Hello, good evening. I'm Natalie Winarillaga and I'm gonna be presenting a webinar on analgesia and anaesthesia in reptiles today. I'm a, Diplomat and zoo medicine, with a specialty in reptilians through the RCVS, and I'm an RCVS recognised specialist in zoo and wildlife medicine.
I work in first opinion and referral, exotic and zoo practise at Chipping Norton Veterinary Hospital in Oxfordshire. As you can imagine, analgesia and anaesthesia in reptiles is a massively broad subject, because of the variety of species, the different taxa, and, we will just be discussing the basics to hopefully give you a foundation, to get you started. So, pain recognition in reptiles is really a little bit difficult.
We do know that reptiles do feel pain. There have been studies that have demonstrated that most nociceptors, nociceptors found in mammals have actually also been demonstrated in reptiles, and they have got well-defined pain pathways. However, the problem is that we do have a lack of knowledge regarding species-specific behaviours, and so, therefore, the changes in behaviour that they might exhibit when they're feeling pain.
And also we know that we keep reptiles in very restricted environments, so they might actually be, some limitations in their ability to express. Normal behaviour and therefore also express abnormal behaviour. So, pain recognition in reptiles can be daunting, and can be tricky.
In other more well-known species, and even in some of the exotic species like your rabbits, we have well-defined, facial grimaces schools. Or ehograms. We don't have that in reptiles, so that makes our job a little bit more complicated.
However, I would like to stress that that does not mean they do not feel pain. We are just worse at actually recognising that. So just going into that in a little bit more detail, we tend to use sort of 5 overall concepts, in reptile pain behaviour.
So we will be looking at changes in physiological parameters, so we can look at changes in heart rate, in respiratory rate, and those might all change when a reptile is feeling pain. They also might express behaviours to defend them from pain, so nose offensive behaviours. And these are things like limping to protect the leg that is painful.
They might be expressing decreased range of movement when they're walking. There might be changes in skin colour in an area that is painful, and this particularly happens in species like chameleons. Another thing that we might notice is actually a decreased interaction with their environment.
So they might be using their environment differently, and this might, show up like a decrease in basking or a decrease in social interaction if there's a species that are kept with, other con specifics. We might even see social aggression if, they're painful, or we might see that they are hiding more, they're burrowing, we're not seeing them as much. So also it's really important to sort of discuss with your clients how that reptile is behaving, how well they know, their patient, and, really ask the right questions, because those might be things that they haven't really noticed, but on using the right questions, they might actually say, oh, yeah, actually, you know, he is, he normally is in this side of his enclosure and now he doesn't go there.
So that's a really useful tool that might give us some indication that that reptile isn't feeling very well. We can also look at changes in mentation, so they might be quieter, they might present obtundid or even moribund. So, the two pictures at the bottom, we can see, on the left hand side of the screen, we can see a, silkatta tortoise that looks quite happy, and is obviously, mounting his friend.
So I would say that that reptile looks or appears to be behaving fairly normally, whilst as if we look at the bearded dragon on the right hand side of the screen. The position of its body isn't right, it's really flat, it's not lifting its trunk, its eyes are closed, its mouth is half open. So if you look at that reptile, you can see that there is something wrong with him.
However, that also relies, in us as vets, knowing what is normal for the species. And that, again, can be tricky because of the variety of species that we might be presented with. So it's really important if you're gonna be seeing reptiles, to sort of become familiar, with what is normal for different types of reptiles.
Another thing that might change is their feeding behaviour, and they might be eating less, if they're feeling unwell or in pain. And obviously something that is quite logical if we think about it, is, does this reptile return to normal once we give it some pain relief? So, you know, if we can't find anything at all, but we still think there's something wrong, it might be, that we try it on some analgesia and see if that behaviour, changes.
So most of our reasoning for providing analgesia in reptiles, will be based around extrapolating from other species. So things that we know are gonna be painful, in a more familiar species. We extrapolate that to a reptile, and we give it pain relief.
These behavioural changes that we have discussed earlier. Also, if we are a little bit more familiar with working with reptiles, we might have, anticipated levels of pain based on our prior experience. And also we need to rely on the physiological changes as those will change when the animal is in pain.
So, in terms of, treatment of pain, so in the past 20 years or so, there's been an explosion of published reptile analgesia information. However, despite that, we still don't know a lot, and we should really endeavour to learn every day and change our practises accordingly. So the administration of analgesia should really be considered, in my opinion, a standard of care.
