So this is a little bit shorter, so this is kind of made to kind of go with the other ones so they go together in time. So this is a kind of a shorter case study that talks about kind of smoke inhalation and dermal burns because I think this is something that I get a fair number of, I mean, we don't see fires all the time, but I get, I get a fair number of calls for consultation with vets about, you know, I got this case here was in a house fire. What the heck do I do with it?

This is kind of designed to kind of touch on the key points here. So, we'll start off with just a case. Her name is Dixie, who is an approximately 8 or 9 year old shih-tzu who was kind of found near church about 12 to 24 hours prior to us seeing her, and Good Samaritan had picked her up, bathed her because she was covered with like certain things from having been exposed to the fire, fire either maliciously or not maliciously, we don't know, and then she was brought to the Humane Society who brought her over to us.

So this is how she looked on the news because it of course made the news that someone had found this poor little dog. So when she presented to us, her temperature was normal, heart rate was a little bit fast at 172. Respiratory rate was 56, and of course, as you can see, there's about a bunch of singed hair present on her face.

You can see the hair is kind of burned between her eyes. And things, you could see some burns around her muzzle around kind of the upper eyelids, and there was some similar kind of pinkish skin where there was some heat exposure on the neck and things as well. Her fur was largely matted, you know, the fur that wasn't wasn't cleaned off of the Good Samaritan has some mats in it, and she did smell strongly of smoke.

And even though her respiratory rate was not too bad at 56, she did have, abdominal breathing and increased effort. I wasn't there when she first came in to get a video, unfortunately, but you can imagine. OK, so, when you look at her, obviously just kind of grossly I should say one more thing, you notice that her eyes, you know, obviously look very abnormal and definitely there was some heat exposure near the face.

So they did make sure to do an ophthalmic exam when she first came in, and she had corneal edoema OU, so you could see kind of the bluish tint to her eyes. And the intern was on. She came in at like, I don't know, 1011 midnight type time frame at night.

And so the intern who looked at her placed some fluoresce stain in the eyes, didn't see any uptake in the eyes, and so, she kind of looked kind of like this type of appearance where she had kind of a diffuse kind of staining type scenario. This is some of her mucus obviously that was stained, but no discrete obvious, obvious ulcer at that time that the intern could call. And you can get a little bit closer look at how her skin looked and how it looked a little bit burned and the singe fur and all that in her photo as well.

All right, so kind of pausing right here when you have an animal's exposed to smoke and or fire, yeah, yeah, you're gonna ask yourself, you know, is there dermal injury associated with the heat exposure? And if there is, how deep into the skin is the dermal injury? So you know, you've everyone's heard of like, you know, you can classify burns based on like degrees 1 to 4.

And so just briefly, you know, first degree burn is the least severe and that it's just going to cause redness and swelling of the epidermal layer. When you go all the way down to like 4th degree burn, that's when you can actually burns are extending down and like you're sending the bones and the bones are actually burned, and then the ones, you know, degrees 2 and 3 fall in between. The 2nd degree burn will be the one that's got the redness as well as the blisters.

And then when you start to see the skin looks whitish or black or even looks like it's, it's charred, like it's dying type skin, dead type skin, that's gonna be more of like the 3rd degree burn type scenario. And again, it all has to do with whether or not it's just the epidermis, it's going into the dermis if you're 2nd degree, if your 3rd degree is at the very bottom of the dermis, almost to the, you know, almost down to, you know, past the skin level to where the bones and such are hitting into the sub cube. And the other thing, the other, the reasons that the degrees are important, there's a couple of reasons, but 2nd or 3rd degree, one of the big things you want to identify right away if you have those deep of a burn, that that depth of a burn, those animals can suffer from hypovolemia.

And remember the skin is going to be the layer that protects the body from losing water. And if you burned away enough of that, you're going to get a great amount of water loss and hence comes the hypovolemia. Dixie was a first degree burn because she just had the epithelium was largely intact.

There was redness to it though because it had been damaged by the heat. So we didn't have to worry about hypovolemia in her case, but the higher degree burns you might. The second question you ask yourself is if there is dermal injury, how much of the body is involved in the dermal injury?

