Join our upcoming 3-month webinar series: 'Prescribing in Surgery' by Mind the Bleep. This series, presented by Dr Hermione Jemmett & Dr Aisha Musa, will comprehensively delve into aspects of managing prescriptions in a surgical setting. Topics of interest included are fluids and VTE prophylaxis, surgical emergencies, and specialties specific scenarios. This series promises to be very practical, designed to prepare you for surgery-specific questions in the PSA and make your surgical job/rotation run smoothly. It's an opportunity not to be missed for those looking to enhance their surgical prescribing skills.
Prescribing in Surgery: VTE Prophylaxis & Analgesia
Summary
Dr. Hermione, a junior doctor in Edinburgh, presents the first webinar of the new series named "Prescribing and Surgery." Co-led with Dr. Aisha, the series aims to educate attendees about prescription guidelines, dose adjustments, and risk factors in the surgical setting while following real-life case studies. The first session focuses on VTE Prophylaxis and Analgesia.
Description
Learning objectives
- Understand the importance and guidelines of VT prophylaxis in patients on surgery
- Recognize local policy variations for VT prophylaxis dose adjustments based on patient's weight and renal function
- Identify thrombocytopenia as a potential adverse drug reaction of heparin usage in VT prophylaxis
- Familiarize with alternatives to heparin in the event of a heparin-induced thrombocytopenia
- Know how to select suitable analgesia for patients post-surgery considering the patients' medical histories and allergies.
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The following transcript was generated automatically from the content and has not been checked or corrected manually.
Hi, everyone. My name is Hermione and I'm a junior doctor up in Edinburgh. Doctor AA and I are the leads for this new series Prescribing and Surgery. And we'll be presenting a different webinar each week over the next three months, all of these series will um be recorded as usual and they'll be uploaded to Medal alongside all the slides. So you'll be able to access them in your own free time. Any questions, just write in the chat and we'll do our best to answer them. Ok. So as I mentioned, welcome to our series Prescribing and Surgery. Um This is the first of this series on BT Prophylaxis and Analgesia. So this is just a quick reminder for everyone at mind the bleep um for anyone who's interested in medical research, um We've got a conference that's being run. Um And the submission for abstracts is in early March and just to introduce ourselves briefly, I've already mentioned my name's Hermione. Um My name is up in Edinburgh. We've also got Doctor Aisha Musa who is one of our other foundation doctors and is the co-lead for the series. And then doctor Sonia who is the lead for prescribing it in the mind, the bleed. And we just have a little disclaimer. Obviously, we are junior doctors who are voluntarily doing these sessions. All the content has been checked by multiple people. Um And so it's accurate to the best of our knowledge. But if you do find any mistakes, please do, let us know and we'll amend it. And this is an overview of the teaching sessions for the prescribing and surgery series. Um So make sure to put them on your calendars. We will be shortly creating events for each of these. So you should be able to sign up to them um on metal. Ok. So we'll get started with case one. So we have a 53 year old female who was admitted with a one day history of right of quadrant pain fever and bitter vomiting. She's got a BMI of 41.9 on examination. She's Murphy's positive and she's diagnosed with acute cholecystitis and she's admitted under general surgery. She undergoes a laparoscopic cholecystectomy and stays in hospital for five days. So these are her bloods, apologies. There are no reference ranges but her white cell count and CRP are raised as you can see, which is not a surprise given she's got an infection. Um her renal function is normal and we've also got some deranged LFT S here which is in keeping with her diagnosis. So the question is whilst an inpatient, what VT prophylaxis should she be on, on a 24 hour regime. So hopefully you just got the poll for that. OK. So I think most of you've got the correct answer, which is Delta Perin 5000 units once daily. So if you look on, on the B NF under VT prophylaxis, um it'll give you this answer. An important thing to say about this is that local protocols normally dose adjust based on a few things such as renal function and weight. Um And we will discuss this in the next slide. But the important thing to say is that you need to know the guidelines that are specific for your hospital. Um So on the BNF, the answer would say delta and 5000 units. However, um based on weight and renal function, there are local policies which vary and they suggest different things for each one. So technically, the people who put delta power in 10,000 units aren't incorrect either. Um But the other ones would be incorrect. So it, it for