So welcome to Capnography. What is it telling me? This is really a webinar to get you into using Capnography at the start, or perhaps you've had it for a little while, or it's just always been there at the practise that you've just joined and you're unsure of what you're seeing and what the numbers mean and what you need to do about these traces that you're seeing on your Capnograph.

So capnography, what is it telling me? So webinars are a little bit different. You don't have anyone sitting in front of you, so who am I?

That's me with my cat B Bertie, and this is me with my boss Rachel Perry. My name is Stacey Parker. I qualified in 2014 as an RVN in the UK.

I then got my ISFM certificate in feline nursing, and I since, achieved my NCAT in anaesthesia and dentistry, and I am currently taking part in the NSA in advanced anaesthesia this year as well. My official job role is I'm a referral anaesthesia and dental nurse for Perry referrals, a specialist veterinary dentistry and oral surgery. I also do do some emergency nursing on the side, and I do join in theatre sometimes as well.

Outside of my clinical work, just like right now, I do provide in-house and external CPD and we do have some learning aids available on patient warming packs, and you're always very welcome to get in touch with me via any of these ways, and at the end there'll be a slide that will have all the different ways of getting in touch. If there's anything I haven't covered or you'd like to know more about, or you just want to have a question, you're very, very welcome to get in touch with me in any way you'd like to. So as I said, I work primarily for Perry Referrals, which is a specialist veterinary dentistry and oral surgery, and I also, we work primarily out of North Down Specialist referrals, which is a multidisciplinary specialist centre in Surrey.

Thank you to the webinar vet for hosting this and for having me. I'm very grateful. They have loads and loads of really great webinars available.

So it's really lovely to be a part of that and hopefully this and other webinars will increase your confidence in your education and what you can do at work. So, well done, first of all for starting the catography webinar. Change is good, but it is scary for sure.

I remember when I first started at my referral hospital, I'd never seen catnography before and I was amazed by it how much information I was getting, but also slightly overwhelmed by that amount of information and what I could do with it. Now we could talk all day about what canography can tell you and the ins and outs of it, but as I said, we're going to start this as a webinar for if you haven't used it before or if you've been using it for a little while and just don't feel confident with it. Hopefully it'll be enjoyable for you, like this little guy on the plane on the right, and we try and make it lighthearted and not overwhelm you with too much scientific facts for this webinar.

I want it to be that you can get a real feel for taking some practical tips and feel confident back in practise. So today's learning objectives are to recognise different waveforms of our Capnograph, how to troubleshoot both hyper and hypocapnia. We want to recognise how capnography can assist us within CPR should we be in that unfortunate situation.

We also need to understand both the Capnograph and the catnogram, and we will just explain to you the difference between those. I'm hopeful that you will then realise the importance of using catnography for all your patients undergoing anaesthesia. I think it can be really easy to not use something even if it's there if you don't feel confident or if you don't have the experience because it actually then becomes a distraction.

So with a little bit of education and support behind you, I hope if you're not reaching for it yet, you will, or if your practise is thinking about getting it, then perhaps we can then push them to get that if you're feeling more educated and be able to facilitate using it more appropriately. So this is us. We also get to go to Marwell Zoo and operate on tigers and lions and leopards, and this handsome chap was having an extraction of his tooth.

My point being that he is very large and this is out in the field, and, you know, the zoo veterinary world isn't overly well funded, but we still were able to use a catnograph for this guy because it really is so, so important for our patients. So that leads us to why should we be using Capnography. What does it tell me about my patient.

To start with, it will confirm that your ET tube is in the correct place, which is in the trachea. It will tell you more information about the metabolism of your patients, their cardiac outputs, their pulmonary perfusion. It can also prove about the adequacy of ventilation, particularly useful in a CPR event.

If your cat the graphs stop reading very, very suddenly, then this can be the first sign of an impending cardiac arrest, and this is why it is really so important that we have catography on board as well as all the other information that we've just discussed, it can tell you, this is the one situation we always dread being in, and if somebody can give you the heads up on that, then that can only be a good thing in my opinion. Solanography measures the carbon dioxide concentration throughout the respiratory cycle in expired and inspired gas. So why is this helpful?

