Good evening everybody and welcome to a Thursday night members webinar. My name is Bruce Stevenson and I have the privilege of chairing tonight's webinar. I have had some glimpses of the presentation and trust me, we are in for a treat again.
I don't think we have any new members on tonight, so, not much housekeeping. Remember, pop your questions into the Q&A box and those will come through to me and we will chat with Louise at the end of it. So Some of you may know Louise, she's been on with us before, but she's currently works as the clinical support manager for Vets now.
And she's based at the 24/7 emergency and specialty hospitals in Manchester. Louise gained her diploma in advanced veterinary nursing surgical in 2004, followed by her diploma in advanced veterinary nursing Medical, 2007. And then veterinary technician, specialist, emergency and critical care in 2011.
And veterinary technician specialist anaesthesia in 2014. Louise has contributed to over 45 books, journals, articles and book chapters. And she lectures regularly worldwide.
And in 2016, she was the recipient of the prestigious Bruce Vivash Jones Veterinary Nurse Golden Jubilee Award by the RCVS for exceptional contributions to veterinary nursing. Louise took over as the role of president of the Academy of Veterinary Emergency and Critical Care Technicians in September 2018. So who better to speak to us about safe anaesthesia and brachiocephalics.
Louise, welcome back to the webinar vet and it's over to you. Thank you very much, Bruce, and I've never felt more old than I do today. Like, when I, I, I, I did some lecturing today, and, and I spoke to nurses and I was like, I qualified in 2000.
I, no, I qualified in 1999, and I'm pretty sure there were nurses in that room who weren't born in 1999. So it made me feel like, oh, so old. But we're gonna talk about brachycephalic patients.
I think all of us would agree that we are seeing more and more of these patients. Present within our clinics, whether it's for routine procedures or whether it's for boa surgery. And in the hospital that I work in, we predominantly see these patients coming in for boa surgery.
So they have lots of issues to start off with. And we potentially give them lots of issues, kind of postoperatively as well, because of the, the, the procedure that these patients are undergoing. But for me, they are a unique group of patients.
They are patients where we almost can't leave them for any length of time when they come in for anaesthesia, when they come in for surgery, because they just have so many problems. And Today I was talking about the fact that we kind of hope that we are beginning to educate the general public more about all the problems that these patients have, but I'm, I still don't entirely remain convinced that we are doing. So we're gonna talk through why we see the problems in these patients, what anatomical changes we have with them.
And why we see so many problems related to anaesthesia and related, to be fair to these patients in general, when it comes to exercise, when it comes to just the these just these patients generally live in a good quality of life. So, we will talk about brachycephalic airway syndrome, and that's the issue that these patients have got. Normally when I sit in a lecture lecture room and talk about these patients with a group of nurses, I make them do all sorts of things.
So I'm hoping that you may do this at home. So when we look at this airway disease, there are primary components and there are secondary components. The primary components are the fact that these patients have these tiny little nostrils, the stenotic nostrils.
If you look at these animals, they've probably got nostrils. That are, if I'm being generous, half the size what they should be normally to probably more like 3 or maybe even 25% of the normal size nostrils. If I, if you will do, if you'll sit at home and cover up even just half your nostrils and try and take a breath in, you will feel how much of a difference that makes to these patients.
Add on top of that, the fact that they've got these overlong soft palates. You have these really tiny hypoplastic tracheas. You can see already how much more difficult it is for these patients just to take a breath in.
And those pressure changes have secondary effects. We get these secondary components to that brachycephalic disease. They end up with inverted laryngeal saccules.
They can have laryngeal collapse. I talk a lot of the time, but I do lots of stories when I lecture. But I talk about one of my friends came in with his mother's dog, and it came in for a routine procedure.
It came in, it had an abscess that we had to flush out. The bride. But actually, we never managed to recover this dog, and we did a tracheostomy, and that dog did not have any normal tracheal rings.
All that happened with this dog was just collapsing down. When we did a tracheostomy, we had to put a full length ET tube into this dog's trachea because it was just collapsing down around it. It was the saddest situation because there was no way I've been able to get this dog back to normal.
They just don't have normal trachea, so they're, they're likely to suffer from tra laryngeal collapse. They have these averted tonsils and all of this adds on top of these problems that they have of these primary components. They add these secondary components on top, and all of this further narrows down all these, these patients upper airway problems.
Clinically, in terms of clinical signs, what are we going to see? We're going to see that stirtle. We're gonna hear that noisy upper airway breathing that.
We think is normal for patients and owners to a certain extent can think that's normal. We've had clients that said when their patients are coming in for, for boa surgery, I hope that she's still gonna snore afterwards because it's really cute and you're like, This is the reason why we're doing this procedure on this patient is to stop this happening. They've got that inspired dysne, we've narrowed down their upper upper airway, so it's gonna take much longer for those patients to take a breath in.
They're likely to have exercise intolerance. They're likely to have collapsing episodes and also on top of this, they can have GI tract issues and they're likely to have cardiovascular abnormalities as well. And the sad thing is, I would say predominantly more in pugs and more in English bulldogs, these issues that they've got can all get worse as these patients get more overweight.
And those groups of patients tend to be more overweight. Because again, owners think it's cute that they eat breakfast with them and things like that. So it all becomes a worsening problem.
So what we've got is these upper airway abnormalities. We've got that reduction in airway diameter and that's associated with that increase in upper upper airway resistance. If you cover up your nostrils, you'll feel how hard work it is to suck that air into your lungs.
They get greater negative intrathoracic pressure. So, what we get overall is we get dynamic pressure changes in the upper airway. We get increased air airway resistance, and as a result of that, we get inflammation and edoema of those pharyngeal tissues, which is just gonna worsen that whole situation.
As we said already, we've got these respiratory changes, but we also have Cardiov cardiovascular abnormalities in these patients. We've also got GI abnormalities as well. So lots of things are gonna add to these, these airway component changes that we've got in these patients.
We know these patients are likely to be a difficult airway. I talk a lot about the use of, surgical safety checklists, and that's one of the things that we stop and think about before we even anaesthetize these patients is, is this likely to be a difficult patient to intubate? And these patients definitely are.
The risk of including the railway, they're not always that easy to get ET tubes into because they've got that narrow trachea, that overlong soft palate. And also they tend to hyper salivate as well. So, for these patients, for me, it's really important we use laryngoscopes.
We've got a wide range of ET tubes that I know, and I'm gonna say this again during the course of this, this webinar, but just planning ahead for these patients is so important because things can go wrong at any point in time. And for me, if I plan for the worst, hopefully, I'm going to achieve the best in these patients. These little tiny nostrils, this is not the worst case in the world.
