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Year 5 Concepts at a Glance: Anaesthesiology - Max Holcroft



This on-demand session provides deep insights into the triad of anesthesia, pre-operative assessment, and ASA (American Society of Anesthesiologists Physical Status Classification System). It aims to enlighten attendees with different types of anesthesia, the role and impact of each element of the general anesthesia triad - unconsciousness, analgesia, and muscle relaxation, and anesthesia-related complications during induction and emergence time. The session is interactive, encouraging attendees to answer questions concerning anesthesia drugs and their usage in various scenarios, explore muscle relaxants, and understand the integral components of pre-operative assessments. It also discusses the Mallampati score for assessing the difficulty level of intubations. The session will prove valuable to medical professionals, particularly those looking to enhance their understanding of anesthesia and pre-operative assessments.
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Learning objectives

1. Understand the concept and importance of the triad of anesthesia, including unconsciousness, analgesia and muscle relaxation. 2. Recognize the difference between regional and general anesthesia, including the respective indications and limitations of each. 3. Learn about the anesthetic emergency cases, with a specific focus on laryngospasm and other complications related to induction and emergence time. 4. Familiarize with various types of analgesic and hypnotic drugs used in anesthesia, and understand the specific scenarios in which they are indicated or contraindicated. 5. Appreciate the significance of the preoperative assessment and the role it plays in optimizing patient outcomes. Understand how to conduct a basic preoperative assessment.
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Computer generated transcript

The following transcript was generated automatically from the content and has not been checked or corrected manually.

I've tried, I've tried to make it, er, interactive. So if you want to er, grab a pen and paper or just open up your notes on your iphone or uh whatever device you're on, then we'll get going. Ok. So what we're going to be going over is the triad of anesthesia, like I said, preoperative assessment and the A SA and then some anesthetic emergency cases at the end. Ok. So before we get onto the triage of anesthesia, uh just a quick, a very quick overview. So, anesthesia is the loss of sensation and can be divided into the two below. So regional anesthesia, which is nerve blocks, things like that and general anesthesia, which is what the public is probably more comfortable with. The idea of. That's why when you go into surgery and get hot under. So, yeah, so there's the triad of general anesthesia, which is these three things, unconsciousness slash hypnosis, analgesia and muscle relaxation. And each of these plays their own key role. So, unconsciousness I think, explains itself with some exceptions, you don't want the patient awake and seeing themselves being cut open and also uh it works synergistically with the analgesia. So the analgesia is usually opioids or sometimes benzos. And it means, and when these two work together, it means you need less of both to induce the patient into this state, which also means less side effects for them and safer surgeries. Finally, there's paralytics for muscle relaxation and similar to, to uh hypnosis, not required for all general anesthetics, but they are useful for facilitating facilitating intubation, improving surgical access and er most importantly preventing movement. Uh I'm sure er many of you know that in your sleep, sometimes you move a boat and rustle, obviously less i less than ideal on the operating table and similar uh in the theme of threes and triads. Er, no, he's giving a general anesthetic. So here it's split up, split up chronologically. So there's inducing the anesthesia, maintaining it and then safe emergence from it often in some, for some drugs, er, induction and maintenance can be used er together and I'm not, can I see the chat in this? I'm not sure. But if anyone has any ideas, uh what's a common complication uh around the induction and emergence time, especially in things like ent surgery where there's blood and all sorts of stuff in the throat. Aspiration. Definitely. But a little more er anesthetic specific. Uh yeah, vomit, vomiting before I guess, but also something called laryngospasm. So um when you get these foreign objects or any stimuli, it can be chemical, it can just also happen reflexively, er, the vocal cords can slams shot which stops breathing. Er, and I might, I can't remember if I put a case on that at the end, but we might circle round to that later and if not, then you can look it up in your own time, I guess. Ok. So, no, just to run through a few of the hypnotics, uh, you will be tested on this in a second. So, uh, take good note. So the two options here, uh IV are inhaled. Uh, the ones in bold can be used to initiate and maintain anesthesia. And uh yeah, so each one has different indications for use. Er, propofol is the most common for IV. And the other thing was uh when to choose