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Dr. Gianluca Bini explores the complexities of anesthetizing dogs and cats with intracranial disease and seizure disorders
197 Plays10 days ago
In this episode of the North American Veterinary Anesthesia Society Podcast, host Dr. Bonnie Gatson is joined by veterinary anesthesiologist, Dr. Gianluca Bini, to explore the complexities of anesthetizing dogs and cats with intracranial disease and seizure disorders. Together, they discuss key physiologic considerations to know before anesthetizing any patient with a brain disorder, including the interrelation between cerebral perfusion and intracranial pressure and factors that can alter this crucial relationship.
From managing intracranial pressure to choosing the right drugs when the brain’s already a bit on edge, they’ll cover the critical considerations that keep these cases from becoming true cranial chaos. Dr. Bini, owner of SafePetAnesthesia LLC and Assistant Professor of Anesthesia and Analgesia at Oklahoma State University, brings his signature mix of brainpower and practical know-how to the table. With experience in both academic and clinical practice, plus a passion for keeping anesthesia safe, he’s the perfect guest to help us navigate the grey matter of navigating the challenges of anesthetizing neurologically compromised patients.
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Transcript
Introduction to Anesthesia Challenges in Neurologic Pets
00:00:06
Speaker
Welcome back, Gas Passers, to another brain-tingling episode of the North American Veterinary Anesthesia Society podcast. I'm your host, Dr. Bonnie Gatson, and today we're diving headfirst into the fascinating and often high-pressure world of anesthetizing dogs and cats with intracranial diseases.
00:00:27
Speaker
These are patients that can present to you with seizure disorders, head trauma, or random behavioral changes that will need sedation or anesthesia for stabilization, diagnostic procedures, or even surgical correction of these diseases.
00:00:44
Speaker
This episode is all about equipping you with the knowledge and clinical pearls you will need to safely and confidently anesthetize these neurologically fragile patients.
Support and Resources for Veterinary Professionals
00:00:55
Speaker
But before we dive into this topic with our special guest, we here at the NavVest podcast want to give thanks to the generous support of DECRA, a proud sponsor of the North American Veterinary Anesthesia Society.
00:01:09
Speaker
With their commitment to innovation and excellence in veterinary care, DECRA helps bring conversations like this one to the forefront of our field. Visit www.decra-us.com to learn more.
00:01:22
Speaker
Also, if you've been enjoying this podcast and you haven't done so already, why not take the next step and become a member of the North American Veterinary Anesthesia Society? As a member, you get access to hours and hours of free anesthesia-related CE and forums where you can reach out and connect with an amazing community of gas pastors just like you.
00:01:46
Speaker
Visit www.mynavas.org to advance your anesthesia journey today.
Expert Insights on Neurologic Pet Anesthesia
00:01:53
Speaker
Joining us for this brainy conversation is none other than Dr. Gianluca Beeney, owner of Safe Pet Anesthesia LLC and assistant professor of anesthesia and analgesia at Oklahoma State University.
00:02:07
Speaker
Dr. Beeney brings a wealth of experience in managing complex cases, and today he's here to help us unpack the physiologic considerations and and anesthetic strategies that matter most when the brain is the primary concern.
00:02:22
Speaker
So cue up your monitors and let's get cerebral right here on the Navas podcast.
Key Challenges in Neurologic Anesthesia
00:02:32
Speaker
Today we're going to be diving in to anesthesia for a tricky but like very super important group of patients, which is going to be those with some kind of neurologic disease, whether it be an intracranial tumor or seizure disorders or those of the like. And so I'm really excited to have an awesome guest on today. We have been friends for a while and actually we were just talking. We haven't seen each other in a long time. So it's really nice to see him again, but i'm going to let him introduce himself and tell us a little bit about what he's doing.
00:03:08
Speaker
Thank you, Bonnie. Thank you for having me. I'm Dr. Gianluca Bini. I'm an assistant professor of anesthesia and analgesia here at Oklahoma State University. I'm also owner and founder of Safe Pet Anesthesia.
00:03:21
Speaker
I started my veterinary journey back in Italy. i got my DVM there. I did two internships in England, one in anesthesia and one rotating. And then I did my residency at NC State.
00:03:35
Speaker
This topic is actually one of my passions. And this was one of my residency projects. like we We actually studied how... You know, propofol, olfaxelone, and isofluorin affect the cerebral blood flow and cerebral vascular activity in dogs.
00:03:51
Speaker
So I'm really, really passionate about everything like neurologic. We did another study with Eric Hofmeister last year, I think, on like how...
00:04:03
Speaker
When anesthesiologist, the cushion reflex doesn't really correlate really well with how how much the brain is herniating or not. Like, you know, the the MRI findings actually don't really matter what we sometimes see on our monitor. So I really love this topic.
00:04:19
Speaker
They're tricky, right? Like these guys are really tricky. There is a lot of things to think about. And unfortunately or fortunately, you know, for us, because it keeps us in business. But, you know, it's really cool.
00:04:32
Speaker
Yeah, I agree with you. And I ask side topic because I hear that you are very excited about neurophysiology.
Choosing Anesthesiology Over Surgery - A Personal Journey
00:04:40
Speaker
But i ask all my guests this.
00:04:43
Speaker
What is your favorite thing about being an anesthesiologist? Oh, I think that, you know, we...
00:04:54
Speaker
you know, caring for these patients in a very special moment for them, right? Like we, anesthesia is probably the closest you're ever going to be to death, right? And i think I think having the honor actually of doing that, right? Like we we keep these patients alive. We keep these patients pain-free.
00:05:16
Speaker
We wake up these patients afterwards, hopefully. If we're going to stay in business, we better be waking up all these patients. Yeah, yeah, yeah. Usually that's... That's how you go out of business if you stand out waking them up. But, um you know, no, in general, like, I think it's a, you know, it's a really cool profession.
00:05:37
Speaker
Some people try to sway me the way of surgery, right? But that earlier on in my career, it sounds very mechanical to me, right? Like very repetitive, very, very...
00:05:49
Speaker
you know, hands-on, but, you know, I think the mental side of things here, like, that's what got me into anesthesia, right? The fact that you need to think a lot and you need to, like, there's plenty of different pieces.
00:06:02
Speaker
It's a huge puzzle, right? Every time we do we do one of these cases, you know, it's, so I think that that's what makes it cool. Yeah, I think i hear what you're saying about the kind of the multitasking or like the mental gymnastics you have to do.
00:06:16
Speaker
but I was in vet school, one of my like favorite things to do, which sounds crazy, is that we would have like rounds, like medicine rounds. And then you have to think about each thing that was happening with the patient and then come up with like a bunch of differentials. So like the dog has ah high white cell count.
00:06:33
Speaker
What are the possibilities? and And then you go to like, what are the tests you could do to figure out which one of those things is going on with the patient? And my brain just naturally does that all the time but like everything.
00:06:45
Speaker
Whereas, you know, surgeons are like, oh, it's bleeding. I just stopped the bleeding, you know, and I, it's fine. Like, that's a great, it's great to be that way. But my brain's always thinking, okay, if this, then that, if this, then that plan A, plan B, plan C, plan D. And I like, I don't know, maybe I'm mentally ill or something, but that's like how my brain structures things. And so I find anesthesia fits so nicely into that model.
