Thank you very much. Right, I hope everyone's had a nice day without any particular anaesthetic problems. So what we're gonna talk about today is reflux, regurgitation, the difference between the two, what happens when things go wrong, and what you can then do about it to lessen the risk and prevent major complications.

So what is it? During anaesthesia you've got two possibilities. You've got reflux or you've got regurgitation, and they're broadly a minor and major version of the same thing.

So reflux is what's happening when you get movement of stomach contents up into the oesophagus. And you can have two major types. You can have acid reflux or you can have bile reflux.

Acid reflux is obviously acidic bile reflux tends to be neutral. If you want to know the difference, bile reflux tends to be fairly bright yellow. There'll be a picture coming along a little bit later.

What I tend to do if I really need to know is get a urine dipstick and dip it in and then read the pH of that. So the problem with this, both acid reflux and bile reflux are irritant, and particularly acid reflux is extremely irritant. So you're going to get intraoperative pain, post-operative pain, and then potentially stricture formation.

And it's a stricture formation that people are seeing as quite a major postoperative complication. The danger here is it happens frequently, up to 43% of routine anaesthetic cases reflux, which broadly means every other every other anaesthetic that you do, your patient is refluxing. One study in cats is showing around about 33% incidence.

Some studies are showing none in cats, lots in dogs. Broadly speaking, you can expect dogs and cats to reflux frequently and in practise, I tend to assume that every other one of my patients has going or is going to have a reflux episode. Regurgitation is the rather more dangerous version of it.

So regurgitation is where the gastric content is coming up into the oesophagus and then it's coming all the way up into the pharynx, around the larynx, down into the trachea, and if you have enough volume, it's gonna be coming out of the mouth and nose. Now there's the tricky bit. Most of these regurgitation cases you're not going to see because the regurgitation volume is fairly small and the pharynx, particularly of the dog is pretty big.

So you're not gonna see material coming out of the mouth and nose unless you're completely overflowing the pharynx. There is a huge reported variation in incidents. Obviously you've got less regurgitation cases than reflux cases, but they are happening.

And we think about 6 to 15% of your anaesthetic cases are regurgitating. So what's that gonna do? You're gonna get all the problems that you've had in reflux as the oesophagus is exposed to this material, and you're dropping very acidic, unpleasant material directly onto the larynx and potentially down into the trachea.

Laryngospasm, bronchospasm, aspiration pneumonia, nasty stuff. What might you see in your anaesthetic? Sometimes not a lot.

So increasing heart rate, increasing respiratory rates, signs that your patient is in pain. You might hear an upper airway noise, you might not. You might see laryngo spasm in recovery, you might not.

But that material could be sitting down. OK, so anatomy of what we're talking about here. Now, what we can see.

You've got the stomach sitting here just behind the diaphragm, oesophagus going up through the chest. There is a muscle sitting at the top here by the exit of the oesophagus. You've got the larynx and the epiglottis sitting here, and then the curve of the tongue going up into the mouth.

So you've got one smooth tube that takes you from the mouth all the way down to the stomach, and that means it's quite an easy path for what you don't want coming back up the other way. So what structures are sitting there in place to prevent this material coming up and spoiling your day? You've essentially got a upper esophageal sphincter and a lower esophageal sphincter, but it's a mistake to think that that sphincter means a ring of muscle because it doesn't.

These sphincters are groups of structures which acting together, prevent this material accessing the oesophagus. So looking at the specific anatomy, this is quite useful when you come to preventing the problem. There is a small length of intraabdominal oesophagus.

That length is different in different species and in different breeds. So we do know that the shorter the abdominal oesophagus is, the more likely reflux becomes. So something like a rat has quite a long section of oesophagus within its abdomen, and rats almost never reflux and regurgitate.

So almost never, it does, it does happen, it is known that it's extremely rare. We know that greyhounds and beagles have virtually no abdominal oesophagus, and we think that some of the breed associated reflux risks that are reported may be related to the anatomy here. My personal experience is that muscular staphies with very low body fat, particularly if you're working in a rescue environment and you're seeing a lot of these young muscly staphies in for castration, they're the ones that I see regurgitating most frequently.

Anything that increases your abdominal pressure, anything that's pushing and squeezing around about this area is obviously gonna make it easier for gastric contents to come out of the stomach and into the oesophagus. So if you've got a 50 kg Saint Bernard dog or something like that, those are the ones that you really want to be thinking about, managing reflux and regurgitation. If they're fat, you're getting more pressure on the stomach.

If you're tilting them, so anything where they're tilting towards the thorax is gonna squeeze that stomach up against the diaphragm, and it's gonna make it much easier for gastric contents to overcome that esophageal sphincter. From a surgical procedure point of view, you might want to think about anything that's, going on in the cranial abdomen. So gastric surgery, obviously, but also laparoscopy.

If you are inflating the abdomen, you are pushing on the stomach, you are making it much easier for reflux and regurgitation to happen. And certainly in humans, laparoscopy is a major cause of reflux and regurgitation associated complications. The esophageal mucosa itself, the ridges of esophageal mucosa will squeeze together and they will give you a degree of esophageal seal.