your VT prophylaxis, we want to be using a low molecular heparin. So that's why we're using Dalteparin. OK. So this might be a little bit small to see, but we're just gonna go back a few steps and start with how you assess for VT prophylaxis. So we know this patient's undergoing surgery and as an inpatient for five days, if we think through the the factors for thrombosis, she's having major surgery. So she's likely to be immobile as well. So she's gonna be need need to be anticoagulated and that goes for almost all surgical patients. Um So I think you can use this guideline if you're ever stuck to just work through the risks and decide if someone needs to be anticoagulated. But if you look at the top, it says mobility, um all patients and any surgical patient automatically needs to um be anticoagulated. Um and just to go back even further, um for basics, the patients can get clots and the best way to manage this is thinning their blood. So that's why we anticoagulate them and we want to um thin their blood to prevent getting these clots. Um and what we anticoagulate them with varies based on the hospital. So these are the risk factors for VT S. So, a tick for any one of these would need mean you'd need to get um the patient anticoagulated according to nice guidelines. So for our patient, she gets a tick for her BM I cos it was over 30 a tick for acute surgical admission and for having significant reduced mobility. So she's definitely gonna need to be anticoagulated. And this is just the second part of that sheet which shows the bleeding risk. So um they're also ri risks for, for bleeding. So you just need to be aware of these and if you, if they, if your patient takes for any of these, um then you need to weigh up the risks and benefits of antic coagulating them and if it's complex, I'd run it past a senior. Mhm. So this is what we anticoagulate her with. It depends, as I said, on local policy, um, the type of surgery and the individual patient. Um, but in general and orthopedic surgery, normally they use low and accurate heparin. So, Darin is pretty universal. Sometimes it's an oxy par. Um, this is from the B NF which suggests 5000 units once a day and this is normally given around 6 p.m. So this is the answer you'd want to give him the PSA if you were asked something along this line, these lines, um and you can find it there. So for those of you who are here to learn a little bit more about if you have a rotation surgery, all of the local policies have dose adjustments. So these are based on weight and on the renal function. So this is something you'd find on your internet, um which have all the local policies and this is certainly what we use up in Edinburgh. Um So if your average person is 5200 kg, that's where they get the 5000 units once daily. But for our lady, she's actually 100 and 3 kg. So that increases her risk of clotting a bit more. So by these guidelines, you would then give her 5000 units twice a day. Um I'm just showing this. So you're aware of the different varying policies. And similarly, if you're less than 50 kg, you need to be anticoagulated. Less next up is similar but a little bit different. Uh the VT prophylaxis in patients with renal impairment. So for this dose adjustment, again, if your EGFR is over 30 so as a normal healthy patient, you just stay on the same normal dose. And uh so in our case, it doesn't change it, but the renal function um function decreases, then we decrease the dose. So less than 30 we're thinking about reducing it to 2500 units daily. And that's because low mi aurate heparin um is excreted through the kidneys. OK. So case 24 days later, our lady is feeling a little bit better and these are her bloods. So the question is, should there be any changes to her VT prophylaxis? So I've just put that pole out again. So her hemoglobin's down a little bit. That's no surprise. Her white cell and C RP are down as well and her EGFR is slightly reduced and her platelets are down a little bit but her relatives are improving. Mhm OK. So I think most of you would have answered here. So the answer is actually e um which I think may have caught a few of you out. Um So we'll talk through this one. So in this case, the Darin needs to be withheld and this is because she's showing she's showing signs of heparin induced thrombocytopenia. So this was a bit mean because I didn't give you any reference ranges. Um But here you can see that the platelets have actually dropped by about 44% if you subtract 100 and 45 from 261. Um and a drop of in, of more than, well, a drop in platelets of more than 30% from the baseline within 4 to 14 days of being given. Heparin is, is classified as heparin induced thrombocytopenia unless there's some alternative cause for it. Um, so quick run over what, um what that is. So it's abbreviated to hit. Um and it's a transient immune mediated um adverse drug reaction in patients recently exposed to heparin. Um and it generally produces a thrombocytopenia and often results in a venous or an arterial thrombosis. So, it is dangerous. Um And it's not