Sorry, my dog is barking in the background. I apologise if you're hearing this in the, in the background of dog barking. I'm sorry.
OK, all right. So she's not in the room barking, so we're OK. All right, so an update on small CPR is our last talk here.
So I will try to keep this here. This is one of my topics I do all day long every day, so I sometimes wax poetic, so I will attempt to keep this to the 50 minutes. I'm looking at my watch right now to make sure we keep this the 50 minutes here.
So, I'm just trying to update you. You might have heard a lot of these things so there's not a. On new in CPR, but if you haven't happened to go to a talk recently, maybe there's a couple things you haven't heard before.
So just briefly, because I think history is kind of interesting, we'll go over a brief history of CPR. We're talking about expected outcomes because if nothing else, I think you need to be able to go up constantly to a client and be like, listen, this is the outcome of CPR. This is what we're expecting, and just to give owner because I think owners really need to have that kind of information when you're talking to them to make sound decisions.
And then we'll go over the steps of CPR and we'll highlight some of the newer stuff that came out, in the newest, CPR thing, which is actually a few years ago now, OK, so brief history of CPR. So this is kind of cool. I thought, I mean, I've always thought I've kind of grown up thinking CPR has been done for forever and actually CPR, as we know it didn't start till like the 1960s, which I actually think is quite interesting that it really has not even been, you know, 100 years of CPR as we know it yet, not even close to that yet.
Prior to that, the first time anybody even. Thought about anything that even remotely resembles CPR was in the middle like 1530-ish area era and at that point somebody had the thought to maybe use the fireplace bellows. That's the thing, you know, you guys know to like move and put air in your fireplace to actually put that in someone's mouth and insert air that way to force air back in line.
That was probably the first documented positive pressure ventilation anyone ever used. And then it took them almost 200 years from that to say, wait a minute. Maybe we can do something like mouth to mouth where instead of using the fireplace bellows, I'm gonna put my mouth on you and actually blow air into your lungs and do positive pressure ventilation that way.
Fast forward like another 160 years. Somebody said, wait a minute, maybe we can actually use some kind of chest compression to actually like push on the chest and actually get, you know, simulate the beating of the heart. And then it took, weirdly, it took like 70 more years for someone to say, wait a minute, we can take positive pressure ventilation, put it together with chest compressions, and maybe we can come up with something that, you know, is more the modern CPR that we know.
And actually, ironically, like, over Christmas holidays, my mom was watching some old movie which had Dick Clark in it, which is weird because I know he was an actor. I thought he just did, you know, the, the New Year's Eve ball drop and all that business. The actor and, there was a part of with some person into PR because there wasn't like this at that era, and I was like, wow, anyway, just kind of highlighting that.
So you know and into the culture that, you know, we, we all kind of, think of it as always having existed. So nowadays we have things like early public access defibrillators. That's where you like walk in the airport and there's a defibrillator, and that will help you through, you know, cases where you're there by yourself before the E.
2 years the last 5 years is really not getting here which all time is starting to do just skipping and in humans at least they've been showing that manual pull over and dive if you're really fine part of that. And so because of that human sentive and your lung, it's just chest compression we'll do enough of it in the lungs that you can for the 911 there so20 something like that, and so that kind of avoids. The reticence that people are reading into their mouth to mouth stranger, and by the time the EFTs arrived, they'll start to actually do legitimate for use the bag during this arrest and 16 guidelines are here.
He's got to come out 5 years the newest guidelines that came out, where in he was to highlight here going forward, so things to kind of pull out as far as survival in people, even though on TV it looks like you're gonna be right out of the hospital as a human, your, your rates, your, your chance of survival are terrible. It's only between 3 and 16% of people out of the hospital. Survive a cardiac arrest.
That they have a better than you, but really still not great because only 10 to 36%, so really no more than about 3 humans even in hospital arrest, which is gonna be different than a like, you know, in contrast, an animal at least die in the hospital, of course, but still gather from in the hospital and so they die or resuscitated and go home probably more than 60% of dogs survive and anaesthetic death. This is where I think the real reason. So, I always tell the vet dudes that you go to CDR realistically like don't expect you're gonna save this though if you do, great that not bringing them back is much more like you than you bringing them back and you know I can this as far as just, all right, so that endocrine disease process how you respond, right?
So those sales you're gonna come out and be OK after CPR CPR. But if you find you're getting closer to go in owner and 3 weeks CPR of 10 to 15 minutes. We haven't had a response.
I response we really should stop, and I think that's really want to spread your conversation with owners, because they, OK, so let's get on to actually the meat and bones of like CPR, how we do it, you know, that sort of thing. And so 2 maybe we'll see if update of it to, you know, early things that you early on and things that you run. We're not gonna talk about this to share at all that we're just talking more about the first.
Roll cart ready to roll. Go down to your local hardware store because we time the draw it should be two ties in the event we need to grab a new one out we all in scope because you always want to learn the scope. And don't be a hero.
Just use the laryngoscope. Like, don't be like, I can intubate without. Don't, don't even try.
Like we want to get it in the first try so we can start breathing. Like you don't want to be like reintubating. That just slows you down.
Nobody wants that, then it's the code. And then we wanna have sure syringe is ready to inflate the cup, for sure I passing on those as well. The of our breathing drawer, for example, we've got our ambu bags ready to go.