And then if you see the angle that the oesophagus enters the stomach, as that comes down from the diaphragm, it's acting like a flap seal. It's called the angle of his, and that also may have some influence when we're looking at brood associated risk of reflux and regurgitation. In cats, they do have a circumferential smooth muscle band at this point here, at the entry to the stomach, which is obviously helpful.

Bear in mind that most of your anaesthetics are having a muscle relaxing effect, and that's reducing that protection. And then as the oesophagus passes through the diaphragmatic constriction, that is a major source of strength in that lower esophageal sphincter. Now this is extremely important.

The diaphragm has got two halves to it, two big bands of muscle. The right diaphragm, the right hand side of that muscle is stronger than the left. So if you dump that animal on its right hand side and you squash that muscle, you're gonna get more effect if if it's in right lateral recumbency than the left lateral recumbency.

So right lateral recumbency is squashing the stronger half of the muscle and your risk of reflux and regurgitation goes up. Left lateral lateral recumbency, you're squashing the weaker half of the muscle and the risk goes down a little. OK, so let's look at the top end now, technically speaking.

There is a transition point just around about here in the dog, specifically in the dog, where the esophageal mucosa goes into the pharyngeal mucosa. And it looks like a sort of little wobbly bit of mucosa. It's, it's a sort of blob of mucosa, and it does give you a degree of seal.

Head position makes a huge difference in my experience, and I've been doing a lot of anaesthetics with the Do feed gel over the last few years. If you flex the neck, so if your head comes down this way, it tends to push the larynx dorsally up against that band of muscle and it improves the seal at that point. If you extend the neck, so if you've got the dog on its back in a normal surgical position, and you just let the head flop free, and this is particularly if you've got the dog in a trough or something like that.

And the head is really hyperextended, you are relaxing this area here. You drop the larynx away from the oesophagus and you make it easier for fluid to come up and into the pharynx. So what I always do is try and support the head with towels or with sponge or something like that to keep the head in a neutral, slightly flexed position.

And you'll see a video later on where I forgot to do that and that was one of the reasons why we have a large regurgitation episode. And then you've got this cricopharyngeous muscle or pharyngeal constrictor muscle which is constricted at rest and then physically relaxes in order to allow the dog to swallow, and that squashes the opening of the oesophagus down against the dorsal larynx. OK, so remember that anatomy when you're thinking about what's going on with reflux and regurgitation.

It's important to go back to those pictures. So you've got an upper esophageal sphincter here and a bunch of things down here that are giving you lower esophageal sphincter strength. And remember that if you are changing.

I'm sorry, I'm physically pointing with my hand, I need to move the mouse so you can see what I'm doing. It's very, very important to consider when you're operating, what you are doing to the stomach and what that in turn may do to the oesophagus. In human anaesthesia, the boss of the Doxin event group that makes the VGLs is a human anaesthetist, and he's been doing advanced anaesthesia in humans for many years.

The major cause of unexpected serious complications and death in human anaesthesia is reflux and regurgitation. It is a major, major cause of emergencies. So this is something they bang on about all the time.

So key points, reflux happens frequently, no matter how good or bad anaesthetist you are, you are probably seeing reflux cases every single day of your working life. It is difficult to identify a reflux event unless you are actively monitoring for it, and we're gonna come onto that in a little while. So there isn't a single clinical sign which I would say this means that reflux has happened.

The most consistent thing is your patient is asleep. Everything is going fine, you're not doing anything different and all of a sudden heart rate or respiratory rates spike during your anaesthetic. That tends to mean that your patient is hurting somewhere, and I would go looking for reflux at that point.

So these cases are starting off as quite a minor mild reflux and they're turning into a more dangerous regurgitation episode. So they're not two separate conditions, they are just two manifestations of the same thing. Positioning affects reflux and regurgitation.

And the interesting thing, Laura Rosewell, who's a very, very good veterinary nurse, she did a study last year and she looked at the effects of multiple repositioning in regurgitation risk. And I think of it like a corkscrew. So the.

Each time you turn the patient, the reflux is making it past another one of those protective mechanisms. So the first turn, they're making it past that little stomach angle, the angle of piss. The second turn, they're making it past the esophageal mucosa.

3rd turn, they're making it past the diaphragmatic. Constriction, 4th turn, you're at the heart place, 5th turn, 6th turn, 7th turn. Now it's a regurgitation.

So think about cases where, for instance, you're knocking these animals down in your in your knockdown area, at your, your nursing home, whatever it happens to be. And then you turn them to start to clip for surgery, then you turn them back, you start taking radiographs, you take 3 or 4 multiple radiographs, then you pick them up, you take them through to theatre, you reposition them 1 or 2 times to get them to the final point for orthopaedic surgery. That patient has probably reflux even before you start surgery.

So consider multiple reposition as a major, major risk. Does that mean you need to panic? No, it means you need to assume that reflux has happened and go looking for it.

