, it may be a large colon volvulus.

In large colon volvuluses, they meet all the criteria for a referral. They're usually violently painful, they're usually severely distended, you can't usually get near them to do much and so you, with those cases you either have to euthanize them or referral for them. In an immediate referrals necessary, those horses can have irreversible damage to the colon within 3 to 4 hours.

So the sooner you can refer them, and that's one indication if an owner calls you, they say the horse is extremely painful, markably distended, especially if it's a postpartum mare. I would just refer them in, even potentially without going and looking at the horse if they're able to get the animal on the trailer. Small intestinal distension, we've already talked a bit about small intestine, but basically you feel those multiple stacked loops next to each other, and they feel like those long, balloons that people fall into different animals and swords and things, and so you just feel those multiple stack loops and often it's as far.

In as you can reach in the rectum, before you can feel them, so pay a lot of attention. Once again, ultrasonography, transabdominal ultrasonography can be good for picking up that. And then anytime you feel an abdominal mass or anything like that, that maybe not necessarily referral on an emergency basis, but it is an indication for referral.

So that's sort of an idea of when to refer, and I think having a good relationship with your secondary or tertiary care hospital is really, really important. So once they get to the referral centre, we're gonna decide if surgery indicated or not, and like I said, about half the horses, at least they're coming to our hospital, and this is probably a fairly representative and up going to surgery. The most, the most common reason for referrals persistent, or sorry, for surgery is persistent or severe pain, and that's mostly indicative of an intestinal strangulation, and I'll talk a bit more about other criteria.

And if you've got an animal that's severely painful, you can't provide enough analgesia to keep it comfortable, and you don't have a choice but to take it to surgery or unfortunately, if the owners aren't willing or able to take the animal to surgery, euthanize it. Anytime there's a lack of response to medical management, and I'll go through these, all these things in a little bit more detail, lack of response to medical management, obviously, surgery would be a next step, signs of complete or partial obstruction, we talked about that a little bit. I'm gonna elaborate that on that further, when we talk about, surgery, and then I'm gonna go in a little bit the sonographic, findings that might help make these decisions.

And abdominocentesis and peritoneal fluid analysis and we're just finishing a study, hopefully we're gonna submit it for publication soon, looking at clinical variables, including peritoneal fluid analysis that can help decide if an animal has a strangulation, or not to try and discern when they're not really obviously painful, if that animal needs to go to surgery. Persistent severe pain, like I said, you don't have a lot of choice if they're severely painful. Also, recurrent pain, so that animal, you give them some analgesics, they get painful, and this may be recurrent pain over several months or maybe recurrent pain over a few hours.

That's an indication. If I've given an animal xyzinebulophenol every few hours. You know, and they're not still not responding.

I think surgery is indicated. And then if they get painful after domidine, I really think they probably have a surgical lesion. And so that's an important part of the history taking.

For me, if, a veterinarian referring a case in for me is given at multiple doses of domidine, I'm gonna be thinking this animal is probably gonna need an exploratory laparotomy surgery. So I've talked quite a bit about strangulation. Horses with strangulating obstructions.

What do these horses look like? A lot of times it's quite obvious that they might be down on the trailer, thrashing around, you bring them into the hospital, they just want to go down right away, persistent severe. Pain.

Often they'll be sweating, and this this horse here, I, I used this picture in another lecture as well, was a horse that had, I think he had about 40 ft. The majority of his small intestine was non-viable, and it was associated with a strangulating lipoma. He was not showing obvious signs of colic, but he was sweating.

He had muscle fasciculations. He had abrasions, all over his head, all over his legs. He was tittnik, and he had this, and you can see his nostrils here.

He had a nostril flare, and he had this crinkle at the side of his nose. I'm suggesting that even though he wasn't being demonstrative of pain at this point, because his bowel was dead, I think a lot of times. These animals, when their ballad's dead, or necrotic, they, they get, they develop signs of shock, but they're not necessarily as painful anymore.

Tachycardia, I already mentioned bulburiy, absent bulburygy, really high lactate, high blood glucose, can be an indication that they have a strangulation. Now, hyperlactatemia is fairly non-specific. You know, probably yourself if you measure your If you go for a run, your lactate's gonna go up.

So it's, it's not, it's not as closely regulated as blood glucose, which is extremely tightly regulated. And anytime there's stress, endotoxemia stirs, you get insulin resistance, you get an increase in release of glucose from all the liver for that fight and fight response. And so, glucose becomes deregulated and can be a useful.

Marker. I mentioned that we, have done a study trying to look at, you know, some clinical variables that might help us, trying to soon if an animal has a strangulation. And one of the main ones was pain.

That was, that was very significant. The interaction between age and blood glucose, and so I, I already mentioned as horses get older, their risk of strangulation of. The odds that they're gonna have a strangulating obstruction increases.