So if we think back to our college days when we were told about how things worked, the body inhales oxygen, the gas exchanged in the alveoli, it's then diffused into the bloodstream and transported to the cell where cellular respiration occurs. At that point, cells are taking in oxygen and glucose. They then release energy and CO2.

CO2 is then transported back to the alveoli, and there the CO2 is diffused into the alveoli and we exhale it. And that point of exhalation is what we'll be seeing on our knograph. And we will bring up this diagram again later to just reiterate why it's so important to use capnography to assess the adequacy of your CPR attempts.

Capnography has its real benefits as well in that it is a continuous measurement. It's non-invasive, which is great, means anyone can use it, and it is super easy to use. What's not super easy is to understand it, but if you're watching this webinar, you're already taking that super step towards understanding it as well.

So you've got the catnography, it's part of one of your multiparametters, or it might be a different multiparameter. There's lots out there. It might be a catnograph on its own, it might be part of a pet map, it might be part of a pulse ox.

There's lots and lots out there, so don't be alarmed if the one you've got isn't like the pictures that I have. Every place will have something different. Just really focus on the wave forms which we'll be pointing out to you, not the machine in itself.

So let's start with the capnogram. Now that is the wave form. Some people say they look like little elephants holding on to one another, which I think is quite cute.

I go with sand castles when I'm training people or my nursing assistants are asking questions and want to know a little bit more information. I say, tell me what's happening to the sand castles. They're the same kind of colour.

Our trace is yellow, and they do like look like quite good sand castles that you may have made at the beach. The capometer is a numerical value, and this will be placed normally next to your trace of the wave, and that sits there. And the respiratory rate will also be given to you by your Capnograph, which is there.

And you should be also able to measure your inspired carbon dioxide, which should read 0, fractional inspired carbon dioxide is just there. So everyone raves about the waveform and all the different ways we may see it, but what is it all about? And this is going to be the chunkiest part of the webinar, and then we'll be moving on to the completely practical what am I seeing in practise that you can then apply, and we'll be giving you some time to have a look at some videos later as well, so that you can decide for yourself what the traces might be before we tell you.

So hopefully we're going to teach you how to understand it, show you what they are, and then reinforce that by you deciding yourself later on what it might be. So this wave form. Now, if you've not seen a catnograph before, or you've not seen it written like this, this can be a bit overwhelming, I completely understand.

So let's break it down. Phase one, as circled in red, is basically the air leaving the dead space. Dead space meaning where no gas exchange occurs, so that can be in the trachea, where the ET tube isn't quite there and beginning of the circle circuit or also extended ET tube if your ET tube is a little bit too long.

Phase 2, which is your upward stroke, is your exploration of alveolar gas and the last bit of that dead space gas. So CO2 from the alveoli reaches the upper airway. It mixes with the air in the dead space, and the CO2 is then detected in the exhaled air, which then shows the upslope, which is circled, which joins phase 1, which we just mentioned, and phase 3.

As circled here. Now this is the plateau phase. All the alveolar gas has been expelled, so this is when they're really breathing out and the blue circle is right at the end of the expiration.

The CO2 will remain constant as the alveolar gas is exhaled, which is the alveola plateau, and that's flat with a slight upward tilt at the end. The end of phase 3 is the end of exhalation, which contains the highest concentration of CO2 throughout the reading, and this is the point that your machine will turn that into a new numerical number which will be shown on your machine. They then breathe in.

So the CO2 drops completely as they're breathing in, as it shouldn't really contain any CO2 and this returns us to phase zero. So this should return to baseline quite rapidly if they're breathing normally. And that's your choice.

So for me when I'm trying to learn these things, if I draw them, whether it's on the computer or by hand and then label them myself, I find that really helps me to remember them a little bit better. And as we mentioned, that's where our numerical value comes from at that point of exploration, the very end of that patient's breath, just before they breathe in again. And it will be written as such on your machine.

