Brilliant, thanks very much. As soon as I finish this webinar I'll be seeing how the peritonitis in this is going, so, it's a good topic to talk about, so what you need to know and how to get the most out of your monitoring equipment. We'll go through what each mon monitor tells you, what it means, what it doesn't tell you more importantly, some of the pitfalls of those monitors and some of the troubleshooting that you may have some questions about.

So our bottom line really, what we're trying to do, we're trying to ensure tissue oxygen delivery. So all of those monitors that we're using for our patient, there is a relevance here to maintaining blood flow to ensure that every single cell in the body maintains the correct levels of oxygen requirements. And thinking about things that are likely to happen every time you anaesthetize a patient.

We have hypertension, hyperventilation, and hypothermia as our three main problems that we should be thinking about with every anaesthetic. How do we mitigate against this? We monitor our patients.

So hypertension, we look at monitoring our blood pressure, hyperventilation, we can look at respiratory rate, tide of volume. You may have a countnograph in your practise, and we'll talk a little bit about monitoring and type of CO2. And of course hypothermia, we know one of the biggest problems with hypothermia is it prolongs recovery from anaesthesia.

That's detrimental to our patients and it also takes up a lot of nursing time as well. This is probably about as complicated as we're gonna get tonight when we think about the physiology, but to maintain tissue oxygen delivery, we need good arterial oxygen content. So we need to ensure that that oxygen is getting from the anaesthetic machine through the patient's lungs into the blood.

And do we have a a gauge on that? Do we have a monitor? Our tissue oxygen delivery also depends on cardiac output, and our two components of cardiac output are heart rate and straight volume.

Now of course it's easy to monitor heart rate and palpate pulse rates. It's a little bit more difficult to ask saying stroke volume. So how do we get a gauge on what our cardiac output is doing for that tissue oxygen delivery?

The closest thing we have in clinical practise is monitoring blood pressure, and we talk about new arterial pressure in the vast majority of cases under anaesthesia, and that's products of heart rate times strike volume times systemic vascular resistance, so a measure of vasoconstriction, hasodilation in those peripheral vessels. Anaesthesia affects all of these areas. Actually, arterial oxygen content, if we've got a fit and healthy patient, certainly in the UK, we use 100% oxygen for our patients.

So we probably deliver more oxygen than our patients actually require under anaesthesia, we certainly do. Cardiac output, our drugs affect our heart rate. The vast majority of anaesthetic drugs will decrease heart rate, if we think about the opioids and the alpha2s.

And some drugs decrease stroke volume as well by reducing our contractility. Probably the biggest class of drugs that we use on a day to day basis are the volatile agents isofluorne sevoflura. They both decrease stroke volume, therefore reduce our cardiac output.

This is a picture of a dog with a classic air hunger posture. You can see that our neck outstretched, the dog's mouth is open constantly. He's panting, gasping for air.

So we're really thinking, actually, there's some pathology going on here that means that your tissue oxygen delivery is not optimal. And we want to anaesthetize you to try and work out what is going on, what that pathology is, whether it's for thoracic radiographs or whether it's something like a thoracic CT to achieve our diagnosis. I'm actually looking at this dog, one of the things I did thinking, can I just flick back to that previous slide, you can't see it so well, but his tongue just doesn't look a nice colour, does it?

It's not a beautiful pink colour that we would normally expect. I thought, OK, how can I use some monitoring equipment pre-anesthesia to get a bit more of a handle on what's going on with you? You can do an ECG.

Easy enough, if you've got a monitor there, let's think about using our monitors before anaesthesia. This is a great example. This is actually taken the, those of you that that are are astute will notice that there's a camera graft trace on the bottom.

So in this patient we applied the monitor before induction of anaesthesia, and we noticed these arrhythmias here. You can see that ventricular premature complex there following our our normal QRS complex. We've then got an abnormal wide and bizarre complex there.

We took this under anaesthesia because I wanted to document how that affects the the plethysmogram trace, the trace on the pulse ox, and you can see here you have this, the blue trace down the screen. You've got the lovely plethysmogram trace, you've got a beat, a pulsatile beat with every heartbeat. And you can actually see how ineffective that ventricular beat is at producing cardiac output, you just get a drop in that plethysmogram trace there illustrated quite nicely.

So these are some of the knock-on effects of pulmonary pathology affecting our tissue oxygen delivery to that patient. And our aims in this dog are focusing on ensuring that the, the dog is, is adequately saturated. You can see here with our our pulse oximeter, because we're delivering that higher concentration of oxygen under anaesthesia, he is indeed saturated very nicely, so we've achieved our aim here of ensuring that what's going into the dog is as optimal as it possibly can be.

So what are our options? We've got the basics and and then we're gonna talk about monitors tonight, but let's not forget about the basics and throughout all of this, what, whatever you see on the monitor, whatever you worry about on the monitor, always go back to basics, look at your tone, look at eye position reflexes, and palpate pulses. You can never replace, our absolute basics.

So nothing to talk about tonight is really a substitute for getting back to basics. We've got positive symmetry, ECG, capnography. We won't dwell too much on temperature, but let's not forget about temperature.