And so, you know, we kind of veterinarians take this body burn injury chart that they use in humans and kind of adapt it over to dogs and cats. So essentially what you do is you say, OK, where are the burns, and you know, are the burn and you add the percentages together. So in Dixie's case, she had burns mainly to the front side of her.

Head, which is probably somewhere about a 9% of her body is, is that area. So kind of burn head neck, face, she probably had somewhere, you know, less than 10% of her body surface area had heat exposure and some burns to it. Let's say she had her chest area as well.

You might add, you know, 9 + 18 to give yourself a 27%, you know, surface area exposure, and that's how you kind of use the chart. So you use some kind of modification of this. Obviously, probably there's a little bit more in the arms, obviously the rear legs in a dog or a cat are bigger than the front legs, but probably, you know, it's not quite the differential like like where the arms are half of the surface area of the legs as in a human, but nonetheless, you can modify the chart and get a rough idea of the percent of the bodies involved.

If there's more than 20% of your body of surface area involved, you worry again about hypovolemia just due to the amount of surface area, and, and, and then of course you're gonna worry again because the amount of surface area is more evaporative loss. Dixie though was less than 20% because it was just, you know, somewhere, something less than 10% was where she was. The other, the other reason that you ask yourself about, you know, depth and and degree is you also have to ask yourself, is there a reason why I might need to use systemic versus topical antibiotics?

In general, people, you know, advocate using topical antibiotics until unless you're forced to not use topical antibiotics in a burn victim. So reasons that you may need to think about systemic antibiotics would be things like I have such a humongous portion of my surface area of my body. Affected that I'm gonna need to have, you know, antibiotics.

So, you know, more than 20 or 30% of your body's surface area you may think about systemic antibiotics instead of just topical, but otherwise, especially if you're less than 20% and the burns are very shallow, so first degree or maybe high second degree where there's some blistering and and such, but not any worse than that, you often are just gonna use topical antimicrobials, and most of the time what you end up treating is pseudomonas, which is gonna be the bacteria present on the surface of the skin. And the other thing to think about with dermal injury is they are going to be painful no matter what, and the more of your surface area and the deeper the burn is, the more painful you are until you get to a 3rd degree burn. When you get to a 3rd degree burn or deeper, you actually burned away the nerve endings, and there actually is not pain associated with the burn itself.

There can be, you know, so the area where the 3rd degree burn is is not painful. If there's adjacent skin that has a 1st degree burn next to that, you know, let's say, you know, you're hit with something, you know. A pointed thing in that area where the pointed hot metal touched you with a 3rd degree burn, you can still have associated burn around it that's like 1st degree.

That would be painful. So you have to kind of think about how much pain they're going to be in and how much the body is going to be painful, and then adjust accordingly with your analgesic plan. And again, most of the time we're going to at least be starting off with opioids, especially if we're concerned about hypovolemia, at which point we're going to avoid nonsteroidal anti-inflammatories until we get the hypovolemia under control.

All right, now the other thing to ask yourself is I've got my burn. I've kind of categorised my burn. If I, if I, you know, now was there smoke inhalation or not.

So was it something where like the animal was burned on a heating pad and there's no smoke inhalation? Or was it the cases with Dixie where there definitely appeared to be some fire related because she had burned, you know, her fur was actually she smelled like smoke. So in that kind of scenario you're worried obviously if there's smoke inhalation, especially because it burns are around her face, where you're going to be worried that there's more exposure to smoke.

And so carbon monoxide is your number one thing that's found in smoke because that comes from burning of carbon. So house fires with wood, anything with wood related carbon, you're going to think about carbon monoxide. And the deal with carbon monoxide is it likes to bind to haemoglobin, and it takes the oxyhemoglobin curve and shifts it over to the left, and when, when that happens, you end up having less oxygen available to go to the tissues because the haemoglobin is being very greedy and holding on to the oxygen and not letting it go.

So you end up with these cherry red mucous membranes for two reasons. Number one, the haemoglobin is gonna have carbon monoxide binding to all of its sites. So anytime haemoglobin has anything binding to it, whether it's oxygen or carbon monoxide, when you shine light into it, it looks red to our eyes.