Now that might be very well, and maybe you didn't fully understand that just watching it once, and that's absolutely fine. If it's just got you into using technography and a slight understanding, you can now read around the subjects, maybe some articles or books, and then you may be thinking, but that's fine, but why do I need to know all of these phases? I just want to know about what numbers they are, what I should or shouldn't do about it.

But it's really important that we know all the phases because any deviation from the normal waveform really must be investigated. So we must know what each part of the waveform represents in order to know where the issue is and how to fix it. When we're watching the waveform, we should be looking at the frequency, the rhythm, the height, the baseline and the shape.

So let's discuss normocapnia. We'll also then discuss hypercapnia and hypocapnia. Before then, before that, we will then go on to looking at the different traces.

So we'll start with the numerical figures to start with and then we're gonna move on to the traces that you may see in practise. The normal cair isnide or CO2 between 35 and 45. So those are the two numbers to try and get in your mind.

Like everything in veterinary and particularly anaesthesia, there are going to be some appropriate and acceptable deviations to the normal. But if catography is new to you or you've never been taught what numbers you're looking for, 35 to 45, and that's millimetres of mercury, is what you are looking for. So hypercapnia is when the ntidal CO2 is therefore over 45.

The maximum permissible that we will accept in the short term in our clinic is 60. Opioids can increase this to 45 to 55. Brachycephalics has slightly different ways of breathing, bless them, and they can also run naturally higher.

So I do anticipate my brachycephalic to be running at the 45 to 55 mark, and I will accept that if every other parameter is normal. So what all hypercapnia look like on your screen? It will have much taller waves, and remember we're looking at the yellow waves that look like sand castles.

They're going higher at that point on our graph, and you can see that the number there is 55, but even if we didn't have that number, we would still be able to see that it is exceeding the normal. So why could this be happening? We're gonna talk to you about why it could be happening, what will happen if you don't fix it, and what could be causing that concern of it happening.

So hypercapnia could happen because your patient is hyperventilating. You could have exhausted sodalime in your circle system. Your patient might be too warm and hypothermic.

They may be in a too deep plane of anaesthesia. There could be an obstruction to the airway. You may be using CO2 in a laparoscopic surgery.

They could be rebreathing, there could be a central nervous system depression, and in some very rare cases you may be seeing malignant hypothermia. So if we are hypercapnic, how can we return this to being within the normal range? For hyperventilating, then we can look at performing IPPV breathing for them.

If the soda line's exhausted, then remember you can change that soda line. And remember that most of the soda lime that you get will change colour, but if it's not changed, you don't change the soda line in good time, it will change back again and very quickly show that it's not, it is exhausted when you go to use it the next time. So remember to always pop a tag on if you haven't got time to change it when you need to in between patients or at the end of the day, make sure that's labelled so someone doesn't pick it up.

If your patient is too warm, we should be checking their temperature every 15 minutes. Perhaps we don't need all those warming aids that we've placed on them. Is your patient in too deep a plane of anaesthesia.

The first step for that is to reduce the volatile. Obviously check all your vitals. If there's an airway obstruction, we need to check the circuit and work out where that could be coming from, and you need to work that right out from the circuit right down to the patient's ET tube, checking every part of that circuit.

If you are performing laparoscopic surgeries such as laphase, the increase of CO2 in the abdomen can actually go through the diaphragm a little bit, and then you can see an increase in CO2. Time will allow that to go down and if you're absolutely sure that the only thing that's causing it, and it's not too high, then you don't need to be concerned. If your patient is rebreathing, then perhaps you haven't got a high enough fresh gas flow, or if they just keep rebreathing and they've got a really high respirator and they're just not settling, then perhaps you'll need to place them on the ventilator or perform IPPV.

If they have CNS depression from a head trauma or such, then we just need to be aware of that. And also we need to be very careful with our drug choices, and again we may need to breathe for them to reduce their entidal CO2 reading. And with malignant hypothermia, again, we shouldn't be having that unannounced, we should be constantly recording and taking our patient's temperature, ideally continuously, but at a minimum of every 10 to 15 minutes.