So when I have a geriatric course coming into the hospital, I always make sure I rule out that they've got a strangulation before I go ahead and put them in the stall. And so, the interaction between age and blood glucose was also statistically significant. And colour duration, and this is really an important thing when you're looking at any sort of models to try and, you know, decide, when the animal.

Needs to go to surgery, not colic duration. Unfortunately, the data retrospectively isn't always great on that. But, the shorter duration of colic, not surprisingly, the more likely the animal had a strangulating obstruction.

Similarly with reflux, and we're gonna talk about proximal enteritis, versus a strangulation in a little bit, but similarly with reflux, if it had a, the the lower volume of reflux. The more likely the horse had a strangulation, especially if it had distended small intestines. So if you've got a 20 year old horse, with a high blood glucose, a short duration of colic distended small intestine and rectal, and little to no reflux, I would be really concerned about a strangulation.

And that's kind of a summary of what our data showed, and I'll talk a little bit more about what we found with peritoneal fluid analysis as well. But these ones are really important to recognise. We already talked a little bit about lack of response to medical treatment.

So what does a response look like? Let's start with that, a response if they're responding to medical treatment, resolution of signs of pain, obviously, and they become bright and alert. A lot of times what I'll do is I'll, I like to have their store window open so they can look out.

I also like to give them muzzle them obviously so they can't eat, but put them a little bit of hay in the corner. And so if they're bright and lit, they're looking out the window, they're trying to eat the hay through their muzzle, that's a good, that's a good sign. Their heart rate, you want to see that start to decrease, you want to see their gut sounds start to improve.

And if they were to stand and you want to see their abdominal distention improve both externally and also on palpation per rectum. So these, these signs tell you, OK, the animal's getting better now and also starting to defecate and have a good appetite. OK.

So lack of response to medical management, persistent pain, change in demeanour, you know, persistent or worsening tachycardia and tachypnia, decreasing test ball bearing, increasing abdominal distension, persistent reflux, or a lot of times these horses with the strangulation when they first come in, maybe they don't have reflux. But over time, as the fluid, builds up in their small intestine, they'll develop reflux. And the reason they don't have reflux, often initially if you get them early enough is because a lot of strangulation strangulating obstructions affect the distal small intestine and ileum.

And anytime, all those signs with, consistent with intestinal obstruction, if they persist, so lack of manure production. A persistent or severe pain, increase in volume of nasogastric reflux, worsening in distention. Decreasing bulbar rhyme.

OK, so those signs, that kind of gives you some idea of, is the animal getting better or not, you know, are they distended, they got poor bulbarigamy, you know, they can all be an indication for the need for surgery. And I think with sonographic examination, it can help, and I will tell you I'm not great at doing ultrasounds. But I can usually tell the basics.

So I'll go through some, and, and we do a lot of the point of care. Sometimes we call in an ultrasound service if it's not really obvious, but this is where it can be helpful, it can be helpful for looking for peritoneal fluid. So, and that can help you guide peritoneal fluid, abdominocentesis and obtaining a sample for analysis, although I will say Even if you don't see peritoneal fluid and you think you need some, to help make the decision to take the animal to surgery or not, I would still attempt, at least attempt, to get some, because it's not particularly sensitive for identifying peritoneal fluid, but you can look at the volume, you can look at the consistency, you can, you know, it can be very useful for diagnosing peritonitis, hemoabdomen, as well.

We're gonna look for any intestinal distension or thickness, and so, this can be particularly helpful for the colon and we're gonna talk a little bit more what thicken intestine might, might might mean. Any sort of anatomical aberrations with something in the, in the, wrong spot. So such as the colon, we'll talk a little bit about, you know, what colon displacements, you know, might look like.

But these are, you can look at the peritoneal fluid, you can look at, you know, intestinal distension, thickness. I mentioned, in another lecture, you can look at the contents, for example, you've got a febrile animal, you know, maybe it's leukopenic, you put an ultrasound probe and you see a lot of, the colon has a lot of liquid in it, that animal's probably going to get. Diarrhoea and then any changes in the anatomy.

So types of lesions, what are we talking about? I already mentioned peritonitis, hemoabdomen. It's really good for identifying small intestinal distention.

So once again if we have a geriatric horse come in, and for example, maybe I don't, feel the 10 of small intestine proactum, but I go ahead and put the ultrasound probe on and see the sten of small intestine, that, that's gonna make me concerned that it has a strangulating obstruction. You can measure the size of the stomach, if the horse isn't really cooperating for passing a nasogastric tube, then you can assess the size of the stomach, to see if the tube you need to persist. Any chronic displacements, I'm gonna talk more about that.

I'm gonna talk a little bit about large colovolvulus, you know, what's, what's currently in the literature. It can be helpful for differentiating a sequel from a colonic inaction, and sometimes it's hard on rectal palpation. Most of the time, you know, it's fairly apparent, but sometimes it can be a little bit difficult.