Both in terms of preemptive analgesia as well as multimodal regimes when we go, to, do surgery. So in terms of what evidence-based data exists, and is this actually directly applicable to my case, and that can be tricky. For instance, there are quite a few studies on efficacy of new opioids in Reddit sliders, and there's, pharmacokinetic studies on meloxicam in turtles, for example.
But does this actually translate to the patient I've got in front of me? Because although it might still be a turtle, it might be a completely different turtle, and they might be, metabolising and using the drugs completely differently. So, That becomes, becomes difficult.
And, and actually, we, we know very little, about snakes. So that is still an area that requires a lot of, of study. In terms of choosing, administering and actually understanding the analgesic use in reptiles, we, we have many challenges.
First of all, there's like an enormous diversity of species in the class reptilia. We have 4 main orders, but with over 7800 species worldwide. Second, they present a huge variation in anatomy, physiology, and natural history between the species, and things like understanding their preferred optimum temperature zone will be really important.
And thirdly, we need more research into effective analgesic, dose dependent effect, duration of efficacy, interspecies difference and potential side effects. And really just as a word of caution, we must be very careful with anecdotal information that might really rely on a single case report and in, in reptile medicine, there's a lot of that. And we might just be reading, you know, one person that gave this one drug or this dose to this species, but that might not be, applicable, at all to the species we're dealing with, or, it might actually cause harm.
So moving on to how we'll be be giving these analgesics. So, as we have sort of already alluded to. There is a lack of pharmaco, kinetics and pharmacodynamic studies.
There are different sizes and temperaments of individual reptiles. So although we have all the roots, in, in, in the box, it might be that the particular reptile that we're dealing with. We can't give something or or to because, it might kill us, or, you know, we might not be able to get an IV on it because it's super small.
And the environmental temperature, will be really important as well. So, drug absorption, distribution and metabolism, and also excretion are all affected by body temperature. So if we are keeping, that reptile at a higher temperature, this will lead to an acceleration of the, the processes, whilst lower temperatures will result in a delay in drug absorption, distribution, metabolism, and excretion.
So in terms of what routes we would use, historically, we always thought that the intramuscular route was superior to the subcutaneous routes. However, for most drugs that we administer, the subcutaneous route, would be my preferred method. I find it's less painful.
It allows delivery of, larger volumes, and it can be performed with less restrain than intramuscular injections. Obviously, we have got the IV routes, although that can be challenging in some species. Intrasalamic is also described, in, in various papers.
It's not that well documented. We don't really know a lot about absorption rates, etc. And also we need to, bear in mind that there is risk of organ damage if we start injecting into the sum, particularly in the smaller species.
Orally is definitely, a good route, if that is possible. And things like Tramadol, we know, are well absorbed and distributed, so that is definitely a drug that I give orally quite often. And then there is a few papers on the use of, transcutaneous fentanyl patches, particularly, in snakes, but I think there is definitely, some more work to be done, on that.
So, what we, I wanted to take this opportunity to talk a little bit about the renal portal system because we do know that blood flows from the tail or the caudal vein and from the hind limbs, both the iliac and the femoral veins, to the kidneys, into the tubules and then to the heart via the post cable vein. So reptiles don't have a loop of Henley, and therefore, cannot produce hypertonic urine. Therefore, once you have a reduction in, water loss, sorry, therefore, once you, to decrease the water loss, what they do is they decrease glomerular filtration.
And through the action of arginine vasotosin, the blood flow through the glomerulus stops. And the renal portal system then continues to supply blood to the tubule cells and prevent basically ischemic necrosis of the kidneys. And although this is a really good adaptation, it might have implications for drugs, administered into the, quarter half of the body, especially, nephrotoxic, nephrotoxic drugs or drugs that actually undergo, tubular secretion.
However, blood can also be diverted around the kidneys, and therefore, the true clinical implications of the renal portal system are actually still not that clear. There is a really good, paper by Peter Holt on, anatomy and physiology of the reptile renal system, in vet clinics of North America, if anyone is more interested in that and, and wants to go into that, a little bit deeper. The other thing that we need to think about is the hepatic first pass, and, in contrast to the massive amount of attention, that we've paid to the effects of the renal portal system and drug kinetics, the hepatic portal system and how the venous vasculature differs in reptiles compared to birds and mammals has not really received much attention in the literature.