them. So IV, and inhaled, uh IV is the more, more better tolerated, but often in some severely needle phobic patients, er, pediatric cases, things like that inhaled can be the better option or where IV access is problematic. Ok. Uh So no, are a few of the questions that I was on about. I have been a little bit naughty. I've not included all the information that's asked so far, but I'm sure you've all been doing your past med anesthetics and peri op er, very rigorously. So I'm sure you'll be fine. So if you all want to take a few seconds and just jot down from 1 to 8, which of which of these, uh, which of these drugs do you think will be best used in each situation so I can put both on the same time. So if you want to take a picture, I'll just make a mental note of the drugs on this screen. Sorry Max has just cut out there. I'll wait for him to join back. Sorry for that. Everyone. Uh uh technical issues. Yeah, no worries comes back and I'll try not to give the questions like, ok, here we are. So, yeah, if you all want to take a photo, uh a quick photo before it crashes again, maybe and then onto the questions. So I'll just give everyone a minute and then we'll start going through. Ok. So, er, question number one, Gyne patient that suffers nausea and vomiting, er, although a little more exciting than your bog standard case still uses the same anesthetic. And that's because Propofol specifically has an antiemetic effect, um which indicated by the patient's history here and the kind of surgery will be best used in this case. Ok. Emergency outside of hospital. So here is Ketamine and the first reason is because of the analgesic effect it has alongside uh induction and we'll get onto the second reason in one short second. Number three. Oh, sorry for not capitalizing the, that annoys me as much as you suxamethonium. So, er, this is most commonly used for rapid sequence induction, which we will also get to in a second. And yeah, no contraindications now, I bet you can guess that number four might be different and ta da it is. So that's rocuronium and that's because suxamethonium increases intraocular pressure. And er rocuronium is the other alternative, er, the other S er suffix uronium drugs and adequate for this is they don't induce fast enough. Rocuronium induces in less than a minute, the same as suxamethonium. Ok, hemodynamically unstable patient, ketamine. So similar to earlier when we talk about the emergency, er ketamine is also good here because it doesn't cause a drop in BP, which in these kinds of patients is very important. Uh course from use in patient with pneumothorax or pneumothoraces, nitrous oxide, nitrous oxide, which can both cause and exacerbate er pneumothorax, contraindication, hyperkalemia, suxamethonium. It can increase the risk of an exacerbate and finally contraindicated in pseudocholinesterase deficiency. And once again, Suxamethonium. And uh if you're ever on a pass med question, suxamethonium is an option. It's U and you don't know it's usually a safe one to go for. Uh it starts with sucks for a reason because the side effects suck. Ok. So no analgesia. So like I said, opioids and then benzos are most frequently used. Uh Not really too much to say here. You have to be cautious of the respiratory depression effect in some patients and oh, I, I'll, I'll try to do the, I'll try and do the chat thing again. Ok. Uh I'm only asking this one cos I got asked it by a surgeon by an orthopedic surgeon in year four and got absolutely laughed at when I didn't know the answer. So, does an, does anyone know the common type of pain medication that you're meant to avoid after orthopedic surgery? Nope. Well, it is apparently nsaids. No, afterwards I was a little disgruntled and II looked it up and apparently in my defense, the evidence isn't water tight. But if you're ever accosted by an orthopedic surgeon, uh you have the answer. Ok, next onto muscle relaxant. So um the two broad categories here are depolarizing and non depolarising. If we all cast our minds back to Moor, er we'll remember that acetylcholine er normally opens the nicotinic receptor for about a millisecond after it binds it dissociates and then it's broken down by acetylcholine erse, the depolarizing er category of drugs such as suxamethonium, er they bind to, they bind in the same way. But unlike Acetylcholine and it's metabolized by the acetylcholine erse which means there's continuous depolarization and er k for some er past me questions also muscle fci, this is what causes the muscle fasciculations that precedes the paralysis. No, the other category is non depolarizing like the rocuronium and Atracurium that we mentioned earlier, these act as er reversible competitive antagonists and they are reversed by cholinesterase inhibitors which work by um inhibiting the effect of choline acetylcholinesterase, increasing the concentration of acetylcholine so that it can compete with the uh competitive antagonist better. Ok. So this is the, er, the peri op bit that I promised at the start. So the purpose is to, well, it, there's these things here but it's three things here. But it's basically to optimize the patient's chances of getting through the surgery alive. To do that. You identify, er, comorbidities and risk factors, er, optimize