And our ultra sonographers, I'm not sure if I would pick this up, but our ultra sonograph. Are fairly good at identifying it on this sand, and what they look at is flattening of the circulations of the ventral colon, in the, just the ecogenicity of the contents, but radiography is obviously a lot better for that. I mentioned tear for colitis.

It can be really helpful. Like I said, if you've got a febr horse, maybe it's a little bit showing some signs of colic, sonography can, can help you with that as well. In this section, I've got a picture here.

It's not a common cause of colic, but, our ultrasound group is actually quite good at picking up at, at diagnosing. Inner deceptions. Anytime you've got an abdominal mass, a sonography can help you, and sometimes you have to do, your evaluation transrecally as well, and transabdominally to try and evaluate, you know, the, the ecogenicity of that mass to get some idea of what, what it might be.

So it can be useful. So this is one of the first studies that came out of Italy looking at what we call flash, so fast localised abdominal sonography of horses, you know, using this obviously to try and identify horses. With a surgical lesion.

So with a 10-minute ultrasound, so it took him just 10 minutes, they were able to identify free peritoneal fluid and abnormal intestinal loops. And so what they found, the value for predicting the need for surgery was actually really good with this, and this is something like I said, I'm not great at ultrasound, but I can usually identify the the loops of small intestine and an increase in peritoneal fluid, with a point of care, ultrasound, and there's a lot of other, a lot of new devices that are available. You can even do it from your phone or an iPad, so, .

It's, it's a very useful, technique. So this is another one also looking at the association between the actual lesion and findings on sonography they found that distended a motor loops, the small intestine were very consistent with the small intestinal strangulating obstruction. Now keep in mind that that's in their hospital, and then.

More importantly, an increase in peritoneal fluid, distended thick can loops of small intestine with abnormal mentality was generally associated with a small intestinal lesion. And I will say in our hospital, and with our study population, what we're looking for, we're obviously looking for the s Its of small intestine, because that's very helpful, and that will definitely prompt us to do peritoneal fluid analysis, at least. The other thing that we're looking for, I'm just gonna go back, is this is obviously the standard loops of small intestine here stacked together.

This one here, this, this just had ileus or enteritis. This was in the, in the lower picture, you can see the small intestine has a thickened wall and there's increased peritoneal fluid and it is dilated, and not moving versus the adjacent loops, to a more normal. They're contracting down completely and so that pattern of the mixed population with some dilated and thick and very thick and associated with the strangulation and other loops more normal is more associated with a strangulating obstruction.

So other things they found in this study, was a failure to visualise the left kidney associated with nephros splenic entrapment. I also want to see the spleen displaced ventrally in those cases as well, not just failure to visualise the left kidney. We've definitely had some false positives, with that, especially with the point of care ultrasound, the left kidney is not always that easy to see.

And so I want to see the, the spleen displaced, the distended colon, dorsal to it, and also, the, the, clinical signs matching, and the rectal palpation findings consistent with the sonographic findings, and that's the nephrosplenic entrapment of the colon. And I'm gonna talk a little bit more about this. There was another study that looked at like this, at this, but thick and large colon strongly associated with large colon formulas.

However, as I said, previously, causes with large cobos are usually violently painful. When we get them, they're usually down on the trailer. We can barely keep them up and keep them still enough to get an intravenous catheter in and get some fluids, going, and so, to ultrasound those animals, we usually don't do it.

But that was, this is the study, that was talking about that and so, basically they were using ultrasound, transabdominal ultrasound to predict large colon vullus, and they used a cutoff of 9 millimetres or greater and it had a sensitivity of 60. 7%, so, so that means I missed a lot of cases. However, if it was less than 9 millimetres, all of those horses did not have a large bone, so it was fairly specific.

So, so it's a useful tool. If you've got an animal, maybe it's a volvulus, it's not that painful, maybe it's a, you know, it's a 180,270 degree volvulus, it's not causing a complete obstruction. Sometimes if they've got an impassion in their right dorsal colon as well and they've got a vulvulus it's not causing a complete arterial strangulation, it could potentially be useful.

We, where we've had challenges with using the results of this study and our study population is we see. Quite a few colitis, and those colitis can be quite sick on presentation, and they too can be down on the trailer, especially if they've got, you know, hyperaninemia, or they're, you know, in severe shock, as well. And so those animals also have a very thick colon.

And so just the finding of the thick colon alone, keep in mind that sometimes they can have other things such as a a colitis. Another thing I mentioned, you know, we talked about nephrosplenic entrapment of the large colon. The other thing that's been, utilised, is identifying the colonic vessels, which remember, usually the axial on the colon, later on the right side, and there's a fairly specific location between the 12th and 17th incostal space at the costs of.