There are a couple of questions in them, the multiple choice, that I've written for you about temperature monitoring, blood pressure monitoring, and the other thing we monitor is the concentration of our end tidal volatile agent. So whether we've got our isofluorine dial set to 2%, what is the dog actually receiving, we can measure that. And even when things are going wrong, you look at this, what the monitor's doing here and it's screaming at you, there's a tachycardia, it's telling you that the, the, the rate is 188, and we think, OK, our SPO 293, that's not particularly exciting.

What's going on with this patient? I need to get hands on, I need to palpate a pulse and verify, is that pulse rate displayed on the screen exactly what I'm actually palpating myself? Do I believe what the machine is telling me?

So like I say, in every single situation, I always go back to basics. For those of you that's. I think, well, I've got a monitor, but oh it's it's quicker for me to do the surgery than it is to put the monitors on.

I just made this video of one of our nurses. Once we've induced anaesthesia, we're about to connect the patient up. Sorry for the, the background rumble there.

It connects the patient to the breathing system after the induction. You can hear that we turn the volatile agent on. A monitor's already on.

What you will notice, it's just flipped to zero now, but there's a yellow reading on that monitor was the end titled CO2, and it read 42, so we know that the trachea is intubated because we use catography to document that. That account graph can take about 1 or 2 minutes to warm up, so I would suggest you make sure your monitor is turned on and warmed up before induction of anaesthesia. That way, when you start applying all the monitoring equipment, you're getting all the readings that you want in the most rapid fashion possible.

And actually the piece of equipment that's going to give you the most rapid response is the cameograph provided it's warmed up and then the pulse oximeter. You can see that pulse ox trace isn't quite happy and it's given a reading 44 in blue there. That's because we were moving around the tongue.

There's a bit of movement going on there. And that took about 20 to 30 seconds to get all of that monitoring equipment on that patient. So it really doesn't take very long once you know what you're doing to get all the equipment on the patient.

And don't keep it in the cupboard. Use it every day. If you've spent between 2000, 4000 pounds on a monitor.

The the every time you use it, it gets cheaper, so I'd encourage you to get your monitor out and use it on all those routine cases so everybody knows what they're doing. Can the cameograph is the bit that kind of puzzles people the most potentially, so I would encourage you to get the catmograph out, use it, recognise what's normal, recognise what's abnormal. If you want a little bit more information on catography, there's a webinar that I did back in January, solely dedicated to Camography, so it, it's pretty much everything you need to know about Caography.

And just another example of monitoring pre-anesthesia. We look at David money we saying, oh, OK. Could you be suffering from some type of cardiac disease, dilated cardiomyopathy?

I've examined you, I listened to your heart, pre-anesthesia, and I'm palpating pulse at the same time. And am I feeling a couple of dropped beats? Hm, OK, is there something going on with my examination of this patient, and I just need a little bit more information.

So a results from an ECG and we just pop an ECG on this patient. Really quick, easy thing to do and indeed look at the arrhythmias that we're seeing there in this dog. It's fair enough, documenting arrhythmias, but what we then want to do is quantify the effect that those arrhythmias are having on that patient because we talked about cardiac output and maintaining tissue oxygen delivery.

How can we get a better handle on whether those arrhythmias are affecting cardiac output? We said the closest thing we can get to measuring cardiac output is blood pressure. So it makes sense that the next monitor we think about using this patient before anaesthesia is non-invasive or oscillometric blood pressure.

And this is a really nice monster here, the card, it measures systolic, diastolic and mean, you can see that. What you want to ensure with your monitor, you can see at the bottom it's displayed a pulse rate. We want that to be within 5 beats per minute of what we're palpating or one of our other monitors is telling us in order to ensure that that reading is accurate.

I know what we always do through readings and look for those readings to be fairly close in order to gauge whether the monitor is telling me exactly what I want to, what I should be feeling or I want to know. We're building a picture here, so I'm actually quite happy with this dog that that arrhythmia isn't causing a significant effect on his blood pressure. And then we've got to make a decision.

It depends on what we're anaesthetizing this patient for. If we're anestheizing for major surgery that is elective, then he probably needs to see a cardiologist first for further workup. It would be the wrong thing to do to go ahead and utilise this patient if he's on the verge of cardiac failure, or if he's got significantly enlarged chambers and a and a dilated cardiomyopathy, there may be treatments that the cardiologist advises pre-anesthesia.

So don't just think about using your monitors for peri-operative monitoring under your anaesthesia. Think about getting them on as part of your pre-anesthetic assessment. Posto symmetry, how does it work?

I think most of us have probably got up on socks. They've come down significantly in price over recent years. You've got a clip with an LED transmitter and a receiver on the other side, so this is known as a transmittance probe, so it actually transmits that light through the tissue, which is why it doesn't work on over a certain distance it works well on tongues, between to webs, for example.

And this is transmitting two wavelengths of light, 940 and 660 nanometers of the wavelengths, and it transmits these two wavelengths because it's looking to to pick up at that receiver. An indication of the different proportions of oxygenated haemoglobin and deoxygenated haemoglobin. And the machine has an algorithm based on those the proportions of, of lights that the receivers picking up as to the actual saturation.

