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Hi Iron. Uh, welcome to our prescribing and Surgery series. Uh, today's our, um, fourth session which will be on prescribing in pre op. Um, and my name's, er, doctor is, so I'm one of the co leads for prescribing in surgery. So just a disclaimer. Uh, the prescribing and surgery series has been created by doing doctors. Um, and it's entirely on a voluntary basis. Um, and all the content is the, is accurate to the best of our knowledge and neither the teachers nor mind the people take responsibility for any unintentional inaccuracies. Uh So as you can see today's session will be on prescribing in pre op and uh next week's session by doctor Gemme who will be on uh diabetes medications. So, going straight away into case one. So case one, a 78 year old male is seen in the preoperative clinic two weeks before his elective knee replacement for severe osteoarthritis in his left knee past medical history. He's got atrial fibrillation. He's had a stroke one year ago, he's got osteoarthritis. Uh, in terms of his medications, he takes Warfarin Bisoprolol and he has no known drug allergies. So the quest and his weight is 84 kg. So the question is preoperatively, how will you manage his Warfarin prescription? Um, so will you continue his warfarin? Will you stop his warfarin two weeks before surgery? Will you stop it five days before surgery? Will you stop it five days before surgery and prescribe treatment dose, er, low molecular weight heparin or you avoid surgery as he's a very high risk for thrombosis. Er, so I just released the pull in the first po into the chat. Ok, so far everyone's going footy any more responses. Thank you, be as well. Can I give you a few more seconds? Ok, fine. So more people are going for D than B so D is correct. Um And I'll explain the thought process now. So if you go on B and F nice, um if you go on the preoperative anticoagulation section, it says Warfarin should be stopped five days before elective surgery, patients stopping Warfarin prior to surgery who are considered to be at high risk. Uh So for example, they've had atrial fibrillation with a previous stroke or a tia A may require interim therapy known as bridging with a low molecular weight heparin using treatment dose. So this is just using uh some information from the mains stone and Tunbridge wells. So, as you can see, um in the top half where you assess thrombosis risk, this patient will be high risk because he has af with previous stroke, er slash T IO and if you follow this algorithm through, it says that if patients are high risk, you would stop warfarin five days before surgery uh to allow their inr to normalize and you would start them on treatment dose low mole heparin. So in this trust, they would start them on dilta. Um And then it has a few more in uh kind of information where it says, you know, take I nr one day prior. Um and if I nr is higher, then discuss with the consultant. So of course, this information will be trust specific. So um always do um kind of follow the guidelines in your trust. So BNF says that low molecular weight heparin should be stopped at least 24 hours before surgery. Um And yeah, so in clinical practice, use your local trust guidelines and in your psa exam, make sure to use the B NF. And this is just the table that the trust gives you on how to dose the Darin treatment dose for Heparin Bridge. So as you can see, this patient's weight was 84 kg. So that's above 83. Um So if his creatinine clearance is more than 30 you would give him 18,000 units once daily. Um And if his creatinine clearance is less than 30 you would give him um 12,500 units once daily. Uh And you would also have to consider uh dosing in patients with renal failure as well. Um and in terms of in the postoperative uh management, so you would restart the low meleate heparin um um 6 to 8 hours postoperatively, if hemostasis is secure and you would recommence the usual warfarin dose on the evening of the surgery if there's no excessive bleeding, uh or you continue the dopar or unfractionated heparin until uh target inr has been reached. So if you check the, so, so in this case, this patient is undergoing orthopedic surgery. So that's a high bleeding risk. Uh The B NF says if surgery carries high risk of bleeding, low molecular weight, heparin should not be restarted until at least 48 hours after surgery. B NF says if hemato stasis is adequate warfarin can be resumed at the normal maintenance dose on the evening of the surgery or the next day, local guidelines may differ. So of course, you use your local trust guidelines in clinical practice and of course, use BF in your PSA exam. So now if we move on to the next case, um So case two, a 65 year old male presents with urinary frequency hesitancy, straining, weak flow and has noticed blood in his urine past medical history. He's got VTE one year