But in fact, it probably has a much greater clinical impact, than the actual effects of the renal portal system. So, we know that the blood flows from the tail and the hind limbs, drains, into the ventral abdominal vein, and this then connects to the hepatic portal vein, and drugs will then reach the liver before they actually reach systemic circulation. So, hepatic first pass, will have an effect if the drug undergoes hepatic metabolism or excretion.
But we need to remember that the ventrococcygeal vein doesn't go into the ventral abdominal vein. So it will actually be OK to use IV anaesthetics and opioids, and we'll, we'll go back to that, in a little bit more detail when we, discuss anaesthesia. So, really, it cannot be assumed that high limb injections, is a generally acceptable or unacceptable drug administration method in in reptiles.
Drugs that are metabolised or excreted predominantly by the liver will undergo hepatic first pass effects. And these will include things like opioids, most anaesthetics, oxytocin, so drugs that we use fairly frequently. And therefore those should not be administered in the quarter half of the body.
However, in contrast, drugs that do not undergo a significant hepatic first pass effect, so things like fluoroquinolones, many cephalosporins, aminoglycosides, etc. Can actually be administered in the cordal body, half of reptiles without concerns about altered drug kinetics. So, it, it's quite complicated, as you can see, and I would suggest, sort of going into the literature a bit more if you're, sort of unfamiliar with these, both those systems.
So we're gonna move on to, the different kinds of analgesics that we can use in reptiles. And first of all, we're gonna talk about the opioids. So we know that new opioids, provide effective analgesia, in most reptile species, except in snakes.
And we also do know that one of the main side effects of opioids and reptiles, like in other species, is respiratory depression. Which in most cases is dose dependent. So we are gonna have to monitor the respiratory, system quite carefully.
I've put a, a table up here with some of the different, types of opioids that have been looked into, in reptile medicine. The ones in red are the ones that, I would say I use more commonly, and they include, morphine. And that's been studied in, in a wide variety of species, including things like crocodiles, bearded dragons, red ear sliders, but, not in snakes.
And tramadol. Tramadol is something I use very often. It can be given orally, and has a long duration of action.
It basically binds to new receptors with less affinity. And so has the potential for less side effects. If we look at tramadol in mammals, the analgesic effect typically begins, around 30 minutes after administrating it, and lasts for about 6 hours.
In the study they did in Reddit, sliders has lasted much longer for about 12 to 24 hours. So I tend to administer it once a day. And it does undergo hepatic first pass, so best, to give it in the foreimbs rather than the back limbs.
There's a couple of other opioids on the table. Hydromorphone, is used quite a lot in the States. I don't think we can get hold of it in the UK, but it's something that is quite, appears to be quite useful in reptiles.
Fentanyl, particularly in patches, has been studied in, in royal pythons, and, and other snakes, so that might be, a good opioid to use, in, in our snake patients. And interestingly, and something I wanted to highlight to people because I do still see people using, both buprenorphine and retorphonal. And buprenorphine has basically showed no analgesic effect in any of the species they've looked at.
So I don't think that should be an opioid that we use at all in reptiles. And but. All the same.
They've looked at various of the species that we commonly see in practise, like Reddit sliders, bearded dragon, corn snakes, royal pythons. And in none of these, but tophinol actually had any an analgesic effect at all. So I would, I would not choose those as my opioids, in our reptile patients.
Moving on to non-steroidals, obviously they're widely used, in, our other companion animals. They've got both analgesic and anti-inflammatory effects. And most studies that have been done in reptiles are actually only pharmacokinetic studies, so looking at, plasma concentrations.
And from a pharmacokinetic study, it becomes really difficult to actually recommend an effective and safe dosing interval, as, plasma concentrations don't always really directly correspond with clinical efficacy or tissue concentrations. There are some efficacy studies in bearded dragons and bull pythons. There's been some PK and safety studies in green iguana.
And some BK studies in, Reddit sliders and other, sort of turtles. So, meloxicam would be, the non-steroidal that we use most commonly, and it's been looked at in a variety of species. And maybe some of the audience might be working with some sea turtles, in which, other non-steroidals like ketoprofen and tofenamic acid, have also been studied.
So definitely something to sort of consider adding to your multimodal analgesia. However, you know, we don't really know, whether those are effective at the doses we are currently using them. So more studies are needed.