So because carbon monoxide is such. A great job binding the haemoglobin. The mucous memories always look really, really pink.

The other thing is, because the haemoglobin is so greedy and is holding on to oxygen even more than it normally would, it keeps oxygen bound to the sites as well. And again, the more sites that are bound on haemoglobin, the redder it looks to us, regardless of what it's bound to. So here's kind of your oxyhemoglobin curve, and again, here's the, the oxygen in the blood PO2 and then the oxygen bound to haemoglobin.

And so the normal curve is gonna be black. We shift to the left when we have carboxyhemoglobin and again, that's gonna be your scenario, that's like the foetal haemoglobin that's redient holds on to oxygen more so. All right.

And because you shifted to the left, it's also harder for you to take whatever action you have and to give that up to the tissue beds as well. So you've moved everything over to the left, so you're really greedy, you're holding on to it and there's less in circulation in your bloodstream. OK, other things you can inhale and smoke hydrogen cyanide, and that's from burning things like wool, silk or nylon.

So again, if house fires closets where there's clothing, you might see stuff like that. The problem with hydrogen cyanide is it impedes cytochrome oxidase in the cells, and as a result, you can't do your oxygen transport chain very effectively. So your tissues have a really hard time using oxygen that comes to them.

So the tissues themselves are hypoxic even if you got oxygen to them because they can't make use of the oxygen that's there. All right. Other things you're gonna worry about is thermal injury and inhalation of particulate matter.

So this, if you have smoke coming at your face, there's probably heat associated with it most of the time. And if so, with thermal injury, it's gonna damage the larynx and the oral pharynx. You're gonna get edoema of the mucosa, sloughing of the mucosa, even the tracheal lining can slough up.

And so this particular cat here was, it's not like we live in the worst part of the world here, but there was another malicious incident with someone torturing this. Cat right here you can see his poor whiskers are burned away and all that, and this cat had a quite a bit of mucosal edoema associated with the smoke and inhale during this kind of a burning event. And in humans they actually talk about the sloughing and this is the tracheal lining sluff that the that the lining sloughing is so bad that they'll go in and scope out the sluff tissue because it actually includes the trachea and the bronchi.

And so they they just pull out these big sloughs of tissue out of out of human patients who are caught in fires. Also, again, you can inhale particulates. So if you inhale a lot of stuff, you worry that it gets into the lower airways and so potentially it's gonna affect your ability for your, your lung appliance or your lungs become stiffer, your lungs can also collapse if there's a lot of particulate matter and it also sets the lungs up for having more likelihood of pulmonary edoema.

So the mucociliary elevator that lines the trachea that should take those particles and go up with the particles actually becomes damaged by the particles and the heat and the edoema and the tendency to fluff, and so it's hard to get those particles up and so the stuff just sits in your lungs, causing trouble as well. So you know, all these things together can kind of set up a negative situation in the lungs. The concern is when you have the dead tissue, the trap, you know, the dead tissue, the particles, that bacteria is gonna get trapped down there as well, and that's gonna cause an increased risk of pneumonia.

So between the fact that your normal things your lungs would do to protect themselves, the mucociliary elevator, the fact that, you know, it's. To get particles down in the deep, deep airways. That's the normal protection you have.

If that protection is gone because of the heat and or the smoke you've inhaled, then you're gonna worry that this patient is gonna be set up to get pneumonia, and you know, that's gonna be a, you know, pneumonia to compound things and make things worse. So good old Dixie, we were worried that there was a risk that she could have pneumonia. The other big differential I should throw is they can get pneumonitis, which is inflammation of the airways without associated infection, and that's always going to be the trouble is do they have just a pneumonitis or do they actually have a pneumonia developing?

And so with Dixie, these are the X-rays we took of her chest the first night when she first presented. And so she absolutely has an interstitial to potentially alveolar pattern up here and kind of the right. Right cranial lung lobes, right cranial right middle lung lobe, but she definitely has it, well, you know, velar pattern, definitely a pretty strong interstitial pattern as well.

And so the question was, is this just pneumonitis because the Good Samaritan had her for a couple of hours before she went to the Humane Society and then she came to us. So there was definitely a time delay in which you could see radiographic changes with just inflammation, or was this the fact that we're actually starting to see pneumonia showing up in her and that was the big question the first night. So you got the scenario, how do we treat this dog, right?