We have suction ready to go. So we just got things kind of organised, ready to go in our drawers. Here's our drugs organized.s are near the drugs so we can use them, and we have, red rubber tubes available if we need to have insurance because a bunch of drugs tube out.
Alright, we always have a chart nearby because we only able to quickly find drugs handies we have inside the cart, and also I find that really quickly and I have their supply the stuff around right I see you looking for this stuff. You got to say, OK, what the heck they're doing your staff depending on you. So code leader, someone running the show, so yeah, share recording goes together all.
But you wanna make like people going to do the either the code leader needs to be very vocal and be able to direct his staff, his or her staff, and most of the time the veterinarian obviously is the code leader. OK, I've got organised. I really would advocate we do it like once every 3 weeks with our students.
We do CPR training. We do with our staff a couple times a year. I really would advocate that and a lot of the more you should train because you wanna be.
OK, so now we're gonna move on to basic life support, which is breathing and beating. That's all basic life. If you're not breathing for them and you're not doing chest compressions, they're no where the state is during CPR.
So you needed, and then we get there and, right? So here we are going to the drawer to get out our supplies so we can intubate and manage the airway. Here we are hooking up our ambu bag tube so we can breathe for them.
And then obviously we've got somebody doing chest compression which we'll talk about in a minute. If we do intubate them, we want to make sure that we're doing 10 breaths a minute, one breath every 6 seconds, and the title volume should be in the neighbourhood of 10 mils per kick. Now if you're using an ambu bag, there's no like metre on there to tell you how many mils per cake.
So we're looking for a normal looking chest rise, normal chest excursion, normal. Exhale, you don't want to be like, where the chest is like super inflated and you want to be able to see the chest rise or you're not doing anything. We want to inhale, exhale and wait.
Inhale, exhale and wait because during the exhalation period you're allowing blood to flow back to the heart. If you're, if you're holding the inhalation, the positive pressure in the chest does not allow blood to go back to the heart very effectively. There is a scenario where you can do a non-intubated patient ventilate for them, and it's mouth to snout, and you can do, you're supposed to do 30 compressions for every two breaths.
So you go do 30 compressions and you go back and breathe 2 times the nose, and then you go back and you're supposed to make a nice tight seal between your mouth and the nose. That being said, I have never done that in my life. I can never see myself doing that.
But ironically, oh, I don't know when was. Over the wintertime we had a client come in who had been doing mouth to snout resuscitation breathing for her dog for 2 hours in the car, bringing her dog from where she was to see us, and the dog was alive when it came. So I don't know how much was the fact that the dog was able to do some.
The dog was paralysed and had diaphragmatic paralysis because it like had a hit it, it took a fall, hit its neck and was paralysed basically and couldn't breathe. It had, I, I, we, we never figured out how much of it was the dog able to do a little bit of breathing on its own and how much it was the owner actually legit being able to save her dog, you know, save her dog to get to the hospital. But anyway, nonetheless, the dog went on the ventilator, what have you and arrived with us, but you can do mouth to mouth ventilation as well.
All right, so typically you put the least skilled person on the ventilation. So once you get the tube in and inflate the cuffs, tie it in, you call your receptionist over, you call your kennel help over, you call the owner over. Whoever's the least skilled in the room, you're, you're, you're observing veterinary student and ask them to start doing the breathing for you.
The, the danger though, the breathing should be the easiest thing. One breath every, every, you know, one breath every 6 seconds, 10 breaths a minute. But the problem is if you, there are some negatives to it, you just have to keep your eye on the breather if you're the code leader to make sure they're not meddling too much because if you breathe too fast or you breathe and hold or you give too high of a tidal volume, all those things are bad.
And what potentially gonna happen is you're gonna increase thoracic pressure, as I said before, that's gonna decrease the ability of blood to come out of the heart and also decrease the ability of blood to come back. The less blood that comes out of the heart, the less you're perfusing the actual coronary vasculature. If the heart muscle doesn't get blood with oxygen in it, the heart muscle doesn't beat because it's a dumb muscle.
So the myocardium has oxygen, it beats. If it doesn't, it doesn't. So there's no blood flow going to it, your heart will not, you have a harder, harder chance getting the heart to start beating again and so.
Also, less blood going up to the brain is bad, obviously more so in humans who have to operate heavy machinery than dogs and cats, but you know, the more you have hypoxic injuries to your brain, the worse you're going to do long term. In contrast, if your respiratory rate is too low or you're breathing too long, like you go, you're breathing really slow, but you're and then you're holding it and then you finally exhale. Or your title volume is too low or you're not taking good enough breath.
All those things are potentially bad also because all those lead to increased CO2 because you're not ventilating enough to get rid of the CO2, and that will cause vasodilation both in the periphery and in the brain. That's gonna have less perfusion. So if you vasodilate everywhere, you have less blood getting out the tissues because the blood vessels are so big and it's hard and so floppy that you don't get good blood flow to the important spots, and that's, that's gonna be bad.
And also, if you vasodilate up in the cerebrum, you're gonna increase intracranial pressure, which is also negative. So all those things are potentially bad. So, so breathing, not enough is just as bad as breathing too much.
So even though ventilation is easy and should be the least skilled person, just keep your eye on. All right, now chest compressions is our next step. So A is kind of like getting your airway and doing the breathing, right?
And, and then C is gonna be chest compressions. Now there is some controversy because in humans we don't even do the breathing at first now we just do the chest compressions like I said. So there is some controversy in vet that about which should we be doing first?