00:07:11
Speaker
Yeah, yeah. it's It's interesting, right? The first question i always get asked, and probably you get asked the same thing, right, from clients or students or whatnot, that they're like what's your favorite protocol, right? And they think that you can narrow it down to a recipe, right? The perfect recipe that saves your ass every time, right? and That doesn't work, right? There is no perfect protocol.
00:07:33
Speaker
Every patient is different. You know, there is no cookbook, right? I mean, there is a perfect protocol, Jean-Luc, it involves ketamine. I'm kidding. Okay. I promise I'm kidding.
00:07:44
Speaker
Especially, I think it's like, that's a really good segue into like what we're going to talk about today because ketamine is like a very controversial drug. Highly debated. Highly debated. With these particular types of patients.
Understanding Cerebral Blood Flow in Anesthesia
00:07:54
Speaker
So I think we should start first thinking about some neurophysiology because I think that will help when we start talking a little bit more about medications that we're going to use such as ketamine, for example.
00:08:07
Speaker
But when we're thinking about anesthetizing these patients, We do really have to have a good understanding of what's happening inside the skull. The skull is special because it's an enclosed space.
00:08:21
Speaker
And so when things go wrong, like you get bonked in the head and there's inflammation or there's a tumor something like that, there's not a lot of room for swelling. yeah And so that's what really complicates managing these patients under anesthesia.
00:08:37
Speaker
And so before even pick up a drug, we really need to understand, you know, cerebral blood flow, cerebral fusion pressure, and cerebral metabolic oxygen rate, and like all these other acronyms, essentially, that can be really confusing to sort through, but are really important to understanding how to actually manage these patients under anesthesia.
00:08:57
Speaker
So let's just start with, can you walk us through what happens when to the brain if you have your intracranial pressure start to rise because you have trauma or inflammation or tumor.
00:09:13
Speaker
So, yeah, as you were mentioning, you know, the skull is an enclosed space, right? There is no way to expand it. There is actually only one way out of it, and that's through the foramen magnum, right?
00:09:24
Speaker
And that's where the brain tries to go when there is too much pressure in it. And that's when you get your cerebral irneation or cerebellar irneation, depends which part, you know, actually does go out of the foramen magnum, really. But The way I always tell my students to think about this is, you know, think about your heart is pumping blood, right?
00:09:46
Speaker
And that blood, in order to make it inside the closed space like the skull, the pressure within those vessels needs to be above what's the pressure inside that space. Right?
00:09:59
Speaker
OK, you know, your body always try to maintain your mean arterial pressure above what's your intracranial pressure so that that blood can actually make it into that space. Right.
00:10:12
Speaker
And, you know, every time that there is an increased intracranial pressure, what the body is trying to do is increase the mean arterial pressure. and to maintain that cerebral perfusion pressure. The cerebral perfusion pressure is the pressure that needs to be the cerebral vasculature in order to maintain the scapularies open.
00:10:32
Speaker
Now, what you're going to see when there is an increase in intracranial pressure, again, it's the increase in mean activity pressure to try to overcome that increase in intracranial pressure. and The body, of course, like is goingnna that's going to trigger bradycardia, right? Your baroreceptors are going to get triggered. And every single time that there is an increase in systemic pressure, there is a baroreceptor response that will cause bradycardia.
00:10:59
Speaker
And that's when you see your cushion reflex, right? That's what we call the cushion reflex. Now, we don't really know how that gets triggered. yeah We don't really know what tells the body to increase the mean arterial pressure, what's the trigger mechanism behind it.
00:11:16
Speaker
We know why it happens, but we don't know how it happens. right So there are some studies done in the 60s where they were injecting ceiling into rabbits' brains and trying to figure out, like you know actually looking at what different like mechanism behind it.
00:11:32
Speaker
i We don't know. It seems that there is some sort of pressure sensors in the brain located somewhere. We don't really know where. We don't really know exactly how. But you know that's what actually happens.
00:11:47
Speaker
The other component of the Cushing reflex that a lot of times gets overlooked is the widening of your pulse pressure, right? So the difference between your systolic and diastolic gets wider, okay? So that's a ah triad that usually you you see.
00:12:06
Speaker
Although a lot of people focus more on the pressure and heart rate rather than that pulse pressure widening, in reality, that's actually really important as well. Now, for us, when we see that, you know when we have a patient that we believe that has an intracranial disease, the first thing we want to do is try to decrease that intracranial pressure, right? When you see that cushion reflex, you're not trying to fix that increasing pressure.
00:12:35
Speaker
If you try to artificially decrease that pressure, you're going to kill your patient. The only thing that keeps that patient's brain alive in that moment is that increase in pressure.
00:12:46
Speaker
So your goal should be try to decrease the intracranial pressure. Do not try to address the systemic blood pressure. You know that, leave it alone, try to deal with the intracranial pressure.
00:13:00
Speaker
The only thing that keeps the brain alive is that systolic pressure, you know, that systemic arterial pressure. Yeah, that's a really good point. But i' kind of circling it back to physiology, because I think we'll get to like managing intracranial pressure, hopefully at some point.
00:13:15
Speaker
So I think ah something that would be really interesting to talk about too is things that are responsible for regulating our intracranial pressure in general, and how those auto regulatory mechanisms are altered during general anesthesia, because you know, we do know that they are.
00:13:34
Speaker
So I always tell people like there's a few, like like a handful of things that will regulate or change your intracranial pressure besides just like having like a physical injury to your brain.
00:13:46
Speaker
And I think the, big ones are gonna be like your your carbon dioxide levels and your oxygen levels.
Managing Intracranial Pressure During Anesthesia
00:13:52
Speaker
And you already mentioned this, but also what your systemic blood pressure is doing. So do you wanna talk a little bit about the relationship between all of those things and how that affects cerebral blood flow and cerebral perfusion pressure?
00:14:02
Speaker
Yeah, of course. So cerebral blood flow, it's affected by several factors. you know The thing that most people talk about usually is your carbon dioxide, but in reality, you know it's affected by your minor theory pressure. right We know that, and actually the response curve there is very similar to your kidneys. right So your auto-regulation curve is very, very similar.
00:14:24
Speaker
If you look at that, most studies say that if you have a blood pressure, a mean arterial pressure below 60 millimeters of mercury, you're going to have a decrease in cerebral blood flow. If you have a mean arterial pressure between 60 and 160, usually you have a stable cerebral blood flow with no real increase or decrease compared to normal.
00:14:46
Speaker
And then when you go above 160, you actually have an increase in cerebral blood flow. The second thing that affects cerebral blood flow, it's your oxygenation status, right? So if your patient has a PAO2, which is a posterior partial pressure of oxygen above 60 millimeters of mercury, usually cerebral blood flow is not affected.
00:15:06
Speaker
So it's it's maintained stable and and normal. But the moment your PAO2 drops below 60 and you havet you go into that severe hypoxemia,
00:15:18
Speaker
the brain is starving for oxygen. And so what it's doing is dilating those capillaries, trying to acquire more blood in order to bring more oxygen in. And so that will increase your cerebral blood flow.