Something that is often forgotten, and I think needs to, be in our toolbox, for our reptile patients is, the use of local anaesthetics. They obviously need to be part of a multi-modal regime. They only block pain for as long as the block lasts, but there will still be inflammation and pain after.
The block, stops at the site of injection. So it shouldn't be your only analgesic that you administer, but, it's a nice part of your multimodo regime. It's also been shown to help reduce the, level of anaesthetic agents.
And there's a couple of studies in, reptiles. There's a study on mepivacaine in American alligators, and I've put the reference, on, on the slide, it's an article in the Journal of Zoomwa and Medicine. If anyone works with crocodilians.
The other one that we use quite often is lidocaine, and we can either use that in ring blocks for things like amputations or line blocks, and we dilute it one in one in saline. The total dose of lidocaine should not exceed 5 milligrammes per kilogramme. And we need to be careful about, sort of, overdosing that as well.
We can also use it, topically, straight onto a wound, or a technique that is quite nice is the intra intrathecal technique. Again, I've put the, reference on there, in turtles and tortoises. And that is basically used in a similar way as, we use epidurals in, in dogs and cats.
So, again, something that, might be worth looking into if you're gonna be, performing quite painful, surgeries. I just wanted to have a quick recap as well of, of other things that we might be thinking of using as analgesia. Obviously alpha 2 adrenergic, things like dexamedatomidine and meatomidine.
They have been, actually studied in bull pythons and tegus and might have, some effect. And, you know, for those of you that work in, small animal practise, the last few years, low dose ketamine and gabapentin, have become. Quite common use, particularly in, sort of, arthritic dogs, etc.
But actually, there is absolutely no evidence at all in reptiles that these work. So I would be a bit cautious about extrapolating our experience from dog and cat to, to reptiles in the case of these drugs. Just as a quick summary, obviously, you know, with the amount of species and, and different reptiles that you might be seeing in practise, I don't want this to be your formulary at all.
I cannot tell you doses to use, but just. There's a sort of summary or overview of what I use mostly in practise. This would be Tramadol, anywhere between 5 and 10 milligrammes per kilogramme, orally, generally, or I do sometimes use this injectable, morphine.
2 to 5 milligrammes per kilogramme subcut, meloxicam, 0.5 mg to 1 mg per cake subcut, and then the local anaesthetics that we discussed. Obviously, again, there is a lot of factors that will, be involved in deciding what analgesia you want to use, and particularly, also, we need to consider potential side effects in terms of kidney function, etc.
Particularly with the use of non-steroidals in, in, in potentially. Dehydrated animals, etc. So, you know, this is, this is not meant to be a slide that you use as a bible, but more of an indication of what sort of values, we can use out there.
If anyone is interested in sort of diving a little bit deeper into pain recognition and treatment of pain in reptiles, these are two references, that are pretty contemporaneous. They're from 2023, so not too long ago, in vet clinics, and they provide a really nice overview, of both pain recognition and treatment of pain, for our reptile species. So, I would really recommend.
Looking into those if you if you're interested. OK, so we're gonna move into, anaesthesia. Again, this is not supposed to be sort of a very detailed, you know, masterclass on anaesthesia, but more of a sort of overview of things to consider, when you're gonna be anaesthetizing a reptile, and then obviously, you know, make sure you dive a bit deeper depending on what species you're gonna be dealing with in practise.
So, as with any other patient, we will first need to do a pre-anesthetic evaluation of that patient, one to make sure that they're healthy and capable of withstanding the procedure. And we can actually go ahead and do that. Importantly and differently from, sort of our dog and cat patients, one of the main things we need to do before considering any sort of anaesthesia is to check the husbandry.
Unfortunately, a lot of, husbandry issues are still, present in our reptile patients. And this will also cause a, an, an effect on their wellbeing and their welfare, and their health. So just make sure that you always go into detail into.
How these animals are kept, what temperatures they're kept at, what their humidity is like, what their diet is like, because we still have quite severe failings in that, if they provide any supplements, particularly sort of calcium and vitamin D3 in some of our reptiles. So take your time. To make sure to not just focus on the problem this reptile has, but also making sure that what we provide this reptile with, is the correct husbandry.
And if not, make sure that you address all of those issues before, going ahead and doing, something quite invasive to it. Obviously, a physical exam is really important. And again, here, it will be, important for you to know what is normal and what is abnormal.