physiological state, look for patients at higher risk and then do your magic. So these are the components of the pre op assessment and we'll go through them at one by one. So, first of all, the history, uh, same as any good history really. Um, particularly on the lookout. I don't know if you can see my most, particularly on the lookout for, er, post operative complications. Last time, cos like we discussed, that can influence, er, agents used. And uh, yeah, also important to take note of these for the A SA which we get on to in a second as well as at this. That's the social history, if you can't see my face and past medical uh, history. Ok. So medication allergist. So, uh allergist for obvious reasons, uh, ask any current medications, but there's these five, they are meant to specifically ask about diabetes, hypertension, anticoagulation, antiplatelets, contraception and steroids. And that's because these will need to be managed either in van in advance afterwards or during the surgery and have a big risk of complications. Ok. Um, I think, I think it's, this is pretty self explanatory three stages of airway assessment. Uh you can look back in the slides in your own time later and now on to the er Melany score. So this is an indicator of how difficult intubation is going to be. And as it says, the top uh examines the relative size of the tongue compared to the oropharyngeal opening. No, the ma ma ma Pati score is er, classified from 1 to 4. Er, does any, can anyone put in the chart? Does anyone know er, what class one would be? How would you classify that? Ok. So class one is as good as you're gonna get. So after you've gone to stick the tongue out and you've uh depressed and you've had a look at the back of the throat, sorry. Uh in class one, you'll be able to see everything and that means it's gonna be pretty easy to uh get uh the intubation through er, class two. I'll, I'll just get up the, get up the picture. Class two is complete visualization, visualization of just the uvula. Class three, only the base of the uvula and class four, you can't see any of the soft palate at all. Um And like I said, predictor of difficult intubation if you've intubated and the patient's O2 starts are suddenly drop in and you can't think of an obvious reason why think esophageal it might be down the wrong hole and does anyone know what the best way is to check this, uh, feel free to either put it in the chat or, or mute yourself. Exactly. Er, very good. So you check the, er, ent tidal carbon dioxide because the esophagus doesn't breathe well done. OK. A sa uh, I originally had some questions on this but I took them out cos I thought we'd be running slow cos I added a few things to last year's slides but it looks like we're OK for time. So, um we'll go through a few in a sec. So these are the uh classifications here. Uh normal, healthy, mild, systemic, se severe, systemic, et cetera, et cetera. Often questions on this fall in categories 2 to 3 and they ask about things like uh w where would someone with diabetes in a well controlled range fall? So if you had a patient with well controlled diabetes and no other uh comorbidities, where would you put them on this? A SA grade again? Feel free to have their own mute or put it in the chart. Yeah, perfect. So that's a SA grade two and uh the same for well controlled hypertension. And uh also being a current smoker and social drinker. Uh Does anyone know the obesity ages and where they, and where they put you on this? So say you were had a BMI of 30 31. Where would that put you? Not quite? So uh yeah, so uh BM I between 30 to 40 is classed as mild systemic disease and above 40 is classed as severe systemic disease. And, uh, it's also important to know that these aren't additive either. So, if you have a patient that's a social drinker with well controlled diabetes and a BMI of 35 just because they have all these mild systemic diseases, doesn't mean they add up to a SA three. They're still in that. A SA two bracket. Well, don't. Ok. Oh, yeah, not really much to say on these. Um, yeah, basically you do these examinations, er, investigations, er, like we said, HBA1C cos that influences both, especially cos that in influences both a sa grading, er, before the surgery and also your approach to surgery in terms of diabetes control, which we'll get onto in a second. Ok. And then in the lead up to, um, to the surgery, uh, you'll often have little old Doris and she wants a cup of tea. She's three hours, um, three hours pre op issue. Ah, oops, never mind. Uh, yeah. So, uh, oh, in fact. Mm. Yeah, I'll ask anyway. So his little old Doris load her cup of tea three hours. Preoperative. Yes or no. Very good. Very good. So, yeah, a, a little bit of a trick question if she likes it milky then no. But, uh, she still allowed it without milk even though not technically clear, I guess. And then, yeah, you can, these, it's just one of those things, learn them. If you want, I'm not gonna talk through them now. Oh, ok. Going quickly. So, uh, case one emergency surgery. So this is the case, uh, 87 year old female listed for emergency surgery after presenting to the hospital with severe abdominal pain, vomiting and constipation, small bowel obstruction and she's vomiting quite a lot. Uh, if you, if you have to