So if it's left heated and they're hyperventilating, that can cause lead onset and being apneic, so not breathing, which can cause cardiac arrest and death. If the sojali is exhausted, then it can cause an increase of tide or CO2 and it will just keep continuing. If they're hypothermic, it can actually cause arrhythmias, which can also lead to seizures and death.

If your patient is in too deep a plane of anaesthesia, then they become can become hypotensive, have reduced cardiac output which can lead to death. Airway obstruction can also cause them to stop breathing, which leads to cardiac arrest, which does lead to death. Increase the CO2 in laparoscopy, we have discussed that this will resolve.

If the patient is re-breathing and you allow them to keep doing so, then they can become hypo perfused. And central nervous system depression can cause brain damage which can lead them to coma and death. I'm aware that this isn't the happiest of slides with the word death written 5 or 6 times, but it just shows how important it is to be measuring our using capnography and measuring that entidal CO2 measurement and knowing what to do about it and what it could mean so we don't fall into these negative outcomes.

And again, malignant hypothermia, just to sort of come up what I just said, they can die from that very quickly. So again, very simple, monitor their their temperature. And you can see every time you learn about a different parameter to monitor, it really does come in the multi-modal aspect of using as much as we can, but also understanding what we can from each monitor that we're using and how they all interlink with one another as well.

So on the flip side, hypocapnia, what is this? Well, if normal is 35 to 45, then being too low, hypo is below 35 tidal CO2. This can be sought after in some cases where there is a risk of increased intracranial pressure.

Also, a higher than required fresh, fresh gas flow can dilute the sample that your machine is taking of your gas, and give you a lower reading. So if you've got a really high fresh gas flow, and you're having a really low entidal CO2 and they're not rebreathing, then do you need all of that fresh gas flow? Can you reduce that and then you should see that it's not being diluted quite as much.

So what does hypocapnia look like as a wave wave form? Well, if the hypercapnia is very tall, then conversely, the hypocapnia is going to be very short, and you can see that my entidal CO2 numerical reading is only 20. So why is this happening?

We're gonna go through this in the same way that we went through hypercapnia. It could be caused by hyperventilation, as we've mentioned, it could be caused by dilution of your fresh gas flow being too high. If your patient is cold, if you have an equipment leak, so they're not getting the machine isn't getting your full measurements.

Damage sample line as well. If you have your ventilator or you're breathing for them at a high rest rate, it can also cause hypocapnia, and you may wish to slow that down. Pain can also cause hypocapnia, a light plane of anaesthesia as well.

A sudden change, as we mentioned at the beginning of your CO2 reading, dropping very low or just stopping can be a signal that impending cardiac arrest. And also if you have an uncuffed ET tube or if the pilot balloon is leaking, you can start seeing hypocapnia. Remember, as I've said twice already, that I believe in it very much, if there is a sudden drop in your Ntide or CO2, if you haven't got your hands on your patient already, then please do feel their pulses, make sure that everything is OK and nothing is about to happen untoward.

So our patient's gone hypocapnia. How can I return to normalcapnia? If they're hyperventilating, which under anaesthesia we class as a respirate over 20 then assess their anaesthesia depth.

Do they need more anaesthesia? Do they just need a little bit more sedation? Are they uncomfortable?

Do they need some more analgesia? Check that your fresh gas flow isn't too high and you're not diluting out your circuits. Hypothermia, again, as mentioned previously, we should be checking our temperature continuously, if not every 10 to 15 minutes.

If there is an equipment leak, and this often happens at the connector, at the end of the ET line, sorry, the capnography line that attaches to the adapter next to your ET tube, and that often can. Get quite loose or just snap or you can't see that it's snapped until you go to wiggle it, so check that point and you need to check the circuit right from the ET tube to the scavenging to ensure there isn't any leak happening. If your patient is in pain of reception at the beginning, then we should be providing additional analgesia.

