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Thank you, Sam. Uh Good evening. I hope it's evening for you. Uh M my name is I, I am a uh senior surgical trainee. I'm almost uh sort of months away from becoming a consultant. So I found over my years of um both training and teaching that the understanding of fluids. I spend every four months whenever we got new trainees rotating into our department, spending the first almost a month trying to catch them to teach them about fluids. So I'm hoping that this will be of some use to you and for your future. Um As far back as 1982 the NC pod findings were that as a group of doctors, we were either overprescribing or under prescribing fluids for our doctors, for our patients. And this has actually led to deaths, which is why this whole thing has come about. And I brought in guidelines to try and create an environment of patient safety. Ok. Um So I'm just going to go through a little bit of basics of, I guess fluid physiology and then we'll get into um some of the more interesting stuff. Hopefully. So, fluid homeostasis, this, we are more than 70% water, you know, fluid makes up most of our human body. And you, you do need to understand that um how that fluid balance works in order to, to improve your patient or worse not harm your patient. So this is just a standard picture from various physiology books that you can find. Um and you can see the, the place that we put the fluids into the plasma volume, you know, that that's probably the smallest amount of volume that we are playing with. OK. And obviously, depending on what we want, we then spread it across the rest of the body compartments. So what's in the um each of those compartments is important because depending on where, what you're trying to do for your patient, are you trying to resuscitate them? Are you trying to maintain them? Are you replacing stuff? You know that it's important what you put in and it's important for you to realize where those electrolytes are going to end up. And I think we really need to understand or have, have, have a, a good idea about Starling's law. You know, the fact that the amount of proteins and the osmolarity of of um the um each of those fluid compartments either keeps or disperses the fluid out of it. And when you try and put stuff into a compartment or you aim it for a certain compartment, you need to figure out how physiologically correct one the fluid is and two, the patient is so that your fluid goes into the right area. So here we go. The other thing you need to know is what's the daily losses from your, from your body? You know, a liter and a half is lost in gastric juice. So if you got a patient that's near by mouth, irrespective of anything, they're going to be losing probably about two or three liters out. And yes, a lot of it will be reabsorbed and processed by your kidneys. But if they're producing urine and if they are passing feces or stoma output or NG output, then they're losing fluids. Ok? And that is a necessity that you need to bear in mind. And obviously, the important thing, people always seem to focus straight away on potassium, you know, because oh yeah, I need to replace the potassium. But you know, the sodium and the chloride are just as important and you need to understand where these electrolytes normally live. Ok. So going back a page. So if we go into the ECF, you will see that sodium is your main component, whereas in the cell potassium is your main component. So just bear that in mind because when we move a bit further on, we will kind of um explore that in a in a bit more detail. Basically, your job as a doctor is to get this part working properly, your small bowel because that will provide what is absolutely needed for the body. OK? All the other stuff that we have that we hang in plastic bags. They are poor approximations of what the small bowel can do. Um OK. So you know what happens to fluids. So you got your colloids, you got your, your album in solution. OK. So that you've got very large molecules that's putting in there. And with Starling's law, it will actually draw fluid in, it will keep fluid in that plasma compartment and it will raise the BP, OK? And you got your, your 0.9% sodium chloride. I know everybody calls it normal saline. We'll come to that in a minute. And your Harman solution, plasma light, whichever concoction you use in your hospital, you know, they, they are there to to to fill this compartment up, OK? They will, they are good resuscitative fluids. Um and they will help raise the BP. Um And obviously you are going to get losses into this compartment, which is why when you are um giving the fluids, when you stop the fluids, the BP can drop in an unfilled patient. OK? And obviously 5% dextrose just goes across the board um very quickly. So now getting back to me saying that you need a understand the physiology. So what I'm showing you here is a capillary and the interstitial tissue around it and I'm trying to sort of expound on uh on Starling's law here. So you got this album in, in, in, in your capillary, your capillary is a natural, naturally leaky. That, that is, er, part of the whole process of how, how our