So that's why when you put the probe on, there's a little bit of a delay the machine's just waiting to get a really nice pulsatile signal, and you may have a, a monitor that's got a pleysmogram trace. It may not have a plethysmogram trace, the, the, the the wave form that you see. And what you want is to see a nice plethysmogram trace before you believe the reading that the monitor's giving you.

Or like the blood pressure monitor, we say that the reading from a pulse rate point of view isn't within 5 beats per minute of what we're actually calculating. We're all very familiar with what our normal values of oxygen saturation are, so 90 to 100%. Some people will say less than 93 is abnormal, some people say less than 95%.

I'm happy 9091. Generally in physically healthy patients, like I say, when you're delivering 100% oxygen to those patients, they don't have a reason to desaturate. It's our patients with pulmonary pathology where you know that that patient has a reason to to desaturate and you can visibly see they're cyanotic, that's the that's where the value of possible symmetry really comes in, gauging how that patient is coping with the anaesthetic.

Like I say, on this machine here, you can see 96 is the oxygen saturation missing there in yellow, and you've got that orange plethysmogram trace. We've got a nice trace there that is, you've got a pleth trace or a beat for every one of our pulse rates or or or our our ECG complexes on that ECG. So I believe what that monitor's telling me.

This is another type of monitor that we have called the, the masterma. This is a specific company that makes this pulse oximeter. And to answer the question, is one pulse oximeter better?

This pulse oximeter has an advanced algorithm. So it may, it's a lot more sensitive. It can work against factors such as movement, different tissue pigmentations.

It works much better when you've got vasoconstriction. So those of you that are familiar with using the alpha 2 agonists, melatoninexx, melatonin or pre-meds, those cause hao constriction, they reduced tissue perfusion. You may well hear the pulse ox alarming more often when you're using alpha 2s because it just can't pick up a great signal.

The masti it can pick up a lovely signal in those alpha 2 anaesthetized patients. And on the top here we've got the oxygen saturation and on the bottom, you've got the pulse rate. On the left, that green bar is an indication of the signal strength, so it's telling you, yes, I'm picking up a good signal.

So when it's in the green, you can rely on the fact that that signal's good and it's probably giving you a reliable reading. On the right hand side, there's a perfusion index indicator, which again, these are both indicators of reliability of that signal. Doesn't have a plasmogrand trace, but it makes up for it with the, the, the signal strength indicators.

And these aren't as expensive as you think, they're approximately 1000 pounds for one of these. Yes, you can get cheaper versions of pulse oximeters, but you definitely get what you pay for. And of course just to say, if it looks blue, the stats are definitely low.

The iPhone is very good at correcting cyanosis when you take a picture of a cyanotic patient, so I'm quite pleased that this, this dog's come out pretty much the same colour as the slide background on the right hand side there, it, it's a very purple tongue. If it looks blue, so that's definitely like. One of the pros of pulse oximetry is the results from the SEPs I've studied, the confidential inquiry into periocative small animal fatalities, documented that pulse monitoring decreases mortality.

And certainly that information is certainly very true in cats. Now, that could be as simple as an esophageal stethoscope or post palpation. But similarly, if we, if we can get a reliable indicator and a reliable reading from our pulse oximeter, then hopefully our pulse oximeters will help us keep a close eye on that patient and aid in decreasing mortality.

Sometimes I quite like the beep on the pulse oximeter. I know it infuriates lots of people. If it's reliable, I like it because it's another safety factor there.

It's an audible signal. You can be doing whatever in theatre, you can be writing your numbers down, or you can be getting some st material from the surgeon, looking at the patient, and you can still hear that sound of the pulse in the background. Troubleshooters movements, yes, that can affect the signal more of a problem than conscious patients.

Lo perfusion states, like I say, the maimo is much better at picking up those those low perfusion states. Pigment chow chows, pulse oximeters will pick up a placigengram trace on chow, but generally won't be able to actually calculate an oxygen saturation, so there's black tongues, the pulse oximetry really doesn't like that. It's a constriction.

And contact and. People argue one way or another whether there's there's a value to putting a wet swab, whether that actually improves just the distance between the, the, the, the LED and the receiver, who knows, sometimes it works, sometimes it doesn't. The New Horizons for pulsar symmetry, we're very familiar with pulsal centres, they've been around for absolutely ages.

This technology in another, another one of the master Ma pulse ox is is moving things on. And what they're looking at is the variation in that plethysmogram trace, so you can see at the top there you've got the waveform trace, the plethysmogram trace at the top there. And variation in this trace indicates variations in pulse pressure.

And it makes sense that our pulse pressure varies if our intravascular volume has varied. So in a patient on the volume, that peritonitis case that's in theatre this evening, that patient's hypovolemic, it's got a reduced circulating volume. So we expect changes in its gramme variation index or PVI.

And we can use that to guide our injury in sclerotherapy. So this is really seeing a very familiar monitor that we've just taken to another level here. It's not been validated in dogs and cats yet because it's just been released to the market in the previous couple of years.

So it's something that's a watch this space, but it's quite exciting. We've got a non-invasive piece of kit here helping us to guide, quite a complicated thing to decide. I mean, I.