A patient that's in pain will be breathing quicker, and that leads us back to our hyperventilation. An uncuffed ET tube can also cause hypercapnia, so we just need to check the cuff pressure on your ET tube and make sure that it's not leaking. And as we've mentioned many times, cardiac arrests, so be ready to give CPR and at least have your hands on the pulses to make sure that that isn't about to happen.

Left untreated, hyperventilation will cause respiratory alkalosis and inappropriate GA depth. A dilution by having a too high fresh gas flow will cause an inaccurate reading. Hypothermia can also lead to hypertension.

Accidental drug overdoses, you don't actually need as much inhalant or drugs if you're cold, which can lead to death on both accounts. An equipment leak can actually cause pollution to staff as well as an inaccurate reading, because wherever it's leaking, if you've got some iso orcedo in the oxygen, which you will to have your patient staying asleep, then you will end up breathing that in. Pain can cause hypertension, which is also a negative side effect, for anaesthesia.

Often we focus on the hypotension, but we can also see hypertension. An uncosted C tube will again cause pollution to staff and inaccurate reading, as well as not having a secure airway. And cardiac arrest can of course lead to death.

So that's covered the numerical forms and a little bit of an understanding of what numbers we would like to see and if we are seeing the hypo or hypercapnia, some ideas and some troubleshooting ideas for you to deal with that. So we're gonna move on to the waveforms now. I'm going to start by showing you several different waveforms and explaining them.

I'm then going to show you some waveforms and give you a couple of moments before I tell you each the answer in the hope that that will reinforce things for you. So. This is a nice trace that we're seeing here.

I know the num numerical number is a little bit low. Perhaps we've only just started the anaesthesia and we just need time for that to come up a little bit, but it's a very nice pattern. This is what you may see if you have accidentally intubated the oesophagus, so make sure you're keeping an eye out as soon as you've.

Connected your catnograph to your ET tube, you may think to start with, oh, lovely, and then you just get this little wiggly worm and then it just goes off. And this is not what you want to see, but don't worry, and it's also a really good tool to have catography if you're just learning about intubation as well. Now this picture is where we have leaking of the cuff of the ET tube, so you can see you don't have a very tall upward stroke, and the inspiratory comes down really slowly as well.

And it all just looks a little bit flat and floppy. So this is the face straight after we have recuffed the ET tube to 20 centimetres of water in a dog. And you can see now we have our nice tall, appropriate sand castles or elephants if you will, and our numbers come up to, and we're no longer going to be polluting the area around us either.

We use Aal coils to inflate RET tubes so that we're doing so safely and we're aware of the pressure on the trachea. For us, we go up to 16 centimetres of water in the cats, 20 centimetres of water in the dog. I will check this every 20 minutes as movement warmth, or a slow leak could occur.

So the movement of the patient can cause the pilot la to move a little, and warmth can just make the UT tube, relax that little bit more where it's nice and warm, and so it may need a little bit more of a cuff. And if the ET tube is leaking, we will dispose of it. We won't let that go back into circulation around the building.

You should also be checking your pilot loons and the ET cuff, ET tube cuff prior to the general anaesthetic of every patient and try and leave them inflated for at least 5 minutes before using them so you can see if there's a slow leak. So this is a normal catnograph to start and you can see the sandcastles getting genuinely and generally shorter when metabolism is changing within the body, and this is generally associated with cardiac arrest or large pulmonary emboli such as air or gas, blood or fat or severe bronchospasm. So it's something to be aware of.

Hopefully it's not something you would see, but if you did see it, you would be aware that you need to check the pulses and make sure your patient is is OK. Equally, if you cuff the ET tube and it starts leaking, it may start looking like this as well. So being apneic, you would have your usual wave form and then it would just stop where your patient has stopped breathing.

Apnea is fast as no breaths after 10 seconds. Annoyingly, your machine does like to calibrate every now and then and it will look the same, but it will say calibrating in small writing near your wave form, so don't panic. Keep checking the bag, your breathing bag on the circuit, your reservoir bag, and make sure that that's happy and check that your machine is saying calibrating.