But you can see, we've probably Increase the diameter of the, those, those nostrils at least 3 if not 4-fold, but just by taking that wedge out, making it easier for these patients to get those, that, that, that air in like just again, hopefully reducing those dynamic pressure changes that we get in these patients. As we said, we see gastrointestinal problems in these patients. We can see regurgitation.
For any group of patients, the ones that are most likely to regurgitate are gonna be our brachycephalic breeds. They, we can see hiatal hernias in these patients. They definitely have delayed gastric empty and that's gonna, again, contribute to regurgitation.
As I've said already, increased salivation, and all of this puts these patients at massive risk of aspiration pneumonia. So many of our really severe BOAS patients that we see within the hospital I work in end up with aspiration pneumonias because they regurgitate and aspirate either or on recovery or during that postoperative period. And that's with nurses almost being one on one with them.
During that whole recovery period. And we just end up in this vicious cycle. There's lots of things that we really need to plan ahead about in these patients.
They have, as we said, that, that upper airway obstruction. We can see all these changes occurring. So these pat, again, we plan these patients we plan ahead for most of the time I'll talk about hypothermia.
And talk about really trying to make sure we have nice warm recovery areas for these patients. We have nice warm areas preoperatively, nice warm theatres. I'm not saying for brachycephalics, we keep them cold.
But we don't want them getting too hot, because if they get too hot, they're gonna start to pant. That's gonna worsen that upper airway obstruction because we're gonna start to get swelling out of the pharyngeal and laryngeal tissues. That's gonna worsen the upper airway obstruction.
We make it more difficult for these patients to get air into their lungs, and we start to get this dynamic airway collapse, that's gonna result in edoema. That's gonna make it more difficult for these patients to breathe. They're gonna pump more, we get into that, again, worsening hypothermic state.
And it's just this total vicious cycle that we have in these patients. So again, we plan for this as much as we can postoperatively. We plan for the fact that we may not be able to recover these patients first time round.
We may have to go back, re-anesthetize them, reintubate them just to make their life a little bit easier to get their body temperature down back to more, more normal temperature before we re-attempt recovering them again. And I'm gonna say this time and time again as I talk through this presentation. So overall, I'm a veterinary nurse, I'm not a veterinary surgeon, but as a nurse.
I know vets are overall under Schedule 3 in charge of what we do in terms of anaesthesia, but I'm the one that's going to be monitoring this patient. So for me, it's really important that I'm involved in assessing this patient preoperatively. I want to be part of that major body system assessment.
I want to feel what the quality of that patient's pulses are like to start off with. I want to look at the overall perfusion, look at the mucous membrane colour, the pill refill time. I want to have a listen to that patient's lungs so that if anything starts to go wrong under anaesthesia, I've got something to compare it to.
I know if these patients sound like they've got any wheezes or any crackles to start off with. As nurses, we never get taught how to listen to patients' lung sounds. So, whether you're a nurse or whether you're a vet, I would say, go back to practise.
And if you're a nurse, ask your vet to talk through how they listen to patients' lung sounds, how they listen to patients' heart sounds. If you're a vet, go and speak to your nurses, because they're the ones that are gonna be reassessing these patients time and time again. And if I don't know where we were to start off with, how am I gonna know if things start to go wrong during that procedure?
We're also gonna assess that patient's central nervous system, so we want to look at that to start off with because that can have an impact on what drugs we're gonna use and what doses of drugs we're gonna use in these patients. We also need to make sure that we've got adequate renal and hepatic function in these patients because the majority of our drugs are gonna undergo hepatic metabolism and excretion. Some of them are under gonna go renal excretion.
We need to need to make sure we've got adequate profusion of the kidneys as well. So all of these are body systems that we need to assess and make sure we're working properly before we anaesthetize these patients. We can add on top of that lab testing.
So again, for Some of our groups of patients, so generally patients under 6 years old, we would do what we call the minimum database. So looking at PCV total solids, blood glucose, kidney function, potentially looking at lab testing, lactate testing. We could maybe add in your analysis to that.
For older patients, maybe it's gonna be full haematology, full biochemistry, electrolyte testing, and other relevant blood tests. Relating to that patient's condition. Or the procedure that they're gonna undergo.
But again, as a nurse, I want to be involved in knowing what's going on with this patient that I'm gonna place, that I'm gonna be in charge of under anaesthesia. We want to get an accurate history on these patients. We want to know their overall health status, if they're coming in for something non-routine, how long that complaint's been going on for, how severe it is, and what associated symptoms do we have?
We've already said, our brachycephalic patients are at much higher risk of regurgitation and therefore aspirations. So if this patient is presenting because they've got a foreign body, things like that, you know, is aspiration pneumonia a consideration for this patient? I talk about exposure to drugs and that includes drugs that are veterinary prescribed and it includes drugs that are owner prescribed as well, because we all know owners will put their, their animals onto.
Some ibuprofen or some homoeopathic remedy. So we want to know exactly what the animal's been taking and again, For some of our medications, that can have an impact if patients are on, things like furosemide, potentially, they may be hypokalemic, and that can have an impact in terms of, we can see tachycardia and arrhythmias as a result of that. If they're on ACE inhibitors, we may want to withhold that dose of ACE inhibitor prior to that anaesthetic, because that can have an impact in terms of hypertension in our patients.
Wherever I can do, if this patient has been into us previously, I'll try and get hold of that patient's anaesthetic record from prior to the, the anaesthetic we're gonna do to see, actually, do you want to do anything differently with this patient for this anaesthetic this time round? Did anything, did anything go wrong last time? Brachycephalics again.
Potentially gonna present for caesarean section. So, again, we need to think about the drugs that we're gonna use in these patients. We need to think about what can change as a result of that, that, that, that pregnancy.
So again, we know with pregnancy, progesterone is gonna relax the, lower esophageal sphincter. It's gonna delay gastric emptying. So again, that places these patients at higher risk of regurgitation, and again, potentially aspiration.
And we'll also talk to owners about when these patients were last fed. We generally these days recommend a fasting time of about 6 to 8 hours. So that means we should be encouraging owners to feed these patients later into the evening, if at all possible.
If we know these animals are gonna only go to theatre. Early afternoon or potentially late afternoon, we could look at giving them a very small amount of a tinned or a canned diet. And the reason for doing that is so that the contents of their stomach have got an increased pH.
