Hi, thank you for joining me. My name is Claire Wolford, and I am OVN and VTS in anaesthesia and analgesia. And today we'll be talking about feline anaesthesia and analgesia.
So gonna cover as as much as I can. So we're gonna cover the common risk factors for cats undergoing anaesthesia, how we can do a proper pre-anesthetic assessments and be prepared for their anaesthetic. Feel an intubation and the problems that can occur around that.
Appropriate fluid therapy, a little bit about alpha 2 agonists and their use in cats. Then we'll cover some analgesia and some pain scoring, a little bit around how to manage sick and more critically ill cats. Anaesthetic recoveries and then a little case study for you at the end.
So we have had some, some, research done over the years into risk factors for cats. In 2007, we had the confidential inquiry into peropative small animal fatalities. And in that paper, the risk of mortality for cats was 0.26, which was a lot higher than dogs and obviously a lot, a lot higher than it is for humans.
And last year, in the vet record, we had, the anaesthetic mortality in cats worldwide analysis and risk assessments, and they looked at many thousands of cat anaesthetics across the world, and their risk of mortality in cats that they saw was 0.63, so even higher. So, cats do have quite a high risk of mortality and morbidity when it comes to anaesthesia.
And in both of these papers, most of the deaths occurred, in recovery from extubation to sort of 24, 48 hours down the line. So recovery is a very high risk period for cats. So in the 2007 study, the particular risk factors that they identified were cats that had poor health, so a higher ASA status.
Cats with increasing age. Cats that are either overweight or underweight. Procedural urgency or emergency procedures.
Endotracheal intubation and fluid therapy. In the 2024 study, the risk factors that they identified were cats that were very underweight. Again, the higher ASA status.
Some very specific procedures that we will go through a bit later on and mechanical ventilation. So we'll look at these risk factors through this, through this talk. The 2024 study did identify some factors that were protective and actually reduced mortality rates for cats under anaesthesia.
And the use of alpha 2 agonists, the use of pure opiates such as methadone, the use of local and regional anaesthetic techniques, all these things reduced anaesthetic mortality. So, again, we'll be looking at these throughout this lecture. So cats do find coming into hospital, very stressful.
It's very difficult for them to have their normal routine, and be taken out of their normal environment and to have things done to them that they particularly don't want to happen or if they're, you know, already feeling unwell. So we can help them a little bit by giving a pre, pre-med, giving them something before they leave home that helps to manage their anxiety, and calm them down a little bit so they cope better with the situation. And that will therefore make their lives easier.
It makes owners feel that their cats are being cared for better and it makes our lives easier because we don't have to handle fractious, anxious, fearful cats. Gabapentin is quite popular these days, for giving that, we can add in either or trazodone on top of that. Some cats respond better to trazodone than gabapentin.
But it's really important that we give it before the stressful event occurs, it's it's a. We're not waiting for the, the, the horse to bolt before you shut the stable door. So if we can give it to owners preemptively and say, you know, we're booked in for this procedure, give your cat this, dose of gabapentin at least 2 hours before they're coming into the practise.
That means it's gonna have time to work and get on board, and therefore, you're going to have a better, effect from its preemptive. Can use 5 to 10 mix a cake. This is my own cat.
She always has some gabapentin before she goes to the vet. And I just put the tablets inside an empty gel capsule, and I often add in a dose of oppotin for her as well. So she often just has one tablet in the Straight down, very easy.
She does have renal disease. It prolongs the action of gabapentin, trazodone. It takes longer for the system to get out.
So you may have to warn owners that maybe it might take a little bit longer than they, they might be a bit wobbly longer than expected. All patients are gonna have pre-anesthetic assessment when they come in. So we want to review their clinical history and see if there's anything in that that we need to pay attention to, such as maybe hormones that have been picked up in the past.
And then that patient's gonna have a TPR, so temperature pulse, respiration, so we have a baseline for that patient. We need to very carefully listen to their chest, listen to their heart, listening for murmurs, new murmurs, gallop rhythms, anything like that. And listening to their lungs, you know, cats have things like feline asthma, so they listening for harsh noises, in their lungs.
Possibly if you can, blood pressure is very nice, particularly in cats that might be at risk for higher blood pressure such as renal disease, thyroid disease, that kind of thing. So if you can, you may add in a blood pressure on top. The results that you're going to get from that physical exam may then send you, down to path to find out what was going on.
So if you could take maybe a new murmur, you might go, OK, maybe it's not a good idea to do this, elective procedure. Let's send the cat to a cardiologist and get it properly assessed. Or let's have at least a look at the left atrium and see, is it, enlarged?
Is there a risk? From fluid overload for this cat. If you hear an arrhythmia, you might want to do an ECG.
If you hear of normal lung sounds, you might want a chest X-ray. You may think, OK, let's do some further, blood tests if you think the patient is maybe dehydrated or something or anaemic. So the results of that physical exam and the review of the clinical history are going to send you down other paths that will help you stabilise that patient and, and gather more information that is going to be useful for your anaesthetic.
Pre-anesthetic bloods, ideally, in all patients over 7 years old, we should be doing some sort of pre-anesthetic blood workup. 30 to 50% of these patients can have some clinical diseases. You can't tell just by looking at a cat that it's, perhaps heading into renal disease.
So you're gonna want your standard preanesthetic biochemistry, maybe haematology. Maybe a PCB in total solids, and STMA is something that I'm using more and more to try and detect renal disease earlier, than your standard urine creatinine can. So we want preanesthetic blood work so we can check that organ function is OK.
We can pick up subclinical disease. To see if anesthesia's going to be safe for that patient. So it may not say, OK, no, we're not going to do this and it, but we may adjust what we're going to do and how we're going to monitor this patient.
It reassures owners that their pet is healthy. And yeah, you might change the antiate plans. It doesn't often change the drugs or drug choices you're going to have, but it may well change your drug dosages and how you're going to use them and how you're going to monitor and manage complications.
The results of this whole pre-anesthetic, assessment is going to help you then assign an ASA status, to the patient. And we know that patients that have maybe an ASA grade 3 or higher have a much higher level of risk for morbidity and mortality. And most of the studies out there that I've seen are mostly done on dogs, but I, I think that can be, applied to cats as well.
Do make sure you're looking at the actual numbers on your blood results. So just because it shows all green, doesn't always mean that's optimal for the patient just because it's within normal range. So things like creatinine, I mean, creatin is not very, it's not kidney specific, so it can be, Changed by things like muscle.
So we need to bear that in mind, but A slightly increased creatinine can put your patient into a grade 2 renal disease. So that might not show. So this is my own cat's blood results.
So she last had a, a creatinine of 145, and that's showing up as nice and normal on those blood results, but actually that puts her into stage 2 renal disease. So looking at the actual numbers that are coming through, and not just that, is it high or low bar, is really important. So I do like to include SDMA whenever I can, .
This detects, changes in filtration rates long before any changes in creatinine. And where I said, cre creatinine is perhaps not completely kidney specific, SDMA is much more specific to filtration rates through the kidney. With creatinine, you've got to lose at least 75% of your renal function before it really starts to creep up, whereas SDMA can identify loss of renal function as early as 23% loss.