Look at the, the dog with peritonitis in theatre tonight. It's got a very high heart rate. His blood pressure's OK though, but it's in the compensatory phase, so it's squeezing desperately.

It's heart rate is high to try and maintain that cardiac output. I know that a dog needs more fluids, but equally, I also know if that dog's septic and it has leaky blood vessels, any fluid I put into the vascular space is gonna third space and leak straight out. Into that third space and pool in places like the peritoneum and the pleural cavity.

So food therapy is. There's a lot of things that we We understand a lot, we don't necessarily have all the correct answers, and this is just aiding our clinical decision making. So I would encourage you to watch this space on this one.

Again, that monitor I said is about 1000 pounds, 1, 1200 pounds for that monitor, so not a ridiculous amount of money, just something we can use every day and that's gonna give us a lot of value. Capnography probably my favourite mode of monitoring modality because it tells you about so much. It tells us about ventilation.

It tells us about metabolism and it tells us about circulation. Why's that? Because CO2 is produced by those cells, the cells that we're delivering oxygen to, they're metabolising, they're producing CO2.

So in a hypometabolic state, they're not going to produce a lot of CO2, so we're gonna see a low end tidal CO2. In a hypermetabolic state, which doesn't actually happen that often, we're gonna see a an increased CO2 production. If our circulation is not in in a good state, we're not gonna get the CO2 from the cells through the circulation to the lungs, so we're gonna have a low title CO2.

And similarly, if our patient's hypoventilating, so either their rest rate or their tidal volume is reduced, or they have pulmonary pathology, we're going to see our endidal CO2 affected. This trace on the bottom here, if you're looking at that something you're thinking, oh, is that normal or is that abnormal? That is an absolutely beautiful, normal trace.

Those are called cardiogenic oscillations. So you have the expiratory phase there to start with. And during that phase, what we're seeing there, there's there's little peaks on the way down from from the the very short plateau we've got there.

There's little peaks on the way down, that's the blood flow through the lungs, just that pulsatar flow, influencing the elimination of CO2. And we've got a normal entitled CO2 there, so our normal entitled CO2 in dogs and cats and rabbits, 35 to 45 millimetres of mercury. Yeah, there we go.

And if we have an entitled CO2 higher than 45, we say that's hypoventilation, so the patient is failing to excrete all the CO2. And if we have a CO2 less than 35, we have hyperventilation. How does it work?

On the right hand side here, this is a side stream capnograph, so it's taken a sample from between the ET tube and the breathing system down this tubing which is aspirated into the machine through this water trap, and then there's an infrared analyzer in the machine that's analysing the, the concentration of carbon dioxide in that sample. Some of you may have a mainstream sampler where the analyzer is actually between the ET tube and the breathing system. Personally, I really like the side stream analyzers because they're much less susceptible to damage.

This is a normal cameragraph trace here. So at our baseline here, the baseline is at 0. So as we start to exhale.

Bearing in mind that we previously inhaled a fresh breath and so in our inhaled gas, there's no CO2, so we have a zero baseline. When we start to breathe out, the lungs empty at different rates, the lung units empty at different rates, so we have a a a biphasic slope to this trace as the CO2 comes up. From the lungs, obviously the gas that's in the conducting airways that hasn't undergone gaseous exchange, so it's actually fresh gas.

So as we breathe out, there's not a lot of CO2 in that first gas that we exhale from the trachea remains t bronchi. So when it becomes that fresh gas becomes diluted with the higher concentration of CO2 from the lungs, we see this increase, it increases to a plateau here, you see there's a slight upstroke on that alveolar plateau. To the point on the right hand side there, before the trace goes down again, that's our end title.

Important things to think about with catmography. The catmograph never lies. Provided, it's serviced and calibrated and the line isn't trapped in cupboard doors.

It needs to be turned on because they have a warm up time. It's really useful for telling us if there are leaks. So if you have a low end type of CO2, it's likely there's a leak in your system.

So we need to make sure that our ET tube is cuffed appropriately. Of course, we always want to cuff our ET tubes, certainly in dogs, to prevent against aspiration if our patients regurge and more patients regurgit under anaesthesia than we actually think. I had a case in theatres today, and I instantly knew that the surgeon who was doing a a a BoAS surgery at the front end, the surgeon had knocked the breathing system and it had become disconnected from the ET tube.

He hadn't noticed because it was under the drapes. I knew because my CO2 trace fell to zero. So it's a really valuable indicator for that patient becoming disconnected.

If I hadn't had the counter graft. That connector was actually under the drape, and I wouldn't have seen it. The first thing I would have known would be the dog coming light and waking up, which is not a great situation to be in.

So if you've got a camera in the cupboard, get it out, use it every single time, you'll avoid those hideous moments where you just have those dogs waking up spontaneously in theatre if they become disconnected. I've got two examples here of a hyperventilation, so a low CO2 on the left here, you can see this is a dog that's panting under anaesthesia. And thedog on the right here, this dog's probably a little bit deep under anaesthesia, so we've got an end tidal just in that pink circle there are 51 very tall trays there.

So traces do look slightly different on on different machines. As I say, if you want to see lots of cameragraph tracers, either have a look at the webinar that I did previously in January, or take a look on Caography.com, where I got those moving images from.