Junction. And that, had the animals that where they identified these vessels had a 2032.5 times odds of having a rightful displacement or a 180 degree large colon bulullus.

So essentially what you're doing instead of those vessels, the axial where the colon sits in the normal spot, you know, the colon when it displaces, rotates 180 degrees. And so you can see those vessels sonographically. There's been a few, studies subsequent to this that maybe it's not as, maybe it's not as clinically useful as initially described, and we definitely use this in our hospital.

We've had plenty of animals where we've synch colonic vessels, we've managed them medically and they've done just fine, so I would not use it as a criteria for surgery, but I guess it is. More information that can potentially help you make a decision about surgery, but it's not just because I see those vessels doesn't mean I'm gonna take the animals to surgery and I want I want my rectal palpation findings and the clinical other clinical findings to be consistent with the displacement before I make that diagnosis, but It's, it's, the more information we can have for our decision making, the more useful it can be. Peritoneal fluid analysis can obviously be very helpful.

I'm not going to go into their technique, but you can do it with either a needle or a tea cannula. My preference is, if I have the standard loops of small intestine, I will always Use a teat cannula. I do get concerned about, you know, with, with the stenos small intestine, I do get concerned about, penetration of the, the intestine, with the needle and laceration with a needle with the sten of loops of small intestine that's just my clinical experience.

The other thing is, usually with those horses that have just a small intestine and I'm trying to make a decision, I really wanna get a sample. And sometimes the needles aren't long enough, to actually get through the peritoneal cavity and, you know, we'll get, you know, be like, oh, I didn't get a sample. There was, you know, there was no fluid and it's like, probably more likely it's the needle didn't, penetrate the peritoneal lining, and that's the reason.

However, if you don't have the stent. Intestine, I just in a small intestine, then using a needle is a lot quicker, and especially if you have a horse that doesn't have a very thick body wall. And sonography can also be useful for looking at body wall thickness to determine what length of instrument you need to obtain the peritoneal fluid sample.

So what am I looking for with peritoneal fluids? First thing clear, I look at the volume, how much volume am I getting, higher volume, more likely associated with strangulation. I want normal fluids clear yellow, so if it's erro synchronous, I'm going to be concerned about an intestinal strangulation and you can look at the total protein, you can At the nucleated cell count and you can look at the lactate and these, these these findings here with the asterisk you can do point of care, which I think is really important.

The more we can do point of care, there's a lot more point of care tests available to us, you know, to help us make some of these diagnoses. I love this study, . This study actually showed basically the colour of the peritoneal fluid, it is probably the most useful in that if you've got erroyguous peritoneal fluid, probably also if it's cloudy, if you've got serosaginous fluid, you've got a, a strangulating obstruction, unless somehow you've got some contamination or something usually you can tell the difference between serrosingguinous and sanguinous, if you're paying attention when you're obtaining the sample, but that's large volume serous singinous peritoneal fluid.

That has some opacity to it, surgery is indicated. And in our study as well, that I have already mentioned, we looked at peritoneal fluid analysis and the finding of er sanguinous peritoneal fluid was so predictive. It was, it was perfect, a perfect predictor, of strangulation, so we couldn't actually include it in our model because it, it messed everything up.

So that's probably the most important thing. I'm gonna talk a little bit about lactate. There's been quite a few studies looking at the use of peritoneal fluid lactate for predicting the need for surgery and intestinal strangulation.

And what, you know, the initial studies looked at an association and so subsequent studies have . You know, really try to look at its use a little bit more, you know, more more, be more predictive, and we looked at this in our study, it was one of the main reasons we actually did the study, because in our clinic. Just the measurement of peritoneal fluid lactate and the peritoneal fluid lactate relative to the concentration in the blood, so comparing the two, the ratio was not particularly important either, in our hospital.

And so we wanted to look at this, to see if we can get more information. You know what we found, in several of our models that actually the difference, not, not the ratio of blood to peritoneal fluid, but the difference between peritoneal fluid and blood was more predictive of a strangulation. It was actually better in horses with small intestinal, a small intestinal lesion.

So, so the difference between peritoneal fluid and blood lactate was more, more useful and more predictive of the strangulation in some of the final models. However, it wasn't as good as some of the other variables such as pain, obviously serious seguinous peritoneal fluid, shorter duration of colic, smaller. Volume of reflux were quite predictive as well.

This is a study that was interesting. It was done out of a private practise in Florida, and they actually repeated the peritoneal fluid analysis, over time, and if the lactate increased in the peritoneal fluid increased. Then the odds that the animal had a strangulation increased.

So, and this was especially important if if the, if the lightate was more normal at the time of presentation. We've, we've tried this in our hospital, you know, we, and we really haven't used it a lot. But the study in which the hospital, the hospital in which the study was performed so a lot of ileal impactions and so what they were really trying to differentiate with an ileumileial impaction from a strangulating obstruction, and so I think, I think this is a useful technique, but we, we haven't found it super useful in our hospital population, but you know, once again, you know, the more information you have, the better you're gonna be.