So familiarise yourself with the species that you might be seeing in practise, and then do a full physical exam. So that will be, nose to tail exam like you would do in your other more familiar species. So, you know, look at any, Sort of discharges from the eyes, from the nose, look in the mouth, check the teeth, look at the colour, make sure you do a good palpation and auscultation.
I normally use Doppler to have a listen to the heart, do a good salamic palpation, look at body condition, look at the skin. So really a full physical exam to make sure we're not missing anything. And we might want to do some further diagnostics as well.
We might want to take some bloods, do some swabs if we've got any lesions for bacteriology and culture, etc. Fasting will very much depend on the species we're dealing with and the surgery we might be doing. Obviously, as with anything, things go very slow in reptiles.
So emptying of the gastrointestinal tract will be delayed as well. So depending if you're gonna go and, do something like an abdominal salamic surgery or an intestinal surgery, anything like that, you might want to consider fasting. but also, on, on the flip side of that, a lot of these reptiles will be presenting anorexic, and some of these for already a very long period of time.
So it might be that you actually want to consider supportive care first, . A lot of things are not emergencies in the reptile. So you normally will have a little bit more time to stabilise that patient before going for, anaesthesia and surgery.
So, supportive care might include fluid therapy, it might include medications such as pain relief, antibiotics if we've got infections, etc. Depending on, on, on the case. And also really importantly, we need to provide thermal support.
Reptiles are poikilothermic, meaning that their body temperature is directly dependent on the environmental temperature and the temperatures we provide, and changes in body temperature will significantly affect both metabolic rates and many other physiological processes. So, drug absorption, distribution, metabolism and excretion, in reptiles will be directly related to environmental temperature. And then consequently, it's important to maintain the patient at its preferred optimal body temperature, so the POBT to achieve more predictable anaesthetic and other drug effects.
So how do we go about administering anaesthesia, so the routes of administration. Can be, IM or subcu, IB in some cases. And again, we've touched on this, but be mindful of the hepatic first pass.
So, just to recap on that, the venous blood flow from the pelvic limbs drains into the ventral abdominal vein, which either passes directly to the liver or through the hepatic portal vein into the liver. So hence, any drugs administered in the pelvic limb first enters the liver before reaching systemic circulation, resulting in this hepatic first pass effect. And that is, if the particular drug undergoes hepatic metabolism or excretion, and hence reduce the availability of the drug with hepatic metabolism, this will result in lower plasma concentrations and or reduced or no clinical efficacy at all.
Having said that, the intravenous administration of anaesthetics in the ventral tail vein of lizards does not result in hepatic first pass, because the coccygeal vein in lizard drains directly into the core the vena cava. So, therefore, IV administration of anaesthetic drugs in the ventral coccygeal vein is routinely performed and would generally be my preferred option. Just a quick, discussion about sedation.
I think this is something that we forget quite often in reptiles, and it's actually really useful for sort of minor procedures. So here on the picture, we've got a, little tortoise that is sedated with low dose propofol IV, and we are getting it ready to place an esophagostomy tube. So for these sort of small, not super painful procedures, I do use sedation quite a lot.
And you can use a combination of either midazolam and, meatomidine, or low, low dose propofol IV, which I find, really quite reliable and nice and safe. Obviously, do remember that none of these, products will provide any pain relief. So going back onto what we discussed before, make sure that you add, some, some analgesia to that as well, depending on what you are doing.
Moving on to anaesthesia, again, like probably all of your anaesthetists, teachers at university have always told you there's no such thing as a safe anaesthetic protocol. There's just a safe anaesthetist in what they're used to. And I think this is also very valid.
In reptile anaesthesia, I think, you know, get yourself familiar with some of the protocols and what to expect and how, the patients will, react to them. And then, and then, you know, use those. And also make sure that your nurses know what to expect.
My, preferred, anaesthesia, Protocols in reptiles, is, is mainly IV propofol, and I tend to use a dose of like 10 milligrammes per kilogramme. And here is a picture of a bed of dragon just having some propofol in the ventral tail vein, which if I can reach that, that tends to be my, my go to in lizards. Avaxolan has also become very popular in the last few years.
And again, the dose is similar, it's somewhere between 5 and 10 milligrammes per kilogramme IV. The nice thing about, Afaxolone is that it can also be used, IM. So in those species that you do not have IV access, alfaxolone can be a good alternative.