What we don't want to do is if these patients regurgitate, and we don't necessarily know that's gonna, will have happened under anaesthesia. Is to give these patients an esophagitis or, you know, esophageal strictures because all they've done is regurgitate just pure acid. At least if they've got something in their stomach, when they, if they do regurgitate, it's not gonna be quite as acidic and quite as damaging.
So again, these are all things that we think about having that impact on anaesthesia. We think about that procedure, how long it's likely to last for, if it's medical, if it's surgical, put together that pain plan for that patient. For me, I want to know if my patient reacts to, to sort a painful stimuli under the, under anaesthesia, what I can add in in terms of a pain plan.
And think about postoperative pain as well. Thinking about the that risk of haemorrhage and what we're gonna do if that patient loses 10 or 20 or 30% of its blood volume associated with that procedure. Does this patient want to be on fluid therapy?
For me, everything that I anaesthetize, I'm likely to put onto some fluids. And we know in 2011, the American, Animal Hospital Association brought out those fluid therapy guidelines that really reduced the amount of fluids that we were given in patients under anaesthesia. So now they recommend 33 mL per kg per hour in cats, 5 mL per kg per hour in dogs.
And then on top of that, we could potentially bolus in fluids if these patients become hypertensive. And antibiotics. We don't now just give routine antibiotics to every single patient undergoing a surgical procedure.
We think, is it relevant? What we want to do has really is have really good aseptic techniques when it comes to the preoperative preparation of patients in surgery, when it comes to our theatre environment, when it comes to personnel in theatre, as we said, how we prep our patients, things like that. So we're not routinely giving antibiotics for every patient.
We're going to tailor our pre-med and our anaesthetic protocol to that individual patient's temperament. We don't just root again, blanket give all our patients the same pre-med because that's all we do within our clinic. You look at that patient's temperament.
If you've got a very sick patient, you may just be able to go with some opioids and not have a sedative component. If they're in a really aggressive patient, you may need to add in multiple types of sedatives to try and get that patient calmer. To have a, a, a, a much smoother induction period during anaesthesia.
In terms of equipment and expertise, we need to make sure that everything that we're likely to require for that anaesthetic, for that procedure, is set up, ready to go. Prior preparation is so important when it comes to anaesthesia. It's gonna minimise complications.
It's gonna minimise stress for us as veterinary personnel. We'll think about breed and as we said, we're brachycephalic, so we talked about all the issues these patients have got. And we're also gonna add an ASA category.
So ASA stands for the American Society of Anesthesiologists category. So this is a scoring system that classifies patients from 1 to 5. Depending on the degree of underlying disease they've got, depending on You know, what, what presentation these patients are coming in for.
For me, in our hospital, any patient that is an ASA 3 or above, we place two IV catheters into those patients because we want to make sure if something goes wrong, we've got a second IV line in. If we need to add in more drugs, we've got a second IV line to do that in that patient. And if that first line blows, we've got a second line in.
We know ASA 3 or above patients have a much higher risk of anesthetic-related death. So that just again gives us a little bit of backup, that little bit more confidence when we're dealing with these patients. So our clinical examination, as I've said already, is gonna be based around major body system assessment, around appropriate laboratory testing for these patients, thinking about diagnostic imaging, so thinking, do we require radiography or more increasingly these days, ultrasonography.
Do you want to do an ECG on these patients? Are we concerned that these patients may have an arrhythmia to start off with? If I have a patient that that develops an arrhythmia during anaesthesia, if I know it was normal beforehand, then it basically Allows us to know if that, that arrhythmia was maybe related to the drugs that we've given to these patients.
So we know that our opioids, we know that our alpha 2 agonists. Are things that can cause arrhythmias in these patients, but it helps us to decide, do we need to reverse that or potentially was that arrhythmia there in the first place and do we need to treat it? And as we said, we'll apply that ASA score to that patient.
So in terms of brachycephalics, when we think about pre-meds, we know these patients are at really high risk of upper airway obstruction. For me, Bracy phallic, get a pre, we place an IV catheter, they will get that pre-med IV and from that point onwards, they are continuously monitored. These patients, as I said already, at high risk of airway obstruction.
We don't want to give them a pre-med IM, pop them back in their kennel, and come back 1020, 30 minutes later to realise actually, That patient has had an entire upper airway occlusion and has gone into cardiac arrest. So for me, that pre-med goes IV and we stay with that patient at that point onwards. They start to be pre-oxygenated at that point onwards.
We ideally want to use short-acting agents and for me in bracket of Alex, I want to use something that's reversible. And again, it's very much down to what you're familiar with using, but ultimately, these patients are very nursing, very labour intensive patients. I don't like to leave them at all once we've got any sort of drugs on board.
So our pre-meds potentially gonna cause deep sedation, as I said already, we get excessive relaxation of those upper airway muscles, we can potentially worsen that airway obstruction. We are very opioid dependent for me, in these patients in the hospital I work in, there's certainly not contraindicated. We know we can get a dose dependent respiratory depression, but as long as you're aware of that, that's fine.
We know we can see a bradycardia associated with our opioids, but as long as you're aware with that, of that, that's not an issue. So in terms of that sedative component, our options really are going to be are also two agonists like meatomidine, dexametatomidine, or phenothiazones like Aceromazine, or potentially our benzodiazepine, so things like midazolam in these patients. And again, midazolam for me, if there are very sick patients, potentially could be an option.
We can reverse, midazolam. But in healthy patients, and probably for the majority of you listening, you're seeing healthy patients coming in. Even our BOAS patients generally are quite healthy, apart from their respiratory issues.
They're very unreliable. They, they can cause, like, a, a, a real excitement, When we give these drugs to patients, that are not dull or depressed. Aceromazine for me, I like it for some patients, but it's non-reversible.
And once it's on board, it lasts for around 6 hours. So if I start to see issues, there's nothing I can do about it. So, in our hospital, we generally use meditomidine or Dexedatomidine because we've got that option.
I've been able to reverse that drug if need be. We want to pre-oxygenate these patients. I want to preoxidate them for 3 to 5 minutes prior to anaesthesia before we give any of those induction agents.
100% oxygen, and that's gonna maximally saturate that haemoglobin. It's gonna increase the amount of oxygen that's dissolved in that plasma. So that's gonna help to prolong that time to onset of arterial hypoxemia.
It's gonna saturate those oxygen stores, and it's also gonna, so your functional residual capacity is for me, the little bit of air that's left in your lungs at the end of expiration. And we're very much reliant on that little bit of air during periods of, of, of, apnea, which is likely to happen during an induction of anaesthesia. So that little bit of air that's left in your lungs, if it's almost 100% oxygen, it's gonna serve that patient much better.