I want to make the right decision for your patient. So I've talked about surgery being indicated in, surgery being indicated in, you know, horses that are painful. What about the horse that's not so painful.

And so this is how I manage them. So, you know, you've got an animal, you think you might need surgery, but it's not painful. I, I avoid giving them Flinnex and megain because I think A lot of animals you can mask a surgical lesion.

I avoid withholding feed, I monitor faecal production, bulb arrhythmia, abdominal distention and reflux, and use those things to help make the decision. So, this is an example. This is a case that we actually had.

Surgery was not an indication, for this, was not an option for this horse is a 12 year old cor Ging. It was presented for colleague and found down in the paddock in the morning. On presentation it was quiet, there were no signs of colic.

This horse never had signs of colic. He think, he did have abrasions, he had muscle fasciculations and he was sweating, you know, so based on these signs, I was concerned about an intestinal strangulation. His heart rate was 48 beats per minute, respiratory rate 16, so not high, abs and bulb arrhythmic, cool extremities, just a small volume of reflux, here.

You know, so based on the clinical findings, even though he's not showing adverse signs of colic, as a little bit concerned, about, an intestinal strangulation. And his blood values weren't, weren't super helpful, his blood glucose was a little bit high which once again supports the need. For, for surgery for strangulation.

So this is this horse. A couple of things to note about this horse, he had this distracted look. His window is open and it's looking out his window, but his head's not up and over the, not out looking, he's not paying attention to what's going on outside.

He didn't have a tonne of abrasions, but he had this little abrasion here, and this is what it looked on ultrasound. All we saw was one single loop, this is the spleen. This is in the cranial abdomen on the left, and you can see this single loop of thickened, small intestine and possibly I think there's some increase in peritoneal fluid.

That's the only thing we saw abnormal on ultrasound, one loop thick and small intestine. Surgery wasn't an option, and this was eventually became painful, even though he spent most of the day just standing there, sort of looking at his window, and he actually had a gastrosplenic ligament entrapment. Which is shown here, this is the spleen, this is the non-viable piece of about, so I think, you know, the take home message, with that is you want those horses that aren't particularly painful, you've got to do as many diagnostic tests, as you can to try and, you know, help make the decision for surgery.

And like I said, surgery was not an option for that case, so we just managed it medically until euthanasia was indicated. So we're gonna go through these fairly quickly, you know, these different types of lesions, you know, what can help you make the decision for medical versus surgical treatment for some of these more specific lesions. So small inta and at least in our population, enteritis, versus a strangulation, and this was a study that was actually done a long time ago by Doctor Janet Johnson out of our hospital.

Horses with enteritis tend to be a little bit older, dull rather than painful, had a huge volume of it's a reflux, it's a proximal obstruction. OK, so, and it's secretary as well. So these horses have 1015, 20 litres of reflux.

And we actually felt like a Already alluded to in our study looking for variables associated with strangulation, smaller volume of reflux, more likely associated with strangulation. There were several other variables. One of the big ones was horses with proximal enteritis tend to have a very high total protein.

And not so high of a nucleated cell count in the peritoneal fluid. So it's something to look out for versus strangulating obstructions that, the peritoneal fluid, nucleated cell count, and protein tend to go up at the same time. And these were associated with the mechanical obstruction, they tended to have, which is most often a strangulating obstruction, higher heart respiratory rate, increased my intestinum palpationectum and, increased nucleated cell count.

So they can help you guide it. So the things that we use for differentiating is pain, progressing the dull demeanour, we think enteritis, peritoneal fluidlatic is not particularly useful for differentiating an enteritis from. A small intestinal lesion and sonography, sometimes you can look at those in more detailed, you know, with the, the thickness, the different patterns of the loops, the amount of peritoneal fluid, the volume of peritoneal fluid to help you decide, and then sometimes you just have to take them to exploratory celiotomy to get a diagnosis, and it's important to remember that's a diagnostic as well as a therapeutic tool.

So just as an example of a case, this is a 2 year old thoroughbred co presented to us with colleaguelic he had 10 litres of reflux. He had no signs of colic. His heart rate at the time of presentation.

His heart rate was and rectal temperature were both increased a little bit, 10 another 10 litres of reflux, when he came into us. He had extended small intestinal palpation per rectum. He was obviously dehydrated, he had a high creatinine, he was asotemic.

He had a high blood glucose and he had a, not surprisingly. A hypochloremia because of loss in the reflux so this was, you know, with it wasn't c like huge volumes of reflux, he had a mild fever, you know, his heart rate wasn't particularly high, so we treated him as an enteritis, you know, with intravenous fluids, some lidocaine, and the frequent gastric decompression. Sonography, he had minimum anechoic fluid, he had multiple loops of small intestine with some abnormal motility.