That's a really good source of cameragraph traces. It's a human website, but a lot of the, OK, the clinical scenarios might be slightly different, but there are lots of similarities that you can gain from that. Come up if he tells us about rebreathing.

That means our soar line may be exhausted. It means we may have faulty valves on our circle and we don't have the unidirectional flow. Or if we're using a non rebreathing system, it means our fresh gas flow is inadequate, so we haven't got enough oxygen being delivered to that patient to eliminate the CO2 out of the breathing system, therefore, we're getting re-breathing.

And when we see rebreathing, what we see is that baseline, that trace doesn't go back to baseline, so you see an increase in the baseline. Consider the case of the 750 gramme Yorkie, and we're trying to keep this patient warm because he's got a bandage on his leg, he's going into this to have a fracture repaired. He could be in size for 2 to 3 hours.

We really want to keep him warm, because otherwise, that's gonna prolong his recovery, detrimental effects on the patient. Don't forget that our oxygen supply generally comes from cylinders outside or at room temperature. So it's pretty cold, it's cold stuff to breathe in, particularly in the middle of winter.

We only need to deliver enough fresh gas flow to our patients to eliminate CO2 out of the breathing system. Whether we're delivering 1 litre per minute, whether we're delivering 5 litres per minute, we're still delivering 100% oxygen. So increasing oxygen flow will not affect your oxygen saturation.

If you think I've got a respiratory patient, I'll turn the fresh gas up. That doesn't make any logical sense because no matter what the flow, you're still delivering 100% oxygen. Our fresh gas flow exists to eliminate CO2 from breathing systems and to carry, to transport our volatile agents, our superfluorine, our isofluorine.

And in this little patient we perfected that fresh gas flow down to 0.5 litre using a mini like breathing system. And you can see here, if we get too low, what's gonna happen is we're gonna see rebreathing, but you can see on this countlogram trace on the left here, our baseline, our trace is going back to the baseline every single breath.

We've actually got those nice cardiogenic ostellations. Caography tells us about our airway, we already talked about disconnection. But imagine a case, I had a case today, a cat with an obstructed larynx.

I was really dependent on my CO2 because I couldn't actually see past the mass, really dependent on my CO2 to document tra kill intubation. So you place an ET tube, you think, oh, am I in the right place? First thing I do is turn around and look at the Camcgraph trace.

If I can see the patient's breathing and there's no CO2 on the catno graph, we're not in the right place, we're in the oesophagus somewhere we don't want to be, so we need to reposition our tube. And this is the perfect picture on the left-hand side here of the kind of spike that you see when we've achieved tracheal intubation. It's something in human anaesthesia, it's gold standard.

If you or I were an exercise in theatre, first thing they'll do. The anaesthetist and the operating department practitioner will turn around and look at the machine, and they'll say, we have intubated the trachea because they know that's the only thing that will stand up in court if you die during induction of anaesthesia. That's the only thing that will stand up in court to say your trachea is intubated.

We think it tells us about circulation. Just on the slide here, this is from a patient during CPR. You can see that from a cardiac point of view, we're not looking too great.

Oh, we've got some pretty hideous arrhythmias there, and look how low our entitled CO2 is. So when we have no circulation because we have no cardiac output, we're not getting CO2 delivered from the tissues to the lungs where we can measure it. So it's quite useful to use during CPR.

Things to worry about, sudden loss of trace. Is it technical, have we trapped the line in the door? Has the patient become disconnected?

No traces at all. Like I say, we're probably in the wrong place. If we intubate and we don't get a trace on our counter graph and we know that the machine's warmed up, we're not in the right place.

One thing you can do, of course, is breathe down the line yourself before you connect the patient just to check that your camera graph is working. If we have a progressive decrease in CO2 that suggests something circulatory is going on, and this always happens in patients before they crash, you'll see that the entitled CO2 decreases, decreases, decreases to the point where we say, right, we need to start CPR on this patient. Persistently high CO2, that's an alarm bell.

We need to do something about that. We need to address why is this patient so deep under anaesthesia, what's going on? For those CPR cases, what we're looking at when we perform our chest compressions and we're aiming to provide return of spontaneous circulation, we want our patient to to start for its heart to start beating for itself, and perfusing these tissues.

In CPR, a useful indicator is the CO2 more than 15. So if you've got a patient that crash, get your monitor on, get your ECG connected, get your capnograph connected. If you've got CO2 more than 15, then you know from people who don't know this in dogs or cats, there's probably a greater chance of you getting them back.

So by all means use those monitors in those situations. So you can see, that's just touching on on Caography tonight. There's a lot more about it, it's a fantastic, really useful monitor.

It's the bit on the monitor that costs the most amount of money. So if you're looking for a new monitor, do not skimp on the counter graph, it costs money, but it's worth it. Our ECG, we all know that ECG is reading the electrical activity of the heart of the body wall.

It's telling us about rhythm, rate, it's not telling us anything about cardiac outputs. We've already looked at case examples where I've suggested applying your ECG before induction and really making the most of it. I'd much rather know that that patient had an arrhythmia before I anaesthetized them than a nasty surprise once we've reduced anaesthesia and we put the ECG on it.