It's gonna increase that time to desaturation. But ultimately, we want to make sure we do this in a non-stressful manner for our patients. If they're fighting with us, if they're not happy about it, they're gonna use more oxygen than we're actually managing to benefit that patient with.
We're gonna increase oxygen demands overall for that patient. So if that's the case, we'll abandon it or we'll try some flow by oxygen or something like that. As for our induction agents, what we want to achieve with brachycephalic patients and with all respiratory patients is we want to get that ET tube in as fast as possible.
We do things very, very differently with our respiratory patients compared to other patients. We are going to bowl the same that, that induction agent. So we've got the option of propofol versus Alfaxan in these patients.
In our hospital, we will generally these days use Alfaxan more for that because we can give that more rapidly. We've got a reduced risk of overdose, we've got a reduced risk of these patients becoming apne. So we can give that quickly rather than trickling it in slowly, get an ET tube into that patient and take over their airway.
And we also want to think about using agents that are going to be metabolised rapidly. I would say both propofol, both Alfaxan are, are, are both fairly rapidly metabolised. We get slightly less hypertension, potentially with Alfaxan compared to propofol, we got because we get a little bit of an increase in heart rate, which will offset that hypertension that we tend to see.
For intubation, nice wide range of ET tubes available and, and a laryngoscope so we can see what we're doing and we're not causing any further damage. We're not trying to, we're not hopefully causing any for any further laryngeal or pharyngeal swelling than we're gonna get with the procedure that we're gonna do. We always have suction available.
We know all patients are likely to have regurgitation on induction and on recovery. So we have it there in case that happens. And also just to clear out that patient's airways so we can see what they're doing.
Brachycephalic patients tend to hyper salivate more than other patients. So it just allows us to visualise that larynx, that trachea, before we intubate. And I also have an airway box which has got little bits and pieces in case the worst scenario happens.
We've got a stylelet, so stylets are the straight sticks with the curved end that helps to straighten out that ET tube. We have bougie, so this is a bougie. It's bottom image.
This is a bendable plastic coated metal stick, which we could use to potentially introduce the very end of that bougie into that patient's trachea, and then we can railroad. We can, we can force an ET tube over the top of that if we're having a really difficult intubation. I make sure I've got a dry swab.
We all know about grabbing hold of those really slimy, horrible tongs and that's very difficult to do. So a dry swab is really helpful in that situation. And then I've got other bits and pieces.
I've got dog urinary catheters that I've got 3 mL tubes onto the end of them. You can put 3 mL ET tubes onto the end of cannulas, onto the end of, needles, or what I prefer to do is get a 2.5, mL or CC, syringe barrel, and you can put a 7 mil ET tube connector into that.
And again, you can add that onto a needle onto or into cannula. And that gives you a little bit of something. It's a little bit easier to hold on to than holding on to the tiny little bit of a of a 3 milli tube connector.
Potentially having tracheostomy tubes at hand just in case the worst case scenario happens and we can't intubate these patients. Eye care for me, really important. The last thing I want to do is damage these patients' corneas by them either rubbing along the bedding that we've got on our theatre table, or from the drying out because we're using forced airworm devices.
So again, our lubrication and potentially taping those eyes down for me is really important. Maintenance of anaesthesia, we know both sevoflurane and isoflurane cause a dose-dependent depression in cardiac output. They both cause a dose dependent vasodilation.
So what we want to do is minimise that as much as possible. They're also going to cause a respiratory depression. All our anaesthetic drugs are gonna decrease tidal volume and respiratory rate by about 25%.
But those doses, those effects are dose dependent. So we want to try and realistically, without being ridiculous, use the lowest effective va vaporizer setting possible. And monitor that depth of anaesthesia.
I'm not saying I'm gonna try and get all my patients on to 0.5%. I'm gonna be sensible.
I look at it in combination with blood pressure. But what we can use is to minimise those vaporizer setting is we can use those, these multimodal analgesia techniques. So we're only using as much as we can use.
So we'll use local anaesthetic techniques. We will think about the pre-meds that we've used in these patients, and we will think about putting together that analgesia plan. So again, For us, we'll commonly use a full new opioid agonist a part of that patient's pre-med.
So for us in our our clinic, it's most commonly methadone. We can think about topping that up. The downside is that methadone's gonna take about 20 minutes to work, so we could think about again, giving bolus of things like fentanyl, if we're doing something very painful to that patient.
We could think about giving a bolus of ketamine. And then we could think about putting these patients onto continuous rate infusions. So again, fentanyl, ketamine, lidocaine, provided their dogs, all these things.
I will have planned out before this situation happens. I'll know that if this patient becomes more painful, I'm gonna add in this and this and this next because I planned that ahead with that vet that's dealing with that case. So, I'm not having to pester my surgeons when something starts going wrong.
I can just say, are you happy for me to do X Y Z? As the next step in that pain plan. In terms of ventilation of these patients, generally, we're happy with their entitled CO2 as long as it remains below 55 millimetres of mercury.
Normal entitled CO2s are between 35 and 45, but we know our brachycephalics will often have higher entitled CO2s. Again, I've talked about these patients having a reduced functional residual residual capacity. They're often overweight.
They'll often have a reduced tidal volume, so the increased risk of a leptosis of collapsed down of some of those lung lobes, and they're not getting effective oxygenation. They're often not getting an effective profusion. So we were considering these patients mechanical or manual ventilation.
So that's was performing intermittent positive ventilation ventilation. Manually bagging these patients, we could potentially even look at including positive and expiratory pressure. So these patients' lungs never actually collapse back down.
We can get negative consequences of IPPV. So we can cause what we call barrow trauma, so alveolar damage, we can cause volley trauma. So applying too much pressure or applying too much volume when we get to these patients, we can decrease cardiac output because if you give a patient a breath over too long a period, it can squash that cranial vena cava, that's gonna reduce preload back to that part.
We can also see changes in acid-based status as a result of IPPV. So it's not an entirely benign procedure. People also talk about vagal stimulation related to brachycephallic.
So if we're doing soft palate surgery, potentially of our vagus nerve slows down that patient's heart rate. So again, we'd monitor that to make sure these patients weren't becoming bradycardic. If they were, and if it was negatively affecting blood pressure, we could look at using an anticholinergic.
So we could use something like atropine. Or potentially glycopyrolate. So we'll have doses worked out ahead of time for these patients.
We're gonna hopefully have these patients on some fluids, so we give use fluid therapy because these patients are likely to have changes in blood volume, so they may be dehydrated, they may be hypovolemic. May have changes in terms of the content of their blood. So they may well be hyperkalemic or changes in distribution.