00:15:31
Speaker
And then they lastly, of course, your CO2, that definitely affects it as well. So usually we do say that your PA-CO2 should sit between 35 and 45 in a normal healthy patient, right? That's their PA-CO2 range. But in reality, the body always strives to keep it around 40, right? The respiratory drive increases significantly.
00:15:57
Speaker
dramatically if you go anywhere above 40. And it decreases dramatically if you go below that. So in reality, 40 is that sweet spot number. But you know if you go anywhere above that, the cerebral vasculature will vasodilate and increase the cerebral blood flow.
00:16:13
Speaker
If you go below that, of course, you're going to have a decrease in cerebral blood flow. Lastly, the other thing that affects cerebral blood flow, and people don't, sometimes they they don't think about this, is your cerebral metabolic c rate.
00:16:26
Speaker
right So the neurons are actually really good at telling your vasculature around them how much blood flow they need. right So cerebral blood, we always talk about cerebral blood flow as a global term, but in reality, the different areas of your brain have different amounts of cerebral blood flow.
00:16:42
Speaker
right And that depends on which areas are activated and which areas are not. So now that you know me and you are talking, probably our auditory cortex is receiving way more blood flow than other areas, for example.
00:16:55
Speaker
And so decreasing that cerebral metabolic rate will decrease your cerebral blood flow. And, you know, we do that under anesthesia. You know, we usually, as we make our patients sleepier, quote unquote, that will decrease their cerebral metabolic rate and decrease the cerebral blood flow.
00:17:14
Speaker
Up to a certain point, right, that there is a basal metabolism, which is, you know, 40% of, at least the studies say that the 40% of the total neuronal metabolism is devoted to basal, maintaining all the basal homeostasis, right? So you can drop it more than 60%. So the other 60% you can get rid of, and that 40% is devoted to maintain the basal homeostasis. You can't get rid of that.
00:17:43
Speaker
So to a certain point, you know, cereometabolic rate, it's a really important piece of this equation as well. Yeah. So to kind of summarize what you're saying from what I'm hearing is that your body tries very desperately to maintain cerebral blood flow in a very like tightly regulated area.
00:18:02
Speaker
And that's controlled by the pressure you need to kind of get blood flow into your brain, cerebral perfusion pressure, and also how much blood is like draining from your brain as well.
00:18:15
Speaker
And the things that can change the cerebral blood flow within your brain, even though your body really wants to tightly regulate it. But if you get any extremes and things like blood pressure, c o two or oxygenation, then that can alter CO2 as well as our cerebral metabolic oxygen rate that's happening as well. Is that, is that right?
00:18:33
Speaker
Yeah, that's basically a it. Yes. Perfect. Nice summary. Yes. Love it. All right. So let's move kind of to our patients and where are all these acronyms and things that affect our patients.
Strategies for Anesthesia in Intracranial Issues
00:18:45
Speaker
When you're thinking about managing an animal with like known intracranial disease, are there any specific strategies that you're routinely implementing to mitigate any changes in cerebral perfusion pressure or intracranial pressure in these particular patients? Yeah.
00:19:04
Speaker
So yeah, when I get these patients, the first thing I do is usually measure blood pressure before anesthesia. yeah I want to know if there is any beginning of Cushing reflex already happening.
00:19:16
Speaker
And then, you know, that gives me an idea of you know, what kind of protocol do I want to use to kind of minimize that change if there is a Cushing reflex already happening. The other thing I do is I always try to avoid anything that makes these patients cough or vomit, right? So anything that both of those actions will increase your intracranial pressure. And so that could be very detrimental for these patients.
00:19:42
Speaker
So drugs like morphine, drugs like hydromorphone, always try to avoid them like the plague for these kind of guys. I usually try to pre-oxygenate all of these patients. Again, you know oxygen is definitely has a big impact if your patient becomes hypoxemic. So pre-oxygenate them for five minutes with a tight-fitting mask.
00:20:02
Speaker
There are studies that show that if you just do flow by, your patient is actually getting only 21% of oxygen, which is basically room hair. So you do need to use a mask if you actually want to pre-oxygenate oxygen.
00:20:15
Speaker
for real, quote unquote, your patient. And then I try to achieve rapid trageal intubation as soon as I can. Usually, most of these patients do get anesthetized with either propofol or alfaxilin.
00:20:29
Speaker
And, you know, something like midazolam, that's usually ah very common anesthetic protocol for these guys. And, you know, both the midazolone, the propofol, or the afaxilone, they all decrease cerebral blood flow.
00:20:44
Speaker
And so that that definitely helps because they do decrease that cerebral metabolic rate. Once they're under anesthesia and they're intubated, we usually ventilate them. We try to maintain that CO2 between 30 and 35.
00:20:57
Speaker
Below 26, there is some study that showed that you could create some hypoxia in some areas of the brain because you decreased cerebral blood flow too much. So that's another thing that probably you need to keep an eye on.
00:21:10
Speaker
I always try to maintain their head elevated, you know, that favors that jugular drainage that you were mentioning, you know, and that definitely helps. Of course, these are not guys where you want to occlude their jugular at any point for a jug stick or anything like that. Like if you're trying to do pre-op blood work, you know, this is a side note, but this is not one of those patients where you want to be putting pressure on their jugulars, for example.
00:21:34
Speaker
And then we avoid inalienable anesthetics like the plague. because inalien anesthetics, we do know that they do increase cerebral blood flow. you know so If you look at the graph for those and the relationship to cerebral blood flow, you know once you have, you are at half MAC, which is half of the you MAC value for that specific species, for that specific inalien, you have a reduction of cerebral blood flow.
00:22:03
Speaker
But once you go Above half MAC, you're going to have a rebound in your cerebral blood flow. That's because your inhalant anesthetic starts to vasodilate your patient and that vasodilation increases cerebral blood flow.
00:22:18
Speaker
And so you have an increase, a sharp increase in cerebral blood flow anywhere you go from above half MAC to MAC. And when you're at one MAC, actually you have the same cerebral blood flow than when your patient is awake.
00:22:31
Speaker
And so you didn't gain anything, quote unquote, by anesthetizing that patient. You know, that reduction that you were hoping to get by decreasing that cerebral metabolic rate actually is not there anymore because of the vasodilation caused by the inhalant anesthetic.
00:22:47
Speaker
And so usually we do choose anything like propofol or alfaxilin. Our study found that telfaxilin was slightly better than propofol in reducing cerebral blood flow. And especially you're trying to hyperventilate your patient and you're in that hypocapnic range, you get more bangs for your bucks with alfaxilin than with propofol. And what I'm saying by that is that telfaxilin maintains cerebral vascular activity much better than propofol.
00:23:17
Speaker
And so what cerebrovascular activity is, is the change in blood flow per change of PaCO2.
Drug Comparisons: Alfaxalone vs Propofol
00:23:26
Speaker
So if every time you drop your PaCO2 by one millimeter of mercury, alfaxanol gives you more reduction of cerebrovascular flow compared to propofol in the hypocapnic range.