system works. You're going to lose a certain amount of albumin per day. It's actually 40 g per liter. You lose that into, into the interstitium. It gets reabsorbed through the um, um lymphatics and you get about 35 g per liter via the thoracic duct coming back into the circulation. Ok. So just understand you've got this intravascular compartment, you've got a loss of albumin and you've got a return of album in and that, as you can see, it's kind of a nice little circle that keeps everything in balance. Now, if we come down to the second um picture you, you'll see, I've shown sort of larger arrows and that's basically to depict a capillary membrane that's very leaky. And I'm going to use pancreatitis as an example because a very common surgical complication that we deal with. So you've got this huge inflammatory process going on in the body capillaries gets leaky. Um you lose a lot of fluid out and with that albumin, the level of albumin outside the capillaries now become much higher, it draws more fluid out. And that's uh and then with that comes um electrolytes and, and, and that is why they get dehydrated very quickly. Now what happens to the albumin? Yeah, it's still, you have lymphatics and it goes around in that circulation. But what returns back to the intravascular volume is still 35 g per liter that you don't get more. So you're losing more, you've got a fixed amount returning. And so you're going to slowly build up the um albumin in the interstitial tissue. And essentially, at that point, your patient begins to blow up like a balloon. You'll see that huge edematous patient. And when you go to put in a cannula, you can't get access to the veins because everything's just filled up with fluid and you can't see anything. So that, that's that pathological process happening um with deranged um metabolism. So the fluids that we actually prescribe you, you have this, you know, plasma volume of, of um electrolytes, we are trying to replace it. Now, I know from talking to a lot of my juniors that um you know, everybody goes on about um two salts and a sugar um which equates to this thing that we call normal saline. And you can see it's giving 100 and 54 millimoles of, of um sodium chloride in, in, in a liter. OK. So, and you're putting in a large quantity of chloride ions and pretty much nothing else. OK? And what you're doing is this thing here has got a Ph that is much lower than the ph of plasma. So you're actually putting in an acidotic fluid into plasma. Now, if your patient is acidotic and you then put this in, you're going to make them worse. Yeah. And also the, the osmolarity, which is important for resuscitation for you to hold the, the, um, the electrolytes in the right place to generate a higher BP. You can see that, you know, it's, it's quite high, which is good. We want that and, you know, it's, it's certainly going to increase the electrolytes in this and hold fluid in um Hartmans. So we have much less sodium, less chloride. We now got a little bit of potassium, not really much. I mean, five milli is um almost negligible. You've got this little bit of bicarbonate given in the form of lactate. OK? And got a little bit of calcium, not a lot. And again, the ph is marginally better, not a lot and the osmolarity better, almost the same as um your plasma volume and then Dextros saline. So we've got almost a third, even less of, of um sodium and chloride. Um We've got a reasonable amount of glucose. Um Ph is acidotic and osmolarity is not bad. So bear that in mind. Um Please don't take notes. I will send this to um Sam who will then forward it to all of you and you can look at it at your leisure. So I want to take you to this um paper. It was published in 1998. Essentially, they took the arterioles from the kidney of sheep. So the afferent arterioles from the kidneys of sheep and they then put in different um concentrations of chloride iron. So your normal chloride iron concentration is about 100 to 110 mils per liter in, in your blood in your plasma. So, as you can see with almost no chloride concentration, that's the lumen diameter quite, quite significant. And when you get down to the plasma level of um chloride ions, you can see the diameter has fallen quite significantly. But this is what the normal kidney arterial will be at running at. And once you get to the level of um your 0.9% sodium chloride in your harmans, look what happens to the diameter of your um sh um arterial. It, it it's almost closed. Yeah. So keep that in mind, we will be coming back to this. I know I'm asking you to hold a lot of information, but we need to understand what's in the fluid and what some of these electrolytes are going to do to it. So I can then explain to you how we can manage things better. So here we have a standard physiology picture of, of a kidney Nephron. So you got your afferent arterial, go through the glomerulus. You have your ultra filtrate going through your proximal and distal convoluted tubes and then you got your efferent arterial and I I'm I'm sure you're all aware you, you've got your jua glomerular pros um body here. Um And what you need to understand is out of this arterial, out out of the ultra