And if you go looking for it, it's quite a simple thing to manage. So this does not require expensive equipment, it does not require huge amounts of skill, it just requires you to have this at the top of your mind. So How do we look for reflux?

You stick a tube down there and you suction. You can do it one of two ways. The VGel airway devices that will be coming on the market at some point, the dog ones have a gastric channel that goes through the middle of the device and out the other side, and that's what we're using when I show you the videos later.

So in those devices, I pass a gastric drain tube through that channel in the device and into the oesophagus. If you are intubating, then you intubate first and then you carefully place a drain tube over the top of the larynx and into the oesophagus as if you were passing an esophageal stethoscope. A gastric drain tube is a normal piece of medical tubing, normally with multiple ports in the end of it.

It needs to be blunt ended so it doesn't cause any damage on the way down and it needs to be well lubricated with a water-based lubricant before you place it, as you would do with anything. So it allows you to say yes there is reflux there or no there's not. It allows you to drain it and measure the volume.

It allows you to get rid of it before it turns into a more dangerous regurgitation event. Now, what we don't know from research is whether draining the reflux before it comes up reduces the risk. We haven't got that proven, but it seems pretty likely to me.

So the other thing that all these things will do is allow you to get fluid away from the airway if regurgitation happens. The larger the tube you've got down there, the better the chance. I'll show you in a second the dog V gel also has the advantage of giving you some degree of separation between the airway and the oesophagus.

So this is a superglottic airway device, a dog V gel. This portion here, think of it like a soft face mask. It's, it's like those, polycarbonate and rubber diaphragm face masks that we all use in dogs and cats and rabbits.

And that seals around the larynx itself. So the larynx sits within this chamber here. This is a completely separate tube that goes all the way through the device and out the other side, and this tip here sits within the oesophagus.

And this is the tube through which you pass your gastric drain tube or your esophageal drain tube. And here we are with a lateral radiograph which shows us a little bit more clearly, so. There you go there, the blue arrow is showing you the airway channel, the red line here is the larynx and the trachea going down here.

And then the oesophagus is this structure here, and that's the esophageal channel. Going all the way through, and that's where you pass your drain tube. That's the opening to the with your channel there.

Now, there is some discussion. About whether you place a tube, whether you're intubating or using a superglottic airway device, whether you place a drain tube just down into the oesophagus, or whether you pass it through the oesophagus and completely into the stomach. In human anaesthesia, you, you would always place the tube through into the stomach, you would then completely drain and decompress the stomach and then often leave that tube in place for monitoring during your during your anaesthetic.

Talking with some of the specialists during the development of the Val device and some of the research work that I've been doing. The consensus at the moment seems to be to be placing that tube into the oesophagus and leaving it at the level of the heart base, particularly in dogs. The people that are placing gastric drain tubes in dogs are finding it very difficult to get a new meaningful material out through them, and it may just be that gastric material in dogs is just too solid to get out through a small esophageal tube.

So certainly when I'm doing these cases, what I'm doing is placing an esophageal tube down to around about the level of the heart base and I'm leaving that in place during the anaesthetic and I'm routinely suctioning it around about every 5 minutes as a monitoring device. The disadvantage of placing that tube through into the stomach may be, and this is unsupported by much in the way of research, but it may be that you're opening up a channel for more reflux material to come through. So really it's an area that we need proper research in and we need to try and identify what the best course of action is and what the gold standard of monitoring and draining is.

And at this stage, we just don't know. So, other species of vials, the cat vials and the rabbit vials which have been around now for about 5 years, I think, they are too small to get a gastric channel through. So they have an esophageal plug there and there, which plugs the top of the oesophagus and it helps to hold any material back in the oesophagus, preventing reflux turning into regurgitation.

Theoretically, rabbits are not meant to regurgitate. I say theoretically, I do a lot of rabbit work in general practise, and I have had quite a few cases where rabbits have regurgitated under general anaesthetic. So whatever the books say, it can happen.

Be aware of it as a possibility because if rabbits weren't difficult enough to anaesthetize. So, airway management. Options that we've got.

Face mask is obviously giving absolutely no protection against reflux and regurgitation. Endotracheal tubes and superglottic airway devices give you degrees of airway protection in different ways. There is no device at the moment that offers you complete protection against reflux and regurgitation.

So endotracheal tubes. The cuff, theoretically we've always been taught to use the cuff as regurgitation protection. Well, unfortunately, that just doesn't work.

An endotracheal tube cuff is there to give you an airway seal, an air seal. The best cuffs are high volume low pressure cuffs. Do not use the red rubber tubes for .

They are there and they will give you an airway seal. The problem is that they're giving you a low volume high pressure seal. They're contacting the tracheal mucosa over a very, very, very short distance.

They will give you a lot more tracheal mucosal damage. They will strip the cilia of the mucosa. Very, very quickly indeed, and they will give you a tracheal injury which will take time to repair.

And that's even if you're inflating them to the minimum possible pressure. Tracheal injuries from tubes like that are, are well proven. So my opinion is, don't use red rubber tubes.

They are much, much more damaging than the Portex PVC tubes. So the Portex ones have a high volume low pressure cuff. They should be inflated to just contact the tracheal wall.