Should we intubate them and then breathe for them, or should we do compressions first? What I would say is most of the time animals die of respiratory arrest. So I'm gonna, I'm gonna have for whatever reason I stop breathing but.
Lung disease. I have an upper airway obstruction, whatever, but I stopped breathing and then because no oxygen got to my heart, my heart stopped. And because that's the typical scenario in animals, I personally, if given the choice, like there's more than just me, will get the airway first because that's usually a two man job and then start the chest compressions.
If it's only me and I'm calling for help and having others come, I'll start doing the chest compressions first. But as soon as I have help, I intubate, then I go back to compressions. I work with a colleague who is very adamant about compression first no matter what.
Bottom line, there's no, nobody really knows. So either way, but make sure in very short order you got your airway, you're breathing, your chest compressions going. So when you do chest compressions, you can do the cardiac pump theory, which is where you're actually gonna be compressing the heart itself and that's what's causing the blood to come back.
Or you're doing thoracic pump theory where you're increasing pressure in the chest around the heart, and that's gonna secondarily compress the heart. Either way, the end game is hopefully you're compressing the heart, right? So where, so depending on the patient position, the type of patient or where your hands are, it tells you which type of pump the.
So for cats and small dogs, you're gonna have your hands kind of around the chest right here and your thumb and forefinger should be right around the heart itself and that should be a cardiac compression, should be cardiac pump and their lateral recumbency. If they're in dorsal recumbency because they're deep-chested like a bulldog, or they're lateral recumbency and they're bigger dogs, you're, you're more likely to do thoracic pump. So with a normal canine, your normal like Labrador style dog, you're at the highest point of the chest with your hands and you're increasing intrathoracic pressure, and that's what's causing a chest compression, thoracic pump theory.
Bulldogs, deep chested, you're at the widest, highest point of the chest on their back, thoracic pump theory. With greyhounds and these other weird sighthounds that the weird sloping chest, you may slide your hands more to be over the heart, and in that case, it's some sort of hybrid between true cardiac pump and thoracic pump for these guys because your hands are closer over the heart and you may get more actual cardiac compression. All right, compressions, when you do that, compress the chest about halfway roughly or a little less, because that's how, you know, and then allow for recoil.
So you wanna go at least halfway down the chest or, you know, just about halfway down the chest, recoil, halfway down the chest, recoil. The reason you must have the recoil is when you recoil the chest, it sucks blood from the body back to the heart. When you compress, you're pushing blood out.
When you release, blood comes back to the heart. So you have to allow the recoil for blood to come back to the heart, and you want to keep your chest compressions up as continuously as you can. So no matter what else is going on, try not to interrupt your compressions for more than about 5 seconds, and that's when you're usually like switching over from me to you compressing or you to high or whatever.
When we switch compressors, we interrupt compressions for a very short period and we also interrupt them possibly to look at the ECG, but I like to look at the ECG when I'm switching people so that I only interrupt one time. And the longer you interrupt the compressions, let's say you got 60% of your blood flow back, maybe you're doing great CPR. If you interrupt your compressions for more than 5 or 10 seconds, you go down to like 0 blood flow and they have to restart.
Do you wanna like interrupt blood flow for as little as you can. And you want to compress 100 to 120 per minute. And so most people, I don't care how strong you think you are.
You probably can't do compressions for more than about 2 minutes, and I'm always yelling to students who I go to the gym every day. I don't care. You probably can't do compressions that are good for more than about 2 minutes, maybe 3 minutes if you're in amazing shape, so.
So don't be a hero. Change over. And if you find you can't even do 2 minutes, don't be a hero, say you need help and let somebody else take over because you don't want to, you know, compromise the animal because you're gonna be a hero and do it for 2 minutes, you know, and we again, we said we wanted to start the decompression as soon as they're reasonable we can and do them good quality the whole time we're doing them.
So the beat that we can follow is staying alive. Let's see if we can hear it here. Be here your What the Let's say a little bit later on in life.
Tell you that if you're a little later in life and I can't get it to work, sorry, you might follow something like Quit playing Games with My Heart by the Backstreet Boys, another wonderful American band, because the actual beat in that particular song is what you're supposed to use for CPR. You can actually Google CPR rhythm song. And they have a whole variety of songs.
If there's a song you like better, you can stick it on your little, you know, whatever CD player, whatever you have that's attached to your crash card and play it during CPR if you wanted to. But during practise rounds, we'll also play music so the students know kind of the rhythm they're supposed to do, but 100 to 120 beats per minute. OK, now people always ask these I just through the slide and what about interposed abdominal compression.
That's where someone's pressing on the chest, and then when you release the chest, you press on the abdomen. So they're going up, down, and opposites. And the theory is if you press on the abdomen, it pushes blood more effectively back to the chest, and then you release the abdominal compression to push on the heart and allow blood to go back out.
And the theory sounds amazing. The problem is in practise unless you have really tried this and you and your partner really can do this properly, it's not gonna work because you're inevitably you're gonna end up like everybody press you at the same time and everybody not compressing at the same time and that's obviously detrimental to do that. So I would say if you have no idea what you're doing, I probably wouldn't bother.
If you do it properly, minimal harm is documented, but we really can't prove that it actually helps for sure. But it, you know, what the heck, if you have a really well oiled team, you can try it. I would say if your team is just barely doing the ABCs, don't bother is what I would say.