We tried an abdominal centesis, we got the spleen, unfortunately. So progression, he had never had, this horse never had any signs of colic. And we even tested for Clostridium toxins on the reflux, and it was positive.

He ended up producing 100 litres of fluid in 24 hours on reflux. So it was this massive volume of fluid. You know, that we had this febrile horses, he wasn't painful, he was bright, he was just refluxing, but we couldn't keep up with his fluid losses, so we ended up taking him to surgery, and he actually had a mechanical obstruction.

He had a genal stricture, with a memento adhesion, and we ended up resecting his bowel. And so just remember, we took this horse to surgery not because of pain or anything, just because the volume of reflux was so massive. And so sometimes you just have to take them to surgery, to, to get a diagnosis, and that can be important, probably should do it sooner than later, in some of these cases.

Large colon passions. I try to manage all of these horses medically, if I can in our hospital, and there's a study a long time ago, out of the Equi Medical centre in Virginia, and they actually hushed the survival force of the large coa in that study. It was a while ago, undergoing surgery was only about 50%, and it was because of rupture.

So how do I decide when I take an inaction to surgery? I tell you, if I take them to surgery, I'd like to take them to surgery early in the course of disease. I monitor very closely faecal output.

They have to be producing some manure, intestinal will be me, any signs of abdominal distention, reflux, and then persistence or severity of pain. Keeping in mind that these animals will get quite painful when the impaction is breaking up because you're putting. Large volumes of animal fluids in to the, to the colon and it gets very heavy and they can get quite painful.

But so long as they're defecating, they have bulb me and they're not getting distended, I will go ahead and continue with medical management, in those cases and in the most, sometimes it can take several days, but for the most part, it's, we can get them successfully. This is just another case example two year old thoroughbred Philly, she had colic has several hours duration, . She was non-responsive to analgesics.

When she admitted, was admitted to the hospital, she had mild colic, physical exam was largely unremarkable, except you could palpate, large colon and passion, so we're talking, left ventral colon, pelvic flexion and passion. The lab work was unremarkable. So we treated her with an water and electrolytes.

We were giving her, and this is a typical regimen, we usually give 5 litres every 2 hours, and we treated her with ferrocoxib. Miss Philly became very, very painful. She was worth a lot of money, her owner had a lot of money, and so it became a challenge, but she was never distended.

She continued to pass manure. She had great bulb arrhythmi, she did not she. Tolerated the enteral fluids very well.

She did not reflux. I did begin IV fluids, but even though she was quite painful, and was making me very nervous because her gastrointestinal tract was still working, we persisted with our medical management and it eventually, resolved. So monitor these horses, try to manage colon actions, medically, however, they've got to be monitored very, very closely based on your physical exam, and your rectal palpation findings to make sure there is no deterioration.

Scal impaction completely, completely different type of impaction. Remember they're on the right, I tend to take these horses to surgery or at least recommend surgery, because in our hospital and also this study as well, and both those references are in the notes, is 25 to 30% of these horses were rush. Within the 1st 24 hours of presentation, and in our, our success with medical management was only about 60%.

It was a lot higher in the study of plumber at L out of Texas. So I tend to take these horses to surgery, just because I've seen too many of them rupture. The study out of plumber showed abdominal pain, was helpful for the.

Need for surgery and peritoneal fluid was analysis was not useful for monitoring these cases. And like I said, rupture is the sequel rupture is the big concern with these and it can be insidious. It's not like they get super painful and then rupture, they can stand there, literally stand there in the stall and perforate their sum.

Small colon impaction similarly, we end up taking quite a few of these to surgery. this study, by Fredericko at out of North Carolina State, showed abdominal distention, was the biggest indication for surgery, and that's probably the case in our hospital as well, abdominal distention, lack of manure production, decreased bulb me, and sometimes it's helpful to take them to surgery just to confirm, your diagnosis as well. I just threw this in briefly.

Sometimes we have a horse with colitis or diarrhoea, and we end up taking them to surgery, and that's sometimes these horses can be quite painful. They can be quite distended, and they can be a lack of faecal production, and they can. Have a clinical deterioration, usually we try and take them to surgery before they deteriorate.

And sometimes you can have a misdiagnosis. It can look like a colitis and it's not. Small colon impactions, for example, will often present for having diarrhoea, and they're not truly a colitis, there's a small colon impaction.

So, you know, any, I, I'm not afraid to take a horse with a colitis, to surgery, to confirm my diagnosis. And, and these are some of the things that you might find. I mentioned small colon impaction.

Sometimes they can have a colonic infarction, that can definitely present like a colitis. And, I've had other horses, actually with a vulus, that presented like a colitis, but they truly had, a vulgar. Sort of displacement.