And that's enough to give you a sufficient airway pressure that you can ventilate your patient. They will protect from aspiration for moderate periods. My opinion at the moment is probably they're giving you about 10 to 15 minutes protection against aspirated material progressing further down into the lungs, and that's based on some information from the human anaesthetic field.

What they won't do is they won't stop fluid penetrating between the tracheal wall and your cuff. So in human anaesthesia, what the doxinovent chap says is that they suction around about every 15 minutes around the cuff to remove any fluid buildup. So don't rely on your cuff to give you regurgitation protection, that doesn't happen.

Remember that if you've placed that cuff quite deep down in the trachea, by the time that the regurgitated material meets the cuff, you've exposed all of the larynx and maybe a third of the trachea to acidic stomach material. That's not good news. Cut your endotracheal tubes prior to use.

You want to be thinking about keeping that cuff. Fairly proximal in the trachea, not necessarily right next to the larynx, but not far, not far off it. There's no particular value to going down deep into the trachea with your cuff inflation.

And then, as we were saying before, consider placing either an esophageal or a gastric tube. And hopefully if we have an evidence base at some point in the future, we'll be able to be more specific on that. But as I say, as things stand, I'm placing them in an esophageal location.

And that is probably gonna help you say there's reflux coming, start draining this patient. So supraglotticic airway devices, the dog ones terminate in an esophageal plug that has a gastric channel in it. So even if you're not using a separate gastric drain tube, then you're still getting protection, you're getting separation of the airway and the esophageal tube.

The cat and the rabbit ones have an esophageal plug which is holding material back, and you've got a degree of separation, as we were saying, between those two structures. In some cases you can keeps glottic airway devices in place for longer into your recovery than you might do with an endotracheal tube, and that does give you the potential to maintain that reflux protection for longer. So let's have a look at some rather unpleasant pictures of vomit, which is my favourite thing.

This is a big puddle of regurgitated fluid. This is what stomach contents look like when it comes up. Now this is a high volume, nasty regurgitation episode and you would see this coming out of the mouth and nose if you had an endotracheal tube down.

They're not always that obvious. This one, was a dental procedure and this probably in terms of volume was 0.5 mL, something like that.

This is what boo regurgitation looks like, it tends to be bright yellow. You would not have seen this in this dog had this dog been intubated. So we're seeing it because we're using a super glottic airway device.

This is one of the prototype devices, that's the, the colour that they come in. If you see these dog devices on the market, they'd be quite brightly coloured. The gastric channel is here and all that material has just come out of the gastric channel.

This is a small volume regurgitate. It would have been sitting in the pharynx, and you might have just noticed a tiny bit of gurgling noise if that. And because of the dental procedure, you probably wouldn't have realised that anything bad had happened.

But that patient is having his larynx bathed in potentially quite aci material for the half hour while you finish off your dental procedure, and then you wake them up and wonder why they're coughing. So be aware of these things. Oh, and notice right lateral recumbency.

That was probably a factor in the reason why this happened in the first place. So this is one of my favourite videos. What we're doing here is we are artificially ventilating this dog, giving it IPPV.

So the red device that you can see here is a manometer. It's a very cheap one from Matins. If you want to monitor your airway pressures and you don't want to spend hundreds of pounds on expensive anaesthetic grade manometers, these are great.

And you can just lodge together some tubing with a 15 mil connector connect it up to your anaesthetic circuit. If you ventilate patients commonly and from an anaesthetic point of view, ventilating patients is actually extremely useful. Monitoring what pressure you're delivering to the patient is very good and it's not necessarily very expensive.

So 1520 pounds can get you one of these minometers. They are quite easy to calibrate and quite easy to look after. But if you drop them on the floor, you may have to bandage them out together as I've done here.

So what we're doing is we are ventilating our patient and as we get the airway pressure up moderately high, not particularly high, this patient regurgitates. So, this is him breathing on his own. And then I take over and I deliver some gas.

Boof, out it comes. 12 centimetres of water, which is what we got here, is a moderate squeeze on an airway bag. It's not very strong.

So we've caused enough squeeze to pop something out there, and that's coming out at fairly high pressure. Again, if we had this patient intubated, there's no way in hell that you would have realised that happened. And so we've got a little pellet of gastric material sitting by the larynx.

And it's quite good odds that that material's gonna get sucked down into the trachea during your anaesthetic, and that is going to give you complications, intraoperatively, potentially, but certainly postoperatively. I wouldn't want to wake up with that in my trachea. So, almost certainly that was material that had already refluxed.

This patient had been anaesthetized in a sternal position, rolled over probably into like the right lateral recumbency, and then rolled over into dorsal recumpancy. So multiple repositions, bit immaterial, sitting in the esophageal, sorry, the tracheal oesophagus. I'm gonna start that again, the thoracic oesophagus, get my words right, and then we've squeezed that chest, we've inflated, we've squeezed the oesophagus, and we've popped that material through.