So they've had they've had third spacing of fluid, so effusions, things like that. So we're gonna use fluids to correct normal ongoing losses to support cardiovascular volume, to to to maintain blood, body fluid volume during long anaesthetic periods and working in referral. We can see some very long anaesthetics in our patients.
We're gonna use it to counteract. The potential negative physiological effects that we get associated with anaesthetics. So hypertension being the big one, vasodilation being another one, and it helps to maintain a patent IV catheter.
It stops us getting clots in that catheter. Because we may need that in emergency. And as I've said earlier, our maintenance rates have now changed from that 10 mL per kg per hour to 3 mL per kg per hour in in cats, 5 mL per kg per hour in dogs.
We want to monitor these patients accurately through that whole anaesthetic period from pre-med. Through to recovery. They need to have a dedicated anaesthetist.
We those need to be happy in terms of the monitoring equipment that use for these patients, but as well as using things like hapnography, ECG monitoring, blood pressure monitoring, we need to make sure we're hands on with our patients, palpating pulses, looking at mucous membrane colour, capillary refill time, jaw tone, eye position, all of those things to build up that bigger picture of what's going on with those patients. So pulse oximetry, really useful. It tells us that patient's pulse rate, it tells us how well that haemoglobin is saturated with oxygen.
Although I'm gonna have it on those patients during the anaesthetic, for me, it's really useful when these patients are breathing room air rather than 100% oxygen because it picks up early on in those patients breathing room air during that recovery period, if these patients are at high risk of upper respiratory tract obstruction. Capnography also useful in these patients. So this top image is a normal catnogram where these patients start to exhale at this point in time.
At this point, they're exhaling dead space gas. So this is gas in the trachea and the oesophagus, which hasn't undergone gas exchange. So it's not got much carbon dioxide in it.
And then we get this rapid up stroke here as we get start to get further down that respiratory tract. Then we get an alveolar plateau and this patient then starts to breathe in here and it decreases very quickly back to 0. With brachycephalic patients, they've got that narrowed down upper airway.
So we don't often get this nice sharp upstroke. We get what was called a sharp shark fincapnogram, and this demonstrates delayed emptying and the alveoli. It's taking longer because of that narrowed down upper airway to get that carbon dioxide being exhaled from those patients' lungs.
Blood pressure, we also want to measure in our patient's blood flow estimates, blood pressure estimates blood flow to that patient's tissues. And blood pressure is determined by that patient's cardiac output, and cardiac output is heart rate multiplied by stroke volume. So stroke volume being the amount of blood ejected from the heart with each heartbeat.
And this is multiplied by systemic vascular resistance, the amount of vasodilation. And the amount of vasoconstriction we've got. So patients will increase or decrease their heart rates.
They will vasoconstrict, vasodilate to keep their blood pressure within a normal range up to a certain point. So when we measure blood pressure, it's written as systolic over diastolic, so systolic pressure is measured when we get contraction of the heart. Diastolic when we get relaxation of the heart.
And we've got two main techniques for measuring. So that's direct blood pressure monitoring or invasive, which involves placing a catheter into an artery in that patient, which is a little bit more technically a bit difficult. It's more invasive versus non invasive or indirect measurements, and that's gonna be Doppler or oscillometric techniques.
So again, a lot of you, if you've got multi parameter monitors are going to be utilising oscillometric techniques. So our big concern about our patients under anaesthesia is going to be hypertension. So hypertension is defined as being a mean arterial pressure less than 60 or a systolic less than 90.
And at these points in time, our concern is that we are not got adequate tissue perfusion in our patients. We're not getting that oxygen being delivered to those tissues, and we're also not getting oxygenated blood being carried to our major organs, predominantly heart, kidneys, and brain. And if that poor perfusion state continues for any length of time, eventually what will happen is we're gonna end up with hypoxia, we're gonna end up with an acidosis.
And so, and that's going to lead to further deterioration in our patients. And that can happen because we've got reduced cardiac output and or because we've got reduced systemic vascular resistance. Those patients that are massively vasodilated.
So we really want to avoid that situation happening as much as possible. It can happen for various reasons. It can happen because these patients have significant bleeds.
It can happen because of reduced venous return, because of hypovolemia, because of haemorrhage, because of the way we ventilate patients. When we give a patient a breath using IPPV, we potentially increase in intrathoracic pressure that can compress your cranial vena cava and reduce blood flow back to the heart. It can happen because of position.
So patients in dorsal recumbency if they're overweight or pregnant or got abdominal masses, can squash your cordial vena cava again, that's gonna reduce preload. It's gonna reduce blood flowing back to the heart. It could happen because of bradycardia or really severe cardiac arrhythmias, because patients are septic and they're vasodilated everywhere, and we don't to anyone in one point in time, have enough blood volume to fill up our whole vascular system.
So those patients having relative hypovolemia. As a result of that. And it can happen in our patients that have got cardiac disease as well.
So we need to think about when we have patients that are hypertensive, why it's happened, it's important to establish whether it's because they're vasodilated, because they're bradycardia, because they've had significant haemorrhage, because they're in heart failure and they've got reduced contractility. So I'll think about the reason why it's happened, I'll have a look at the depth of my patients. So I'll look at cranial nerve reflexes.
I'll look at entitled CO2 and think, can I reduce my vaporizer setting in this patient? I will think about, are they massively vasodilated? And if so, we would look at potentially using drugs that are gonna make these patients vasoconstrict.
So that's looking at using our vasopressors. So think looking at using things like noradrenaline or norepinephrine. I'll look at using things like atropine.
If this patient's bradycardic and it's impacting on blood pressure, I'll look at how I can increase, increase that patient's heart rate. I'll think about has this patient had significant haemorrhage? If so, do we need to give blood products?
Do we need to give a bolus of crystalloids to increase preload in that patient's heart? When we're looking at blood pressure, it's important to make sure we're using the right, the, the right size cuff on that patient. That's really important to make sure our blood pressure measurements are accurate.
If that cuff's too big, it's gonna under underestimate blood pressure. If that cuffs too small, it's gonna overestimate blood pressure. And also, that wants to be about the same height, about the same height as that patient's heart.
So again, we'll think about positioning of that limb to again, to make sure it's accurate. So that cuff, that width of that cuff wants to be about 30 to 40% of the circumference of that patient's limb, and that's really important. All your measurements are not going to be reliable.
We want to think about ECGs in our patients. So I'm doing a quick, very fast whiz through of that specialist conduction system. So in the heart, electrical activity is conducted in one of two ways.