So you can pick up renal disease a lot earlier, and that gives you a chance and the owner a chance then to manage it, much earlier than you would before and and to hopefully have a a longer, happier life for the for the cat. So with renal staging, stage 2 when it's mild at this point, you will start to see an increase in STMA. Whereas you have to get to 75% function loss before you start to see an increase in progressing.
So you have quite a, a head start on treating renal disease and managing that renal disease, Properly during anaesthesia and looking after that blood pressure, looking after that renal function, if you're using this on pre-anesthetic bloods. There are some common comorbidities that cats suffer from hypertrophic cardiomyopathy, renal disease. Degenerative joint disease and obesity, these are 4 very common things that you can see, in cats.
So hypertrophic cardiomyopathy, HCM, this is a very hidden disease in cats, and they can show almost no symptoms at all. So an assessment by the cardiologist is advisable if you pick up a new murmur, particularly before any anaesthesia, we need to know what stage. That HCM has got to, and whether there is a risk of fluid overload.
We will then know and have the knowledge to be careful with fluid therapy and perhaps avoid fluid boluing. Alpha 2 agonists, their use here is quite interesting. Normally in any patient with cardiac disease, you're going to be either avoiding them or being extremely careful with their use.
They can be a little bit helpful in cats with HCM, particularly if they have an outflow tract obstruction caused by the HCM. When you give meatomidine or dexedatomidine, that causes peripheral vasoconstriction. That gives you a little bit of after load increase, so it's a little bit of pressure that the heart has to push against to get blood out into the system.
And that creates a little bit of back pressure on that outflow tract obstruction and can kind of hold it open physically and allow a little bit of flow through it. So it's a fine line. We need to be very careful that we don't cause problems with the heart by dropping the cardiac output with big doses, but just very tiny little doses can really help a sedate and calm your cat, but also can help if you have an outflow tract obstruction.
Renal disease, this is a very common thing with cats. It's one of the #1 causes of death in cats over 5 years old. A very high percentage of cats over 10 years old will have some form of chronic renal disease.
80% of cats over 15 can have chronic renal disease. And that compares to dogs where, you know, about 3, 3.5% will have chronic kidney disease.
So it's a really big thing for cats, and if we can catch it early. On those routine blood tests, that gives us a head start on being really careful with their blood pressure and looking after their renal function when we anaesthetize them. So it's really important that we have good hydration prior to anaesthesia in patients that have renal disease, we want to make sure there's enough blood flow around to help keep that kidney happy and supply that kidney with all the oxygen that it needs.
Kidneys do have the ability to auto regulate their own blood flow. So within a certain blood pressures, sort of 60 to 160 or 180 depending on which book you read, your, kidneys manage their own blood flow very well. However, when you have chronic renal disease, that autoregulation window shrinks.
So by the time you've got to a blood pressure of aerial pressure of 60 millimetre mercury, which might be OK for a healthy patient, you're already dropping the blood flow through kidneys that are already damaged. So we need to maintain their blood pressure a little higher than we would with a healthy patient, perhaps maintaining a mean pressure of 70 or higher, rather than Letting it get down to 60. Hypotension means we're not supplying blood, we're not supplying oxygen to those kidneys, and that means we are worsening their function.
Kidneys are very hungry for oxygen. They need a lot of oxygen, so they get a really big percentage of your cardiac output, up to 25%. Every time your heart beats over that minute, 25% of that blood is going into your kidneys.
It's one of the best perfused organs in your body. So they have a very high oxygen requirement. Once that blood is delivered into the kidney, 95% of that blood flows to be delivered to the cortex around the outside.
Once you get to the medulla. There's a lot less blood flow. It's only 5% there and it has a lot less oxygen in it.
So you only have A partial pressure of oxygen of 10 millimetres of mercury compared to. 50 to 100 millimetres mercury in the vortex. But in this medua, that's very metabolically active.
That's where that loop of Henley is, and that's where a lot of things are happening. So, although there's poor oxygen delivery there, it needs as much oxygen as you can get. So it's very sensitive to having a ischemic injury.
If that blood flow drops to that kidney, we're going to get even less oxygen delivered to this cortex, sorry, to the medulla here. And you're going to get nephils that are gonna die and you're gonna worsen that blood pressure, so that renal function. So it's really important that we identify renal disease early, and then when we anaesthetize these patients that we really work hard to maintain their blood pressure.
Arthritis in cats, again, it's a very common thing. Most cats sort of over 12 years old will have some form of, of arthritis going on. And sort of 68% of these cats can also have renal disease alongside it.
It's too painful to get up and walk to the water bowl. So you live your life all the time, chronically dehydrated and that affects their kidneys. So it's very common to have these two conditions together.
And a lot of these patients, if that arthritis pain is not well managed, they have a chronic pain going on. And that can make them very sensitised to any acute pain that you had on top. So if you can do any surgery or have them in for dentals or something, that acute or chronic pain can be very difficult to manage.
So having that chronic pain dealt with earlier, again, it's gonna make your anaesthetic a lot easier to manage. Obesity, this is a very common, problem, and cats that are weighing 6 kg all up are 3 times more likely to die in that peropterative period, and that comes from that sepsis study in 2007. So important that we try and, dose our anaesthetic drugs for healthy weight, not their actual weight in the day, and be prepared to ventilate.
Once they're anaesthetized, we have a lot more pressure on their chest wall and on their diaphragm, so they may not ventilate very well. So we need to pre-oxygenate them. Before we start, anaesthetic conduction.
And recovery when you're taking them off 100% and putting them back onto room air, it's very common for them to drop their oxygen saturation. So we might want to, I give them some supplemental oxygen in recovery as well. So being more aware of.
Ventilation and oxygenation in these patients. Weight loss, this is a symptom of illness in cats. And having a cat that is very underweight has an increased risk of death, compared to cats that have a normal body condition score.
So underweight cats should be considered a high risk anaesthetic. So it's very useful, to score your patient, body score them, looking at not just body condition score, but muscle scoring as well. There are free downloads off the internet, so you can have these easily available.
But that will help you to identify patients that have lost weight, particularly if they're very fluffy or they're long haired, and it's not always very easy to see. You kind of need to get your hands on the patient and assess not just their body score, but their muscle scores as well. IV access, obviously this is mandatory.
Any patient undergoing anaesthesia must have IV access. Make use of the tools we have. So things like EMLA cream, if you have time for that to work, it does take a good sort of 1520 minutes to work.
Or you can use cold sprays such as ethiccom, to numb the skin, if you don't have time for, EMLA to work. We have to have this IV in for fluid therapy so that we can give our anaesthetic drugs and know that they're definitely going into a vein so that we can give emergency drugs, if anything happens, . You can never have enough IV access, particularly if you have a sick cat or an injured cat.
If you're thinking you may end up with more than one infusion and fluid therapies, just pop up another IV and you can always take it out before they recover if you need, if you want to. But you can never have enough IV access, particularly in sick patients. Preparation for anaesthesia is really important.