But you shouldn't hurt if you try it. It may or may not help basically if you're doing it properly. OK, so now open chest CPR, another question always comes up.
Should I even recommend this? How do I do it if I need to? So first of all, let me preface this by saying that I do critical care ECC for a living, and I've done one open chest in my life other than a laboratory where we practise, and we know how to do it.
So, you know, do I think there's a real place for it? Not really. Do I recommend it to my clients?
Not really. The theory is it's supposed to be more effective than closed chest. The theory is you're gonna get in there.
You're gonna see you're basically gonna have the animal lateral. You're gonna just, just cut into the chest between the 3rd and 4th ribs ribs. I'm gonna rib spread and reach my hand in and start directly compressing the heart.
That's the idea, right? And so the theory is, oh, I'm gonna get a much better chest compression on my hand directly on. Hart than doing it outside the chest, especially for giant breed dogs, or if there's obviously some pathology like pleural effusion or pneumothorax where when you try to compress the chest, you can't.
And so in theory it makes great sense. And in a laboratory setting, it is more effective at getting a chest compression than closed chest. The problem is, you need a pretty skilled team because in order to actually get into the chest quickly, quickly, quickly the way you need to.
So you, you're gonna start regular CPR. You're gonna have somebody grab a scalpel blade and put some gloves on, and someone else is meanwhile standing by with rib spreaders and they basically come over and you cut and go in as fast as you possibly can, cut in the pericardium, reach in and grab the heart, right? So.
If you have no idea what you're doing or your team is not very well oiled, that's not gonna work and you're gonna end up interrupting oppressions for so long that it's gonna be detrimental. However, there is, you know, I like, I, I see the theory where it should work better. My other issue with, and here I am reaching inside in the lab testing it out.
My other issue with it is that once you're done doing open chest CPR, what do you have to do with the animal? OK, you got them back, they're alive theoretically, right? Now I have to take him into an OR.
I have to lavage the chest out. I have to place a chest tube. I need to close the hole in the chest, and then I need to hope that they don't die again from whatever disease caused to die in the first place.
So you can see that my normal scepticism here is that it's probably there's a lot of stuff that I'm not saying there aren't animals that have been saved by open shafts, and my mentor always reminded me that there was one that he had when he was a resident. The thing is though, to me, the additional steps are not really worth it for the 11 case out of 100, you know what I mean, where this actually works. So I'm, I'm naturally sceptical if you do it and you're good at it, phenomenal.
I just, I'm not a huge advocate of doing this. I will say that, but again, if you're faced with the owner of like a mastiff and you know you're not gonna be able to do a decent compression or you believe the animal has pleural effusion and, and then they, you know, if they die from that, what do I do? Yes, you know, you can say that open chest may be more effective, and, and you can have that conversation with the owner, but I do tell the owner that, you know, we do have a lot of it does potentially, make morbidity afterwards worse.
The other place I do think there is a good spot for open chest is if you are doing. Surgery, sure, go ahead and do open chest because you're already there in the chest, so you just, you know, reach to the diaphragm quickly and you're there. That's completely reasonable, and I, I've definitely participate in those postoperative, you know, post arrest, and they've done well, but I wouldn't be like cutting into the chest and ICU very often is what I was saying.
So all right, OK, now moving on, so I've got the breathing and the beating on breathing, compressions here we go. Now what do we do? All right, so now we're moving on to advanced cardiac life support because once you're breathing and beating, you've got the basic life support.
So we mentioned ABCs, right? So airway breathing and compressions are basic life support. There's still two more Cs that you need to think about.
So after you get through airway A, B, and then C for compressions, then you move on to say, OK, another C is crystalized fluids. So you need to ask yourself, do I need fluids for my patient who's dead? And if they're hypovolemic, your answer would be yes, and that would be an example.
An animal was hit by a car like sort of trauma case or something like that who came rushing into your clinic. That animal's probably in hypovolemic shock or proven otherwise. So I would give fluids at that point, and I would, figure out what my shock dose is.
So 90 mL per cake for a dog, 60 mL per cake for a cat, and I would give a quarter to 1/3 of that and a bolus, yes. If my animals normal bulimic, it's been sitting in ICU for 2 days, sitting in your hospital for 2 days getting fluids. Well, that animal probably is not hypovolemic, so probably does not need a fluid bolus.
It actually is detrimental to give fluids to animals who are normal bulimic that that don't need it. And they're hypervolemic, you died of heart failure. Please don't give the animal crystalized fluids either.
However, I will always hook up a bag of crystalloids. So part of the CPR is we always have a bag of crystalloids hanging ready to attach, because even if I don't decide I need to bow as fluids to the dog, I may need to flush my drugs and you always, always, always, always want to have fluids available to flush your drugs because if you have a catheter in your back leg and you need to get the fluid all the way to the heart because the fluids have to get to the heart to work. So you might need to flu you know, on a big dog, 100, 150 mLs to get that drug you gave in the back leg all the way up to the heart.
You know, if, if the cat is in the front leg, maybe you only need 30, 40 mLs to get the fluids. You get the drug, I'm sorry, all the way up to the heart. The thing is, what the end game is, it's way easier to flush by like opening up a bag and squeezing it than to like be pulling up syringes and trying to flush your drugs that way.