ago, secondary to malignancy, he's undergone a TBT for his bladder cancer. So that's a transurethral resection of the bladder tumor. Uh in terms of his medication history, he's uh he takes Apixaban, he's got no known drug allergies and his creatinine clearance is 60. Um So when you do ad re you not, you note a hard mass on pal palpation of the prostate. And his PSA is more than three, a multiparametric MRI prostate scan is conducted and prostate biopsy is advised he's scheduled uh for a prostate biopsy in two days to investigate for bladder cancer. Um So question prior to his prostate biopsy, how will you manage his Apixaban prescription? Put the ball up and I'll give you a few minutes to answer that question. OK. So, OK, so 50% of people going for hold Apan 24 hours before and 33% going for hold Aan 48 hours before and some going for 72 hours before. Ok. So the correct answer is to hold Apixaban 24 hours before. Um And this is just to quickly show you guys how to, how we calculate creatinine clearance. Um So this is using MD CALC. Um So when you calculate the creatinine clearance, you need to take into account their gender age weight and their creatinine result. Uh Just to note if your trust has an online gentamicin calculator, for example, which works out your creating clearance uh as part of it. Um Do use your trust guidelines in um sorry, your trust calculator instead of the MD CALC because sometimes there may be variation in the MD CALC. So again using uh Maidstone and Tunbridge Wells guidelines. So in this case, this patient has moderate risk of thrombosis because they have VT E provoked by malignancy and they have a standard risk of uh bleeding uh because they're awaiting a prostate biopsy. So, in terms of the preoperative management, because the creatinine clearance is between 50 to 80. Um and they're on Apixaban and they've got a standard risk. You would hold uh the Apixaban for 24 hours, uh preoperatively and postoperatively, you would resume it 24 hours postoperatively at the normal dose. Uh So in terms of the B NF guidelines, so if you go under the surgery and long term medication section of the B NF, it says that anesthetists and surgeons should assess the relative risks and deci and decide jointly whether the antiplatelet or the anticoagulant drugs should be stopped. Um ok, so a lot of people got the answer right for that question. So next case, so case three, a 29 year old female presents to preoperative clinic one week before her elective C section. She's 37 weeks pregnant with twins. Um her past medical history, she is diagnosed with Myn Gravis medication history. She takes prednisoLONE 60 mg as her daily maintenance dose and she's been taking it for four months and she's got no known drug allergies. Uh So in terms of the question, what would you prescribe during her C section at the induction? So give you a few minutes to answer this question a few seconds. Sorry. Ok. So most of the people going for methylprednisolone, uh with a third of people going for hydrocortisone, 50 mg. IV. OK. So the correct answer is E hydro hydrocortisone, 50 mg IV. So if we look at the hydrocortisone section of the B NF, it says that if a patient has corticosteroid replacement, uh more than 10 mg of predniSONE daily or equivalent within three months of moderate or major surgery. Then at induction of surgery, you should give 25 to 50 mg of IV hydrocortisone. And this is following their usual oral corticosteroid dose on the morning of surgery. Ok, if that makes sense. So we're gonna go straight onto case four. So case four, a 48 year old man is undergoing a minor proce procedure, skin abscess drainage tomorrow morning past medical history, he's got type two diabetes in terms of medication history. He is on Metformin 500 mg twice daily, HumuLIN I 10 units once daily in the evening and he's got no known drug allergies. His HV A1C is 60 his EGFR is 70. So prior to his minor procedure tomorrow morning, how should we manage his HumuLIN eye prescription? Let's get a start report. Ok. Yeah. Ok. So most people are going for no dose adjustment needed. Um, with around 14% going for omit it the day before and uh, reduce the dose by 20% on the day before as well. So the answer is actually a uh, so the day before reduce the dose by 20%. Uh So if we go on the nice guidelines on use of insulin during surgery, it um it says that patients uh are undergoing elective surgery, minor procedure with good glycemic control. So in this case, his HP A1C is less than 69. Um On the day before the patients, usually insulin dose should be given as normal. However, uh once daily long acting insulin should be given at a dose reduced by 20%. Ok. And this is just the center of perioperative care which shows that in the case of once daily long acting insulin being given in the morning, you would uh give uh 80% of the dose. Wouldn't they use LA for I and D of an