So obviously oxygen is gonna be your ##1 thing, #1 thing, number one thing, even though they're not disc when they come in, you give them oxygen. The reason you give them oxygen is it reduces the half life of carboxyhemoglobin. So it takes that abnormal haemoglobin, which is binding to carbon monoxide instead.

Of oxygen and it and it allows that that haemoglobin to release the carbon monoxide more effectively and then bind to oxygen instead, which is what we want because then the oxygen gets the tissues. Also we're able to metabolise and break down the carbon monoxide faster so that there's less of it available to give to the, to give to the to the haemoglobin. Cyanide is gotten rid of more quickly as well.

It's also good, so we want that as well. And some people believe so strong actions they think hyperbaric oxygen chambers is the way to go. And if normally the half life of carbon monoxide is like 6 hours in normal room air, it goes down to 60 minutes in in just just giving supplemental oxygen, right?

And that's if you gave 100. Oxygen it would go go from 6 hours to 60 minutes if we're giving something like 40% oxygen in a cage, I would imagine you go from 6 hours to 2 or 3 hours as far as your elimination time. So definitely oxygen helps even if they're not distant you absolutely want to put them in oxygen.

So usually we would put them in action for the first night or something like that, the 1st 12 to 24 hours, something like that. And actually could be given as we said before in the last talk to these prongs you can give oxy through a nasal cannula. You can put them in an oxygen cage.

I don't really care. Just give them oxygen however you want to give them. And so little Dixie went in an oxygen cage, and of course, oh, I, in case you were in my last talk.

You can always take your cat or dog carrier, stick your oxygen tubing in the front of the carrier, put a plastic bag around it, cut a hole in the back and voila, you've got temporary oxygen cage for them as well. So anything you need to do to get them oxygen is like the number one most important thing that you could do with these guys. OK.

Now, blood work, so the question was now, so we had her on oxygen, little Dixie. The question now was, did this dog have pneumonia that we need to treat or does she not? And so basically we did a CBC chemistry to try to help us out.

And so she had a neutrophilia, but it's fairly mild. She did have a little bit of a left shift as well, was fairly mild, but it was there. Question was, is this infection or inflammation, and it was kind of hard to tell.

She did not have her temperature was like 100.6, so she did not have a fever. Chemistry panel is pretty unhelpful, just elevated ALT and ALP, so nothing too terribly helpful for this setting.

So you know we kind of had this yes or no kind of conversation going back so things that would tell you, maybe she really did have pneumonia. She absolutely had burns to her face so she probably had smoke inhalation. We know what that does to macrophages that the macrophage and the and the layerways don't work as well.

We know we've got all those changes to the lung. You've got all those changes to the to the defence mechanisms in the lungs. All those things are gonna set us up for bacterial colonisation.

All those things, and Dixie, you know, probably had all that going on, so that would make her more likely to have pneumonia. She did have the left shift and she, we did have the lung pattern. So that was kind of in our pro column.

And our negative column was, well, pneumonia is usually secondary like, and she didn't have anything in addition, like she didn't have intubation, you know, because she has smoke inhalation. She didn't have a tracheostomy. She didn't have any dermal burns that were terribly infected that will lead to sepsis.

And usually it takes a better part of a better part of a day. To see a true infection showing up and we weren't really exactly at that time point we didn't think so that was kind of in the no column for her. Also, she didn't have fever and the inflammatory changes we saw were fairly mild.

So there was this debate as far as like what should we do? Should we give her antibiotics or not? What would make the most sense back and forth.

And so the problems we ended up having where she had the first degree burns the face and neck. She had the lung pattern, and then she had the corneal disease. So we ended up giving her our treatment plan we decided, and, and I will tell you why this first thing don't do it.

We ended up giving her topical prope cane overnight, Q4 hours because the intern, and this is where nobody was in the building with the intern, and I'll admit that when I was consulted, I didn't even think about this, but she was taking the eyes. Are painful, which they were probably because there was definitely stain uptake, and she gave a topical anaesthetic, which is, which is fine. However, ophthalmology came and slapped our wrist the next day because proparin actually slows corneal healing, so that was really bad that we did that.