Spending a little bit of time making sure you've got everything ready will save you a huge amount of stress later on in the anaesthetic when you need things. So have a think about the anaesthetic, what you're doing, and the patient and their, pre-anesthetic assessment and what you found, their history. Have a bit of paper and just make a list.
Of all the possible things that could go wrong, OK, make a potential complications risk list. So hypertension, hypoventilation, hypothermia, pain. All the things that might happen.
And then make a plan. What are you gonna do if there's hypertension? What are you gonna do with that?
Are you going to reduce the IO? Are you going to give a flu polus? Are you going to use drug management?
How are you gonna deal with that? If they don't ventilate well, what are you gonna do about it? When they're painful, what's your rescue analgesia plan?
So if you have all this written down beforehand, and you have a little discussion before you start amongst your team, your, your vet, a clinician, your your nurse. Have a little discussion about these anticipated problems. Agree a treatment plan so that if it happens during that anaesthetic, your nurse can just get on and treat it because you've pre-agreed what you're gonna do.
Makes your interventions much quicker, smoother and a lot less stressful for everybody involved. So being ready for anaesthesia does not mean putting out a breathing system and a syringe for the propofol. You need to have everything.
So all of your tubes, maybe your selection of tubes, tube tie, oscope, in bees, monitoring, have everything that you could possibly think that you need ready before you start because then everything's a lot less stressful for you and you can focus on your patient. Always leak test your breathing systems. You don't want to have complications occurring during your anaesthetic that could have been prevented if you checked your circuit beforehand.
So you can have leaks in your circuit, so you can see there's a hole in my anaesthetic rebreathing bag here. They're just doing a very quick leak test beforehand can save you a lot of time. If you have a T piece, we can very quickly and easily check, this is working, functional, doesn't have any holes in it.
So just tap the end, close the APL valve, allow the bag to fill up and expand. Turn off your oxygen flow rates. And the bags should stay inflated.
It stays inflated, it's all good. Open the APL valve, be paranoid about that. Takes a matter of seconds, but it just eliminates things that could cause you a problem during your anaesthetic.
You don't have to use tea pieces all the time in cats. I often put cats on circle systems. It helps to keep them nice and warm.
So you can see little kitty cat here on a circle. So we look at the canister here. And you can see I'm actually only on 0.5 litre per minute.
We're on a 500 mL bag. I have a nice cater graph and I have no rebreathing at all. So you can get circle systems for cats that have narrow bore tubing, which reduces resistance, and we can have APL valves that are adjustable on the top as a safety measure, so that if the bag overinflates, it will allow a spill out into your scavenging.
So that we do have safer and more appropriate ways to use surface systems or cats now, and it, they cope with it very well, and it does help to keep them a little bit warmer and it humidifies and warms what they're breathing in. So when you come to your anaesthetic induction. Always pre-oxygenate by whatever is the lowest stress method for that particular cat.
Face mask if you can, if it won't, it's flow by. This helps to replace some of the air in their lungs with a higher concentration of oxygen. That protects you against hypoxemia.
If it's a difficult intubation, if you need to take your time cause the larynx has been a bit tricky, it buys you many more minutes of time before they start to desaturate. So pre-oxygenation is really important. Don't leave your anaesthetic monitor in theatre.
If you spent a lot of money on your really nice anaesthetic monitor. And it's sitting in theatre waiting for you. You That the complications that occur.
At induction. So things like apnea, hyperventilation, drops in blood pressure, changes in heart rate, you're missing all of these complications that occur at that point in time because your monitors sat in theatre. So bring it out.
I attach everything that the cat will allow me to attach prior to anaesthetic induction. So, I'll always have an ECG on if I can. If they're allowing a tight fitting face mask, you can even have cat graph in there, you know, pulse ox, you can have blood pressure.
So just attach everything the cat will allow you to attach, and then you can monitor them during and immediately post induction, and you will catch when they're not breathing quicker. You'll catch when they're hyperventilating. You'll see the drop in blood pressure caused by the propofol and the isoflurane.
So don't leave your monitor sitting in theatre, bring it out and use it. Do your safety checklist at this point. So whatever your practise has, these are free to download from the AVA website, or you can adapt them to suit your own practise, but make sure you've got the right patient.
Everybody knows what you're doing to that patient. Your IV is patent, your breathing systems have been checked. You have all the ET tubes and intubation equipment that you need.
Somebody has been assigned to monitor that anaesthetic. That's their job. This is your time to talk about those anticipated complications and what we're going to do about them.
Time for you to ask your vet any questions that you might have the anaesthetic is your anaesthetic safety checklist. Now, when it comes to cats, particularly in the 2007 sepsis study, intubation was considered to be a high risk thing to do for cats. Hopefully, we've moved on a little bit and become, we've got some safer options in terms of ET tubes now.
We have to have proper airway management, for safe anaesthesia so that we can safely deliver anaesthetic gases, we can deliver oxygen, and we protect their airway. So they're going to lose their laryngeal and pharyngeal reflexes, and although it's less common in cats, they can regurgitate or vomit, so we need to protect their airway against that. Respiratory depression is very common under anaesthesia, we need to have an airway in place so that we can provide IPPV if we need to.
But we know there are some risk factors around cats, and there are a few reasons for that. Tube selection is one of those. So red rubber tubes, all.
Very risky for cats. We are, they are known to have a higher risk of causing tracheal rupture, sorry, tracheal damage. The cuffs on them are low volume but high pressure.
So the pressure points that are in touch with the trachea are much smaller, so that pressure is focused over a smaller area of the trachea. The longer these tubes are used for, the kind of harder they become over time. They don't really soften.
They don't have a Murphy's eye, which is the little side eye that you see on other PVC tubes or silicon tubes, so you don't have that safety feature. So there's a much higher risk of tracheal damage and rupture, in the tube blockage with these guys. And we really shouldn't be using them at all anymore.
So, it's time to throw them all away and upgrade to some more modern substitutes. The PVC tubes are very popular, they have low pressure, high volume casts, so you can air in them, but they spread that air over a large area of tracheal wall, so that pressure is spread out more. Much less risk of tracheal injury.
Once they are at body temperature, the material does soften in the trachea. They're transparent so you can see blockages or fluid moving around in them. Unfortunately they can't be autoclad, but you can cold sterilise them, which is important.
We have, viruses that cats can spread through their saliva, so it's important that we use sterile tubes, so you need to cold sterilise these ones. Soft silicon tubes, these are my, my personal favourites, they're again high volume, low pressure cuffs, they spread that pressure over quite a nice large area. They're very soft.
They don't have to wait to body temperature to be soft at at in the ska. They are there already. They're clear so you can see blockages, they have the Murphy's eyes, so they have a safety feature there and these ones can be autoclaved on a gentle cycle.
So just gonna let you know that, the next is my personal opinion. I don't yet have any evidence for it, but one day, maybe. So, looking at some of the PVC tubes, they, they're curved.
They come curved in the packet. And that's because they're initially designed for humans. And in humans, we have a right angle in our airway.