abscess, local anesthetic. Um they could use local anesthetic, but it does depend on the size of the abscess. So if it's a really large abscess, you might require um kind of general potentially. Um OK. So case five. sorry, I hope that answers that question. Uh So case five, a 57 year old man is scheduled for an outpatient coronary angiogram tomorrow to diagnose coronary heart disease. Past medical history, type two diabetes, medication history, Metformin 500 mg BD allergies. Uh he takes penicillin and his EGFR is 55. So prior to his Coronary angiogram tomorrow, how should we manage his Metformin prescription? Ok. So uh 50% of people are going for a Metformin on the day of the procedure, but continue it the next day. Um, 16% going for Metformin on the day of the procedure and for the following 48 hours and 33% for continued Metformin twice a day. Ok. So some variation. So the answer is D and Metformin on the day of the procedure and for the following 48 hours. So if you look at the nice guidelines, it says that Metformin is really excreted renal impairment can cause accumulation and lactic acid dosis during surgery. Um And they said if contrast medium is to be used or if the EGFR is less than 60. So in this case, the EGFR was 55 then Metformin should be admitted on the day of the procedure and for the following 48 hours. Ok. So we move on to case six. So a 60 year old male is scheduled for a hip replacement today for his severe right hip osteoarthritis past medical history, he's got type two diabetes. He's got osteoarthritis medication history. He takes Metformin 500 mg BD Lantus 10 units once daily in the morning, he started on standard rate, variable rate insulin. His Lantus is reduced to eight units. Uh So it's reduced by 20%. Um Metformin is held whilst on variable rate insulin, his capillary blood glucose is measured hourly and the nurse informs you that his CBG is now two considering his CBG is two. How should we manage his variable rate insulin prescription. So I'm gonna start the po so. Ok, so we've got four responses so far. Fine. Ok, fine. So it seems like everyone's going for stop vertebra insulin and give 20% glucose 100 mL. IV which is the correct answer. Um You would give 10 20% glucose, 100 mL or 10% glucose, 200 mL uh to treat the hypoglycemia. Um So quickly just to show you guys that in the case of Metformin, when a patient is on variable rate, insulin, you would hold the Metformin and you would only commence it when the variable rate insulin is down and the patient started to eat and drink normally. Ok. So quite a bit of information here, but we'll go through it slowly and we'll go through it um using trust guidelines which will hopefully explain it a bit more. So this is um the nice guidelines on a variable rate incidence. So, um it says that if a patient has a major procedure, so basically a surgery requiring a long fasting period of more than one missed meal. Um or if their diabetes is poorly controlled, they will require a variable rate insulin infusion, um which will be continued until the patient is eating and drinking and stabilized on their previous uh glucose lowering medication. So, on the day before surgery, you would give the once daily long acting insulin at 80% of the usual dose. Um and on the day of the surgery and throughout the intraoperative period, you would give long acting insulin. Um a log again at the 8% of the usual dose. Um On the day of surgery, you'd start an intravenous substrate infusion which would contain potassium chloride with glucose and sodium chloride. And that's to help replace the electrolytes. Um whilst they're on the variable insulin. Um so the variable rate insulin infusion is made up of soluble human human insulin, which will be in sodium chloride, 0.9% infusion. Um And again, you would co prescribe IV glucose 20%. And that's in case of hypoglycemia. So, this is using uh trust uh information on variable rate insulin from Doncaster and Bass Basset Law. Um And essentially what you can see in the red that I've circled is that if the capillary blood glucose goes below four, you would stop the variable rate insulin and you would administer 100 mL IV 20% glucose or 200 mL IV 10% glucose and you would only restart um the vari insulin uh once the capillary blood glucose is above four. So if you go to the bottom, you can see that there's different rates of insulin. So standard rate is for most patients, reduced rate is if they're insulin sensitive and increased rate is for patients that might require more insulin, for example, if they're on steroids. Um And if you see on the top right you can see that the soluble uh insulin, the human insulin is the human actrapid. Um And that would be 50 units made up to 50 mL with sodium chloride, 0.9%. Um And then if you see below that, which I've circled. Uh So that's the IV substrate fluid prescription, which you would co prescribe to