As we know, a respiratory arrest can lead to cardiac arrest. And this is the big one that we look out for, particularly in dentistry, or any surgery, it's super important to be aware of, but particularly if you're using, sort of circle a circuit that's on the opposite side to the patient. So you're moving your ET tube and with oral surgery, the ET tube can be moved a little bit more.

So you can see we've lost the plateau, of our face there on the top, and that's not something we wish to see. So this can be that there's a potential obstruction of your ET tube or maybe the surgeon has leaned or someone has leaned against the breathing circuit, which has seen to happen before and it's kinked the expiratory limb on the circle circuit perhaps. It could be bronchial spasm, there could be some mucus from body in the ET tube.

So. It's really important that if you keep seeing this, we need to have a look and see what's going on with our patient and do they need any assistance? Do we need to change anything, any positioning?

Have we kinked the ET tube, have we got any mucus in there? Can I hear it? Do I need to replace the ET tube?

Do we need some drugs to deal with any bronchial spasm at all? Cardiac oscillations are very normal, particularly in deep-chested dogs, and what we're seeing here in the wiggly line going downwards as they're breathing in is actually the heartbeat of your patients. So your lungs obviously sit either side of your heart, and as your lungs are breathing in, they're getting bigger and bigger and they may then feel the reverberations of the heart as it beats, and that is literally what you're seeing just there.

This is rebreathing, so we've lost our nice sand castles or elephants in that middle yellow line. It looks like lots and lots of blades of yellow grass in my opinion, lots and lots of yellow triangles. So we're rebreathing, we've got a high res rate, we're not returning to baseline, so our trace just keeps going up and up.

And we've also got a fractional inspired CO2 of 5, and as we discussed, ideally that should be zero. So they're some of the main traces that you may see whilst using your catnograph. So now we are going to give you a few moments as I bring each new trace up so that you can have a think about what trace it might be with the information that I've already given you and what you may.

I've picked up already you'll be seeing in practise, and then I will tell you what it is. So I'll just give you a moment to have a look at this one. Remember to have a look at the trace and the number, look how tall or wide it is, look at the rhythm and see if it's returning to baseline too.

So this is rebreathing with hyperventilation. You can see that the res rate is 65 and as we mentioned, ideally I don't really want my rerate under anaesthesia to be over 20. We're not returning to the baseline.

And we also have the increased inspired CO2. Now that one was maybe a bit easy because I'd literally just told you about it and I didn't want you to feel uncomfortable, so we'll move on to the next one. So that's cardiac oscillations, and you can see that they may not be as profound as this picture here.

They may not be touching the lungs quite as much and they're having so much going through. They can be more minor as they were in that video than this picture, so well done if you got that right. So that is a normal trace.

So I wasn't trying to trick you, but I think it's super important that as well as working out and understanding what is abnormal, we also see what is normal. So our number is between 35 and 45. The restrate's below 20, which is great.

This is a cat, so the heart rate's around 120, which is lovely under the anaesthesia. The fractional of inspired CO2 is zero, and I trace of some really good sand castles or elephants there. They haven't lost their shape at all, and you can see all the phases that we went through together at the beginning of this lecture.

So this is hypercapnia. You can see on the number that we've got 55, and even without that, we can see the trace is very, very tall, and we also have quite a low rest rate. We've got a little bit of inspiratory there as well and quite a low heart rate.

So this guy was probably a little bit too deep under the anaesthesia, and that would have been amended, and we probably would have breathed a little bit for them to reduce that Ntide or CO2 reading. We'll have a look at this case. Are you happy with it?

And is everything OK with your patients and your connections? Would you be comfortable seeing that screen and be quite happy just looking at that screen that everything was all right? So this is the adapter that you can place on your ET tube and you can see the little thin line that's going over the circle circuit there is your catnograph line.

Now you can see the catnograph adapter is attached to the patient, so yes, we did have a nice trace. Yes, it was a little bit low and tied the 30, but we would think that everything was OK, but particularly with oral surgery or head surgery. We can't get to that patient's face very much.