Just remember to inject it into the cranial half of the body. In some of the larger species where, IV is not an option, and IM, medications might mean that the volume is really too big. So I'm thinking mainly of sort of your large, aggressive big tortoises.
I quite like using ketamine and meatomidine combinations, I am, as well. With IM, it does take a little bit longer to take effect. We need to ensure that, during, the induction, we keep them at the right temperature to speed up, the metabolism of the drugs.
And also I find that I am absorption can be quite variable. And, yeah, reptiles are one of those species that, you know, you use the same protocol in, in, in two individuals of the same species in the same way. And sometimes the, the effects that you're getting are completely different.
But yeah, I am, combinations are also, do have, do have some place there. I've put on here gaseous induction, with a question mark. I, it's not something I particularly use.
I think most reptiles are able to breath hold, so that really does, become a problem when you're trying to induce them with, with gas. I think there's also, a health and safety concern, in terms of, you know, having. Lots of gas in the environment.
So it's not something that I use often, but it is described and, you know, potentially if, if you've got nothing else, it, it might be something, to consider, but as I say, question mark on that. And then something that I wanted to touch on, quite quickly, is something that has been used, in, in the last few years, and it's what we call neuractial anaesthesia, mainly in, in lizards. And this is the paper it comes out from, in the Journal of Veterinary anaesthesia and analgesia, and they tried this on Bearded dragons.
And it's basically providing anaesthesia to the caudal aspect of the body. So that would involve, the cloaca, the pelvic limbs, and anywhere between 25 to 50% of the trunk. And that has been described using, sacrococcygeal neuractual injections.
And it's a regional, regional delivery of anaesthetic and analgesic drugs, that, might offer substantial benefits for lizards undergoing various surgical procedures of their caudal body. So things like tail amputations, colochoscopies, and there's been some studies published that have shown that. Drug doses and efficacy will vary between lizards and chonians, and, but that effective and safe ne actual anaesthesia can be induced either using bpivicaine or lidocaine in some cases.
So again, if you want to know exactly how to do it, this is a really good paper. But hopefully you can download and, and sort of look at and it's quite a, a neat way of not providing sort of full anaesthesia, but more concentrating just in the area of interest. So once we have induced our reptile, we obviously need to maintain them asleep.
This is usually done with volatile anaesthesia, so either sevoflurane or isoflurane. We need to intubate our reptile patients. They, have a tendency to breath hold.
So in most cases, if not all, we need to provide, IPPV. In terms of intubating. We might need to be, a little bit, we, we might need to think a little bit outside the box as to what to use.
So obviously we can use the uncuffed ET tubes that we've got available in small animal practise. But in some of our smaller species like our, leopard geckos and so on, we might need to adapt little IV catheters and attach them to a 3.15 blue ET tube adapter.
And obviously, when we come to work with sort of the more larger species, like, crocodilians, here, we were, doing a surgery on one. We were using a big, dog ET tube. And then again, you might become a little bit resourceful as to what to use for things like mouth gags, and this, just for fun.
I put this picture in to show you that, you know, we, we use the bottom of, a sharp spin, To to avoid. This patient biting onto the, the ET tube. In terms of IPPV, the inspiratory pressure, we normally looking at, less than 10, millimetres of water, and the respiratory frequency anywhere, between 4 and 8 beats per minute.
Due to their particular cardiovascular anatomy, they can do what we call right to left shunting. And if that happens, this will decrease the blood flow to the lungs, which will impair gas exchange. And just to go into that in a little bit more detail, as you probably know, reptiles have a three chambered heart, so they've got 2 atria, one ventricle, and they've got an incomplete septum in that ventricle.
And that basically allows for intracardiac shunting of blood. And that is generally associated to the patterns of ventilation. So when they are breathing, we have got a low pulmonary resistance and an increased pulmonary blood flow.
But if they are in apnea, you increase the vas vascular resistance and therefore decrease the pulmonary perfusion and right to left shunting happens. And as I say, that decreases the blood flow to the lungs, impairs the gas exchange, and might affect your anaesthesia. So that becomes, Something tricky to overcome sometimes in, in our reptile patients.
So how do we monitor our patients? So, you know, a lot of people really stress about this, but actually, you can apply all of the same measurements and methods that we would in our more common species. So we will, monitor the respiratory system.