particularly common, it's about 5% of people um getting um fractioned heparin. Um And about 1% who receive low molecular weight heparin. Um So it's just something to be aware of. Um, if you notice that the platelets are going down while someone is being treated with um aac great Heparin, then you'd need to stop it. Um And your clinical features are all in your platelet count. Um, and it can be with or without er, thrombosis. Um, and the reason you'd want to switch it, so you'd want to stop it, but you'd, you'd want to switch it as well. That's what the advice is. So you'd switch it to something else such as Fondaparinux or droid. Um And if you look up Fondaparinux, it will show you the dose, which is about 2.5 mg. Um And I hope that makes sense. Ok. So case 3, 73 year old female who's coming into trauma and orthopedics with a neck of femur fracture, she's undergoing some surgery and has some pins in her fracture. Past medical history of osteoporosis, rheumatoid arthritis, glaucoma, and Long Qt and gout. And she's got some allergies there to codeine and traMADol and that's her weight and height. Here are her bloods. And the question is what analgesia would you prescribe for an admission? So we've moved on from some other VT prophylaxis onto admission, analgesia. What you would give someone as soon as they come through the door, she's had her surgery. What kind of analgesia she's gonna need? Ok. So I think most of you got that one right. A is the correct answer. Um So the first thing to do here is always start with your allergies and remember that Cocodamol has codeine in it. So that rules out B and E dihydrocodeine and Cocodamol both have codeine in them and we know that she's allergic to that. So we're gonna have to get rid of those two options. Um The next thing is that we wouldn't normally start with MST. So if someone's not got any background of having any medication, um modified release medications are not what we'd start off. They're very, very addictive. Um So we normally start with short acting opioids. Um And see if that helps and then we can always step it up to the MST. So that rules out C um and then D is incorrect for two reasons. Um So the first one is that we try not to use 1 g of paracetamol in patients that weigh less than 50 kg. So that was again a very small detail. Um with oral paracetamol, it's less of a hard rule. But with IV paracetamol, it is very, very important to remember. So if they're less than 50 kgs, we normally reduce the dose from 1 g to 500 mgs instead. Um And the other thing with that one is that um it's also quite poor practice to have APR N at a higher dose than a regular. So we normally want to give them the regular pain medication to keep on top of it and then give them a small dose of APR N and as and when they need. So that why, that's why that one's not as favorable as well. So um A is correct, we always like to have regular paracetamol as a base analgesia and then you want a regular immediate release opiate which we normally use morphine. So something four times a day. Um And then APR N of the same o opiate but at a slightly smaller dose, uh, I hope that all makes sense. Ok. So on to case four. So this is the same lady. Um, and the question is, what other medications would you want to prescribe along the analgesia as soon as she is admitted? So this is before she's had her surgery as soon as she's admitted. What other medications do we want to be giving her alongside that analgesia, that morphine and the paracetamol. So I'll make another poll. Ok. So well done. I think quite a few of you got c as the answer there. Um So there's a few things to consider here when you're giving any patient opioids, you've got to remember that they can cause a few nasty side effects. So the first one is constipation. So, constipation can cause a whole host of issues with your patients. Uh pain and delirium urinary retention. So any time you're giving a patient, a opioid, we want to prescribe a laxative alongside it. Um So that's the first thing. Um And the second thing is that antiemetics are also important as opioids can make people very nauseated. So we'd want to be giving them um an, an um an antiemetic written up as in lots of different modes. So you want to give them something that's IV and subcut. Um if they're actually actively vomiting, but also something oral in case they're just nauseous and a few notes on this. So we don't give IV cyclizine because it's highly addictive. Um And we don't give Ondansetron if they've got long QT because it prolongs the QT even further. So the best answer here is c because we need an antiemetic, which is your cyclizine. We're giving a laxative macrogol and we're giving IV fluids because she's got a bit of an AK I, so her EGFR here is 46. Um And so we're gonna, that's what we would start off with. Um, the other ones, none of them are quite the right answer on Dansetron wouldn't be appropriate here. Um You wouldn't be giving metoclopramide and prochlorperazine at the same time as a starting um thing for antiemetics. OK. So this is just to