So I always, always, always use a bag of crystalloid fluid that are hanging to flush my drugs. Now, as I mentioned, we need the drugs to get to the heart, so we flush and flush and flush a lot. And so D for drugs is the next letter of the actually I didn't mention the other C, which is catheter, but presumably if you're going to get fluids, you've thought about putting a catheter in the dog too.
So you have a catheter in, you've got your crystalloids ready to go if necessary. You have a right to flush drugs. And now I move on to D for drugs, where I'm going to give drugs.
And remember that you can give drugs IV if you got the catheter and you're gonna flush copiously, or we can give them intratracheally. So I kind of me in the beginning that we use that red rubber catheter, so I intubate the dog. I grab the red rubber catheter.
I feed it down the tube. I detach the ambu bag, feed the catheter down the tube, flush my drug in. I'm going to give at least twice, if not, they say now for epinephrine 10 times the dose of epinephrine, flush it down the red rubber tube.
I'm gonna open my syringe and flush air in in the same amount. I'm gonna kink my red rubber, pull it out, and then I'm gonna reattach my boo bag and I'm gonna keep breathing for them. And ideally, when I put the red rubber in, it's either gonna go so I can't insert it any further because I'm gonna lose it or until it hits something which is gonna be the carina.
And that's where you're gonna stop with the red rubber when you inject the drug. And as I mentioned, we increase the dose up to 10 times for epinephrine, at least 2-3 times the dose for every, every other drug. All right, the other D we think about is defibrillation.
So do I need to defibrillate this animal? And if so, and I happen to have a defibrillator in my hospital, I'm gonna grab the defibrillator. I'm gonna put some gel on the paddle.
Do not rub them together, and then I'm gonna place the paddle on either side of the chest and administer my shock if I need to. So you're probably saying to yourself, well, how do I know if I give drugs or how do I defibrilllate? Well, that all comes down to what a rest rhythm does the animal have.
So if the animal has asystole, you're gonna give drugs for that. And the drug of choice is usually epinephrine, possibly vasopressin. We'll talk about those more in a second.
If you have pulseless electrical activity, so I see something on the machine and even could look normal on my ECG machine, but I don't feel a pulse, that's pulseless electrical activity. That's also treated by epinephrine or vasopressin. If I have a ventricular fibrillation, so a scribbly line, whether it's a fine scribble or a coarse scribble, ventricular fibrillation is also treated, it's treated by defibrillation.
So that's the only time you need a defibrillator is for ventricular fibrillation. The other two arrest rhythms you treat with epinephrine. 95% of animals who die have asysto or pulseless electroactivity.
So when in doubt during CPR, even if you don't have an ECG hooked up yet. Give Epinephrine because if if you're in Las Vegas, and I keep saying, you know, they put all your money on your dog not dying of ventricular fibrillation. If your animal by chance did die of ventricular fibrillation, it's like, it's a vast minority that's going to do that, and those are the only animals that need defibrillators.
And in my, my life experience, I can think of there's one or two cardiology patients that I can remember fibrillating and that probably had to due to the fact that there was something significantly wrong with their heart, and they were already on a lot of drugs for it. And then I can remember one rodenticide dog I had that bled into its myocardium and and fibrillated, but those are like the exceptions rather than the rule everybody else is the other rhythms. So I always still regardless I reach for epinephrine first.
OK, so speaking of epinephrine, what is it epinephrine is an adrenergic agonist, and it's gonna bind to both alpha 1 and alpha 2 receptors, but in CPR, I want it to bind to alpha 2 because I want it to vasoconstrict the alpha 2, yeah, the vessels attached to alpha 2s, and those vessels tend to be in the periphery. So I would prefer to vasoconstrict in my periphery and push that relatively useless blood from my fingers back to my heart now during a crisis where I'm dead. So that's why I like to use epinephrine, and I like to use this low dose of epinephrine because that tends to bind to alpha 2 receptors the best.
The older published doses of like, 0.1B per kg, which is 1 mL per 10 kgs, is nowadays we used to use that as the actual dose of CPR, but that tends to have a lot more alpha 1 effects, and alpha 1 receptors are clustered on the big vessels. And if I add vasoconstrict and alpha 1 receptor, it's gonna vasocon it's gonna vasoconstrict a big vessel like the renal artery.
I'd rather not vaso. Constrict that vessel if I have the choice, I would rather vasoconstrict the small peripheral vessels in the fingers and toes, which is what alpha 2s do. So that's why I use the low dose of epinephrine, so it's 0.1 mL per 10 kgs.
If we've been doing CPR for 10 minutes and we got nothing, what the heck? You can go ahead and give the higher dose of epinephrine. You got nothing to lose, but you know, in the beginning we start off with a 0.1 mL per 10 kg type dose.
And we tend to dose it every 2 to 5 minutes. So roughly every time you change a compressor and kind of get reorganised and you look, you know, in changing compressors you've looked at your ECG if, if you have it set up, and you've confirmed that the rhythm is still one that needs epinephrine, you then will redose it. So it ends up being you can press for 2 minutes, you change over, you look at the ECG, and then you start compression again, and I'm like, oh, I need more epinephrine.
It's been about at least 3 minutes or so. So roughly every somewhere between 2 and 5 minutes we redose epinephrine. More often than that probably won't do any good for you either.