00:23:39
Speaker
It's very common for most anesthetic to have two different actions, whether we're talking hypocapnic versus hypercapnic range. So the curve It's not linear. It actually changes. the The angle that you would see on that curve if you graph it out, is you know there is an angle. It's how much blood flow change happens in comparison to one change and a change in one millimeter sub-mercury of the ACO tube.
00:24:09
Speaker
Gotcha. Yeah. I was always taught that for every one millimeter of mercury change in CO2, you get like a two like mil per kilo per hundred gram tissue change in your cerebral blood flow.
00:24:24
Speaker
And those kind of change in the same direction, basically. Like usually if you look at a graph, it's not It's very like linear as far as that. But you're saying that when patients are under the influence of different anesthetics, that curve will change. It's not as linear anymore.
00:24:40
Speaker
Exactly. It's definitely not linear. And actually, the value is actually a little bit higher than that, right? So if you're in the hypokapneic range, you know, alfaxalan drops your cerebral flow way more than than two.
00:24:57
Speaker
It's actually more sitting around, you know, four to eight you know depending on which agent you're using. But then when you go into a hypercapnic range, the change is different. okay So like the vasculature reacts differently. and And this has been described both in humans and with our paper in animals. but um i's That's not something I knew about already.
00:25:22
Speaker
Yeah, it's it's it's interesting. Like it's something that people don't haven't been focusing a lot, like cerebruscular activity. And it's actually really important because every time you're trying to manipulate that, suit you having something that gives you more bangs for your butt, it's definitely important, right? It depends on how bad, you know, your injury pressure is and how much clinically, how much of a difference it makes is.
00:25:46
Speaker
It's probably dependent on how bad your situation is. But if you're trying to maximize, you know that's something good to know. Nice. Okay. So you gave us a really nice journal picture of like how we're going to approach these patients. I'm just going to like break down each part of that anesthetic phase and just kind of ask you a few like follow-up questions about those, starting with your like pre-anesthetic planning.
00:26:08
Speaker
So we'll get into drug selection in a minute, but really I'm just curious, let's say you're not sure if a patient has intracranial tumor or not, you know, the patient might be like a,
00:26:23
Speaker
seven-year-old dog with a recent onset of like seizure activity. And we're going to be doing some imaging to find out whether or not this patient, like what's what's causing this patient to have a ah seizure essentially.
00:26:36
Speaker
And so what are some possible information from the history or blood work or anything like that that might make you more concerned that you might be dealing with a patient with intracranial disease versus not?
00:26:50
Speaker
One thing I found is that a lot of times it's really hard to detect, right? like they do The ginormous masses in the brain, sure, you see altered neurological status, mental depression, head pressing, anisocoria, lack of pupillary reflexes.
00:27:14
Speaker
Some patients do vomit as well. you know They have this, that triggers vomiting in them. But For the vast majority of them, it's really, really hard to detect, right? Like when you have these subtle changes, it's it's it's hard sometimes, you know, it's not always as obvious, right? And I've been tricked by it. So what I've been doing is I, if you have any history of seizure till proven otherwise, I treat you as if, because you never know till you actually get those images if there is a mass or not, or if there is an increase in endocrine pressure.
00:27:48
Speaker
Yeah. One other subset of patients that tricks you a lot is those that come in through a rhinoscopy because ah lot of the times those little nasal tumors, they they like to ah penetrate your skull and they do so by, you know, creating lysis on the creviform plate and whatnot and they try to invade in that area.
00:28:10
Speaker
I've literally had a cat once that, know, it came in totally neurologically normal, right? There was no, or at least apparently, right? And then it had this nasal tumor. And basically, yeah this call looked like a pie chart where three quarters was the tumor and the brain was you you know compressed to like this.
00:28:30
Speaker
yeah it It was crazy, right? But neurologically, you couldn't tell. And everybody was like, oh, no, it's fine. I mean, why you even do TIVA, right? And I was like, yeah. I don't have this feeling, but you know, so till proven otherwise, those guys, I just put them on.
00:28:47
Speaker
ah just treat them as, you know, if they have but potential and increase insulin and pressure. The only other thing I try to think about too is always make sure these patients are really worked up for like extra cerebral causes of seizures as well. you to make sure they don't have like a shunt or other kind of metabolic disease that could like cause all of this.
00:29:07
Speaker
The only other blood work thing I was going to ask you about was about hyperglycemia, which I think is something that is more common to see with like trauma, especially head trauma.
00:29:18
Speaker
But there is some evidence to suggest that animals that present with hyperglycemia and with intracranial disease, they're likely to have worse outcomes. Yes, absolutely.
00:29:29
Speaker
Do you pay special attention to this? Are you giving hyperglycemic animals insulin? What are you doing with these guys? I always monitor and make sure that like, you know, I always get a BGF induction for any of those patients.
00:29:44
Speaker
I want to have a a good picture of like how that blood glucose status is, again, you know, there is plenty of evidence in humans. I don't think that there is good evidence in vet med yet. i don't know if you're aware of any studies out there, but I couldn't find like, you know,
00:30:05
Speaker
anything in vet media, but definitely, you know, it's something that I've been keeping an eye on for sure. And I do treat those. Like if your glucose is above 200 or whatnot, I do give insulin.
00:30:17
Speaker
If it's below that, you know, I've had that happen too, right? Like you have a patients with hypoglycemia and, yeah you know, sometimes those patients with that trauma, you know, they, if they come in really quickly, then it's fine. But if they've been you know, like that for a day or so, maybe they don't eat.
00:30:32
Speaker
right So it's actually, I've seen it both ways. And, and, you know, if they have hypoglycemic, of course, you do need to give them that shards. And so blood glucose, homostasis, it's really important as well. um If you have a patient coming in on anticonvulsants, this is a question get asked a lot, which is like patients that, let's just say they're not coming in specifically for neurologic issues.
Managing Anesthesia with Anticonvulsants
00:30:58
Speaker
it's just a patient that has had a history of seizures and the owners don't want to invest in like figuring out why this patient is seizing. And so they put the animal on Keppra or phenobarbital or something and the animal's been on it for a while.
00:31:15
Speaker
So how do you advise that people incorporate anticonvulsant therapy or think about anticonvulsant therapy when they are anesthetizing patients that are on these medications already?
00:31:28
Speaker
So, you know, bear in mind that, you know, those always have a depressant effect on your neurons, right? Like in general. And Usually what I've found is that your anesthetic requirements do decrease, especially drugs that you're going to be giving to effect. You definitely need to use way less than that than what you would normally use.
00:31:52
Speaker
Do I change my doses frequently? For opioids or benzos, I usually don't really, but definitely your propofol or your alfaxalan doses, I know this that you need way less.
00:32:06
Speaker
I usually tend to, this is another question I get a lot, is whether they should keep Giving the medication up to the anesthetic event, yes. Like, you know, usually the morning dose, I just, if they get the morning dose, I'll have them give it.
00:32:21
Speaker
The last thing you want to do, it's interrupt that, you know, treatment. and And the earlier they can get their healing dose, the better it is too. Yeah. Yeah. I always try to maintain that, you know, blood those blood levels, ah trying to disrupt them as less as possible.