So they have to be curved to allow use. The cats and dogs as well have a very straight airway. So if you're putting a curved tube into a straight tube, you're going to drag along the ventral wall of that kin and you can cause a little bit of damage there, which is why I like to use the silicon tubes because they're straight and they're much softer, and they don't drag a tip on, on the bevelled edge along the ska.
But like I say, I don't have evidence for this yet. Cats are very prone to laryngeal spasm. So if the larynx is kind of poked or irritated by an ET tube, it can seize up spasm and completely shut down.
This can occur at intubation or extubation, and it's better to prevent this with it because once that lax spas and it is very difficult to manage. So if you do have this occur, it's very important that you stop trying to intubate the cat because the more you poke that larynx, the more it's going to spasm and you can start to damage it and then you risk edoema developing. The tight fitting face mask provide ox.
Check your patient's anaesthetic depth. If they're a little bit too light, then you may want to give some more propofol or alfaxolone whatever you're using. Very fine line for this, we want to get into an appropriate depths of anaesthesia where the larynx may relax.
We don't want them to get to a point in too deep and they then suffer with hyperventilation or apnea, because that's going to make the situation worse. You can consider applying more topical lidocaine and be careful not to overdose the cat. You could consider some IV midazolam as a muscle relaxant.
And you're gonna have to just give it some time to relax. So be a little bit patient with it. It can be quite frustrating, get them to a better plane of anaesthesia, provide them oxygen, just let them relax and, and wait a minute.
Then do consider whether it's worth it to give them some steroids. If you feel like that larynx has been traumatised, and is at risk of developing edoema, it may be something to think about. The laryngeal edoema can occur following a rough or difficult intubation, and it can cause an airway obstruction in recovery.
It takes time for it to develop. It doesn't happen straight away. So, in the sepsis study, 63% of intubated cats died in recovery, and that may be due to perhaps those red rubber tubes being used, difficult intubations, not being, careful enough around their legs.
In recovery, that swelling and edoema develops, and that cat gets an airway obstruction, and if it's not monitored closely during recovery, it's easy to miss that. So if you think that's a risk for your particular patient, make sure someone stays with them in recovery, monitor them very closely, respiratory rate and effort, and do consider whether it's worth, giving them some steroid. Tracheal rupture can occur from excessive inflation of the cuff.
So again, using high volume but low pressure cuffs, you can put a lot more air into them, but the pressure is spread out over a wider area. That's going to reduce the risk of rupture and also necrosis of the mucosa. So again, this is the red rubber tubes really dramatically increase the risk of rupture.
So how can we safely intubate a cat? It's really important that we pre-oxygenate them. So once you, pre-meded them, we're going to provide them oxygen any way we can.
Once you start with your induction agent, you can then get a face mask on and make sure you give them time to breathe in plenty of oxygen. Make sure they are an adequate plane of anaesthesia. Don't start trying to intuate them when they're too lightly anaesthetized.
We need to spray the local anaesthetic directly onto the larynx. So it's it's not just spraying it randomly in the mouth or on the tongue or the base of the tongue. We need to direct that spray onto the larynx.
So you get that, your introy spray and aim it right to the larynx. Take care not to overdose the cats, particularly very small cats and kittens, if you're doing lots of sprays of, of lidocaine, it's easy to overdose your cat. And then you're gonna have to be patient.
We need to allow that lidocaine time to work. And some studies recently have shown that at least 45 seconds is needed. And that can feel like a very long time when you're waiting for it.
So do your spray, put the face mask back on, and just be patient. Allow it the time it needs to work. Maybe use that time to pre-measure your ET tube so you know whether it's going to be too long or too short or anything when the cats.
Always use a laryngoscope. So we're gonna use a laryngoscope with a good light. We're gonna put that on the base of the tongue and push firmly down, open the mouth right up, so you have a really nice good view of the larynx.
And then you can introduce your ET tube over the top of your, your laryngoscope, and then just wait. Make sure you can see your larynx is nice and open and relaxed, and then you can just pass your tube slowly, through the larynx and in into the trachea. Tie your tube in place, we apply the oxygen.
Then we can start thinking about the cups. So with a larynge scope, you get a really nice view, good lighting. And then you can just slide that tube directly in.
You can inflate the cough on cats. I always have done, you just have to be very careful how you do it. So to safely inflate the cough, you can use your, your cough buff.
You can either give a manual breath yourself or ask your assistant to do that for you, and then have a close listen, put your, your head right down to their mouth and listen. As the, your assistant gives a breath, you'll hear a little gas leak. You're then going to just inflate that cough until you hear that gas leak stop because that means you've got the cough in contact with the trachea, but you.
So just stop inflating when that gas leak sound stops. So just give them a gentle breath and inflate until you hear. That we've got that gas leaks.
Or you can use a manometer. We're using this quite a lot these days, so you attach that to your ET tube pilot balloon. Inflate the cough.
And then just make sure you reduce it so it comes within that nice green zone. That means you are at a safe pressure that is allowing blood flow through the tracheal mucosa, but you have a sea. And if you attach just a narrow, kind of, almost like syringe driver give line or some manometer line from your manometer to your pilot balloon, you can leave that attached during your whole anaesthetic and continuously monitor your ET tube puff pressure.
So you can see if there is a leak developing before you will see it anywhere else. And that's good for not only the patient, but it's good for you, so you're not getting exposed to anaesthetic gases. Has the ET tube gone on the right hole?
The only way to know this is to use catmography, OK? So, once your tube is in, attach your breathing system with your catmograph and watch your cat. So putting a little bit of fluff by the ET tube does not confirm tracheal intubation.
Pressing on the cat's chest. Does not confirm quill intubation. Only your cat graph tells you that you're in the right place.
OK? And this is why we pre-oxygenate. If we have a period of apnea, following our induction agent, we will know about it because when we're using a monitor during, our induction, and we can see straight away that we've got a tube in the chir because we've got a proper cat graft line.
So that's the only way to know for sure that you've put the tube in the right hole. Fluid therapy, we do want to supply some fluid therapy under anaesthesia, the drugs that we are going to give such as propofol, isofluorine. Produce vasodilation.
That means all your blood vessels get dilated, once they're dilated, all your piping is bigger, but the circulating volume within that piping hasn't changed, so the pressure in the system drops. So this is why we provide fluid therapy to kind of deal with that much relative hypovolemia. This ensures that many organs, like those all important kidneys remain well perfused.
Now cats, because they don't tell us very well about their heart disease, they like to hide their heart disease. We're gonna use a slightly lower rate than we would in dogs. So 3 mL per kg per hour is recommended.
And we want to aim circulating volume. So we don't want them to be underloaded, we don't want them to be overloaded. And we're gonna carry that through therapy on maybe just for an hour or two post-op, just while they're waking up again just to help support them, flush out those anaesthetic drugs, keep everything hydrated, .
If they're hydrated, organs are gonna work better, kidneys, guts, brains, hearts. If it's hydrated, it works better. So aiming for normal circulating volume, if we're hypovolemic, we have a low blood volume, we're going to have a poor level of oxygen delivery to the tissues.