have those sheets of paper, uh, what's the most appropriate way to manage her airway and induce her for surgery? So, here you'd want to do something called rapid sequence induction. So RSI shot. So in cases where, er, like someone said earlier, er, aspirations a big thing, people, er, anesthetists are worried about. So in patients where there's a high risk of aspiration, er, like here where patients run faster in an emergency, you do something called rapid sequence induction and, er, the steps are here, er, a muscle relaxant is key for this cos you're gonna be, you're gonna be putting endotrachial intubation in, uh, important to note, er, because sometimes they ask about, er, airway devices and in what situations to use, which ones are not in any vomiting patient don't use a laryngeal mask, er, very bad for gastric content coming up and stopping people aspirating case two, she's got a 42 year old female, uh, elective surgery for a protid tumor. No comorbidities, uh, no medication, drug allergies. Uh, she has just the base of the uvula if you remember visible from a swelling secondary to the protid tumor. And, uh, you don't have a clue about reaction to anesthetics or anything like that. You use propofol and Suxamethonium to induce and ventilate with oxygen and Halothane and then 15 minutes into surgery. You see these, does anyone have any idea? Er, I'm trying to, I'm trying not to click the next p, there we go. Does anyone have any idea? Er, yes, perfect. Well done guys. So malignant hyperthermia and er suxamethonium. True to name sucks. But also er these two other drugs here can cause it. And this is basically due to a problem with er calcium release. Er genetic problem, autosomal dominance in heart, do autosomal a autosomal dominant inheritance, apologies and er the excessive release of calcium er causes muscle contraction, er causes hypermetabolism, er causes the hyperthermia and then that can also induce more calcium release, making it into a vicious cycle to manage a patient like this. You want to discontinue these triggering agents and hit them with uh Dantrolene. Ok. So here we have a 30 year old male, 38 year old male underwent an open reduction and internal fixation for radial fracture uh induce using succin methonium and during emergence, patients make no effort to cough or breathe spontaneously, pulse and BP begin to raise rise even does anyone have any ideas? What this could be uh very good suxamethonium apnea. So, er in the earlier question, like we said, uh in a patient with pseudocholinesterase deficiency, you don't give them suxamethonium and, er, this is why they have problem metabolizing it and they stay paralyzed for longer. Uh, the treatment's quite intuitive. You just have to keep them under sedation until eventually it, the, er, the drug does wear off and then unfortunately extubate when they're awake. Do I have another? Ok. Ok. So here's a problem with using the pullout method, with not using the pull out method even. So, a 43 year old man attends hospital for a routine surgical procedure under local anesthetic, er, administered with lidocaine by a junior clinician and then becomes restless and agitated. He gets muscle twitching and becomes drowsy, bradycardic and hypotensive, er, any ideas for this one? Very good on fire. So this is local anesthetic toxicity. And uh well, ii guess I've given the, the game away. So when you're given local anesthetic, uh you always aspirate first to make sure you're not er, in a vein or artery, I guess because if you are, you're more at risk of this. Uh it causes C NS over excitation, which were the symptoms that we just discussed and if not treated then leads to seizure, respiratory arrest and coma as it then causes uh C NS depression. Uh management is with er IV 20% lipid emulsion and that's because the anesthetic, the local anesthetics are highly lipophilic, which means the emulsion absorbs them and then can be excreted safely ok. Uh, obvious, uh, we whizzed through that, uh, apologies if you didn't have any plans for the next half hour, but we've just gone through the treatment of anesthesia, er, preoperative assessment and A SA and these four cases here. Er, I do have some more cases, er, later on the slides when I send them out. So if you're particularly keen, you can go through them in your own time. But yeah. Uh thank you, everyone. Er if you don't mind scanning the QR codes and leaving some feedback, it will be greatly appreciated. Thank you. Uh Yeah, if, if you thank you, thank you very much uh Max uh for the talk uh just for the, the questions on the chats. Um I'm gonna grab you the, the feedback link now. Um And I'll also put the uh Google Drive in the chat as well, uh which has all the slides for the, the talk so far this year. Um But yeah, thank you, everyone for coming. Uh As I say, at the start, our next talk will be seventh of February. Uh So you can learn a little bit about dermatology. Um But yeah, I'll just grab the link and if there are any questions feel free to, to shout out. Yeah. Thank you, everyone. And sorry, I didn't have any prizes for the uh top scorers on my questions. All right, feedback form is here and uh the slides will be up on the community at Medil Drive, um, of the next day. Um, I think, I think, yeah. Uh, just.