So here you can see that that's giving you a nice reading even though your patient is disconnected from your circuit. They're still breathing room air, they're not gonna have any iceo or Sibo though, so they are gonna become quite light, which is probably why we've seen the end tidal drop to 30. So this is why we must check all of our system, all of the time during anaesthesia and not just rely on staring at the screen, because if we'd been looking at the reservoir bag of our breathing system, then we would have seen that the bag was no longer moving and we would have made an adjustment and realised that perhaps we'd become disconnected.

Perhaps the surgeon hadn't smed the IO or CO because they hadn't been disconnected for that long, but it's still something we need to be aware of that can happen. There you go. So what is this tray?

So this is a cuff of the ET tube that is deflating for the pilot balloon. You will need to find that and recuff your ET tube. So you can see, as we mentioned earlier, there's a very long downward slope as they breathe in, and it's all just a very short wave form and your ntidal CO2 is also low.

So this patient is rebreathing, as you can see from the fractional inspired of 5, and it's not returning to baseline. They're also hypercapnic at annidal of 54, which you can see on the numerical value and also that it's going above on the waveform part of the machine. This is actually quite an old cat, they're on their back for anaesthesia.

Yeah they're quite old and they've obviously had muscle relaxants for the anaesthesia as well, so the muscles are becoming quite fatigued. So although the respirator of 12 is OK, they're just not breathing as efficiently as we need them to and they're not able to blow off as much CO2 as we would like them to, so it's building up a little bit. So I would then assist with IPPV for this patient.

This is hyperventilation. We've lost all the accuracy of those nice sand castles or elephants following one another on our trace, and we've just got all these horrible triangles, yellow grass areas. I mean you can see the respi rate is 85, which is far too high.

So this patient likely needs to be in a deeper plane of anaesthesia or perhaps it just needs some more sedation. Perhaps that alpha 2 that you gave 45 minutes ago has now worn off. So this is our shark fin that we were speaking about earlier that we really need to make sure we are aware of and investigate the second we see it, so this could be caused by an obstruction either internally or to do with the NET tube or the breathing system.

We mentioned it earlier, how can capnography assist me in CPR? Let's bring us back to this chart. We'll go through it together again.

So the body inhales oxygen, gas is exchanged on the alveoli. It's then diffused into the bloodstream and transported to the cells. Cellular respiration occurs, so cells take in oxygen and glucose and they release energy and CO2, and then CO2 is transported back to the alveoli.

CO2 diffuses through them and is breathed out. Now there's two elements of this which will not happen if your patient does not have an appropriate speculation. So if you're doing well with your CPR, you will keep this going and therefore you will see that your Nidal will be above 15.

If it's below, then we need to be more effective with our CPR to encourage these two parts to happen so that we do get that CO2 reading. As I said, Nid or CO2 above 15 is an indication of an effective CPR. So hopefully you are now more invested in capnography and we haven't scared you away, but you don't have it.

What do I need to use capnography? Ideally, your patient would be incubated with an ET tube. You can use them with laryngeal masks such as the B gels.

You can questionably use them with a tight fitting mask, but they won't be as accurate. Well, you will need the line that will connect from your ET tube to your machine, and you will need an adapter to connect the two together. There will be a water trap involved that your line connects to which goes into your multiparameter or whatever catnograph you have.

There are two types, mainstream versus side stream. Mainstream is a real-time judgement and it is slightly more accurate in smaller patients. It does use an infrared reading.

However, it does increase your dead space. It's very bulky. It's expensive to replace, and they do tend to malfunction quicker.

Not ideal for oral surgery, particularly dentistry. You're going to be getting it wet and it's going to get damaged. And also it's not really used for long term use, kind of more for a CPR situation.

Side stream is much more common, much more easy to use, and I find a lot more appropriate. There is a small time lapse, but it, it's negligible as far as I'm concerned, and I'm quite comfortable with it. It can be less accurate in your much smaller patients.