But if we overload them with fluids and they get hypovolemic, we're going to get tissue edoema. Tissue edoema then gets in the way of perfusion to tissues. So again, we end up in a situation with poor oxygenation in tissues.
So we just want to maintain a nice normal situation with our fluids. Alpha 2 agonists, so these were identified as a protective factor in, the paper that came out last year in 2024. So they've been shown to reduce mortality risks in feline anaesthesia.
And that's because they reduce injectable requirements, so you propofol, your fax, you're gonna need less. They reduce inhalants, so you're not gonna need so much isofluoran or CV fluorine. In fact, you, you may get away with up to 80% less dosing on your inhalant anaesthetics.
They produce vasoconstriction, therefore we get better blood pressure. It reduces patient stress. They provide some level of analgesia.
And they're reversible, so we can get rid of them if we need to. So you can see that the top picture here, very low blood pressure on this patient. This patient has had a dose of aromazine.
So you can see that it gives us basodilation. The pressure in the system drops dramatically and you end up with a really bad blood pressure and then a lot of problems that you have to deal with. Whereas down here we have a cat here who's had meatomidine.
We've got a really nice blood pressure, breathing well, oxygenating well, it's got a nice heart rate. It gives you a much more stable anaesthetic and a lot less worries to deal with. It's really important that you understand how the alpha 2 agonists work, because they can provide.
Will produce quite profound bradycardia. We need to understand why that is. So when you give meatomidine, we get peripheral vasoconstrictions, so all your blood vessels in your periphery squeeze up and constrict.
Because we've made the piping system smaller. We get an increase in pressure. So your blood pressure goes up.
Your brain recognises that the blood pressure has gone up. And tells your heart actually slow down because that's your blood pressure's really good, you don't need to beat so fast. So that's why your patients become bradycardia, because they have high blood pressure.
So we don't need to worry about it so much. You can see in my picture here, a patient has a very high blood pressure. It's just been given a, a little loading dose of dexammidofaidine, so you can see I've got very high blood pressure.
But I've got poor peripheral perfusion. So my SP2 isn't gonna work properly because there's not a lot of blood flow in my tongue around at the moment that I'm using on that patient. My non-invasive blood pressure isn't going to work because there's not enough peripheral blood flow.
But because I'm lucky enough to have an arterial lining, I know my blood pressure is very, very good indeed. So don't worry quite so much about bradycardia when you've given an alpha 2, it means that your blood pressure is probably very high. Your alpha 2 is going to last 30 to 40 minutes.
So if the bradycardia is persisting beyond that, you may think about treating it with glycopolate or atropine. But within that time frame, your blood pressure's going to be probably pretty good. Now analgesia are really important and historically cats have missed out, and we haven't had a lot of choice, but these days we've been, we're very spoiled for choice.
We've got a lot out there that we can use in cats. Their masters are hiding their pain, but we're getting better at reading them. We're getting better at understanding them.
OK, so it's time for the cats to catch up a little bit on perterative analgesia. So yeah, we're spoilt for choice now. We have licenced opiates like methadone and fentanyl.
We have a better understanding of how to dose those drugs so that we don't end up in patients that have dysphoria. We have a better understanding of how to use other analgesics such as ketamine alongside them. We are much better at our local anaesthetic techniques, and we're better at that kind of fear free handling, feline friendly handling techniques, which again, reduce stress and anxiety and that improves patient experience.
So don't forget the pre pre-med. If we can get them that gabapentin, trazodone, whatever your choice is before the visit, that's really going to help when they come into the hospital. So stress prevention and aiming for that feline friendly environment.
Opiates, I still find practises that are very fearful of using pure opiates like methadone in cats. And that's possibly due to worries about side effects and causing dysphoria in cats. But most of the studies, that have talked about dysphoria in cats have used very, very high doses of these drugs.
And if you're using a, a more clinical dose of methadone, I'm sort of 0.1 to 0.3 megs per kg, you should really only see euphoria.
So cats that are a little bit happy on the methadone rather than distressed methadone. And pure opiates in the paper from last year, 2024 paper, use of pure opiates reduces the risk of anaesthetic mortality. And that's probably because we manage pain better, we get a smoother and more stable anaesthetic.
There can be quite an individual vari variability in how cats responds to some opiates. This is very well known in humans and is related to our genetics, it's probably very similar in our patients. So we do need to fit the analgesic plan to the patient needs.
So you may start out with something that's fairly, you know, everybody gets 0.2 mes methadone, but you might find some cats maybe need a little bit more or maybe less frequent dosing. Buprenorphine can have very, variability, variable effects, sorry.
It seems to work for some patients really well and other patients really not. So these are two, cats. They're brothers from the same litter.
They both came in to be, neutered. They both had meotomidine buprenorphine. It worked for one cat.
It didn't work for that one. So you can see our black and white friend here is much happier, sat up and looking around. She's eating some food.
Where his tabby brother there is not happy, curled up tent with a tense face. Very painful. So it can have been much more variable with buprenorphine, and I don't tend to find that myself with methadone.
So identifying what euphoria is versus dysphoria, euphoria are cats that are super friendly, happy, they want to interact with you. OK, they're pain-free, they want to come and chat and tell you all about it. They're very happy.
Whereas dysphoric patients are patients that are not enjoying their medications and it's very clear to see, so you can see in this cat here. This is a cat that's, had a femoral fracture repair. You can see in his face, he's just, he's not enjoying the situation.
He doesn't want to interact at all with people. And he actually became a little bit aggressive towards himself, towards his own injury. So he was both painful and dysphoric at the same time, which is a bit of a challenge to manage.
So it's important to understand that cats that are euphoric and high, that's, that's not a problem as long as they're enjoying and they're happy. If you can't comfort them and they're not enjoying the situation, then that's a diss for you. So buprenorphine, has a wide variation in its duration of action.
We can give it to many different, routes. We can give different doses, and there are lots of studies all looking at very different methods of giving these. So it can be repeated between half an hour and 12 hours.
So you need to be there assessing your cat to know when the cat is due for it. It has a very high affinity for your opiate receptors. But it needs to, occupy more receptors, than you, a pure opiate in order to have some effect.
And once it attaches to those receptors, it really likes them. It's very difficult to displace them. It can have a ceiling effect, so giving more buprenorphine does not necessarily produce more analgesia.
You don't get the same level of analgesia that you would from methadone, for example. Buprenorphine, IV and IM, and probably in cats, submucosally are the best routes of transmission. Subcutaneously, it's been shown to have quite poor absorption and limited levels of analgesia.
Whereas methadone is licenced pure opiates, it has a bit of an edge over all the other opiates in that it's anti-hyperalgesia, so it helps to prevent central sensitization to pain. So no others that we know do that at the moment. So it's got a nice extra benefit.
It'll give you 4 to 6 hours of pain relief. It's got ma reduction and that means you can use less ace fluorine and less sevofluorine, turn your gas down, you get better blood pressure. And yeah, you use it in cats.
Please use it in cat C, respond really well to it, at those clinical doses. So this paper showed a nice comparison between methadone and buprenorphine, in cats, being spayed. They looked at postoperative pain levels.