So this one is a slightly more extreme event, but again, we're ventilating our patient, we're being good and we're monitoring the airway pressure. It's a big dog and unfortunately what I've done here is I've used a trough. I'm not particularly keen on troughs from an anaesthesia point of view.

They do compress the thorax rather a lot, and with a heavily muscled dog, what you tend to be doing is squeezing on the muscly shoulders, and you're putting more pressure on the chest and potentially on the abdomen, which may increase your risk of reflux. And then I forgot to support the head properly. Had I lifted this head a little bit, this may not have happened.

So here we go, we're about to start ventilating. Going up to 17 centimetres of water. Little bit surprised, and then there we go, big puddle of regurgitated material came up.

And again, this is probably material that was already sitting in the oesophagus and then as we've squeezed the thorax, this material's just rushed out. Now again, this one you would have seen and then you would have panicked over. Because we had a V gel in place here, I had the isolation between the airway and the oesophagus and I was able to continue to ventilate while I was sorting out the mess.

And screaming for my nurse. So One thing I would say here is if you have time, put gloves on, it's a mucky job. I didn't have time.

So what we're doing here is we're getting rid of the rest of the reflux. Now we're lucky enough with the V gel in place, we've checked the airway, there isn't any material in the airway, so we can be cleaning up the pharynx, the oesophagus, getting this material out. The major, major thing you want to be thinking about is getting rid of any crud that's still in there so you can't get any more coming up.

You want to be thinking about protecting your airway. Has any material, if you've got an intubated patient, has any material entered the larynx and the trachea, get rid of it if it's there. In addition to that, I think that you want to be flushing.

Ideally with sterile saline to remove the residue in addition to getting rid of the worst of the muck that's out there. Now, there is again some discussion with this. There is some work that's been completed recently that suggests that there's no significant difference between just draining and getting rid of the muck and draining plus flushing.

I would like to see quite large patient studies before I start to not clean it up because my feeling is if you've got acidic material coming up, a bit of a flush with sterile saline is probably a good idea. It is possible that flushing with a mucosal protective agents such as sacralfate may help. We don't know that for sure and you want to be thinking about giving proton pump inhibitors omeprazole specifically postoperatively.

But the big deal is if this material's coming up, get rid of it. So low intervention patients, and I'm thinking here about routine cases, neutering, dentistry, day to day general practise patients that has no particular increased risk of reflux and regurgitation. I say that with a degree of care because with close on a 50% rate of reflux, I don't think that you can say that there's any dog patient, particularly that isn't at risk of reflux and negotiation, but let's stay cheerful.

The biggest thing, think what your stomach feels like if you haven't eaten for 12 hours. You are hungry. We know that the stomach produces more fluid when you're hungry.

Common sense. So why are we starving for 12 hours? Starving for 12 hours makes it more likely for reflux and regurgitation to happen.

So that is increasing your risk, not decreasing it. The average recommendation for starvation is around about 5 hours. There's a lot of discussion and not a vast amount of evidence.

Personally, what I'm saying in practise is around about 4 hours. So, as a rule of thumb, and again this is very opinion based, you want to be feeding a small, high quality, highly digestible meal, not raw food, not dry food, absolutely not either of those. We know that that increases the gastric emptying time.

So if they're feeding raw or dry food a few hours before anaesthetic, then that will increase your anaesthetic risk. I feed the Royal Canon gastro food, other foods are probably available. And I treat it.

I don't know if anyone, anyone does this, but you know, when you send them home with cans of digestible food and say it's part of the anaesthetic, that's what I do before the anaesthetic. So if you're going to be anaesthetizing around about 11 o'clock in the morning, then you want to be giving a, an early morning feed around about 4 hours before that. Personally, I would say around about 1/3 of the normal volume, although there are some anaesthetists that give considerably more than that.

So the key point is do not starve for 12 hours, it increases the anaesthetic risk that we absolutely know. Feed a small volume, highly digestible, canned food around about 4 or 5 hours before you're planning to induce that patient. The other advantage that you're giving is that you are feeding that patient, you are allowing that patient access to glucose, which is certainly gonna help in terms of your anaesthetic recovery and probably immune system function afterwards.

And definitely with paediatric patients, you do not want to be fasting them for more than 4 hours. So if you walk away with no other information from this webinar other than that, that one's important. Intraoperative period.

If your patient is not sufficiently sleepy, technically speaking, they are more likely to realise what you're doing and react. And one of the ways that they're going to react is to reflux. So surgical plane of anaesthesia, so they are properly stable and you've got that anaesthetic properly controlled, and particularly so when you're moving them, twisting them, turning them.

Light planes of anaesthesia, or sorry, that's not correct, overly light planes of anaesthesia so your patient is twitching and moving, are dangerous. Support your patients during anaesthesia. We know that if you distort the diaphragm, you reduce the seal in the diaphragm, which is helping keeping that gastric material back.

So you supports that mould, that's why I don't like the troughs. Foam beanbags, the cruise beanbag. I would mention, by the way, when I'm doing this, I do consult the Doxin event.