We've got, we've got cell to cell transmission, which is a little bit like dominos. So if one muscle cell fires, the one next to it will fire. But there's got to be something else that stops that, that when we look at an ECG it being just one big wave, and that's the specialist conduction system.
So that's the sinoatrial node, the atrioventricular node, the bundle of his left and right, and the Pikinji fibres. So every normal cardiac cycle starts in the sinoatrial node. It's in the wall of the right atrium.
It's a specialist group of cells, and that's our primary pacemaker. So that's where, if everything's working as it should do. Every normal cardiac cycle starts there.
So our cells in our sinoatrial no depolarize. We get a wave of depolarization across the atria. And when we look at our ECG that's what we're seeing when we see our P wave.
That P wave, when we look at it, when we look at that whole ECG, we've got a little bit of a pause between our P wave and our QRS complex. And that's because we've got a fibrous ring that sits between the atria and the ventricles, and that stops that wave of depolarization immediately spreading to the ventricles, and it stops it being just one big wave altogether. But there's got to be a way of that electrical activity getting through to the ventricles, and that's through our AV node.
Our atrioventricular node is the only electrical connection between the atria and the ventricles, and that's made up of slow conduction fibres that cross that insulating layer. So that's why we see that slight pause between our atrial and our ventricular contractions. And when we're looking at our ventricular contractions, That's when we're seeing our QRS complex.
So this is where we've got that bundle of his, as you can see here, conducting that wave of depolarization down the septum to the apex of the heart. We then have our Pinji fibres that conduct that impulse from the apex of the heart to the myocardium of the ventricles. So that's our QRS complex.
So when we look at an ECG, and I know this is not an entire elect on ECGs, but that's when we look at our ECG, we've got to have our P wave, which is our atrial depolarization. And as we said, we've got that little, little pause, whilst that impulse, that electrical activity gets through that at the AV node before we get to our ventricular depolarization, or QRS complex, and then we get our T wave of ventricular repolarization ready for everything to happen again. So why is this relevant?
Well, our big concern with brachycephalic patients. Is they're becoming bradycardic. They're much more prone to bradycardia.
Heart rates are often reduced under anaesthesia because the drugs that we use, all of our drugs are going to have an impact on that cardiovascular system. For me, depending what drugs they've had, my concern is if animal, if dogs have a heart rate less than 50 to 60, if cats have a heart rate less than 100. Now, that will very much depend on what pre-med they've had.
The impact that bradycardia can have on anaesthesia is it can reduce cardiac output, it can reduce blood pressure. We know certain drugs are going to cause a bradycardia. Our opioids, particularly if you bowl us in, an opioid can cause a bradycardia.
Our alpha 2 agonists, bradycardia happens for a reason. It happens because these patients become hypertensive because they vasoconstrict. So again, when if I've got a patient that's had metomidine.
I'll look at that bradycardia in relation to that patient's blood pressure. If their blood pressure is fine, I'm not always that particularly concerned. I don't think about reversing it.
Other things can impact hypothermia, vagal stimulation, and the vagus nerve is particularly important to our brachycephalics. I'll talk about that in a second, if they're too deep under anaesthesia. So one of the things that we can see in our brachycephalics is sinus arrest.
So sinus arrest is where we get a big long pause between ECG complexes, and we'd be able to fit in. Two other complexes normally during that pause. So they're irregular pauses and sinus arrest is exaggerated by patients with vagal tone, and our brachycephalics are patients that have increased vagal tone because they have those upper airway changes, they ultimately have upper airway obstruction.
So when we're putting this all together, we want to think about all that information, as I keep saying, we're building up that big, bigger picture of what's going on with these patients. We're using our hands-on monitoring. In combination with using that information that we've got from blood pressure, from catnography, from ECGs, from pulse oximetry to figure out what's going on with these patients.
What's also important is the use of accurate anaesthetic record sheets. If you've got not got anaesthetic record charts that you think are the greatest, the Association of Veterinary Aesthetists have a wonderful website. You can join that organisation, you get webinars, you get access to the Journal of anaesthesia and analgesia.
And, but you can also download the in the, the, checklists and the charts. So you can download their anaesthetic monitoring charts. You can download their anaesthetic checklists that go through anaesthetic machine checklists that go through patient checklists that go through breathing system checklists.
They're well worth downloading just to try and prevent problems happening in our patients. Coming towards the end of this, when we think about recovery of patients, for me, I will try and recover these patients from external recumbency. I'll try and keep their head elevated.
The one thing I didn't say at the beginning was for induction of anaesthesia, for brachycephalic, we will keep their head up during induction. Until they've got an ET tube in place and until that ET tube is cuffed. Only once that ET tube is cuffed do we put them into lateral recumbency because of our concern about these patients regurgitating and aspiration.
We know regurgitation is most likely to happen on induction and on recovery. So we really want to plan ahead to avoid problems happening. The other thing that I always talk about is avoiding that aggressive initial stimulation.
I've seen it happen so many times where nurses want these patients to wake up because they know they need to get on with the next case. We avoid overstimulation. If I wake up in the morning, I'm a massive snooze button person.
So, if I woke up in the morning and I, instead of pressing, pressing snooze on my phone, I press stop. And then close my eyes, I'm likely to go back to sleep. And I always think it's the same for our patients that during recovery.
If you try and wake them up too quickly to extubate them, put them back in a kennel, they're likely to go back to sleep again. And our brachycephalic patients, we've still got that relaxation of the upper airway muscles, laryngeal pharyngeal muscles, and they're likely to occlude their airway. I love to use pulse oximetry in these patients during that recovery period.
We know it's going to be much more useful. And patients breathing room rather than 100% oxygen. We also plan a Head for whether we want to supplement oxygen in these patients, you can see this little, this little brachycephalic patient here has got a nasal oxygen catheter in.
I generally tend to place nasopharyngeal oxygen catheters in these patients rather than nasal oxygen catheters because Their nose is so close to their eyes. If we pre-measure that nasaloon catheter, the medial or the lateral campus, it's not gonna sit that far into that patient's upper airway. So I tend to pre-measure to the, to the, the, the, the ramus of the jaw, to the angle of the jaw and insert it that distance.
And it sits over a much wider space so it's much more comfortable for those patients. So these are the ones where we know we've done lots of surgery on them. We know they're likely to require oxygen supplementation.
So we'll place these at the end of that procedure. For me, all those patients get recovered with an additional amount of induction agent, as we used to induce anaesthesia, and at the size of ET tube placed and at least 1 or 2 sizes below that because these patients are at high risk of occluding their airway during that recovery period. We also make sure they're not at risk of overheating.