Oh, hang on, I'm not quite happy about that. The peritonitis case going into theatres tonight, examining that dog. We expects a.

Hypovolemic dog with peritonitis to be experiencing some type of arrhythmia. We examined the patient tachycardia 180. Occasional pulse deficits.

I think, OK, fine, what's going on here? Let's pop on CG on. Yes, that dog was experiencing periods of ventricular tachycardia.

The rate is higher than 180 and it's a ventricular rhythm, so we call it ventricular tachycardia. Less than 180. Some people say less than 160, we're talking idioventricular.

The next thing I did in that case was use an oscillometric blood pressure monitor to work out what effect the aid is having on that patient. And actually, his new arterial pressure was in the 80s. So I'm using that to build a picture and say how much stabilisation do I need to do in this patient before I anaesthetize him.

We actually started a lidocaine infusion after a lidocaine bolus and the lidocaine infusion, it helped to resolve that ventricular tachycardia. Quite a nice example of seeing those things work in front of your eyes. Dogs in theatre hasn't experienced any more ventricular tachycardia.

What are we looking for? We're looking. Is there a QR for every P wave that we see?

We're looking at the regularity of that rhythm. Is the number displayed by the monitor the same as what we can palpate in that patient? Do we have any of those wide bizarre complexes that we saw before?

We've got a normal ECG on the left hand side of the screen, and you can see on the right, we've got normal complex, followed by something abnormal. It almost looks like you've got. P QRS, got a little bit of a T, and then we've got something wide and bizarre there and it's repeating.

That's ventricular by Germany that we're seeing there, so a normal complex followed by a ventricular complex. Is a place up at that? Troubleshooting our ECG, you may use clips on your ECG, you may use pads on your ECG.

If your patient is draped, how do you know which of those pads is the one that's causing the problem if you've got a problem? You can go through the leads because obviously you triangulate your ECG lead placement over the heart, and we use 3 leads under anaesthesia, left arm, right arm and left leg. Your machine will be able to flick between lead 12, and lead 3.

To work out which one of those is lead 12, and lead 3, you count the number of L's, so left arm to left leg, there are 3 Ls. So that lead is lead 3. Left arm to right arm there's 1 L, so that's lead one leading between those two.

From right arm to left leg there are two L's there, so that's lead 2 that we're reading. So, if you have a problem with your ECG and you flick through lead 1, lead 2, lead 3. And you get a reading 1, but not in lead 2 or lead 3, it must be the left leg that is the problem.

So you can either direct your efforts at putting new pads on that left leg, or you can continue monitoring in lead one. We tend to monitor lead2 under anaesthesia because it gives us generally the most consistent complex recording. And he talks about using blood pressure to complement what we see on our ECG, and there are 3 types of blood pressure.

I'm sure the vast majority of practitioners have adopted blood pressure in the clinic. We use it for our old kidney and thyroid cats. But as well as those cases, let us use it under anaesthesia because I think this is an amazing monitor.

Yes, we know it's technically challenging. OK, if you can do that and really hyperthyroid cat, it's so much easier to do on an anaesthetized cat or a dog, trust me. We talk about it measuring systolic.

Certainly in dogs, the doctor measures systolic. In cats, the studies have shown that it probably reads close to to mean in cats. Or oscillometric, the cardel is the example that I've given you there.

These are the automated blood pressure monitors, they measure systolic, meaning a diastolic, they cycle, they display the pulse rate as well. And invasive monitoring, our gold standard is using direct blood pressure where we place a catheter into the artery. That's what I've done tonight in that peritonitis dog.

He's got arrhythmias. I definitely want to know exactly what's going on with that patient's blood pressure. Very useful for us working out the influence of those arrhythmias on the blood pressure and guiding some of our fluid therapy because we can look at the trace that we see and work out whether we need to give more or less fluids.

So it does need a lot of practise, technically, challenging to learn how to play it probably takes about 3 months of of consistent opportunity placing those. The Doppler here just on the cat's paw. The thing I love about the Doppler, he talks about audible pulse monitoring and the pulse oximeter.

I love the fact that with the Doppler, it gives you blood pressure, but you can also hear that that cat a million miles away from you under the drape, you can still hear that lovely. Of the Doppler blood pressure monitor, I find it really, really reassuring. OK, we hate the really screechy bit and they don't get on well with diathermy, but I absolutely love a Doppler.

And let's look at blood pressure just as an example, you can see nobody wants to be in this situation with half of sort of blood volume in the suction container. This was a case that I guess we will see every now and again, a splenic hemangiosarcotais, so splenectomy, open the dog's abdomen, and this is all in in that suction container there, bleeding abdominal mass. This is the dog's blood pressure prior to the start of surgery.

And you might think, oh, actually, the blood pressure's not very good there, we've got me in 53, that's not great, is it? With these cases where there's ongoing bleeding, what I actually want to do, I'm not trying to restore that dog's blood pressure in much higher than 60 millimetres of mercury because we run the risk of promoting further bleeding. What I'm gonna do is just add some fluids.