So you know, during the course of a normal 15 minute code, probably not more than about 4 doses of epinephrine, something like that. OK, vasopressin is the other drug we mentioned we can use for pulse selective activity or for asystoy as well. Epinephrine, I'm sorry, vasopressin is another pressor agent, as the name would imply.
The advantage of it over epinephrine supposedly is that, or not supposedly it does, it does work better in acidotic situations. So if you're dead, you're probably acidotic because you have a lot of lactic acid build up. And so if you're dead, maybe vasopressin will work better.
The only thing is they actually couldn't prove in humans that it was any better than. Epinephrine. So nowadays you can use it.
It's gonna vasoconstrict. It vasoconstricts by different receptors in epinephrine. So maybe that's good, but there is no proof that it's any better than just giving epinephrine repeatedly.
So most people, if they use it nowadays, go epinephrine for the first dose of drugs. Vasopress for the 2nd dose or epinephrine epinephrine and then the 3rd time do vasopress or something like that. Honestly we haven't used it much recently because it's something like 300 bucks a vial now.
It went up in price like to this ungodly value right now. So we uncommonly use vasopressin now because it's not been proved to be any better and it's very expensive. All right, now atropine is another drug most people are familiar with in their crash cart.
So the thing about epinephrine nowadays is they have never been able to prove in any of the millions of human studies that there's any actual benefit in CPR to giving it. And there is some evidence in humans that it's actually detrimental to give atropine to a dead patient. So nowadays, if you're gonna use your dose of atropine, and I have written that in the slide for you, it's a little less than we used to say we used to say 1 mL per 10 kgs, we're saying a little less than that now.
We say because we know in humans that the more atropine you give and the higher dose you give, the worse outcomes they have. What we're saying nowadays is the time to use atropine is when you believe there's high vagal tone that led you to, to rest. So you went into asy or PEA pulses electrical because you had high vagal tone.
So what, when would that be? You vomited and died. You had diarrhoea and died.
You had just had abdominal surgery and died. You know, you have a giant mass in the abdomen, your vagal tone is high and you died. So essentially the Elvis sort of death, because Elvis, as you might may or may not know, died while defecating.
So, Elvis had some heart disease as well, but Elvis actually arrested because he was defecating an increased vagal tone while he was, you know, on the toilet there. So if you have a death like that where you believe vagal tone caused this animal to arrest, so you grabbed him out of the cage and there's a whole pile of vomit, then go ahead and get some atrophy. If if they arrested in other settings where you don't believe vagal tone and anything to do with it, avoid the atropine.
And nowadays we're saying to give one dose and that's it. So give one dose and be done with it. Don't keep giving it repeatedly during CPR.
The other time to use atropine is if you are seeing a bradycardia, so only ay or PA with high vagal tone, or if you're truly seeing, sorry, truly seeing a bradycardia where the heart rate is actually very slow prior to prior to your resting, then if you're getting. Beats that are slow atropine can be used at any point. So true bradycardia, use atropine.
You died because of high vagal tone, use atropine. Use one dose of atropine in that case, and that's it. If you're treating bradycardia, you can use multiple doses if you need to.
That's kind of the atropine thing now. OK, now lidocaine is another thing everybody has their crash cart. And so lidocaine is not truly a drug for arrest.
It's like to prevent you from arresting sort of drug. So we use it in cases of ventricular tachycardia, so wide bizarre QRS complexes, and they usually have some, some pulses with them, but not every bee has a pulse. But you are feeling some pulse activity, so it's not pulseless electrical.
You can use lidocaine and it's 1/10 kgs. You can also use amiodarone 1 ml for 10 kgs. Either one of these drugs theoretically is gonna convert you from ventricular tachycardia back to normal sinus, hopefully.
The danger with ventricular tachycardia is it can lead to ventricular fibrillation. And if you start to go from VTA to Vfib, then you need to, and you need to defibrillate them obviously in that case. And this is bad.
If you get to Vfib, you go from V tag to Vfib. That's bad. So we want to go the other way and go back to normal sinus.
So if you did defibrillate, as we said before, you can, depending on what machine you have, either mono or biphasic, biphasic is all the newer ones are biphasic. You need less energy if it's biphasic to defibrillate, and you're gonna go ahead on that same CPR chart I showed way back when, you should have, a listing of like for this amount of weight, what sort of charge charge do you need? And you set the machine and you go ahead and give the charge, give it.
To that patient and when do you do it? So usually you do, you're doing CPR, you get your basic life support set up so you're breathing and you're beating. You change over, you're like, oh my goodness, it's Vfib.
So someone starts doing compressions. You keep breathing. Someone starts doing compressions and someone runs over and gets a defibrillator because you just saw Vfib on the ECG.
We put the gel on, we hurry over there, we put the paddles on either side of the chest. We clear away from the table, you depress, you know, and you give the energy, and then you're defibrillating to asystole. That's what everyone on TV defibrilllates to normal sinus rhythm.
That doesn't happen in animals. You defibrillate to a flat line and how do you treat a flat line? You continue doing chest compressions and you give some epinephrine.
So that's what we usually say is you will do a single shock and then you do 2 minutes of normal CPR where you're doing compressions, breathing, giving epinephrine, and then you reassess and see how the patient is doing after that point. If you're doing it multiple times you do increase the dose for monophasic by hay defibrillator, you just keep the same dose each time you do it. And if you've ever watched any show where they did the precordial thump, my favourite one is that, that ridiculous show Lost that was on probably 10 years ago now, where they pre-cordial stump and brought the guy back to life.