So just keep, keep this in mind, once again, surgery is diagnostic, as well as therapeutic. A lot of time if I do take a colitis to surgery, I'll do a pelvic flexure enterotomy to empty the contents. We have, I haven't transformed one, yeah, but that would potentially be an option.

Usually I go ahead and treat them with some DTO specs make tape, which is also called bio sponge, to try and help them. So peritonitis, I'm gonna go over this fairly briefly. We did do a study some time ago looking at this.

The key thing I want to point out is, you know, sometimes you got a horse with a peritonitis, do I take them to surgery or not? A lot of horses with peritonitis do respond, medically, however, if they need to, so for example, they have non-viable intestine, and in fact is something you really want to take those animals to surgery. So not surprising, .

The abdominal pain. If you've got a horse with peritonitis and they're painful, take them to surgery. If they're not painful, manage them medically on this.

If you just focus on the pink bars here, these are the horses that survived to discharge without surgery. If they were not painful, over 80% of them survived to discharge without surgery. However, the one With as the pain increased, the need for surgery also increased as well.

Similarly, if you just focus on the the pink vase here, the ones that survived to discharge without surgery had normal buy. However, you can see the absent animals with absent bary at admission, few of those animals survived. So horses with peritonitis, no reflux were more likely to survive the surgery than horses, with flat reflux.

And also, obviously, we've already talked about this with the colour of the peritoneal fluid, so the yellow. Orange peritoneal fluid obviously did better than once again if they had seriousyous peritoneal fluid, and peritonitis is just defined as a peritoneal fluid, nucleated cell count, greater than 10,000 cells per microliter. So they've got no signs of pain, no normal bulbugy or normal or improved bulbuy, normal faecal production, no reflux, and that yellow orange peritoneal fluid, they're a lot more likely to survive the surgery, than if they don't.

So this is just a case example. This is a 10 year old thoroughbred brood mare. She, presented sign for colleagues.

She's 3 days postpartum. At the time of presentation she was dull. She had a heart rate of 48 beats per minute.

Burrigney we reduced. She had a little bit of reflux, not a lot, just a little bit of reflux. Blood work was not, too.

Largely unremarkable for a postpartum there, when we did abdominocentesis, she clearly had peritonitis with over 100,000 cells per microliter and a total protein of 6 grammes per deciliter or 60 grammes per litre. We actually took her to surgery and we found nothing. I don't know, I don't know what was the source of the peritonitis if she had a small, injury area of injury to.

Urus or an area of injury to some bowel that we couldn't identify but we didn't find anything she drained large volumes of peritoneal fluid through her incision unfortunately, but otherwise she did she did very well so it was an explore to get a diagnosis and so in this case this is one case I wish maybe I hadn't taken her to surgery quite as soon I wish maybe you know I'd monitored her progression for a little bit longer. So the other issue, to sort of finish up is, you know, when do we euthanize horses without surgery. And then obviously financial constraints, you know, you've got to talk to the owner, you've got to know the cost of both medical and surgical treatment at a at a tertiary, secondary or tertiary care facility and have that conversation right up front with the owner.

Other reasons people euthanize animals without surgery is a possession that the horse. Not do well, for example, if they have recurrent colic, if they've got, if they're older, even though all courses can do very, very well, with colic surgery, I'm going to briefly talk about some prognostic indices, and I'm going to also briefly talk about gastrointestinal tract perforation as well in those clinical signs because that's obviously an indication for euthanasia. This is when I'm talking to owners about the decision to go to surgery, I always recommend an exploratory laparotomy to assess prognosis, unless the, unless it's really obvious.

That the animal has a poor prognosis, and I'm going to talk about some of these prognostic indices. I'm going to talk about some of these prognostic indices, you know, that can help make the decision, you know, whether to pursue treatment, and even if you're under general anaesthesia, whether to recover the horse. And so if you focus here, the orange bars are the horses that were discharged from the hospital line, and this is horses with large covulvullus.

This is data from a long time ago out of Colorado State University. And the main thing that I want you to look at is as the heart rate increases. The survival decreases to the point where you've got, you know, when you've got heart rate in the 90s, 100%, the survival is like 20% or less.

Similarly, as your pack cell volume increases. Your survival of the orange bars decrease. OK.

Similarly, your creatinine concentration and all these things, as I talked about in the, the lecture on assessment of emergency cases, all these in this prognostic indices an indication of the degree of shock, the degree of Perfusion and potentially organ dysfunction. Similarly, as your creatinine concentration and your blood glucose concentration increases, your chances or the percentage of horses that were discharged alive decreases. There's been some studies looking at blood glucose in horses, you know, as a prognostic y, and multiple studies have shown if as your blood glucose increases, your prognosis for survival decreases.

We talked a little bit about lactate as well. These two studies showed increased lactate, decreased prognosis. This first study was specifically looking at large covulvuloses and horses with a lactate of over, you know, over 10, I, I believe none of them survived.