um supply the patient with the electrolytes whilst they're on the variable rate insulin. So in this trust, the first line is 5% dextrose with 20% uh or 40% of KCL. But what you need to know is that the fluid substrate that you would prescribe would depend on the trust that you're at. Um So it depends from trust to trust based on availability. So in clinical practice, make sure to follow your local trust. Um And yes. So on the top, it says prescription of IV management of hypoglycemia. So, again, the 20% of 100 mL IV um glucose or the 10% of 200 mL of IV glucose. Um And if you see where I've underlined, so yeah, just make sure to check potassium levels. When you're co prescribing a patient with substrate fluids, they may require 20 millimoles of potassium or 40 millimoles of potassium depending on their potassium levels. And uh if you see at the bottom in terms of exit criteria, so we stop very insulin when the patient is able to eat and drink uh without nausea. Or vomiting and when they're able, um, to restart their normal antidiabetic medications. Um, so I hope that makes sense. So, on to case seven. So case seven, a 63 year old female is scheduled for an elective hemorrhoidectomy tomorrow morning. Past medical history. She's got type two diabetes medication history. She's on Metformin 500 mg, BD pioglitazone, 30 mg once daily allergies. She's not, she has no known drug allergies and her EGFR is 80. So how would you manage her pioglitazone prescription preoperatively? Mhm. Yeah. Ok. So we've got six responses so far. Um with 50% of people going for omit on the morning of surgery. Um So omit on the morning of surgery and the following 24 hours after equal amount of people going for continue as normal and some going for omit on the day before surgery. So the correct answer is a continue as normal. Uh So if you just have a look at the guidelines, so on the left, you've got guidelines from the B NF which says Pone can be taken as normal during the whole perioperative period. And on the right, we've got guidelines from the Center for Perioperative Care which says pioglitazone can be taken as normal the day before admission. Um and also for patients that are having am surgery, patients for having PPM surgery essentially for the entire perioperative period, you can continue your pioglitazone as normal. Ok. So this brings us on to, uh case eight. So case eight, a 34 year old female is seen in the preoperative clinic. She's scheduled for an elective inguinal hernia repair in six weeks past medical history, she's got diagnosed with eczema medication history. She takes um this uh combined oral contraceptive pill and she has no known drug allergies. So, the question is prior to her elective hernia repair, how will you manage her? A combined oral contraceptive prescription? And this is our last question. Ok. So, um most people going for stop, combined oral contraceptive four weeks prior to surgery and provide alternative contraceptive with some going full stop, uh cop two weeks prior to surgery. So the correct answer is to stop combined oral contraceptives four weeks prior to surgery and provide alternative contraceptive. So this is a nice uh guideline. So it says that the combined er hormonal contraceptive use should be discontinued at least four weeks prior to major elective surgery. Any surgery to the legs or pelvis or surgery that involve uh prolonged immobilization of a lower limb. Uh, an alternative method of contraception should be used to prevent unintentional pregnancy. Um, and that the combined hormonal contraceptive may be recommenced two weeks after full uh immobilization. Um, it also states that in accordance with the UK medical eligibility criteria for contraceptive use, you can use progesterone only pills, injections, implants and intrauterine systems, uh as contraceptives in females undergoing surgery. So, these are all types of contraceptives. You can give to the patient, um, instead of the combined oral contraceptive pill whilst you're holding it full surgery, I think that makes sense. So, just in terms of, uh, your clinical practice and also, uh, to help, uh, in your P SA preparation, um, the B NF has a section on surgery and long term medication. Uh, and this kind of contains, uh, their guidance on medications that you have to continue e even if the patient is having surgery or medications that you need to hold. Um, and, and some medications that, you know, it, it, it depends, um, and you can kind of discuss it with, with seniors in clinical practice as well if you're ever unsure. Ok. And these are the references that I used, um, and this is just a feedback form, uh, for today's session. Um, I'm just gonna release it into the chat, uh, and this is just to help inform, uh, kind of feature sessions on things that went well, things that can be improved and I hope that helps and I hope that today's session was useful.