00:32:38
Speaker
Yeah. I do something super similar to what you're talking about. I think there's like a few little small caveats you have to think about. Like if your patient's on potassium bromide and you look at your blood work beforehand, it's possible that their chloride is going to be all weird because some of these, the monitors like can't distinguish between like chloride and bromide. So your chloride is going to be like,
00:32:59
Speaker
you'll get your chloride back be like what is this? yeah yeah That is true. Like that has happened to me several times. I think Keppra and Zanizamide, like I don't really have any, I just keep their doses going. I don't think I have any special considerations with those particular medications.
00:33:16
Speaker
I think phenobarbital is the one you got to think about. I think the most personally, it depends on like, uh, if they've just recently had like an induction dose,
00:33:27
Speaker
because then they get very sleepy. And I feel like you're your doses of inhalant really, really, like you don't need as much inhalant at all. And then you also have to remember that it can cause alterations in your liver enzymes too.
00:33:41
Speaker
And this particular medication can also like induce hepatic enzyme activity. So sometimes it makes it so that you have to give drugs that are heavily metabolized for the liver, to give them like a little more often.
00:33:54
Speaker
because the liver is like on overdrive. And so sometimes I feel like with opioids, depending if you're doing a painful procedure or not, you've got to be a little bit, I guess, on top of your pain control is usually what I what i say for those.
00:34:08
Speaker
And i'm trying to think if there's anything else, phenobarb we got to think about in particular. don't think so. Yeah, no, that should be it. Yeah. That should be it. Oh, phenobarb levels. I think that's super important.
00:34:19
Speaker
If you're doing like a procedure that you can plan for, Sometimes it's nice, especially if the animals are going to have like breakthrough seizures and you know, they're on fetal just grabbing like a level before you you drop them, I think is is a nice thing to do if you can plan it.
00:34:34
Speaker
Yeah, no, that's fair. That's fair. I usually don't, I mean, I usually, I can say I've done that before, but yeah, I mean, if they have it, it's nice to have it. But like in reality, like, you know, a lot of the things we do are like, you know, to affect anyway. So like, it's true.
00:34:53
Speaker
I want to talk to you something else that was kind of it was kind of controversial, depending on like what neurologist I was working along with, which is administration of diuretics before anesthesia.
Pre-Anesthesia Use of Osmotic Diuretics
00:35:09
Speaker
Yeah.
00:35:10
Speaker
Have you found some controversy with this as well? and You mean like, you know, ah manage like something with an osmotic effect? like Yeah. or Okay.
00:35:21
Speaker
Yeah. Because, i mean, we didn't talk about that. You mentioned this very briefly, which is that if you're seeing animals with like a Cushing's reflex, you know, You know, the goal is to try to drop your intracranial pressure. One of the things you can use are these like osmotic diuretics. And so like mannitol and hypertonic saline.
00:35:39
Speaker
So when I was in my residency, I had one faculty member that was like, give everything mannitol before you start. Like. if it If you suspect an intracranial tumor, just give mannitol like low dose and but like 20 minutes before you drop them.
00:35:53
Speaker
And we would do that. And then I feel like there were some neurologists that really did not like that because these drugs are not like benign either. so So I'm wondering if you ever choose to use either mannitol or hypotonic saline before you even inducing a C-shed. If you choose to do that, why would you do that?
00:36:12
Speaker
Like what patient population would you consider that in? If I really see the neurologic signs like head pressing and whatnot, probably I would resort to like hypertonic saline at induction or or before induction.
00:36:25
Speaker
i I'm really not a huge mannidol fan. I'm way more of a hypertonic saline guy. Is there a reason for that? So first off, manidol takes 20 to 30 minutes to exert these osmotic effects.
00:36:38
Speaker
right So if you really need it, that ain't the drug for it. like It's a good maintenance drug, but it's not a drug where if I need it, I give manidol. No, if you need it, you give a bretonic saline.
00:36:50
Speaker
Hibertonic saline is much faster. Also, you don't have to deal with keeping it warm because it crystallizes a room temperature. You don't need to deal with the filter. And if you read the package leaflet, technically you should have a dedicated calendar for it, right? Because it reacts with a bunch of other stuff, including LRS.
00:37:09
Speaker
So... I think that the level of complication that her has when I have something that I can just, you know, throw up and push,
00:37:22
Speaker
Yeah. Then, you know, it's a no brainer, right? Like it's a really good maintenance drug because, you know, its effects last longer than hypertonic selling for sure. Right. So if you're in a ward setting or like ICU setting or whatnot, then yes, sure. Manadol is your go to. But for our purposes, I feel like something, you know, hypertonic selling is much easier to deal with.
00:37:43
Speaker
ah yeah. Yeah. I think the other thing with mannitol or like that I've heard in the past is that it also depends on whether or not your patient has any interruption of their like blood brain barrier because of the blood brain barriers broken up.
00:37:57
Speaker
Maybe due to trauma, then you can actually get leakage of mannitol like into the, your like cerebral interstitial and space. And then you can actually like draw volume like into your cerebral interstitial space.
00:38:07
Speaker
I don't know why, something like hypertonic saline wouldn't do that. But I think the big difference is that manadol lasts so much longer than hypertonic saline. If you have an effect like that, then it's, it at least with hypertonic saline, it's more like short lived.
00:38:20
Speaker
Yeah. In reality though, like if you, if you go read in the human literature, like they still use manadol to maintain those guys anyway. And so like, I was under your same impression.
00:38:33
Speaker
yeah then And then I went to dig and do human literature and whatnot. And I was like, huh, you guys still do this anyway. So yeah does it this is just like a ah funny like tidbit, but I had to anesthetize like a ah dog that had like really bad head trauma.
00:38:50
Speaker
And just for like a, like a CT and the dog was very uptunded. And I don't know if the dog had gotten any osmotic diuretics at that point, but I remember asking, you know, one technicians was like, is somebody just like grab me some mannitol? Cause I think like, that was just like the drug that popped into my head right away.
00:39:06
Speaker
was like, is someone grab me some mannitol? And then the technician came back and was like, the ER doctor wants to know, like, what the heck are you doing with this like old drug?
00:39:17
Speaker
I was like, mannitol, you can still use it.
00:39:21
Speaker
But I get it. Like i'm I'm a huge fan of hypertonic saline. And so i think that if I needed to use something really quickly, you said all the right things, right? Like you don't have to worry about a filter. You don't worry you have to worry about the temperature that you're storing the drug at. It's so easy to use. So like I get it.
00:39:39
Speaker
The only caveat is that every single time you crack a bottle of hypertonic saline, you trash three quarters of it because the bottles are huge. They don't sell... so yeah it right I I feel bad that you know you have this little bottle that now I cracked and probably I won't use it for the next three weeks. and so it's It's a huge waste, but besides that, i' been you know there is no other major drawback to it.
00:40:07
Speaker
I mean, the electrolyte imbalances that it can cause, right? like You need to be worried about you know, if you give too much, you may see some electrolyte imbalance, right? But right in reality, you know, there's studies that show that if you stay below like nine ml per keg,
00:40:24
Speaker
total, usually you don't see any ah major electrolyte imbalance. So I usually do way less than that. Like usually start around three ml per kg.