I do have a commercial interest with Docsin Event and their VGL devices. I have no commercial interest within any of the other products that I'm mentioning. But I do use the Cruz anaesthetic beanbag.

I do think it's extremely good, and that's my favourite anaesthetic support for both small and large patients. Towels work quite well as well. Anything that moulds to the patient and supports it and doesn't squash it.

Raising the head slightly, keeping it in a neutral flex position may reduce the risk of regurgitation, that's my clinical personal opinion. Monitor very carefully when you're squeezing that chest, and if you're going over inflation pressures of 12 centimetres of water, which is relatively common, that will squeeze the chest enough that any reflux material may may turn into regurgitation. And when I'm saying monitor carefully, have a drain tube down there at around about the level of the heart and suction during your 5 minute checks.

And I would normally put a 5 or 10 mil syringe, ideally with a 3-way tap on the end of that catheter so that it's nice and easy to suction frequently. And most of your anaesthetics, you're going to get very small amounts of reflux fluid coming out. Anything where you're squeezing the abdomen, you're going to increase the risk of reflux.

And if you see unexpected increases in heart rate or respiratory rate that might indicate pain when you've got no real reason to suspect that that animal may be in pain, think about reflux and regurgitation. And then post-operative period. Those dogs that wake up and they're salivating and you think mm, I gave it methadone, he's probably feeling a bit sick.

No, it's very, very likely that that dog is feeling sick because it's got an oesophagus full of acidic material. If you're seeing hyper salivation, swallowing, coughing, neck stretching, don't want to eat, don't want to walk, uncomfortable, whining, these are all signs of throat pain. Very, very important.

If anyone's had heartburn, think about the pain that you can get from heartburn. That's what some of our patients are probably experiencing. Cheerful thought.

High intervention patients, these are patients that we think, yeah, this guy's probably got all the risk factors, we could have a catastrophic reflux regurgitation. We had a pug recently at my practise that was regurgitating after the pre-med, had a sort of quarter dose of ACP and that good and regurgitating. So we actually cancelled the anaesthetic and then we gave it a preoperative omeprazole and some other bits and pieces and did the anaesthetic a couple of days later.

So preoperative pre preparation, omeprazole, as far as I'm aware, is still unlicensed for dogs in the UK, but omeprazole and cisapride has been associated with decreased incidence of reflux, which is not surprising. Metoclopramide, IV bolus, CRI, has been shown to reduce incidence of reflux and regurgitation quite considerably. This next For diazepam, essentially, every anaesthetic that you give, every anaesthetic agent that you give, gives you a degree of muscle relaxation.

If you are getting muscle relaxation around your lower esophageal sphincter, components, then you are going to increase your incidence of reflux. So don't worry about thinking about which anaesthetic drugs are most likely to do this. Every anaesthetic drug is likely to do this.

There isn't a way of delivering an anaesthetic as I, as far as I know, that does not increase your risk of reflux and regurgitation. Again, cheerful thought. Be very wary about giving prep preventative preoperative oral antacids.

Because if you anaesthetize this patient with an oesophagus full of antacid and they aspirate, they can be very, very dangerous indeed. So personally, I wouldn't. If you get a regurgitation event or or personally, I would also say reflux event, pass that catheter, flush the oesophagus with sterile saline or water.

Reasons that I use sterile saline over water, and some anaesthetists use one and some anaesthetists use the other. I have a bag of sterile saline. And an esophageal catheter and a three-way tap and a syringe, or in a little bag sitting on the anaesthetic trolley, which means they are always sitting there, they are an arm's reach away.

I can get to them in moments and I can start flushing and cleaning. And it's normally much easier to take it out of the of the saline bag than it is to start running backwards and forwards to the sink. So that's why I use saline.

The other thing is if you've got damaged mucosa, probably the best thing is isotonic saline to be, to be bathing it with. But anaesthetists could use, use both. So if water works for you, crack on, that's fine.

The important thing is to get rid of that material. So suction and flush until the material is clear. If you have an endotracheal tube in place, then your priority is the airway, not the oesophagus.

So get rid of the material over the larynx and anything that's into the trachea first and then start going down the oesophagus and clearing and flushing the oesophagus. But don't stop until every single piece of the that material has been removed. You might then want to consider whether you go all the way down into the stomach and decompress the stomach, or whether you just stay in the oesophagus.

And that depends on the breed and the presentation and the length of the anaesthetic procedure and a whole bunch of other things. If that stomach is full, if the abdomen is under pressure, I would probably be going in with a large bore, esophageal tube, and getting rid of as much gastric material as I possibly could. So there's a high risk of inhalation pneumonia with these cases.

Think about antibiotics, think about anti-inflammatories, auscultation, radiographs, supportive care. There's also a high risk if you've got a large volume of material coming up of post-operative, esophageal stretchers. So you want to be thinking about giving, antacids and mucosal protectants to these dogs in the post-operative period.

Small volume frequent feeds do appear to be useful. My personal opinion is getting these dogs, dogs up and walking, so giving them frequent short periods of very gentle exercise. So just up and around the kennel room to get them moving is probably useful in settling the stomach down, but that is my opinion, not based on research.