filtrate, you get chloride ions coming out and sodium ions and various other stuff that chloride ion actually causes depolarization of the basement membrane and causes that to release Adena zine, Aden zine is normally a vasodilator. Ok. I I accept that except in this one part of your anatomy where it is a potent vasoconstrictor and uh that it is recorded in, in in literature. So, what you've really done now is by giving, by getting the kidney to secrete a large amount of chloride ions, you've reduced the blood supply into the kidney Nephron. Ok. So given that most of our um reason for giving large volumes of fluids to our patients is to treat them for an acute kidney injury. And we give them huge quantities of sodium chloride. And what we do is essentially take an injured kidney and treat it by reducing its blood supply and asking it to work harder. So that, that, that's what the 0.9% sodium chloride is doing. And I hear you thinking that what about Hartmans? And the process isn't completely understood, but the lactate, the bicarbonate that's in Hartman's somehow protects this area and prevents that depolarization. So it actually protects the kidney afferent arterial from um narrowing its lumen and causing it to um squeeze. Ok. So something to bear in mind. Here we go a little more theory for you. Um It's from a paper from 2012. From the annals of surgery. Essentially, they took ICU patients um and split them into randomized them into either a balanced fluid in which in in this paper, they used plasma light or not 0.9% sodium chloride, which is the gray one. And you can see those patients required more buffers. They required more blood transfusions. They had more derangements in their arterial blood gas. Uh they had greater lactic acidosis and they required more renal support than those patients who were on plasma light. Ok. Obviously, these are real patients if they're in ICU and and things aren't right. But you know, the the the fact that they did randomized patients that were almost the same cohort. So they both let's say pancreatitis, they, they only randomize pancreatitis patients. So they have it, you know, that's what happens. Um the difference between giving balanced fluids and giving just normal saline. So this is a really interesting paper um that came out in 2000. Um Professor Lobo who is a um HEPA a biliary surgeon at Nottingham University. He did this where he called in the, the F ones or house officers, whatever they are and senior house officers. So Fy ones, Fy two S and CTS and they just called them up and just asked them some simple questions on, on fluid management. And essentially this was the conclusion there was inadequate knowledge and sub optimal prescribing of fluid and electrolytes and this was, you know, due to poor teaching at undergraduate level that, that, that it, it's not your fault, it's our fault. We haven't told you what you need to know, which is why you don't know what you need. When you start that, that, that, that, that's basically it. The other myth. I know everybody goes on about potassium and what to do with potassium, right? I want you to imagine that you have a patient who is nil by mouth, OK? They got bowel obstruction. So got an NG tube in. You got large output coming from that. You're giving some II I think most people now would give Saline. So normal Saline as we call it goes in and you check their bloods every day and the sodium and potassium, they're all kind of OK? They're staying in the normal range, maybe going down a bit, but still keeping there. OK? And you go on about 34 days down the line. The potassium starts getting lower and lower and starts heading towards hypokalemia. OK? And that's the point where you react, you, you, you, you see the hyperkalemia, it drops below your threshold and you suddenly start giving the potassium. OK? And the potassium really doesn't pick up very well. It it in, in fact, maybe to start with it would actually become more hypokalemic. OK. And do you think why is this happening? It's very simple. We all have a daily requirement of electrolytes in our body, we need a certain amount of potassium, a certain amount of sodium, a certain amount of fluid. OK. That, that's fixed whether, whether it's me or a patient, that there is a maintenance requirement of electrolytes for everybody. So if you are nil by mouth and you're not taking any food in, you're getting some water as in you're not 0.9% sodium chloride and you're getting salt and you're getting chlorine. Nothing else. Really. Why is the potassium originally stable? It's because it's coming out of the cells. Remember I told you earlier on the, the the main intracellular electrolyte is potassium, the main uh extracellular or intravascular electrolytes sodium. So you know, and just by you know, osmosis just you got this massive difference, sodium potassium pump working. It's shoving potassium because out of the cell into the intravascular volume, which is why you, you keep it normal for a while, you then give potassium. So the potassium concentration in the in the um intravascular compartment rises, it still stays low because it's now replacing the potassium that's been