As I said, I tend to keep the kennel area a little bit cooler. Ours will always get recovered in our ICU area, which is open plan. So it tends to not get as warm as some of our kennel areas because we don't want them to get into that vicious cycle of getting too hot, panting, overheating, and causing, again, laryngeal, pharyngeal swelling, edoema.
So this is a classic patient where we had to sedate this patient, we had to go back in, reintubate. It was following a a a tikka surgery. But if you look at him, he's just getting so stressed, he's gonna overheat really quickly.
If we don't over, if we don't intervene, that patient's likely to go into respiratory and cardiac arrest, so we do something about it sooner rather than later. For recovery, I'll keep their mouth open, I'll keep their tongue pulled out, as I said, potentially think about sedating them if they're getting stressed. What I also like to do is put a little bit of bandage or something.
Between the incisors. So if they do start to get light a little bit too soon, and I, and I don't catch them, it means that they'll bite down on that rather than biting down on their their ET tube. So I can remove that without the risk of them biting through it.
And I've said already, I'll keep them cool and we recover them. Me and Bruce were just chatting about this before the webinar started. I used to have a video of a bulldog walking around our prep room in my previous practise, but you can see from this dog, he's up.
He's pretty awake there, he's aware of what's going on, he's looking around, but he's still intubated. It's a recovery, an ET tube is a holiday for a bracket of Alec. One of the things that we, so there has been one paper on this that I know was published by Liz Lees and I think one of the author that looked at the use of adrenaline to try and reduce the incident of edoema, incidence of edoema in these patients.
So they're basically nebulized adrenaline. That adrenaline's going to cause vasoconstriction. It can reduce that .
Edemia, it can also potentially cause some bronchodilation, which may be useful in these brachycephalics. And so basically, the paper that they talked about, talked about using 0.3 mgs of adrenaline diluted into 5 mLs of saline and nebulize to these patients over 5 minutes.
Again, we want to protect their eyes and you could potentially repeat this. So this is what we may consider in those patients where we are really struggling to recover them, we've maybe done it once, twice, 3 times before. And had to go back in and reintubate.
The other thing that we could potentially look at using is antihistamines in these patients, using things like chlorophenamine. In human studies, they talk about, decreasing salivation in these patients. So again, that's potentially an option that you can go to if you're really struggling to recover them.
One of the things that I like to do is dental or facial blocks in these patients. The one, and again, we will do this because a lot of the time we're doing this, this not the, the surgery on these patients' nostrils to open them up. Again, and I'm always about the analgesia.
So one of the procedures that we will do is an infraorbital block. Now, in a normal shape patient's head, that infraorbital canal is reasonably long. In a brachycephalic, it's almost nonexistent.
And basically, placing that block into that infraorbital canal will desensitise everything from this point forward, forwards. So we can use it for dental procedures, but as I said, I use it a lot when we're doing nostrils on these patients. But just being aware of how short that is.
So in a normal patient, I would introduce a needle into that infraorbital canal. With a brachycephalic, I'm not gonna do that. And this is a cat skull and for the same reason in cats, we're a little bit more cautious because what I don't want to do is pop that patient's eyeballs.
So I will literally introduce that block. I place my needle just at the entrance and inject there, and then put a finger over once it's done, and it will help to desensitise that whole nerve. In terms of anaesthesia protocols, we want to think about careful conservative use of sedatives in these patients.
Think about things that are reversible. I want to get them up and back to normal at the end of that procedure. I'll have a nice wide range of ET tubes.
I want to pre-oxidate these patients in a non-stressful manner. Utilise that rapid intravenous induction technique. It's almost the opposite of what we're we're familiar of doing.
We're normally used to trickling in our induction agent and these patients we want to get them asleep, so we can get that ET tube in. Think about using agents, as I said, that allow rapid return of consciousness. So a reversible agents.
Keep that ET tube in as long as it's possible, and once we extubate, keep a close eye on them. Observe for abnormal breath sounds, listen to their chests, observe their respiratory pattern, look for things like paradoxical respiratory patterns that can indicate these patients are in respiratory difficulty. Use pulse ox image to guide you if these patients are hypoxemic.
And be prepared to To be prepared, be prepared for these patients to need reintubating if they do obstruct. So again, try and keep that upper airway open during recovery. In terms of fasting times, we, again, I think I've said this already, we've generally patients for about 6 hour fast though they don't have big full stomachs full of food that are going to compress the diaphragm, reduce tidal volume.
If we've got patients where we know they've been repeatedly regurgitating, we would think about placing a nasogastric tube conscious prior to anaesthesia. And suctioning out the con the, the contents of the stomach or immediately following induction of anaesthesia and intubation, we will place a stomach tube to empty out the stomach contents. So during the anaesthetic period, they're not gonna have anything in their stomach, so it reduces the risk of regurgitation and potentially aspiration and certainly regurgitation and causing esophagitis.
Or esophageal strictures. We think about using, so most of our patients, we will put on proton pump inhibitors a couple of days prior to anaesthesia. So they're gonna increase that gastric pH.
They reduce the risk of a gastroesophageal reflux. You could think about using things like metoclopramide that will promote gastrointestinal motility and again, reduce that incidence. Of reflux in these patients, and also the use of neurropotent.
So, the murropotent is gonna be useful in terms of post-op nausea and vomiting. Pooperative nausea and vomiting is a common phenomenon in human anaesthesia. And our patients probably have the same issues, but unless you're looking, we see so many patients that are nauseous postoperatively.
It's got to be wholly unpleasant. So again, we can use drugs like Neropotin to reduce that risk. And if you feel nauseous, you're likely to hypersalivate, and our concern in brachycephallic is hypersalivating and aspirating that saliva as well.
So these patients were constantly aware of that risk of airway obstruction. So in summary, we avoid excessive sedation in these patients. We use.
Alpha 2 agonists very carefully. So we tend to use dexamedatomidine at 0.5 to 1 mcg per kilo.
If you're gonna use aceromazine, you will use that maybe at half your normal dose, very, very low dose. Certainly pre-oxygenating them for 3 to 5 minutes, if possible, using a fairly tight fitting mask. So we're gonna maximally saturate our haemoglobin.
We're gonna increase our our PAO2 in these patients. Using short acting induction agents, a nice wide, wide range of ET tubes and only extubating these patients when they're up, they're around, and they're starting to really chew on the ET tube. So they're bright and alert and being really careful if you do perform those infraorbital blocks, because that infraorbital canal is so short in this patient.