So key points with all of this. As I said before, if you walk away with one piece of information, do not starve your patience for 12 hours. It is not making it safer, it's making it more dangerous.

It's making it more unpleasant for the animals. It's making everybody's life harder. 4 to 5 hour starvation times, small volume, highly digestible, wet food meals, and as I say, Royal Cannon Gastro would be the one that I would choose.

Careful positioning and support reduces the risk of reflux and regurgitation, maintain a good surgical plane of anaesthesia when you're moving your patients, and try not to do multiple repositionings without a good reason. So don't just randomly turn them all over the place. Think about that as an increased risk.

Try and avoid right lateral, if you can use left lateral and it'll still work, do that instead. Airway protection of some description is essential, so good, . Low volume, sorry, yeah, high volume, low pressure, cortex endotracheal tube, or a superglottic airway device and some kind of additional esophageal or gastric drainage tube.

Suction and clean that flank, get rid of all your crud. And then sucralfate, omeprazole, cemetidine, monitidine, they're all useful management tools. The dose rates that I gave you in the last slide are published dose rates, .

And then assume that this is happening on a daily basis. Look at your patients postoperatively, if you're looking at your patients and they are uncomfortable, if they are dribbling, if they won't eat, if they're whining, if they're in pain. Little light bulb in your head, could we have a reflux of regurgitation event here?

Shall we give some gastric protection? Should we give additional pain relief? Should we be monitoring this dog?

Should we be giving more digestible food? And that is gonna help you significantly. So that's me done.

I hope that's been useful to you all. Certainly it's something that when you start looking for it, you will see it. It is something that is going to reduce morbidity.

Reflux and regurgitation are killing dogs, but not very often. So referral clinicians are seeing dogs and unfortunately euthanizing dogs that have postoperative esophageal stretchers. But this is something that might happen to you once every 5 or 10 years.

What is happening is our patients are in pain most days, and that's why I think it's important. So that's me done, thank you very much. I'm happy to take any questions.

Thank you very much, Ivan. That was a brilliant talk, very informative, and thorough. Lots of great information in there.

Thank you. Thank you. I always say if there's at least one thing that people can take away from the webinar, and it's been successful, and I think there are a whole host of things there which, which people would be able to take out into practise with them.

Good. We we do have a couple of questions coming in, so to the audience, if you do have any questions, please do submit them into the box now and we'll get through them, in the time we have remaining. Question, the only thing I would say, if anyone wants dose rates, write in and we'll, we'll send them around because I have my dose rates written down and I never remember them off the top of my head.

Perfect. What's the best, contact details for that, and I'll put it into the chat box. Probably Iroota so I C R O T A Z oh actually no, the docsint one, I IC at docs invent.com.

Do invent.com. I see at docs invent.com.

Perfect. I have submitted that into the chat box, everyone, so if you do want to drop Ivan an email, you should be able to find that there. That's the first question that's come in is from Danielle.

She's asked, does the 4 to 5 hours starvation time also apply to high intervention patients? Yes, absolutely, and probably more so than low intervention patients. So you are not making your patients safer by starving them for longer, you are making it more dangerous.

The only time that I wouldn't be doing that is if I had a patient that I knew that the stomach wasn't going to empty. And then GDV dog will be the classic one. So you're not gonna take your GDV dog and muck a bit of food down there and then go to surgery, but that would be the only exception in my opinion.

Perfect, thank you, very good advice there. We have a question here from Christiana, who said, cisaprid is not available in Germany. Is there an alternative that, they could look at?

I think that you may be able to get cys applied in a special treatment authorization, but I don't quite know. I do a lot of work in rabbits and I know that rabbit clinicians in Germany can, can access Cissaroid because it's a very important drug in rabbits. .

And they are probably doing that under some kind of special licence. Let me Let me have a look at that. In the absence of cisapride, I will be using omeprazole and sucralfate, both of those available in Germany.

Don't work back in quickly enough, but. No, we'll wait and see, but that's, that's interesting information, . We can obviously, yeah, Cristiano, if you do want to contact Ivan, it's probably best if you use that email address as well and might be able to help out.

Probably the best direct alternative to Siri is metoclopramide. Metoclopramide is a prokinetic and it does work at the stomach end of the intestinal system. Ranitidine does have reasonably good prokinetic properties, but it tends to work at the other end, .

So I, I would probably go metoclopramide and that, that, CRI dosing that we were talking about is, is the first dose rate that I would reach for. But I would have a look and see if cystoro can be made available under a special treatment licence. The only thing to be aware of with .

With these, some of these drugs is that they can have, unexpected side effects. It's well worthwhile with all of the unlicensed medications. Go and have a look at the licencing that's available in the species that they're licenced in and assume that any of those side effects can be relevant in dog patients.

Perfect, thanks for that, Ivan, that's great. OK, so a couple of questions here about actually about fluids as well. So Leticia asked how about water withholding period, seeing water regurgitation.

Yeah, you're probably looking again at around about 3 to 5 hours there. So I would give a small amount of water with that feed. We don't.