So that you had 120 cats, that were split and either given buprenorphine or methadone within a quad protocol. And then they assessed their pain. Cats that had methadone had significantly lower composite, pain scores, so using things like the Glasgow Pain School.
18 out of the 60 methadone cats had required some sort of rescue analgesia, whereas 29 out of the 60 buprenorphine, cats had to have rescue analgesia. So it showed quite clearly that methadone did provide. Better analgesia than buprenorphine for ovarian hysterectomies.
And to show you that, again, this is a, a cat that's been spayed, it's gone home, it had, meatomidine, buprenorphine, ketamine, tammeacam. Been sent the photo I can see the cat's in pain. Look at the cat's face.
It's a very tense, unhappy. Its back legs are pulled up to its abdomen and that's a sign of abdominal pain in cats. So they might look OK while they're kind of in the hospital and they, they try and hide their pain really well, but then they get home and they, they're in their own environment and they relax, and that's what they look like when they get home.
I'm gonna compare that out when she was spayed. So she had, meatomidine, methadone and some local, and then she had methadone postop and buprenorphine before she went home. So she's having a great time, and you can see a very different face to what you're seeing in the, in the first case.
Her ears are up, her eyes are open, her head's up, she's looking around. She's got those big pupils. She's Was happy to interact, so.
It really does make a big difference switching buprenorphine to methadone. And if your patients have less pain. You need less inhalant.
If you turn your gas down, you get less hosodilation. If you have less hosodilation, your blood pressure is better. The better blood pressure, we're looking after all those organs and we're supplying oxygenated blood to them all.
That means you're gonna have a good recovery, not just then, but long term. And you are going to have a lot less stressful anaesthetic, because you won't be dealing with that roller coaster pain patients that it's painful and then they're too deep and then they're painful and then they're too deep and. Becomes very stressful for everybody involved, and it's not good for the patient.
If you give them really good pain relief, you'll have a better anaesthetic for everybody involved. And we want to make that analgesia as multi-modal as possible. So with your pure opiates, you may think about using something like ketamine, you want local anaesthetic techniques.
Using those alpha 2 agonists, they provide some analgesia and then your nonsteroidals. And that means we're tackling that pain pathway at lots of different points, and we're going to have a more successful analgesic protocol and hopefully better use lower doses of everything because we're attacking that pain pathway at lots of different points. So think about analgesia in advance, make a plan, make it preventative, so you're preventing pain throughout the whole procedure and at home when the patient goes home.
Make it multimodal as possible. I think, is it gonna be OK with just having bolus if it needs to top up or should we be thinking about putting it on CRI if it's a longer procedure? What local blocks can you provide?
Can we put in, you know, dental blocks and ring blocks and incisional blocks? What can you do? And then having good pain scoring post-op so you can make sure it's working for that individual.
So this is a little kitty cat having a maxillary block prior to dental extractions, so we're just putting a little bit of buppivacaine. In there, that's gonna numb up that whole top jaw for that patient. So, you won't be able to feel any of that for the next 6 hours.
When it comes to neutering, we can do testicular blocks. Super cheap, very quick, very effective. 0.1 mL of lidocaine.
Into each testicle, aiming towards the spermatic or when you inject, just aspirate and inject. Works very quickly, will last for about 2 hours. You can do intraoperative blocks for females, and you can add in a little incisional block which is literally just subcutaneous lidocaine, bine or whatever you want to use on either side of the incision.
So quick, so easy, very cheap. Mm ketamine, we can use this really, very effectively, as a rescue. Or as an ongoing analgesic throughout an anaesthetic.
We can use it at sub-anesthetic doses, for its analgesic benefits. It blocks these NMDA receptors, and they are always a little bit of wind up. It's what makes that pain pathway worse.
So, if you put a lot of pain signals passing down your spinal cord, that's like a really busy motorway, those cars being pain signals going down the motorway, it gets very busy. When you provide a patient with ketamine, we can shut down that pain pathway and turn it back from a motorway so that head back down to a country lane and quiet that pain pathway down again. So very good for acute and chronic pain.
Anything with chronic pain involving. Coming in for surgery or dental or anything like that, ketamine is going to be really helpful part of your multimodal anaesthetic plan. So this is a patient that's having a ketamine bogus, so you can see that we've got a lot of breathing, huffing and puffing.
No, my heart rate really doesn't change very much. We're huffing and puffing. So we've given a ketamine bonus.
Give it a few seconds to work. I'm not gonna touch my vaporizer at all. I'm just gonna give it a minute, let the ketamine find cells to work on.
And there we go, it starts to work. Everything just calms back down again. So I've not had to touch my vaporizer, I've not turned any anaesthetic gases off.
I've not given any profile, just given a half mop kick of ketamine to this cat. It just calms everything down, it's very low stress. It works and it doesn't ruin your blood pressure.
So if you want to do a ketamine CRI, it's very easy to do if you bought a syringe driver, great. If not, you can make of ketamine up and use it on a drip pump. So if you want to do a bag, you can make like 100 mL bag of saline.
We've put 1 mL of niketamine in, it's gonna give you 1 mg per mL solution. If you want to use a syringe driver, you can make 20 mL or 10 mLs up whatever you want. 1 mL in 20 will give you 5.
For cats, generally, I, I make the 1 mg per mL. It's a more sensible amount going to be delivered to the patient. So you can put 0.2 into 20 mLs and you'll have 1 mg per mL, and that will last you through your whole surgery and probably for a couple of hours post up.
If you want them to calculate a ketamine CRI or a CRI of anything, I don't bother. OK. Don't worry yourself about the maths involved.
If you want to know the maths involved, feel free to get in touch with me and I can work through it with you. But these days, we have a lot of tools out there that make life easy for you. So, there are CRI calculators on the internet.
I particularly, like the, IVAPM one is very useful. There are apps that you can download onto your phone that will do all the calculations for you, so you don't have to be stressing over that. What I would say is just always make up the same dilution every time.
So make up different dilutions, make it always make it the same, and that's one bit of maths you will never have to do again. And then you just send that into your CRI calculator on the computer. It will tell you everything you need to do.
So that kind of helps to avoid, Maths errors cause everybody can have bad days in the maths. And we need to assess these patients and their pain, because we need to catch when they are due the next dose. And is it enough for that patient?
Have we done enough for that patient and cats, the changes in behaviour can be very subtle, and you need to be able to be doing it all the time, and you start to pick up on things much quicker. So it does take a little bit of practise, but then we do have some great pain assessment tools available to us. So I particularly like using the Fion Grimace scale.
It's very, it's validated, it's super fast and quick and easy to use. It's been validated for acute medical, surgical and oral pain. They have a great website, loads of information on their website, all their research and, lots of training tools available there.
And they have an app that you can download to your phone. So download it from your app store, wherever you get your apps. And then you want to pay and score a patient, you just open up the app, score away.
It takes a minute, less than a minute to do. It was called a patient for you. So the grim scale is looking at 5 different facial changes that are seen in in painful cats, and you're scoring them 0 if it's absent, 1 if it's moderate, or 2 if it's very obvious.