Get a control on that blood pressure until the haemorrhage is under control, and then I can start restoring this dog's circulating volume, giving blood, give you fluids as required. There's no point in me pouring expensive blood that's been taken from a blood donor in at one end if it's just gonna pour out into the abdomen and then the suction container. To use the fluids, this was probably about 15 minutes after fluids and blood was administered to that dog, and you can see those changes, you see that heart rate coming down from 100 down to about 80, a little bit more settled knee arterial pressure improving vastly.

Much better position and as I said, we did indeed give this dog some blood. Little troubleshooting tips with your BP. You want your cuff width to be 40% of the limb circumference.

And you've got a diagram there that shows you your width and the circumference. I normally just measure this around the patient and then make sure that my width is 40% of the circumference. If the cuff's too big, the blood pressure reads low, if the cuff's too small, then the blood pressure reads high.

So just be aware that your cuff size will influence your blood pressure reading, and also that cuff position relative to the heart. So the cuff, once it's on the patient should be approximately at the level of the right atrium. So if it's hanging off the table, you're going to get a much higher, if it's hanging low off the table, you're gonna get an increased reading.

And a false representation. You mentioned direct blood pressure, we have a catheter placed in a peripheral artery, connected to a transducer, and then attached to our monitor there, and you can see that red trace on the bottom there, mirroring what's going on with our pulse oximeter. And when you get an arrhythmia, you can see the influence of that arrhythmia on the blood pressure trace.

OK, so putting all that together looking at a case study, something that I saw, I think this is about 18 months ago. An anaphylactic reaction. This was the dog that was in CT and we administered iodinated contrast agent as we do to enhance the, the images of your CLCT, but you could equally see this with intravenous antibiotics.

So there are a number of agents that we know if we administer. The IV there's a risk of anaphylaxis. What does anaphylaxis look like?

Circulatory collapse. First thing I noticed in this patient was a low end total CO2, so we had a normal, lovely normal trace, give you the contrast, come out of the room because obviously you have to leave that controlled area. Once that contrast's gone in, we noticed this dog CO2 had dropped, so we instantly know, right, there is a problem.

This isn't machine making something up. When you see the CO2 change like that, you go straight back to the patient, you palpate a pulse, you give them a breath, you check that everything is connected. He had poor pulses and the other thing that happens is the non-invasive blood pressure monitor, the osteometric monitor kept beeping because it wasn't reading.

I think it was tachycardic, so all the things we'd expect, circulatory collapse, vasodilation, response to that is tachycardia. This dog responded really nicely to adrenaline. And we maintained him on an adrenaline infusion, waiting for that contrast to be eliminated from, from the body.

But if we hadn't had this level of monitoring, we wouldn't have noticed that reaction. So personally, I think every case that you're if you're, if you do have the luxury of a CT scanner and you're using contrast, this is the level of monitoring we should certainly be using in all of those patients for those reasons. One of the things that you often hear people say is, OK, I can feel the peripheral pulse, so the blood pressure must be X.

Must be above 60, 70. This was a study in cats admitted admitted to an emergency clinic where they looked at femoral pulse, metatarsal pulse, palpation quality, and they compared that to Doppler blood pressure readings. This ephemeralus quality correlates strongly with systolic blood pressure, but it disappears when you have severe hypertension.

So actually, if you can't feel the femoral pulse, things aren't great, are they? A Little bit more specific with the metatarsal pulse, so absent metatarsal pulses in cats has quite a high likelihood of that systolic pressure being less than 75. So start palpating metatarsal pulses in those cats.

If you get a critical cat and you can't palpate a metatarsal pulse, its systolic pressure's probably less than 75. It gives you a great idea before you even get the blood pressure monitor out. And in those really sick cases, if you can't feel a femoral, you can't feel the metatarsal pulse, the median systolic blood pressure in those cases was it was 30 millimetres of mercury.

So those are pretty sick cats. It's quite nice to have a study that supports things that people have been saying for quite a long time. This is work in cats.

There hasn't been a similar study in dogs. I don't know if that's in the pipeline, but I don't think the physiology is that different between cats and dogs. So let's get used to palpating pulses and not femoral pulses.

We palpate femoral pulses when we're listening to hearts to feel if we have any pulse deficits, and we palpate femoral pulses during a crash situation. Under anaesthesia, we want to work out whether we have that peripheral oxygen delivery, that peripheral flow, so we're feeling peripheral pulses. Put it all together 11 year old Borzoi with degenerative valve disease, she's got anorexia lethargy.

Colleagues in medicine want to work this case up. She's got a mitral murmur, 2 out of 6. We've got a GA her for thoracic and abdominal imaging.

Do we run bloods? Is that gonna help? Potentially not, a dog with cardiac disease, but she's 11, we know that if we run bloods in dogs over 8, we're gonna make a new diagnosis in 30% of cases.

Is the dog on meds? Should it be? Let's assume this dog's had a cardiac workup, doesn't need to be on meds.

What do the cardiologist always say with mitral valve disease, go easy on the fluids. Which monitors do we think about? Are there any drugs we would avoid in this case?

Of course we're thinking about tissue oxygen delivery, so we're thinking about heart rate, stroke volume, cardiac output. Contractivity in these guys is usually good. That regurgitant fraction across the mitral valve does reduce our cardiac output to a degree.