00:40:36
Speaker
um I'm conscious. Like if you go and give more than one bolus, then, you know, ill start thinking about it. But, you know, one or two boluses like that is probably fine.
00:40:49
Speaker
Okay, so going to get into the fun part because we're anesthesiologists.
Suitable Anesthetic Drugs for Neurologic Patients
00:40:55
Speaker
So we're going to talk about drugs. Drugs. Yeah. So, you know, choosing the right medication for these patients is really important. It does matter for these patients. I'm not always like the person that when things go wrong, I'm jumping straight to the to the drugs as being the source of the issue. But I do think that for these patients, choosing the right protocol is actually important. So what I think I'm going is I'm going to like shout out different types of anesthetic drugs.
00:41:25
Speaker
And then I want you to give like your thoughts on them. Okay. Okay. In the context of like the neurologic patient. Okay. So would you give acepromazine?
00:41:36
Speaker
No. Why? no it's proven to increase cerebral blood volume and injury pressure. So you want to also just briefly talk about like the acepromazine and seizure thing.
00:41:50
Speaker
oh Oh, yeah. So the studies that demonstrated that decrease in seizure threshold were done with chlorpromazine, not ace-promazine. And they're actually studies in with acepromazine that disprove that there is any alteration on seizure threshold.
00:42:08
Speaker
But again, acepromazine vasodilates, right? It's an alpha-1 antagonist. And so there is a study that actually did use MRI to show an increase in cerebral blood volume with acepromazine.
00:42:21
Speaker
Yeah. Okay. So dexminetomidine, would you use it? So I tend not to. It does decrease in intracranial pressure. it does, and we know that. But it mimics your Cushing reflex.
00:42:35
Speaker
And so because, again, it vasoconstricts and it drops your heart rate, you know, it doesn't cause the Cushing reflex, like bear in mind, but it does mimic it.
00:42:46
Speaker
And so if I can avoid it, I try to avoid it. In reality, though, like if you have a patient that's uncooperative and they do need to use it, it's definitely better giving that than, you know, Ace-Promantane or anything else, really.
00:43:00
Speaker
so Yeah. Man, you took the words out of my mouth. Nothing more to add.
00:43:06
Speaker
Benzodiazepines. Yeah, no, those those are fine. You know, they we do know that they don't have any major impact on endocrinic pressure. on They slightly decrease the cerebral blood flow.
00:43:19
Speaker
Yeah, those are totally fine. Okay. This is like a big category, but opioids. Yes, except for any of those that would cause vomit, right? So hydromorphone, morphine, stay away from those.
00:43:33
Speaker
Yeah. Especially even in pre-med. Yeah. Did you see that study that just came out? I think it was like a month ago or so, maybe two months ago about butorphanol and sedation scores.
00:43:46
Speaker
Did you see that study? No, I've, yeah, butorphanol, it's, It's an interesting in syndrome. Yeah. So the study was looking at whether or not you can use, if you have a patient that you are worried maybe has an intracranial tumor, apparently seeing how sedate that patient gets off of like a 0.2 migprocig dose of butorphanol will give some indication about whether or not that patient will more likely have an intracranial tumor or not.
00:44:19
Speaker
Oh, wow. I think there was study where they looked at like, think it was like 30 50 dogs or something like that. I can look I can, I will link the study in the show notes so you guys can tell me if I am wrong, but these are all animals are getting MRI imaging because of like seizure activity some kind of other like behavioral change or something that would indicate maybe these animals had intracranial disease.
00:44:41
Speaker
And they gave you torphenol like 0.2 mg per kg IV. And then they did like sedation scores or they got saline. Like I think they had a control group in this. And then they looked to see how sedated these patients got off of like a validated ah sedation score. And so the patients who had intracranial tumors based off of like MRI imaging, they had way higher, like statistically significantly higher sedation scores than dogs that didn't.
00:45:06
Speaker
Oh, wow. Right. Using butorphanol as a diagnostic tool. I think somebody mentioned anecdotally this, and then i guess they picked it up and they did the study. But yeah, no, I heard something like that before, but I didn't know that somebody was actually doing a study on this. Yeah, someone did that study. it was fascinating because I always felt that way, like clinically. When I'd have like that dog and I'd give it like a little, small, very clinically normal dose of butorphanol and then it would get laterally recumbent, I'd be like, oh, that poor dog probably has a tumor.
00:45:40
Speaker
Nice. But I'm glad someone did that study. Okay. Yeah, that's cool. Yeah. so I agree with you with the opioids. I think the problem with opioids is that they can't like, obviously your fulmio agonists are more likely to cause emesis.
00:45:54
Speaker
So i try, if I need to give a fulmio, I try to use use it IV or also use antiemetics as part of the the protocol. They also cause hypoventilation. So if you're going to use a fulmio agonist, you just, I mean, you you already emphasize this, but you've got to mechanically ventilate these patients.
00:46:12
Speaker
Yes. Yeah. we You would anyway for those, right? Like usually you would ventilate them anyway. The other thing that, you know, some people may think about is, you know, we do know, for example, that this is for cats, that some opioids do increase sympathetic tone in cats, right?
00:46:30
Speaker
And so like there are some studies out of Davis that, you know, showed this and like, so... ah cats are not dogs. So for these guys, you know, sometimes something like buprenorphine, for example, or butorphanol, for example, may be better than, you know, giving something like hydro or methadone or anything like that.
00:46:52
Speaker
You know, sometimes full mu opioids do increase sympathetic tone in these guys. So... Yeah. I think we already talked about propofol and alfaxalone. It sounds like your preference is alfaxalone. I've used a lot of propofol personally just because i guess I wasn't as aware of your studies, even though you're a friend of mine. And so i always was like, well, propofol either does nothing to cerebral blood flow or decreases it like a little bit. So we'll just use propofol.
00:47:20
Speaker
And also, I guess this is just a personal preference. But if I'm going to use total intravenous anesthesia, i i personally tend to like the way propofol works in these patients over alfaxilone Tevas.
00:47:34
Speaker
I don't know what your preference is. I just know, I don't always love the way the recovery looks with alfaxilone. The recovery is usually prolonged with alfaxilone, right? Like, so yeah depends on the case, right? Like if it's really bad and I, and i you know, with those cases that show plenty of signs beforehand, I may try to do alfaxilone if I can. But if it's a dog and...
00:47:58
Speaker
you know, or or a patient in general that, you know, comes in and where I'm doubtful or maybe, you know, it's that patient that has seizures, but, you know, I'm not sure if he has an endocrine mass or whatnot.
00:48:09
Speaker
At that point, I would use Propofol. If there is something that screams at me, hey, I have an increased endocrine pressure, probably would resort to that Faxaline CRI and just deal with the prolonged recovery.
00:48:20
Speaker
As I said, I also know some people who like to use for induction either propofol midazolam or propofol lidocaine. The thought about the lidocaine being that there's some studies in dogs, not cats, but dogs that like one or two migberkig bolus can like reduce coughing.