show you how you look these things up on the B NF. Um So looking up cyclizine here, you can see it's 50 mg three times a day and very helpfully, it's the same dose regardless of if it's oral or IV or subcut. And this is for Ondansetron. So, in your contraindications, it tells you about your Long Qt syndrome. So it's important to keep an eye on that and it's 4 mg, that's your dose and then the same goes for laxatives. So you can look up laxatives on the B NF. Um And it's, I think it's quite important to know about the different types of laxatives. So you can sort of be a bit smart about how you prescribe. Um, for us we generally just start with Macrogol. Um, but again, it depends on the local policy. Um, so we'll talk through those. This is a table that just breaks down, er, the different laxatives and explains how they all work. Normally. Osma osmotic laxatives are the ones that are favored in, um, as a first line in surgical patients. Um, so that's your lactulose and your macrogol. And it's important to remember that we want to avoid stimulant laxatives in any POSTOP general surgery patients if they've had any sort of surgery to the bowel. Um, and that's just because if we've recently been, uh, suturing the bowel or it's damaged or, um, we don't really want to be getting it to contract lots. So we try and avoid that if they've any, had any recent surgery to the bowel. Ok. So on to case five. So following her surgery, she's had some complications and had a short stay in HD U. She had some pain issues and she's been started on a PCA pain's improving and she's stepped down to the ward and the registrar asks you to take down her PCA and prescribe appropriate oral opioid medications. So you can see what's in her, the prescription for her PCA. And the question is what regular medications we would give to amount the same pain relief as the PCA was giving. Ok. Ok. Ok. So you've got quite a few varied responses to that. One. So usually it needs to start their P CS. Um But as an F one or two, you're expected to take them down and convert them onto their regular meds. Um So to work this out, the first thing you need to do is work out the total number of milligrams that's actually been given through the PC, so that we can ensure we give the same amount um when we're giving it in our sort of morning and the evening um regime and with Apr N, so in this case, there's nothing else you need to count in. But don't forget you'd need to count any sort of Pr Ns or, you know, patches and things like that to work out the total amount of opioid analgesia they're getting through the PCA um in total. So here we're told that she's used 15 mils in the last 24 hours. Um So that means she's had 15 mg of, of morphine sulfate. So once we've worked that out, that's IV. So we need to convert this from IV morphine to oral. Um So subcut, an IV morphine are double the strength of oral morphine. So 15 mg IV is equivalent to 30 mg orally. I hope that's making sense. So what we've done is we've counted how many, how much uh she's had overall in 24 hours and we've converted it from IV to oral once you've worked out the total amount for 24 hours. Within the normal thing to do is to split the dose in half for the AM and the PM dose as modified release. So this would give you 15 mg BD, so 15 in the morning, 50 in the evening and then breakthrough is normally 1/6 of the total amount. So 1/6 of 30 gives you 5 mg. So that gives you a as the answer, an answer, 15 mg morning and evening and then 5 mg as your breakthrough P RN. Just so, you know, there's quite a low amount of morphine. So it's unlikely that the they would have been on a PCA for this, but it's just so we can work through an example together and just to explain why some of the other answers aren't correct. Um We don't normally like mixing opioids. So if they're on um morphine as an, as a, as a modified release, we then wouldn't normally give something like oxyCODONE. So that's why E is incorrect. Um We wouldn't give a different opioid as the P RN. So this is just a good um opioid conversion chart to help you with these calculations. Um And they're all linked at the end of the powerpoint, but it's just good to be able to see what your conversions are. And this is another one which helps when you're converting things from one to the other and through different modes. And this is just to show you that the BNF also has a good section. It's actually under the palliative care and it just shows you the equivalent doses to 10 mg of oral morphine. So you can work out pretty much everything from that. Ok? On to case six. So overnight, the patient claims to see her dead husband and lots of animals in the room you see in her notes that she's also having visual hallucinations in ICU, she's got no signs of infection and is otherwise, well, she denies hearing voices or hearing her thoughts broadcasted. What is the likely cause of her hallucinations? Ok. So the answer is be here. Um So, morphine is a very common cause of visual hallucinations. So, um if anyone's acutely um begin seeing things um