So this is very sad. This is my old brachycephalic that I lost. 2 years ago now, we still miss him in our house.
He was the loveliest mastiff. So even though I talk about not recommending them, he was just the loveliest dog. Laziest but loveliest.
So I'll hand back over to Bruce for questions. Thanks, Louise. That was absolutely amazing and like all good leaders and that it's do as I say and not as I do.
I think. Louise, that was, that was really a, a whistle stop tour and I feel like, had you not been talking all day and had we had another hour or two, we could have kept you going on and on and on and I'm sure everybody would have been hanging on every word. So thank you so much for your time, your effort, your long drive to get back to us tonight in time.
You're very welcome. Most of the questions that have come through, you've already answered and, some of them, the people that posed them have gone, oh, OK, thanks, she's answered it now. So we don't have any extra questions for you, tonight.
I think your presentation was fabulous and You, you have covered all the things that were popping into people's minds as we were going along. We do have a lot of thanks coming through and, as Anthony always likes to say, if we were in an auditorium, you would be getting thunderous applause. You're too kind, Bruce, every single time.
Couple of things just to discuss quickly with you. when you have these little brachiocephalics, they often are so hyper-excitable. How do you find that, putting a catheter into them without stressing them and putting them on oxygen without stressing them?
That's a good question. So I mean, we love to have our plans in place, but we did have a, an English bulldog a few weeks ago. That came into the surgery for boas for a boas procedure and he hated being there.
And I think the problem that we sometimes can have with these patients is particularly bulldogs tend to have pretty horrible skin as well. And that dog was just getting so stressed out. And I always say we place an IV catheter and then we sedate them.
But this dog, it was just not happening. There were 4 of us, and that included 2 ECC diplomats trying to get an IV line into the dog, and it was just getting worse and worse and worse. And we ended up going IM sedation.
And we repeated that procedure twice till we finally managed to get an IV catheter into them. So, we can all talk about what happens in an IV ideal world, but, you know, Sometimes you've just got to say. This patient was meant to go into theatre 23 hours later, but we just had to take him into theatre there and then.
And we got so close, like, we were very concerned he was going to go into respiratory arrest because he was just getting so stressed out by the whole thing. So, we did do IM sedation in that patient. The one thing I would say is we use 1-inch needles rather than 5/8s to make sure those drugs go IM and not subcutane subcutaneously, because these patients are often overweight.
So, and again, if I'm really struggling to get a cut down, I will go, rather than going cephalic, I'll go a little bit further down. And we had a patient on Wednesday where he was only 7 months old, but he just had the worst skin. I could not feel a cephalic vein, and I couldn't even go dorsal pedal or anything like that.
We eventually managed to get an IV line in him, but our concern in those patients is we struggle to get IV access sometimes. I've got, I've got no real answer, otherwise, other than we'll give them some sedation, try to calm them down a little bit, and then get IV access. And if you're gonna do that initial sedation, you're using meatamidine or Dexatom.
Yeah, just so that I I just like to be able to reverse them. Yeah, especially when they, the ones that are bouncing off the walls are the ones that tend to go flat. And the problem with it, you know, I mean, I don't dislike Aceromazine, but the problem is you can't reverse it and once it's on board, it's on board for about 6 hours.
The other, the other thing that you mentioned which I, I haven't seen before, which is a really, really neat trick, is that bandage between the incisors. What do you use? Do you use a, just a, a little bit of crepe or what do you use?
I mean, even if you just save the cardboard, that's from the inside of your cohesive bandage, just something, just to put between those incisors. So if they start to bite down on that ET tube, you know, you can remove it, and you know you can get that bandage out. So, rather than waste a little bit of Duraport or whatever you've got in the practise, just Keep those fold, keep those, those cardboard rolls at hand so you can just fold them in half and pop them between the inside and they're not exactly, exactly.
And they, and to be honest, they don't tend to do. We can normally manage to drag it out. Yeah, as as we were talking before we went live, these guys are so pleased just to be able to breathe that most of them are quite happy to just leave it in place.
And, you've mentioned it quite a few times, but, having them up in sternal recovery, sternal recumbency for recovery and induction is so, so they're gonna be able to ventilate and therefore oxygenate much better if they're internal compared to that they don't panic as much when they wake up internal. Yeah, I mean, if you've, if anyone's ever had an aesthetic, it's not a pleasant process like. I'm amazed that they tolerate ET tubes because I've had surgery and my outstanding memory was waking up with an ET tube in and not, and I, I could breathe but I was probably panicking about this thing being in my throat.
So the fact that these patients are fairly calm about it says that they must spend their life, I mean they spend their lives dysneic and probably hypercapnic as well. Yeah, it, it's sad, but it becomes the normal state for them. It becomes a normal state, and I feel like we think we're educating owners much more, but still owners.
Don't realise that it's pugs and French bulldogs as well as English bulldogs. Yeah. I think another thing that's really important is, is, you know, don't, don't try and shy away from these anaesthetics.
Nowhere in your presentation did you say, oh God, don't give these guys anaesthetics. You've you've gone and said no, pre-plan. Prepare for the worst and then make it the best.
Yeah, absolutely, and I, I did a lecture in San Francisco last year. And someone stood up in the audience and said, what I do for my bracketcephalic is I give them some oxygen with a mask, and I was like, perfect. And then he said, I slowly turn up the vaporizer, and I was like, Oh my God.
I've just spent 45 minutes saying, we need to get an airway on these patients. Like, they're so high. Like, I know of, like, I know of patients that have died, not in my clinic, but in other clinics because they've had a pre-med.
And then gone back to a kennel and been left there. They're just such high risk that I would never leave them alone. I mean, but I'm very lucky because I work in a clinic where we can do that.
Yeah, but you know what gassing them down was was what, 2025 years ago. It was considered to be the least stressful way of anaesthetizing them. But then at those stages we were, and I'm I'm I'm joining my age to yours here that we were using things like thiopentone.
So it maybe was better to give them inhalation anaesthesia. I didn't hate that. It was all right as long as we knew what we were doing.
But they just tended to sleep for a long, long. Well, if they were fat, they were fine. It was, it was our skinny little greyhounds that were the issue.
Yeah, you showed them a bottles, that's all we have time for tonight. I'm sure like you would love to just get Louise. On another presentation and just keep going.
But I promise you we will, we will convince her to come back again. We love listening to you, Louise. Thank you for your time.
I really appreciate it. Thank you, Bruce. You're always too kind.
Folks, that's it for tonight to fill my controller in the background. Thanks for everything and helping it run smoothly. And until the next time, goodnight everybody.