But so don't do that. Don't do that. One time to do your test and we're done.

So, what we should have done and what we did not do is put her on some kind of systemic pain medication and I don't know why. I, I, I'll take responsibility. I don't know why I didn't think about that when she called me, but it escaped my mind when we were talking.

The animal was in the oxygen cage. We did pulsize her for curiosity. She was running a little bit low at that time, and then she, we started her on eventually we decided to start her on antibiotics, partially, the Humane Society helped us to make the call because they said that they really would like to minimise their hospitalisation time, obviously due to funding as much as possible, and they would rather that we kind of, there was pneumonia start treatment now rather than waiting till it got worse.

So we started her on, ampicillin and sobactin as well. Next day ophthalmology looked at her and actually what was mistaken as just kind of a diffuse superficial corneal ulcer was actually very severe denuding of the corneas bilaterally, and she had, I mean, yes, they were they were superficial ulcers, but they were humongous ulcers, and she actually on the left eye had this stromal. Ulcer as well, so her eyes were more significantly affected than had been appreciated on the overnight.

Obviously there was a corneal edoema, we knew that and she was blind on both sides. She had a cataract in her right eye, which was obviously preexisting, that led to the blindness, and they couldn't see what was going on in the left eye, but she maybe there was a cataract there as well, who knows. So she was switched to Topical Neopolybaitracin Q6 Hours, topical serum Q6 hours for the ulcers as well, and then they had us doing artificial tears to keep our eyes moist as well.

We also, you know, started her up on injectable antimicro, sorry, pain medication, sorry, and that was both for the eyes and the skin, and then we tested her out of oxygen because it had been about 12 hours now at this point, and she did seem to have increased respiratory effort outside of the cage, so we put her back in and honestly, probably that's gonna be in her case, an indication that we probably were dealing with more of a true pneumonia rather than just the smoke inhalation because of the persistent need for oxygen over a 12 hour period over more than 12 hours. While she was in oxygen, she pulse acts great. When she came out of oxygen, she definitely was dropping as far as pulse oximetry again.

That to me led more cre the fact that we were probably dealing with pneumonia as well rather than just the pneumonitis. And we did a blood gas and she was hypoxemic as well. So we took more radiographs because that's what we do at the university, and she still had a pattern present.

It was a little bit more alvear actually on the right side, which to us also was like, well, it probably is more consistent with this being more of a true pneumonia because pneumonitis should start to look better or been static rather than progressing and getting more ovular. So we continue on the episode subb and we add an and refloxacin as well for this presumed pneumonia that she had. And on the 3rd day, the next day, she was tolerating room air.

She was pulse acting normally at room air, and we were able to get her out of the oxygen cage. And we're at the university. We must take more X-rays.

So we did. So here's how she looked. I wouldn't not have necessarily taken these, honestly, but this was more of a we were curious and we paid for it, out of our department.

And so the alveolar pattern is becoming more interstitial, which we, we felt like that was indication that things were getting better rather than getting worse, as far as her condition and clinically she was way better, of course, as well. So, she actually went, went to the Humane Society that evening on the lavamoxin and refloxacin. She's on tramadol and carprofen for skin slash eye discomfort and same eye medications they had her on before.

And she ended up going to a foster home, which is a couple of vet students. I got some good pictures. This is her kind of initially at the foster home, and over time she started to look better, and they were treating her eyes religiously the way they were supposed to.

Unfortunately, the left eye, though, the stromal ulcer, stroma ulcer never healed, although the right eye and all of her skin did heal, and so they nucleate the left eye, but she didn't really care because she continued to look better and better every time we got a new photo on how she was doing. And eventually she was adopted by a couple of folks in the community, and you can see that she's really enjoying her new her new owner, and she doesn't want to go back to where she came from. So she ended up doing very, very well.

So she healed very completely like any first degree burn will heal very completely and normally like this. She's a great example of that. And other than the Losing your left eye, her right eye healed up great.

She actually did very, very well. So that's kind of in a nutshell how you approach one of these cases. So does anybody have any questions?