The theory of pre-cordial sum is the same thing as defibrillation, because each of those techniques, defibrillation or precordial hum is. Supposed to take this wild electrical activity in your heart and kind of stop it that the pacemaker takes back over and you go back to some sort of hopefully some sort of rhythm or at least you stop the electrical activity so you're you're asystole and then you can try to resuscitate them from there. That's the theory.
OK, other things to have in your cart. I would definitely have some reversal agents. So if you died from a after getting opioids, not from, but after getting opioids, you died, you reverse them with naloxone.
Flumazinil is used for diazepam, and, adappa isol is used for dexametotonin. So I would definitely keep these things handy in my cart in case you need them because that definitely can be part of an arrest that you need to don't worry running around the hospital looking for the drugs. Steroids are something that people love giving.
Currently, they're not recommended. And the reason they're not recommended is the fact that steroids potentially can suppress the immune system, so long term can be bad if you actually got them back. They can have negative effects in the GI.
They can have negative negative effects in the kidneys. And again, if you actually get them back, you don't want to have renal failure or something because, you know, you gave them too much steroids and they can lead to bacterial translocation. But more importantly, they probably don't do a darn thing for the actual death event.
And so if they're not going to help you in the death event and they have the potential for all these things that are bad later, it's no reason to use them basically at this point. So don't use them. The only time I would even think of having a steroid anywhere near an animal that has died is if I thought it died because it had upper airway obstruction from a tonne of inflammation.
So let's say it had a bee sting, and had anaphylaxis, and it had this huge amount of inflammation at the throat, and that's why it died because then arrested because it couldn't breathe. Sure, OK, give a dose of steroids to that dog. That's fine.
But short of something like that, a normal code, I would not use corticosteroids. Similar bicarbonate, we don't really use it. The problem with giving bicarb is when you give HCO3 to bind up hydrogen, that sounds good because they're acidotic, right?
But then you're going to shift the equation over and make a lot of CO2. And if I'm only breathing one breath for 6 seconds, or yeah, 1 for 10 seconds, yeah, one breath for 6 seconds, 10 per minute. My concern is I don't increase my respiratory rate during CPR cause you told me to breathe, release and wait, breathe, release and wait.
I'm not going to know if you gave bicarb I need to increase my respiratory rate to blow off the CO2. And if you have too much CO2 in your body, it causes acidosis, it causes a respiratory acidosis and also can cause vasodilation like we talked about. That's bad.
So bicarb is, it's a little too much, too tricky, don't use it, and it hasn't been proved to help anyway. So not recommended. Potassium only if they died from hypokalemia, which is uncommon.
Calcium don't bother during CPR. Like it's unlikely you died from, I mean, if you, if you know they had eclampsia and they died because they are, you know, because of how, how hypocalcemic they were, sure, give them some calcium, but that's obviously very uncommon. So standard wise, just don't give calcium the standard thing.
That's not a good idea. OK, doesn't help you. All right.
Last thing to quickly talk about in the last couple of minutes is some of our monitoring that we do. And so notice that I have monitoring way down or not me, but we have monitoring way down here in Link 4. So you know, if the choice is do I give a drug or do I hook up a monitor, you always give the drug first.
If the choice is do I do chest compression or or hook up the ECG, always start chest compressions first, so. Important if you're prioritising with very few people helping you in a code that you get the breathing, the beating, and then get, get the drug therapy on board because you're guessing it's going to be PEA ory anyway, to give epinephrine. And so do all that first and then when people start to become free and available, you know, if you didn't have a lot of people to start with, they can hook up all the monitors because the monitors really like, help you be like, oh yeah, you're for sure dead.
And you're dead for me Sicily, although I pretty much guessed that, or you know they're useful like after you come back and during CPL there's one that can help us gauge how well we're doing so. ECG we talked about already where you know ECG is helpful to know what drugs to give and you look at it every time you switch compressors and so that's probably the first one I hook up. And title CO2 is the next one I'm gonna hook up because Eital CO2 we'll talk about in a second has some actual positive things during the code.
Checking electrolytes, checking blood gases, that's stuff I don't do typically in the middle of a code unless I'm like someone's like, oh jeez, yesterday the potassium was really low. We don't know what it is. OK, well then maybe I'll check it now, you know, that type of thing.
But standard. I don't do blood work of any sort during a code. I just do an ECG and a total CO2.
So we talked about ECG. Let's talk about entitled CO2. So entitled CO2 is measured by catnograph.
The actual entitled CO2 monitor thingy goes between the endotracheal tube and the actual ambu bag. And what happens is every time you breathe and release, you should see an increase in CO2 during expiration. And then when I inspire, the CO2 going by that little sensor should be very low.
So inspiration, expiration, inspiration, expiration. We expect entitled CO2 to be 35 to 45. That's if you're normal and alive, or you're breathing spontaneously, I should put it that way.
If we're doing chest compression, if we're doing, if I'm doing 10 breaths a minute like I should be, that should not be fast enough to drive this number down. So what we want to look for during a code is what is the actual entitled CO2 number that I get because And total CO2 is a couple of things. Number one, you have to be inside the trachea to get, to get the CO2 coming out.