when they're on opioids, you really want to be considering if it's something to do with that. Um She's not on any steroids that we've mentioned at the moment. Um she could have been for her rheumatoid arthritis, but at the moment, we haven't mentioned that. Um So there's no reason for that to happen acutely. Um And cyclizine isn't known to cause um acute hallucinations and there's no history that fits with sort of schizophrenia. Um So, yes, it is morphine sulfate. So, we've figured out that the hallucinations are due to the morphine and the nurse then asks you to change her analgesia. So this is what she's currently on, written it out for you again. And I'm asking what changes would you make to her prescription given that this morphine is what's causing the visual hallucinations. Ok. Yes. So it looks like most people have got this one correct. Well done. So the answer is to switch morphine to oxyCODONE. Um So oxyCODONE has a better side effect profile and so it's preferred in the elderly. Um and it's a common switch. Um if people are struggling with hallucinations or um severe nausea and things like that with morphine, um you could reduce the dose. So some people put b that's not a bad idea. Um And that could be something you'd want to do. But I think given that she is requiring the pain medication. Um in this case, we wouldn't want to reduce her dose because she's requiring that much analgesia, but it wouldn't be incorrect to do that in some situations. OK? So this is case eight. So her morphine regime is then switched to oxyCODONE with the same overall analgesic effect. So we want to keep the analgesia at the same amount and then we're gonna switch everything to oxyCODONE because of the better pro profile for the side, uh the side effect profile. Sorry. So the question is how much oxyCODONE would she need in a BD pro um regime with some Pr Ns? So this is the final question. OK. So it looks like we've got some varied answers here. It is a tricky question. The answer is e so I'll talk through this for you. So to start with, you need to know that you need to divide by 1.5 to go from oral morphine to oral oxyCODONE because oxyCODONE is stronger. So you need less of it to have the same um analgesic effect. So again, as we normally do, we start with working out what you have in 24 hours. So from her previous medications, when she was on morphine, she was having 15 mg twice a day. So that's 30 mg and then she had Apr N on top of that. So we divide 30 by 1.5 and that makes it 20 mg. That's the total amount of oxyCODONE she'd need. So that would be 10 in the morning and 10 in the evening. OK? And then for the P RN, we do the total amount in the day which we've worked out to be 20 mg of oxyCODONE and we times that by 1/6. So 1/6 times 20 gives you 3 mg. So you would end up with 10 mg modified release in the morning and the evening. And that's equivalent to your 15 mg of morphine sulfate. And then you would have a 3 mg of your immediate release, oxyCODONE P RN for her to have um which would be equivalent to the 5 mg of the morphine sulfate. So this is just to give you a rough idea of when we use each opioid. And why? So morphine is our first line. Um But as we've discussed, it can cause hallucinations. Codeine is frequently used alongside paracetamol as a base for analgesia. So sometimes patients will come in and if they're surgical, we'll give them regular paracetamol four times a day and regular codeine as a baseline and see if they need anything more than that. And then we can add in morphine as they need. Um oxyCODONE is preferred in the elderly and those with renal impairment, which is important to know and a fentaNYL is good in renal impairment as well and it acts very, very quickly. But the important thing to remember about a fentaNYL is that um firstly, it can only be given IV or subcut. So um they need to have access and they need to have nurses being able to come and do that regularly because it's got a very fast time to peak. Um but it is very, very good um for patients in pain. Ok. And this just highlights again some of the alternatives to morphine in certain situations. So, because we normally start with morphine in most surgical situations, you will come across patients that need to be switched to something else because of their renal function or because of their hallucinations or because of their nausea. Um So it's important to be able to know what to switch to. So people use fentaNYL as well and severe renal impairment as well. And these are just the references if you want to find any of the information we've looked at today and this is just for some feedback. So, thank you very much. I hope this was useful. Um As always, we really appreciate feedback as it helps us improve the webinars. Um And hopefully we can improve them so that they're better for the rest of the series. Um So please do take the time to fill it in and our next session will be on fluids and electrolyte balances. Um And that will be with Doctor Mosa. Um So please tune in again next week and thank you very much and goodnight.