The heart rate is usually normal and we want to keep the heart rate normal. I would say we only need to give these dogs meds if they're actually in failure, and if they're in failure, I don't want them coming here anywhere near me in anaesthesia. They need to be stabilised before we consider anaesthesia.

Let's think about the cardiovascular system because this is an older dog. Reduced cardio, cardiovascular reserves. Those receptors that detect vascular volume are reduced as far as their sensitivity capacities go.

These patients have less of a response to catecholamines, so the normal response to increase the heart rate, increased blood pressure and response to hypertension are obtunded. Therefore, we're looking at reduced cardiac output and probably a lower blood pressure. We know that cardiac out pre output is pre-load dependent, so rather than deprive these dogs of fluids, they need to be optimally hydrated, so it's probably one of the most important things in these cases that their hydration status is appropriate.

And if it's not, they're probably best having, rather than trying to get fluids into them over a short period of time, rehydration for from the night before anaesthesia and anaesthesia the next day. We're looking at reducing after loads, so we don't want to give any agents that increase after load, and those are constrictors, we don't want to use the alpha 2 agonists. We want to maintain our heart rate and contractility.

We talked about pre-load. For me, I use aceromazine and an opioid in these cases, and I would avoid alpha 2 agonists. Monitor wise for this case, the best monitor in these cases, like I say, coography is really, really valuable.

For a simple quick monitor, a pulse oximeter can be very useful. But blood pressure really is a very useful one in these circumstances. ECG wise, you think, well, it's a heart case so an ECG doesn't that make the most sense.

Well yes, it does, but from a mitral valve disease point of view, these dogs don't normally have arrhythmias, and they're very unlikely to develop arrhythmias during anaesthesia. So, let's say you've ECG'd that dog pre-anesthesia, it's really unlikely to change. I'm not asking you to pick one monitor over another, and I think you'll have ascertained over the the course of this webinar that each monitor compliments one another because they tell us something slightly different in order to optimise our tissue oxygen delivery.

Of course it's not what you've got, it's actually what you do with it. Get the monitoring on before induction of anaesthesia, particularly in those critical cases, like I say, the peritonitis dog, ECG, blood pressure, those were all on before induction of anaesthesia. There's brachycephalics, when they're in recovery, probably the most valuable thing in those circumstances, especially once we've extubated them, is a pulse ox.

And I love the mastoid pulse ox because you can put it on the lip, you can put it on the ear, you can put it on a toe web, and generally it gives you a really good reading. You've got a great handle on that patient you're worried about that was on 100% oxygen under anaesthesia. Once you extubate them, then you can give the mask oxygen, but we're really trying to transition them back to that 21% oxygen in the room there.

Let's use our pulse oximeter to work out how well those patients are transitioning. We know that mortality figures in the recovery period are the the the riskiest time of anaesthesia, we know that they're high, so take your monitoring equipment into recovery. Those post-op splenic hemangiosarcomas, take the blood pressure monitor with you.

Let's make sure that all that work we've done under anaesthesia stays true in the recovery period and that our dog's blood pressure is appropriate. So There's a lot that we can do with our monitoring equipment. I'm really happy to take any questions that people may have now.

OK, thank you very much for that, Matt. Once again, as always, very informative and really giving those practical tips and advice on really how to, you get the most of this time out your monitoring equipment and, really, so please do, you know, take some time. I've got some time for I take some questions before, Matt has to, dash off and see how his peritonitis, cases, .

But I think, you know, obviously you demonstrate at the beginning there that, you know, it isn't a laborious task to get all the, monitors in place to begin with. You know, it is, and it is very worthwhile, a time, you know, even taking up 30 seconds to 1 minute to get it set up just to give you that extra level of, knowledge and in assurance really, when you're doing the operation. Was that a tiger that I saw that you were, demonstrating on where to place the probes?

So I was looking at that before and I was like, I'm not sure how many of them you get at your, you at the hospital. It was, that was, that was when I was in practise back in, Worcestershire. We used to do the work for the West Midlands Safari.

Park, last time I went, I went there 18 months ago and she was still roaming around her enclosure. She, we amputated her tail, because she got clawed by one of her litter mates. So of course you get a white tiger and of course you have to take photos of it.

So everyone goes to West Midland Safari Park, say hello to Tubs for me. You know, I was just looking, I was like, I think that is actually a tie. It's just not a zoomed in picture, so.

So no, so, well, everyone's, I think you've probably must have covered everything because there's no questions coming in, Matt. I think they're, taking, pity on you and letting you, shoot off so they know you've got a long night ahead, which is absolutely fine. But what I would say is, obviously, .

It'll pop up when you, navigate away from the webinar, a feedback form. Please do take your time to fill it in. We do really appreciate and take time to look at your feedback to help us develop our programme and also, feed it back to the speakers as well.

So please do complete that. So, if you don't have any questions, there doesn't seem to be any coming in. We'll leave it there.

Thank you very much to, Peter for being on the technical side of things today, monitoring the emails, etc. Unsung heroes ears. Thank you to yourselves for attending, and obviously, finally, thank you to Matt.