I don't know if we've got good evidence that water exits faster than the soft food. I suspect that they are relatively similar. And of course if you're worried about hydration in your patient, IV fluid will be a safer way.

Yeah. Great, thank you. That's, that's really useful.

OK, that's those answered. Andre's asked an interesting question here, practically, how do you decontaminate the trachea? Very difficult.

Very, very good question, right. Not easy is the is the quick answer. So this is again personal point of view, this is what I would do if I was faced with that situation.

Get a handful of surgical gauze swabs, moisten them with either sterile saline or water until they're quite soggy. Get your hand up into the mouth, obviously hoping your patient is at a surgical plane of anaesthesia. And use those swabs to rapidly decontaminate the pharynx so that you're not getting any more material moving through.

In certain situations, if the mouth is big enough, you might be able to plug the oesophagus with one of those gauze swabs, but you'd be talking about quite a big dog before you get in that far. Providing then that the pharynx is clear of the major contamination and that we're hoping that you've got a decent quality Portex tube in place with an inflated cuff. If you have the head slightly down over the table, any further material should, exit and not go down the trachea.

It should just drop into the ventral pharynx and stay there. So we've got rid of the worst of the material from the pharynx and the periphery of the larynx. What I would then do is get a new sterile, flexible catheter, soft bit urinary catheter is probably the best thing that you can use here.

Make sure that it's got a blunt end on it with side ports rather than an end port that could scrape and traumatise the trachea as you go down. And you want to introduce that, through the erachinnoid cartilages going alongside your endotracheal tube. Very, very carefully then you, oh, sorry, I forgot to mention, I've lubricated this catheter with a water-based lubricant before I've placed it down there.

So I'm, I'm going down alongside the ET tube. I'm very gently suctioning as I'm going, and I'm suctioning up any puddles of material working around the periphery of the ET tube and up and down. And you're trying to go down to the level of the tube cuff.

If I've got either no material or very, very small volumes of material, then I might not wash at that stage because the risk of washing is that you might be forcing material past your cuff. If I had a large volume of material going through, then I probably would be very gently flushing with maximum. Probably maximum of a mL of sterile saline and then aspirating it straight back.

And obviously if I had the time, this would be warm sterile saline, but you're probably not gonna have the time. So the key point is suction it out first and then flush afterwards, but I probably wouldn't take the risk of suctioning unless I had a decent volume down there. So far, every regurgitation event that I've seen has not involved gross tracheal contamination.

So at that point, I've checked, but I've not needed to do much suctioning. My suspicion is that if this is at the top of your mind as an anaesthetist or as a surgeon, you're probably going to identify it more at the reflux stage than the regurgitation stage. And it's quite common then that you'll be able to pick it up from the oesophagus and not see the regurgitation event in the first place.

Or if you do see it, you'll be able to act within seconds rather than that several minutes later when the regurgit's been sloshing around the pharynx for a while. So you being aware of it is probably going to decrease the risk considerably. Mm.

Is that, is that the level of detail that you need? I mean, that's excellent. It's a great question and a very thorough answer.

I think that's great. Thank you, Ivan. OK.

Just the final question we have here then. Michelle's asking, please can you clarify why light, excuse me, I put my teeth back in, right lateral recumbency increases the risk of regurgitation. Yes, absolutely.

It's, it's, it's a good point. So the diaphragm muscle is in two halves, one on either side of the chest joining up in the middle, separating off the chest from the abdomen. Actually, I'm just gonna go back.

This is a lateral view and we're just in the left half of the diaphragm, so that you've got one big sheet of muscle on the left and one big sheet of muscle on the right. The left hand side is a weaker piece of muscle than the right hand side. So Whatever side you turn this big heavy dog onto is getting squashed.

And when things get squashed, they don't work properly. So if you turn the dog onto the left hand side and squash the left hand half of the muscle, the left hand half of the muscle is weaker, and it wasn't really contributing that much to your seal at this point. So if you put them onto left lateral recumbency, you have less of an effect on the seal.

If you turn them onto their right hand side. The right hand side of the diaphragm is stronger than the left hand side, so if you squash the right hand side and stop it working, it's gonna have a bigger effect on your esophageal seal. Does that make sense?

Mhm. OK, so under ideal circumstances, if you have a choice of putting this dog on its left-hand side or it's right hand side, you're a bit better off sticking it on its left hand side. Perfect.

Oh, that's a great answer, thank you, Ivan. Quite how much difference that makes in practise, I don't know, but that's, that's the, that's the decision that I tend to take. Excellent, very useful once again.

There's been, as I say, a wealth of very useful information in this webinar, so we thank you very much for that. Pleasure. I believe that is all the questions we have.

So there's a couple of comments coming in saying thank you so much for a brilliant webinar, all very positive feedback, which is always lovely to see. That's always nice. So yeah, I'd like to say thank you very much to our speaker tonight, Ivan Krote.

It's been a pleasure and we've really enjoyed the the webinar. Good. Thanks to everyone for joining us, and we'll see you on another webinar soon.

Thanks and good night.