00:48:37
Speaker
Yeah, I do that. I do that. So I do usually either a facsoon or propofol and then I do midazolam and lidocaine. Yeah, nice. Just to try to minimize, you know, that respiratory depression from the either a factor of propofol plus having that quote unquote anti-cough kind of property of your lidocaine, right? So there are studies in, I think they were ah Probably a couple of decades ago now, you know, they did this study where they showed that an IV bolus of mg per kg of lidocaine decreases the coughing reflex at intubation in dogs more than actually spraying the retinoids with lidocaine, right, in dogs.
00:49:19
Speaker
In cats, of course, you know, you don't really want to give lidocaine... Or that high of a dose of lidocaine IV anyway, because, you know, their threshold for lidocaine toxicity is way lower. but Yeah, i I tend to still spray it on the arytenoids. I think there was a study that showed that the maximum peak effect is actually 45 seconds after you spray. Yeah.
00:49:41
Speaker
I think it's just important to like wait, wait it out, even though we do want to rapidly intubate these patients. But I think if you spritz it and then like try to intubate them right away, you're not, not it's not going to do anything. No, it's not going to do anything.
00:49:53
Speaker
Yeah. Let's talk about ketamine with these cases. There's a lot of controversy about using ketamine in animals with intracranial disease.
Debate: Ketamine Use in Neurologic Cases
00:50:03
Speaker
i have heard criticalists who are very pro using ketamine in animals with traumatic brain injury.
00:50:12
Speaker
I've heard anesthesiologists that are very conservative with ketamine. i think yeah there's it's there's a lot to be said about it. So I just want to hear your take on it.
00:50:24
Speaker
Yeah, I try to avoid it. So there are studies that show that, you know, it does decrease the blood flow. There studies that show that it does increase it. It seems to be dose dependent. To be honest with you,
00:50:36
Speaker
We have so many other options, right? Do you really need to use ketamine? That's my question, right? and And the answer is usually not. So I try to stay away from it just because of, you know, quote unquote, play it safe perspective.
00:50:52
Speaker
Am I right? Am I wrong? I don't know. But that's what I Yeah, I think I'm all right. which i i i mean, i think I'll use it at lower doses as part of a multimodal analgesic plan.
00:51:06
Speaker
for a very specific type of population. And honestly, i think I really tend to gear towards using it again at low doses for that like traumatic brain injury type of case. rather than like we're going to be doing like a craniotomy.
00:51:19
Speaker
You know, I'm not going to be using ketamine usually for those cases, but I like to use it with the traumatic brain injuries. I think there's some evidence that it might have like this like cerebral protective properties that might be really helpful, especially for like the second phase of inflammation that occurs after a traumatic brain injury event that And again, this is more like studies are coming out of human medicine, but and whether or not it translates to to dogs and cats is ah as a good question.
00:51:47
Speaker
But I also think if you're dealing with an animal, not just with head injury, but having like multiple injuries on top of like a traumatic brain injury, ketamine just like a wonderful analgesic drug that's very safe, has a very high therapeutic index.
00:52:00
Speaker
And you can use along with like a bunch of other drugs to kind of do this like multimodal approach to analgesia, as long as you're using these like low- Dose by low, I mean like one meg per keg or something like that. Right, right, right.
00:52:11
Speaker
Yeah. Yeah, in those cases, you know, it's something that definitely think about, but, you know, if you have a patient that comes in that's and just head pressing or, you know, if it's a patient that comes in with seizures and, you know you know, unless they have this huge source of pain that's the trauma, usually try not to go for it, to be honest.
00:52:32
Speaker
Right. Okay. So let's talk about what we're going be looking for either during anesthesia or like in the post-op phase when our patient's getting into trouble.
Monitoring and Managing Complications
00:52:41
Speaker
So we talked about the Cushing's reflex already. Are there any other signs that you could see in a patient that might be indicative of elevated intracranial pressure? You mentioned that Cushing's reflex again, which is that increase in blood pressure and drop in heart rate, that that's not necessarily sensitive for your patient having too high of an intracranial pressure.
00:53:02
Speaker
So if it's not the most sensitive marker of that, what else are you looking at for these patients? You know, again, some of the neurologic signs, right? So if you have any anisocoria, if you have your, you know, how depressed that patient is, right? Like, you know, there is a, you know, coma scores out there for it But a lot of this is going to be more like geared towards neurologic signs.
00:53:29
Speaker
It's not wrong to keep monitoring your pressure and your, you know, heart rate and, or pulse rate but again that doesn't necessarily correlate so usually yeah a visual assessment of the signs is that usually what you know kind of helps you and there isn't really a huge much more thing that you that you you can do much more than that unfortunately you know unless you have any better suggestion but i No, not really. i mean, i think that when I'm anesthetizing patients with intracranial disease, I'm doing a lot more like I'm learning like the prevention yeah of like what we know about how all these different biological markers affect intracranial pressure. Like i'm I'm focusing a lot more on, on just, I call it prevention, but it's like maintaining CO2, maintaining heart rate, maintaining blood pressure.
00:54:24
Speaker
I think, and like oxygenation. So I'm going to be working to make sure my oxygen is as normal as possible. My CO2 is in that like 35 milliliter mercury range. I'm going to make sure my patients have as normal blood pressure as possible.
00:54:38
Speaker
And, you know, if I need to do arterial blood pressure monitoring, this is like a great case to do that with. But you mean like, sorry, I thought that the question was more like geared toward like post-op.
00:54:49
Speaker
Oh yeah. Well, that's true too. We'll we'll we'll get into post-op, but like for the pieces. Yeah. That's something that post-op, there isn't really much you can do, you know? yeah I'm just doing like lots of just like maintaining heart rate, maintaining oxygen, doing all those things. And obviously if my patient starts having a Cushing's reflex or I'm suspicious of that, then I'm going to be using hypertonic saline.
00:55:09
Speaker
In recovery, i think that the only thing I usually plan for, and I tell everybody this is like, sometimes these animals, they take forever to recover.
Post-Operative Care for Neurologic Patients
00:55:21
Speaker
the neurologic status is usually worse, right? Yeah. The neurologic status is worse. And sometimes these animals need to go on a ventilator post-op. yeah I've had a few of those need one not a lot, but if the animal's taking a really long time to wake up, I think I have a case that I'll never forget. It was like this little, it was like a little chihuahua from my residency that I had to nestize in like the middle of the night.
00:55:47
Speaker
So I was like by myself and And the dog had been like picked up by a pit bull and like shaken by the neck. And so the dog actually broke its like C5. So it was going into surgery to fix like a really unstable neck fracture.
00:56:02
Speaker
So I wasn't even thinking like traumatic brain injury, but while I was inducing the dog, it wound up developing this like crazy Cushing's reflex and the heart rate jumped, like went down to like into the twenties and the blood pressure skyrocketed.
00:56:16
Speaker
nice and so obviously I wasn't even like thinking about that even being a possibility, but you know, that we met, that we treated it with all the things we talked about. um I did actually give that dog a dose of atropine because I was kind of scared of the heart rate.
00:56:30
Speaker
Yeah. But followed up with hypertonic saline. And then and we post-op the dog, like we were in recovery. And we obviously mechanically ventilated the dog the whole time. But every time the dog would brace spontaneously in recovery, it's CO2 would be in like the 90s.