Looks at ear positioning, or whisker position, muzzle tension, and head position. And if you get a score of 4 or greater, that means that can requires RG. So when it comes to ear position, as cats become more painful, the gap between their ears widens and then eventually their ears flatten and turn outwards as they become very painful.
Orbital tightening, so their eyes should be nice and open wide. As they start to squint, they're becoming painful. Once their eyes are squashed squinted and closed, they are very painful.
Muscle tension, this is probably the one that's the most difficult for people to, to score when they're starting out. So we're looking for. This down here to be nice and rounded and relaxed.
As this model becomes straighter. And straighter, the cat is in more and more pain. But this is one that if you're not sure if it's present or not, it's probably best to just give it a score of one because it's fairly obvious if it's not there.
Whisker position, we want the whiskers to be nice and relaxed, so they should be open and relaxed downwards, nice and rounded shape to them. As the patient becomes more painful, the whiskers become straighter and bunched together. And as they're very painful, they can get pulled back onto their face a bit more.
So we're looking for nice rounded, relaxed whiskers. And head position, I want the head to be hot. Above the shoulder line.
If it's in line with the shoulder line, then they're a bit painful. If their head is actually down on the ground or they're lying down, that's very painful. So you just go through each one, school your cat, add it up.
If it comes to more than 4, it's time for more analgesia. So here's a couple of cats. So this is, again, my cat who's, had one of her dentals, she's got her ears up, nice round eyes.
She's got a nice relaxed muzzle, and her head is up. You can't see her whiskers very well, but they're nice and then relaxed. This cut here we can see his ears are pulled apart.
His eyes are fairly open, they're OK. We do have some nozzle tension and our whiskers are a bit straighter and a bit bunched. And another cue for this cat is that he's got his legs pulled up to his abdomen, so that suggests abdominal pain.
And this cat here we can see we've got a little bit squinty eyes, our eyes are apart. We've got a fairly. Flattened muzzle here in comparison to my cat here and our whiskers are quite straight and pulled back so again cat's quite painful.
The 2024, study did, name some procedures that are quite high risk for cats that we need to be aware of. So cats undergoing abdominal surgery, that being gastrointestinal, hemohaabdomen, diaphragmatic rupture, septicandomen, things like, a very hysterectomy, had like less, of a, a risk associated to it because it's so commonly done, generally done on very healthy patients. Orthopaedic surgery, interestingly, fractures, luxations, particularly trauma surgeries.
And cats that have physiological disturbances, so if they're anaemic, electrolyte disorders, hypothermic, things like that, physiological disorders puts them at high risk. So when you score your patient, we know if they're gonna be an ASA 3. That increases their risk of morbidity and mortality, and you can see there's quite a jump between the 3, particularly 3 and a 4.
There's a quite a big jump going on here in their risk factors. As a, . Status is, is fairly easy to find on the internet so you can download an image of one and pin it up on the board so you can know very quickly and easily which category your patient's going to sit in.
Sick cats, procedural urgency, we know that they're at a higher risk for morbidity and mortality, and that's when people are rushing. The cat is sick, we need to get her to sleep. We need to get things done quickly.
We all want to go home on time. But that's when rushing, that's when things get forgotten. The preparation isn't quite done to the same level as you would, for a routine procedure.
And cats don't always read the book when it comes to shock. They can do slightly different things to dogs when they, they become more bradycardic rather than tachycardic, for example. So we need to get them stable before anaesthesia, ABCs.
Look at their level of consciousness. We're gonna give them oxygen. You're never wrong to give oxygen.
Get that analgesia on board. We know that's gonna help. We want to stabilise their blood pressure, that might be giving them some fluid therapy.
And make sure you fully examine the patient. They can have more than one injury. So sometimes the patient that turns up with facial injuries that really sticks out.
You can see they've got broken face, they've got broken jaws. There's blood everywhere. It looks dreadful, but they can have other injuries.
So you can see this cat here and his jaw fractures, but actually, He had a bigger problem, which is this really big pneumothorax, and that's going to kill him long before his jaw fractures. So make sure we are doing a full examination of the whole patient. And then cats, things like renal, and urinary tract damage and neurological damage are very common, results from trauma.
So we need to look a little bit more carefully for that, particularly this renal and neurological damage, which can be very hidden. Blood loss, this can not always be very immediately obvious on your initial blood work. When patients, you know, for example, hit a car and they have a big pelvic fracture or a femoral fracture, they bleed.
When they're bleeding, they're losing whole blood, red blood cells and plasma together. So your PCB initially may be fairly normal. But the next day and the day after that, as your patient corrects their circulating volume by shifting their own fluids within the body, so moving interstitial fluid, and we put them on a drip and perhaps give them some fluid bonuses, we start to dilute things.
And then over the next 24, 48 hours, that PCV can drop very dramatically. And it can take 3 days, 4 days for it to start to creep up, and then 2 weeks for it to really properly get back to normal. So if you have a patient that requires trauma surgery for a big fracture, pelvic fracture, whatever.
We make sure we're checking that PCV again prior to anaesthesia, because that PCV may have dropped to a point where it's no longer safe to do the anaesthetic. So PCV less than personally I like 22, I would not like to anaesthetize that patient. I'd like to wait for it to be a bit higher.
So these are the results from a cat that came with a pelvic fracture, 24 hours post trauma, we've got a hematocrit of 25 and a total protein of 58. Another 24 hours later, that PCV's dropped to 14, and our total solids have dropped as well. So at 14, it's probably not safe to do a surgery or an anaesthetic.
We need to either transfuse that patient or be patient and wait for those, that patient to produce more red blood cells itself. So always check that PCV again. Your anaesthetic itself is going to drop that PCV even further.
Another risk factor that was recently identified for cats is mechanical ventilation. Proper ventilation is really important. We want to maintain normal oxygen and carbon dioxide levels during anaesthesia.
But a lot of our ventilators are not really designed for the very small cats that we have. . There are some newer ones coming out which are gonna, which are better, but some of the older ones are just not really designed for tiny cats.
It's very easy to over ventilate them. And if a patient has perhaps been through some trauma, any kind of RTA CAT, they're probably going to have a level of pulmonary contusions, pulmonary damage, even if that's not very obvious on clinical examination. So we really do risk barrow trauma, which is too much pressure, or volume trauma, which is too much volume to the lungs.
So adequate training on mechanical ventilation, if you have that available, is absolutely essential. Anaesthetic recovery, we know this is a high risk time for cats, and most cats will die in the postoperative period. It's really important that we don't leave them alone.
Somebody has to be with them, recovering them, and continue your monitoring, particularly pulse oximetry and temperature monitoring in recovery. And ensuring your staff that are there are trained how to monitor them and how to recognise problems. So if you're making use of perhaps your, your VCA team, your care assistant, team, make sure you provide them some training in what to monitor, how to monitor, and how to recognise problems so that they can bring that to your attention quickly.
In our 2024 study, and in the SESA study in 2007, most cats start in recovery. In this study, we can see this, this line here is a recovery. 75% of cats are dying in recovery.