So if for some reason you were getting like complete zero numbers and you weren't seeing that wave form at all with your breasts, you're probably not inside the lung. So it helps a little bit in the very beginning of the COVID death. And so if you see something like this where you're in the oesophagus, you know, you're, you're doing, you're breathing for the animal and you see pretty much nothing going on with the cattogram, that's probably because you're not in the right spot.
So it's helpful for that. But once you pass the point that you have the tube in the right spot. The reason where the titled CO2 comes from is not only from you ventilating and bringing air from the lungs out, but you also have to get CO2 from the body to the alveolus to breathe it out.
And if you, that means you have some degree of circulation. So if I swear my breathing person is doing correct breathing and doing 10 breaths a minute, and Doing any more than that, that should be appropriate ventilation to get, you know, CO2 out of the lungs. So if you're seeing this really, really, really low entitled CO2 and you know the breather first, it is not at fault, and you know that that the tube is definitely in the right spot, then you start to ask yourself, am I not perfusing the lungs well enough?
Am I not doing good enough compressions? And so let's say when you first hook up an animal, let's say, let's say you first hook up an animal, you know, you, you intubate them, you're doing your thing, you do a couple of breaths, and I'm not doing any chest compressions, so they're dead, they've arrested. That CO2 number is going to be super duper low after the first couple of breaths because you're not bringing any more CO2 back to the body.
Then when I start doing compressions, you should see the CO2 number come up because I am compressing the heart and circulating blood, and I hopefully I'm getting somewhere between 15 to 20-ish if I'm doing really good compressions. Then if they spontaneously come back, so the animal is back and alive again, you'll actually see the CO2 number go up, and it can actually get up kind of high, like in the 50s for a while, and then you'll see it kind of drop down to where it should be in the 40s and that's what you'd see if you're able because the heart always does a better job beating than we ever would. And so that's what you'll see if the heart comes back and starts beating again.
And then, if everything's going great and you turn your head and look back and all of a sudden you went from a gramme of 40 because the animal's heart is beating and things seem good down to 0, and you're still breathing the same rate you were before, the heart stopped again. So it's very helpful to tell you if you're arrested again. And like I say, it tells me about my compression.
All right, so what numbers do I want? So they actually have some studies done in a K9 model. It's experimental model that if your end total CO2 is less than 15 during CPR, you have a 94% chance of not coming back, no return of spontaneous circulation.
If your entitled CO2 is kept above 15 during CPR, yeah, in contrast, you have an 86% chance of return of spontaneous circulation. Now note this doesn't mean you're leaving the hospital. It means your heart comes back and starts beating again.
You can still rearrest again, obviously, but you have a much better chance of getting the heart back if you keep the CO2 greater than 15 because your compression are good quality. So when you're doing compressions and you're like, oh, you're ready to change. No, I'm fine, I'm fine.
And you know that they can't keep the CO2 above 15. You're like, no, no, no, you're not fine. Get off, get off, stop doing compressions.
Let somebody fresh take over for a while. And if they start off in the 20s and they drop down, then that person is getting fatigued. You need to get somebody else doing compressions.
So Capgras is super helpful for that. OK. All right, so a couple quick summary points and we're done here.
Number one, we want to start. So if you remember nothing else in this exciting talk we had really good quality compression. So start compressions, do it 100 to 120 beats per minute.
Start them as soon as you can and make sure that at the end of the day you've got breathing and the heart beating stuff as quickly as you can and most efficiently in the beginning to get basic life support. 10 breaths per minute. Use low dose epinephrine, which is the 0.1 mL per 10 kgs, and if you want to use vasopressin, they're supposedly roughly equivalent, none, none, neither one is better than the other as far as getting, getting an improvement in clinical science.
Use only atropine if you're bradycardia or have increased vagal tone only. don't use it just kind of as I always use atropine during CPR but when there's no heartbeat, like that doesn't make any sense unless you think you died of a vagal event. Defibrilllate if you have ventricular fibrillation.
And fluids are only given for hypovolemic, although you do parenthetically, parent parentheses use fluids for flushing, which only bolus fluids that are hypovolemic. Do not use any corticosteroids for these patients. And you should be good to go.
If you do that, you have the best chance that you're gonna have of having an animal come back knowing again, flashing back that the outcomes are not amazing for CPR on a good day. So, all right, does anybody have any questions? Thanks, Liz, that's great.
I like the little picture down there as well. Yeah, there's a couple of questions coming in, I'm not sure if you covered this, but Eileen asked a little while ago said . Do different breeds affect figures on successor CPR?
Do brachycephalic dogs, are they more likely to die? Yeah, that's a good question. I don't know that there actually has never been anything I've ever seen about breed predilections for death.
I would say breaking the phallics are much more likely to die of like them to have respiratory arrests in some of the other breeds, yes, and like, especially like, you know, around the time of anaesthesia and stuff are very high risk of, of coding, but no, I don't know that there's that actually would be an interesting thing to look at. I don't know that there's any numbers out there for different breeds or anything that I'm aware of, so. Henry has also said thank you for letting us off the hook with the open chest compression.
He said it doesn't sound right there with you. Had a lot of comments coming in just saying what a great, presentation. This has been a great session, so thank you very much.
We'll, we'll leave you there, and thank you for everyone attending the virtual congress and this emergency and critical care session. Just want to point out. That, there are a lot of, webinars, to edit and get on the, the website, so the recordings will be available, on the twenty-ninth of January, so it give us a week to get them all edited and all up at the same time.
You will all be emailed when the recordings are available.