00:56:47
Speaker
Oh, wow. Which obviously is like not acceptable, especially for a patient like that. So we wound up transferring that patient onto a ventilator. wow. And in the ICU, and he actually only needed to be ventilated for like a day or two.
00:57:01
Speaker
and they got him off the ventilator, but he just needed more time for like that, that like second phase of his injury to kind of like all that swelling to kind of go down. on yeah And then he, and then he was dishing. He did great.
00:57:14
Speaker
That's awesome. No, I mean, yeah there's a that's a really good case, but yeah, no, it's, Yeah, I mean, besides all of that, i mean, I think, you know, I never, i don't think of had a patient have to go on a van But usually the patients I deal with is mostly like tumors, right? It's not like, you know, the the trauma in in comparison, if you look at percentages, right? I think that the the trauma patients are way less common than, you know, brain tumor kind of thing you know, seizure kind of patients. are ah They're way more rare, right? So I didn't have to deal with that yet. Probably i will at some point in my life. but
00:57:53
Speaker
Yeah. I mean, if there's something I can say about anesthesia is that you think you've seen everything until you've seen something you've never seen before. yeah Yep. Yep.
Real-Life Anesthesia Cases and Lessons
00:58:03
Speaker
I tell that to students all the time, right? You've never seen it till you've seen Right. Yeah. Yeah.
00:58:08
Speaker
So I guess to to wrap things up, I'd really love to hear about like a real life case since I shared my real life case. im I want to hear you share, you know, like a real case where had to manage anesthesia for a patient with like seizures or neurologic disorder. Like what did that look like? What was your strategy? Did anything weird happen during the case? Do you have anything you want to share? Yeah. So yeah, I've dealt with many of those, both patients.
00:58:37
Speaker
pre and post residency. When I was back in England, we probably like 12 to 14 SMRIs a day. It was insane. So we would would see a bunch of those, right?
00:58:48
Speaker
You know, my protocols for these guys pretty standard. Usually I e ah use, if it's a dog, i use i i've you know I've done methadone and then we'll give them like propofol, midazolam, methadone,
00:59:05
Speaker
And then i would put them on a Propofol Tiva and um plus minus Phantanil sometimes, you know, to to cut down the amount of Propofol. One thing that I definitely have been burned by is that at the beginning of my career is that those patients do tend to die in recovery, right?
00:59:28
Speaker
That moment where you... take them off the ventilator and they need to start breathing on their own. And that CO2 rises and rises and rises.
00:59:42
Speaker
that's when they try to herniate and die because that CO2 rising will increase your cerebral blood flow and will increase your endocrine air pressure. So don't think I have a super specific case or I totally don't remember their name, you know, and it's that's like thousands of patients, but I've definitely had a couple of those and now I'm way more cautious on that. Like I i definitely...
01:00:03
Speaker
try to especially now that you know we have access to more advanced ventilators with the you know the support modes of ventilation like CMV or VS, you know you can make sure that your patient can ventilate adequately and without having its PACE or juice skyrocket too much before you take them off the vent.
01:00:31
Speaker
And I think that that's it made a huge difference in how i manage these patients. And then, you know, I'm thankful that work in a place where I can do that. Not everybody has access to something like that. I'll do nowadays. Machines that have those functionalities pretty affordable, actually, you know.
01:00:52
Speaker
So, you know, those are my my two cents, as somebody would say. No, I agree. I think I kind of made this point earlier, it's like during anesthesia, we have control of everything. So these patients tend to do, I mean, in experience, they tend to do pretty good when they're anesthetized because you're giving them medications that like suppress their cerebral metabolic oxygen requirement, giving them lots of oxygen and you're like controlling their CO2 and you're controlling their blood pressure.
01:01:22
Speaker
So they didn't do like cruise through that. And then you transition them into off of of anesthesia and their breathing room air. And then you've given them all these medications that like make them make their respiratory centers depressed.
01:01:39
Speaker
Plus their respiratory centers can be depressed from their neurologic disease on top of that. So i do I totally agree with you. I think the this tricky part of these friends is the recovery phase and making sure that if they are having a lot of respiratory depression, trying to like use drugs that are reversible, trying to eliminate the medications being the problem as much as possible, and then just get comfortable. Like you might be there a long time helping these friends wake up from anesthesia.
01:02:06
Speaker
Yeah, bring plenty of snacks. Yeah. Yeah. Yeah. Like every time I'm recovering a craniotomy, I'm like, I'm like, where's my chair? Somebody order me a pizza. I want my bottle, my water bottle nearby.
01:02:21
Speaker
because we're going to be hanging out for a while with this friend. Yeah. Yeah. Those are the long ones, but yeah, no, I mean, I think that's really important, right? Like, you know, you can do everything right during induction and and during anesthesia. Then they, they, they turn,
01:02:38
Speaker
badly into recovery. that's That's the key moment for these guys. All right. Well, you know what? I am so grateful that you spent time chatting with me today about, like I mentioned earlier, these very tricky patients.
01:02:52
Speaker
And I also think that this was packed with a lot of practical tips. So I just really appreciate you coming on here and sharing your experience with me.
01:03:03
Speaker
And thank you so much. Thank you, Bonnie. Thanks, everybody. Thank you for listening. If listeners want to like find you, where can they find you at if they want to get in touch with you?
01:03:14
Speaker
So social, we have our page, Safe Path Anesthesia. You can email us or reach out, send us a message, Facebook, Instagram, Treads, LinkedIn, or our website, you know, safepathanesthesia.com.
01:03:30
Speaker
And I also hear you have your own podcast. Yes, that's the Random Anesthesia Topic podcast. So come check us out. Yeah, absolutely. Okay, well, thank you again. Thanks.
01:03:43
Speaker
Thank you.
Join the Community for Continued Learning
01:03:50
Speaker
Thank you for joining us today. If you've enjoyed this episode, we invite you to explore the North American Veterinary Anesthesia Society and consider becoming a member. Membership with NAVAS provides incredible benefits, including access to anesthesia and pain management CE events,
01:04:07
Speaker
informative blog posts, fireside chats with board certified anesthesiologists and specialty technicians, and so much more. If you're interested, visit www.mynavast.org to elevate your anesthesia journey today.
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Speaker
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Speaker
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01:04:51
Speaker
We love to hear from all of you. Special thanks to our sponsor, DECRA, for making this podcast possible. To learn more about their veterinary anesthesia products, visit www.decra-us.com.
01:05:04
Speaker
And of course, a big thank you to our esteemed guest, Dr. Gianluca Beeney, for this insightful discussion on anesthetic management of patients with intracranial disease.
01:05:15
Speaker
I also want to thank the editor of this podcast, Chris Webster of Chris Webster Productions, and to Saul Jimenez for providing technical support for this podcast. Finally, thank you to all of our gas passers out there for spending time with us on the Navas podcast.
01:05:32
Speaker
Veterinary anesthesia is a lifelong journey of learning and growth, and we hope you'll join us next month as we continue exploring it together. I'm your host, Dr. Bonnie Gadsden. Thanks for listening and stay tuned next month for another episode of the Navas podcast.