So we need to improve our post-anesthetic care of these patients. So I don't make sure somebody with things like larynguledema develops over a matter of hours. You think they're OK, you come back and check them, they're not.
We need to actively heat them until their body temperature has returned to normal. We need to make sure their analgesia is adequate, . We need to be there monitoring and pain scoring so that we catch breakthrough pain, so we're gonna pain school and probably hourly, 2 hourly.
We just need to be there and make sure that we catch problems early. Monitoring pulse oximetry, in recovery is a really important thing to do. Always check your patient's pulse ox, when you take them from 10% oxygen, you take that away, you put them on room air, you want to know can they cope with it.
So this is a healthy 6 month old cat, who spay. I still got a tube in, but I've taken the oxygen away and I'm gonna monitor what happens to the saturation. So we can see already it's dropped 94, it gets to 93.
I'm gonna put the oxygen back on. So she's entirely healthy, she has no lung disease, no problems, no health problems, but she's still anaesthetized. She's got some nice painkillers on board.
She's just not taking deep enough breaths on room. She can cope with it on 100% oxygen. She's not taking deep enough breaths on 21% oxygen in the room to maintain her saturation.
If I wasn't wanting that, I wouldn't catch it, and that saturation would just continue to drop, drop, drop, and then we're getting hypoxic damage to organs. OK, same cat, so now we've got the tube has been removed, been extubated. She's got lovely white feet, so I've been able to carry on monitoring her SPO2, but we can see again it's dropped down again, back down to 94.
So I'm just gonna provide a little bit of flow by. Just while she wakes up, once she sits up. And starts to look around, she'll take some nice deep breaths, and she'll maintain saturation, no problem.
But it's that very acute period between turning off your anaesthetic gas and putting them in wards thinking they're OK, you're missing a level of hypoxemia. And it doesn't happen to every patient, but you'll be surprised the number of entirely healthy cats that you can see this in. So, quick case study.
So, this is, Peggy, this is my own cat. So she's an 11 year old with short hair. She, has stage 2 renal disease.
She has hypertrophic cardiomyopathy. She's got IBD. She has idiopathic hypercalcemia, and she's got arthritis, and she needs a dental.
So she's a classic veterinary nurse's cat with all her problems. She's stable. All her all her conditions are stable.
She's managed on probiotics, hypoallergenic food. She has cheer seeds for her hypercalcemia, and she has, Calencia for her arthritis. So her, we wanted to manage her arthritis cause we don't be dealing with acute and chronic pain.
So that was her beforehand. And here she is. A week later, so much happier we're managing that chronic pain well.
Her pre-anesthetic blood work shows that she, her STMA is a little bit at the top of normal, 13. She has her race crest in at 150. Ua is not too bad, 7.
Her ionised calcium is slightly high, it's better than it has been, and her potassium is sort of bottom end of at the moment. She had a recent, echo to check what was happening with her heart. So she has stage one HCM.
So that means she does have HCM, but she doesn't have an enlarged atrium. So that's nice that I know that I have less of a risk of fluid overload for her. So it's nice to know things are stable, haven't changed.
She's lost a lot of weight. She has appeared on steroids, and you can see she, she put on a lot of weight, but we've worked hard and we've get her back to a healthy weight. So that again, makes her anaesthetic risk better, makes her safer.
So she's had her, give her a gabapentin and Murropotin before she leaves home. Get her into the hospital, we take the bloods, we're gonna get an IV catheter in place. And I'm just gonna start her on just some maintenance fluids just to make sure I've got some hydration whilst I go and prepare everything for her anaesthetic, she's gonna just stay there and, and get nicely hydrated.
So I'm looking for that nice balance of a normal circulating volume. I want to keep her kidneys happy. I don't want to give so much that I make her heart unhappy, so we're aiming for a nice normal circulating volume.
So she's had a gabapentin. I've given her methadone, and I've given her gramme per kilo of Dexedatomidine at very tiny dose induced with alfaxolone. Given her some IM ketamine as a background analgesic.
We're gonna maintain on either the flura. She'll have dental blocks with bupyvocaine. And I'm gonna put her some fluid therapy now at 3 mL per kg per hour during the anaesthetic.
So, this was her, ECG. So sometimes with cats that have an alpha 2, they get bradycardia, and they get bradycardia, they can develop an arrhythmia called AV dissociation. And that just means the top of the heart and bottom of the heart aren't really in very good, they're not really talking to each other properly.
But it's OK. We just, we want to maintain a blood pressure. That's all right.
You can see, we're not maintaining blood pressure. So it's very low and my Doppler reading is agreeing with that. So, I've done one small flow bolus.
So I've done literally a 3 m kilo bolus. That didn't really help. I started then at dopamine CR1.
And that's a drug that's gonna help improve her cardiac contractactivity, period. And that worked really well. Her blood pressure came up to normal.
The ECG arrhythmia continued, but that's OK. As long as I can maintain a good output from her heart, looking after her kidneys and the rest of her organs, then that's fine. She, breathing settled what she had apiine blocks.
And after that, everything remained, thankfully, very stable. And that was, you know, there was a lot of thought and planning went into this. I knew that her blood pressure was likely to be bad.
She's done it previously in other anaesthetics, so I was prepared for it. I had a plan worked out for fluid therapy. I had a plan worked out for a dopamine CRI if I needed it.
So it was just a matter of going, OK, blood pressure is low. OK, let's treat it. We'll just start with C right.
This is her in recovery, so she had a normal body temperature, but she really didn't wake up. She was still very sedated 40 minutes after extubation. She really wasn't kind of coming to.
And one of the problems with calcemia is that it can make drugs last longer than you think. So despite the fact that she's only had a very low dose of dexamincomidine a very long time ago, it may be that it's lasting longer than I think it is. So, can I give her some atoprazole, reverse that, see if that makes any difference.
And yeah, that did. Within 5 minutes, she was sat up looking around and interacting with, with me. So that really made a big difference.
So being where things like that background hypercalcemia, it's gonna make my anaesthetic drugs last a bit longer. I may have to reverse it. And here she is at home enjoying the promised bowl of tuna.
And for her, you can see her ears are up together, her eyes are open. She's got a nice relaxed muzzle. She's got nice relaxed whiskers, her head's up.
She's not in any pain, and that's because she's had really good multi-mod analgesia all the way through and it's going on at home as well. So, it's really important to remember that cats aren't dogs. They do do things their own way.
They have a very unique physiology. And they can hide their problems. They hide heart disease.
They hide kidney disease. They won't tell you about it. You have to go looking for it.
And they hide their pain well. So practise your pain scoring and get better and better, build your experience with it. And it doesn't matter how short the procedure is, it may only be a cat castrate.
They need to have all the monitoring, so you can pick up problems when they happen. They need to have the fluid therapy to keep their, bodies hydrated. They need all the analgesia to help them maintain a good good blood pressure even.
And if you have all of these things, that will make life less stressful for you as well as better for the patient. Thank you very much for joining me on this webinar. Please get in touch if you have any questions, I'll be happy to answer them for you.
Thank you.