Again, it uses infrared to work, much less dead space than the mainstream, less drag, it's not something heavy pull down your ET tube, and this one is a lot cheaper to replace parts and lines that you may need. You can also reduce your fresh gas flow when using an accurate kenograph, which is better for the environment. We're not going through so much 02.

It's better for your patients because you're not making them so cold, lots of cold oxygen, and good for your boss because you will not be spending as much money on oxygen. So you can work out your fresh gas flow by all means for every patient that will change every time your respirrate changes, of course. But also you can be guided when using the capnograph that if you don't have rebreathing, then you're still using an appropriate level of oxygen.

And I've certainly found since using an understanding catnography that a little bit better, I've definitely been able to use much lower flow rates on my patients, which definitely helps their temperature. We must remember that a capnograph is going to be taking a small sample of what. What is being delivered to your patient and what is being breathed out by your patient, which if they're on an insolent such as Sio or IO, is not good.

You don't want to be breathing that in. Once the machine has interpreted that sample, it spits it back out. But there are ports that you can attach onto your multi parameter orcanograph, which you can then attach into your scavenging, so that no one's breathing any of that in.

It is a small amount, but it's still, you know, an amount that we should not be breathing in. Look after your machine, I've just chosen Burton's because they happen to look after our multi parameters at the last few hospitals, but there are many other companies out there. They should really be serviced yearly and any concerns you have should be contacted to the manufacturer or whoever you've chosen to be looking after in servicing your machinery.

My recommendation is that they are serviced yearly. They are plugged in when they're in use, so we're not draining the batteries. The water trap ideally should be changed monthly, or sooner if they're getting very wet.

Check them for breakages every time you're using them and damp dust them at the beginning and end of each day, and I would put the multi-parameter on wheels if you keep carrying. Them around or they're just hanging around on the edge of a table or a surgical instrument tray. I've seen far too many go for a little roll and break and it's heartbreaking because we need these machines.

They can tell us so much and it is often quite difficult sometimes to get them in practise, particularly because they can be a little bit pricey. I think they're worth their weight in gold, but we must look after them when they have them. Well done for getting this far.

I hope that that has been helpful for you, and if you've just started using catography, it hasn't scared you away. Have confidence in yourself, of what you've learned. Read around the subject further, make diagrams that work well for you, and keep practising, and if you're seeing Tracey.

In practise, take a picture if you're not sure what it is, ask a colleague, email someone, Google it, have a look in a veterinary book. Never be afraid to keep exploring and keep trying to understand so that we can do the best for our patients. And ultimately if you have a deeper understanding, and can troubleshoot things for yourself, your day will be less stressful as well.

A lot of these lectures were built upon by these two books. They have some really good information regarding capnography and all other elements of anaesthesia. The one on the left is good if you're just starting out, if you've been qualified a couple of years.

I mean, you just want to learn a bit more in depth and I would advise the one on the rates. I will be creating or finishing creating our managing hypertension under anaesthesia and capnography, pocket guides and posters to be sold soon, so get in contact if you'd like any of those. And as you can see, I'm doing a webinar for you today.

If you'd like me to come to your clinic or do a webinar for you, a tailored one for your practise, very welcome to get in touch. And we also have lots of patient warming packs to keep our patients warm. Thank you very much to the webinarve for hosting me again.

I've had a lovely time delivering this lecture, and I hope it has been helpful for you. And here's all the ways you can get in touch with me. As I said, if anything didn't make sense, you have any questions, you'd like some direction of where you can get more information and you haven't been able to find that for yourself, or you just had a genuine question about anaesthesia or indeed dentistry, you have my email, check me out on Facebook and Instagram.

We get lots of. Interesting stories we post on there, and you can have a look at our patient warming packs and support guides on our Etsy store. My work number's on there, you're very, very welcome to send me a WhatsApp if you prefer that or call me.

It is my work number, so don't feel it's being invasive, and if you'd like to discuss anything further that we've spoken about today or in any of my other lectures, then I would love to hear from you. Well done, and thank you very much.