They also looked at lactate post-op and if the lactate remained high after surgery, after correction of the lesion, that was also associated with a Ultimately a poor prognosis for survival. And then this study by Brett Tennant Brown, which was done at New Bolton centre, actually showed that lactate was a better predictor of survival or non-survival in horses with more serious disease, so it was a better predictor of survival in horses with lesions such as large and vullus or colitis. And once again, Both these studies show that it's, well, the initial lactate is important, if it's extremely high, so if it's 10 or over, and that's not a good prognosis, however, it's the response to therapy as well, so how quickly that lactate decreases and returns towards normal, it is a critical prognostic indicator.

I, I've showed this study before, it's one of my favourite studies, but basically, this study shows. That the patients, this was in humans, that the big toe temperature was just as predictive of outcome for that patient as several more invasive and expensive techniques. So don't forget to look at your patient, touch your patient extremity, temperature, jugular refill time, just their demeanour, their behaviour, can give you a lot of information.

This is an example of a case I. Had 12 year old thoroughbred brood mare, colleaguelic of unknown duration. She had severe pain.

But she was really, bright. Her jugular refill was really good, easy to get a catheter in. Her skin was warm.

She didn't have that poor jugular refill. She wasn't cool and clammy. However, we got her blood work back and it was horrible.

She had this PCV of 61%, not a good prognostic in. Her lactate wasn't 10, but it was approaching 10. She was azotemic, although mild.

And so we got her blood work back and we were like, this is terrible. However, like I said, she was very, very painful. She clearly needed to go to surgery, but, you know, her physical exam, I think ultimately, was more representative of her prognosis, than the lab work.

So when she actually had an excellent outcome, she did great. We were able to rotate her vulvullus, and she was discharged within 72 hours of admission. So for me, this is a clear indication that we can use our blood work for prognostic indices, but looking at the patient is the most important, and then monitoring, monitoring them as well and how they respond.

The gastrointestinal tract. Is obviously an indication for euthanasia. What do these courses look like?

They're often dull, they may be anxious, they may be painful, but often they're dull. They don't want to walk. They've got severe septic peritonitis, and they're sweating profusely, and if you've had the misfortune of seeing a horse actually rupture while you're examining it, you'll just, what you see is they just They just break out into a lather of sweat.

They have muscle fasciculations. They're very tachynic, and they have the nostril fla that I described previously and the increase in effort and a lot of times you can see their injected mucous membranes even in their nasal passages. I mean, these, these signs all develop very, very quickly when they rupture.

Tachycardia initially might not be too bad, but it becomes. Over time, 80, 90, 100, or higher. These animals are often febrile, and this is something that people don't talk about a lot because, you know, they've got intestinal contents in their peritoneal cavity.

They've got severe, you know, septic peritonitis, and so they, they are usually febrile. They have abs and bulb arrhythmi. And a lot Sometimes they have abdominal distension as well.

For me, when they present like this, we're obviously always concerned about rupturing. We usually try to not take these horses to surgery, sometimes you have to. And so what I always look for, I always run some blood work on these patients just to kind of give us more information.

These animals are usually markedly, markably leukopenia. They have Maybe even a few 100 neutrophils per microliter, total white cell count is often less than 1000. As you're monitoring their PCV goes up, then the total plasma protein goes down, so it, it, it splits, and they usually have a marked hypoactatemia that tends to, that can get worse, with even with fluid therapy.

So what do we do to confirm the diagnosis? I always, tell, students and, house officers, you can only euthanize them once. We usually do peritoneal fluid analysis.

Palpation per rectum can be helpful. You get this sensation that the cause of the positive, Because of the positive pressure in the abdomen, the rectum is actually collapsing around your arm, and you get this floating sensation, occasionally you can feel a roughened serosal surface. Sonography, obviously can be helpful for looking at the increased volume of peritoneal fluid, and then obviously peritoneal fluid analysis is the most diagnostic.

You're looking at the gross appearance. And then the other thing importantly that you're looking at is intracellular bacteria and this here is a neutrophil and you can see there's bacteria actually in the cells and that's pretty much, you know, with the other clinical findings is diagnostic, and euthanasia is indicated, and occasionally we do, we do end up exploring them. So take home message from this.

Most horses are going to respond to medical treatment, but any time they've got persistent pain or severe pain, that's an indication for surgery, and the sooner we can get these horses, you know, to surgery, you know, at the referral hospital, the better the outcome, and I can't. I can't stress that enough. And so, you know, the goal of my research is is really looking at early ways to get to identify horses with strangulation.

Most of my dad is obviously in a tertiary care facility, but I'm really looking to extend that to, you know, what this looks like in primary care, which obviously has a completely different population. So thank you, and if you've got any questions, I've included my email address in the notes, so please feel free to email me. Thank you.