Brilliant, thanks, Liz, that's that's great. I, pace actually had a house fire when I had, well, when I first had my golden retriever and and he suffered from a bit of smoke inhalation, so no, it's yeah. Yeah, yeah, he was, he was very lucky though, it was just a bit of mild smoke inhalation.

. Henrietta's asked, she said hyperbaricco 2, she said the two atmosphere is generally described as toxic. -huh. That said, that's sort of a problem.

OK, so the so the question is, is it toxic to do hyperbaric oxygen? Is that what that what she's asking? Yeah, at two atmospheres.

She said it's. So I'm, I have to preclude I've never used hyperbaric oxygen in my life, so I have no idea what the setting would be. I will tell you that straight, straight up.

So I can't answer that part of the question. I will tell you that if they do hyperbaric, I, I, my understanding is, you would do like one session of hyperbar. Auction treatment with these guys and and within that one session, which is probably like 15 to 30 minutes max, I don't think it's that long, you're able to displace all the carbon monoxide and then you don't need to do it again.

But I honestly have no idea what the setting is. I'm sorry. I can't answer that part.

It's all right. Someone else has asked, is there a specific, time range for keeping the dog on oxygen, or does it depend on severity? So time rates for us.

So I would say minimum I would keep on oxygen because we know that 100% oxygen displaces carbon monoxide, you know, the half life goes from 60, 6 hours to 60 minutes, and so it depends on how much oxygen supplementation. So if you're doing like an oxygen cage and it's 40%. You probably need to do at least 2 to 3 hours minimum for one half life and usually we, we recommend doing, you know, 3 to 4 half life, you know, to get rid of the CO, you know, so if it takes 2 to 3 hours to do one half life you're probably looking at something 9 and 12 hours something like that.

So it's not so much a severity, it's more just the having a half lifetime. So I think your bare minimum at 40% would be like 12 hours. If you were doing a lesser percentage of oxygen, it's longer.

If you were doing a higher percentage of oxygen, it would be shorter. That so it's more the oxygen percentage rather than the the severity of the of the smoke inhalation. So most of the time.

Our rule of thumb is somewhere between 12 and 24 hours because we usually have them in the 40% oxygen cage, and we know that we keep opening the cage and then it drops every time we open the cage you do some of the animal, it drops down from 40%. So we know it's not 40% all the time. So we usually err on the side of like a little bit longer, like closer to 24, something like that, so.

Brill. And er Christine's asked, is there a maximum time? For, staying in oxygen?

Yeah, for an oxygen cage. No, there's no maximum. I mean, as long as the only time oxygen is really toxic, toxic other than hyperbaric is when they're at 100% oxygen for, for more than like, you know, 8 to 12 hours.

So if you're doing 40%, 30%, even 60%, you, you can say days upon days if you need to. So you know, I would say minimum would be your 12 to 24 to get rid of the carbon monoxide. Dixie ended up staying in for about 48 hours before we took her out.

So, and we'll have animals and oxygen in ICU for days and days and days if they need it. So there's really no end point. As long as, you know, if they're intubated 100%, that'd be the only time I would say that that could be bad after more than a day or so.

So. Mm. And Eileen's asked, what topical treatment do you use for burns?

Oh, I didn't have to put that in here. I forgot, I forgot to mention, I should say, yeah, so usually the topical antimicrobial is gonna be like silver sulfurdiazine is the number one choice, and that's gonna get in almost all cases that'll be good enough for you. There's another thing called, God, I just forgot the name of it.

There's another topical that they'll sometimes use if you end up having resistant bacteria growing, but that is very, very few and far between for our animal patients. So it's almost always like 99% time silver sulfadiazine. And if you do need to cover.

Cover like if you do put silver sulfadiazine on if it's more than a first degree burn, you always keep the burn covered to try to prevent the evaporative losses through the skin. So just have a nice moist bandage, so you have silver sulfadiazine, non-adherent dressing, and just keep it nice and moist under there, for as long as you need to the skin heals, so. Brilliant.

OK, so we've got just just over 1 hour left for the 3rd and final presentation from yourself, Liz, if you want to get that ready and then we'll, we'll dive straight into that.