Obviously, because most of your patients are going to be connected to a ventilator, the respiratory rate and the rhythm will be determined by the ventilator. Really important that we still check for the rise and fall of the, of the sum, OK? And don't just rely on the beeping of the machine, because sometimes, particularly if we move the patient and we put them in different positions, that rise and fall might not, might not be happening, and we connect them to a canograph, as well, to, to monitor respiration.
If we are gonna put, reptile patients on their back, like on this picture, it's really important to remember that they don't have a diaphragm. So, all of the, xalamic organs will sort of fall onto the chest. So, we always put them with, with the chest sort of slightly elevated, as we can, we can see here.
Monitoring the cardiovascular system, we can look at things like capillary refill time, mucous membranes colour, although again familiarise yourself with what is normal. A lot of people still think that bearded dragons are yellow and jaundice, which actually, Is mostly normal. But, you know, also some of these reptiles might have, coloured mucous membranes, so that will not be very helpful.
I, always use a Doppler, and that will give you an indication of what the heart rate and the rhythm are doing, and you can see on this picture it's connected to a Doppler in, in tortoises we normally use sort of the. The thoracic inlet, in lizards, we can put the Doppler straight over the heart, or also, there's a, there's a couple of papers now out there that you can put the Doppler on sort of the, occipital area of the head. And you can also get some really good, Doppler readings, there.
We can, put on ECGs. We can use pulse oximetry. But with any of those, I don't normally get too, bogged down with numbers, but I look at trends more than anything.
So, you know, although they're not sort of validated, it might still be a useful tool to have on there. Looking at reflexes, obviously, response to stimuli, you know, if, the heart rate, respiratory rate, etc. Goes up, when we're doing something, it might be that we are not, asleep enough, changing in cardiopulmonary variables, and then we can do, our reflexes like our head and limb withdrawal, popebral, corneal, toe, tail, clo or pinch.
And again, as we have touched on previously, monitoring the temperature is really important. If these patients get cold, their metabolism will slow down and it will affect, our anaesthesia quality. In terms of recovery, as I said, everything goes slowly in reptiles, so we want to start recovering these animals, earlier than we would do in our dog and cat or mammal, patients.
So I tend to turn off the inhalant, when I'm closing up, rather than wait until I'm totally done. Historically, we've always used room air to ventilate during recovery, but this is currently being debated. So we've always thought that, ventilation can be depressed with oxygen supplementation in reptiles, and this could then affect recovery time after inhalant anaesthesia.
So we've always been taught to IPPV with room air, with an ambu bag, like you can see. On this picture here. However, there's some recent studies that have shown, not shown any effect of inspired oxygen, either room air or 100% 02 on ventilation during recovery and lizards.
So that's an interesting set of papers out there, and I think, you know, we will keep an eye on developments in, in that, . But I still currently use, IPPV with, with room air rather than 100% oxygen. Need to make sure that we keep them nice and warm, and they're on their preferred optimum temperature zone.
So, you know, use, heated tables, heat mats, hot hands, and, I tend to put my recovering reptiles in, in the incubator as well. And then we will extubate once they're spontaneously breathing. And just a word of caution, you know, I would be, a little bit cautious to extubate too quickly, because a lot of these reptiles will pretend they're breathing, will pretend they're OK, and then suddenly fall asleep again.
So close monitoring during recovery, is really necessary, and it's not as, as quick as it would be in your dog and cat, so it will need. A nurse to sit with your recovering patient. And just something interesting that has come out in the last couple of years as well is, the use of adrenaline, and this has been reported to, hasten recovery from inhalant anaesthesia in Chileans and American alligators.
And they think that the mechanism is based on an increase in sympathetic tone leading to a reduction to in right to left shunting and more efficient washout of the inhalants. However, the effect of, adrenaline on, inhalant anaesthetic recovering lizards, hasn't been studied at all. So I think that, you know, again, that is something to keep an eye out for these, the papers that I was talking to you about, both the, induction and recovery parameters, comparing isofluorine in 100 oxygen.
Versus lower dose of oxygen, and also the intramuscular administration of, epinephrine or adrenaline in the two species. So, something that again you might want to read on to. And I think that sort of finishes our.
Whistle stop tour on analgesia and anaesthesia in, in reptiles. I would like to thank you all for your attention, and I've put my email at the bottom as well. If there are any questions, I'll be happy to answer those.