dragged out for the last four or five days. So what you've essentially created is a re feeding syndrome. You've depleted the cells of the patient in order to make yourself feel better because when you looked at the bloods, it looks like the potassium is normal. So that little bit of a thought process. If something is normal and they're not getting any input Where is it coming from? Ok. What, what, what harm am I doing to the patient? And the harm in this case is we're quite happy. Sodium's normal, potassium's normal. He's peeing. Yes, he's obstructed, but we expect him to settle down over the next few days. But in that meantime, that, that that amount of time, few days you have, you are slowly depleting the cells and making them function less. So you are essentially harming the patient whilst waiting for his obstruction to recover. And obviously, if the cells aren't working properly, the chance of his, the time it takes for that bowel to start working again properly is just going to get longer. Ok. So another paper just to show you this was a randomized control trial that had to be stopped mid trial. And what they took was kidney transplant patients. OK. So these are patients who have no kidney. So we are transplanting a new kidney which means that organ that manages the electrolytes is not there. OK. So they were given plasma light and they were given 0.9% sodium chloride. OK. And then this all of these were individual patients each line. OK. And you can see baseline, start of the operation or start of the surgery. You can see their potassium levels are pretty much the same. OK. Mid operation, look at the peak of potassium levels on your plasma lights and on your normal saline patients so that you you've deranged the physiology, so much of the tissues that the potassium level in the, the potassium's come out of the cells and it just peaked. I mean, it's gone up quite significantly. You are hyperkalemic, aren't you? You are going to go into cardiac arrest fairly soon if you carry on like this. So you can see the, and they have to stop the uh trial because they realize they're actually harming their patients by, by continuing with this. So I never concluded um those are just some figures from it, feel free to have a look at it later in your own time. So let's have a look at the effect of giving this naught 0.9% sodium chloride metabolically. You're going to cause a hyperchloremia acidosis. OK. And which means then you need more buffers to correct that acidosis. So if you remember those graphs were the graph that we were looking at with the ICU patients that this sort of kind of um condenses it the body water. So you, you damage the endothelial glyco calyx. Um interstitial fluid rises and you get that edema. You know, you're de the tissues renally. We've gone into it in quite detail. So we've said that you're, you're going to squeeze the afferent arterial, you're going to reduce the blood supply into the kidney. Now, if you think about it, you're giving 100 and 54 millimoles of, of um sodium, but you're not going to give just 154 are you? Because you need to give them, um, what one, 2 to 3 liters. So that's 300 to maybe 450 millimoles of, of sodium. And which organ needs to sort that out. It's the kidney, but you've now now reduced its blood flow and it's already injured. So, have a think and gastrointestinally. So this is sort of something that I, you know, being a colorectal surgeon. I, I'm sort of quite, I worry about a lot is that you get this, we've talked about the body water and the interstitial edema that happens. Well, that's everywhere that includes the bowel. So if you just made a fresh joint, there is going to be edema there as a natural healing process, you then give a load of sodium chloride and make that edema a bit worse. Um, because you, you're, you're damaging the Glyco Calyx, you then get this a acidotic picture which makes that, um, edema a little bit more worse. So what you get now, now you've got, um, bowel that's normally quite floppy and moving around, you know, peristalsis, those of you are surgeons, you cut open the bowel, you could see the small bowel moving around quite happily. So if you now made the walls really turgid by injecting with fluids, filling it with fluid. So it's like a hose pipe. You got one that's floppy when it's empty, you fill it with water. It becomes quite hard. Well, that's what you've done to the, the bowel. And what that means is the myosin acting fibers that move to give the, um, muscle contractions to cause peristalsis now can't move because it's, it's rigid, you fixed it, there's your ile s ok. That's what's caused the, um, worsens, the ile s because obviously they have a certain amount of ile s from. You have, handle the bowel, you then treat the ile s with large amounts of fluids. And then you make the bowel even more edematous with the wrong fluid and then you fix it really hard so it can't move. So that, that, that there's your sort of pathology of what's happening in the bowel worse. You've got a fresh joint, so you've got a nice staple anastomosis that now swells up and you're going to stretch the staples, ok. They're going to cut through a little bit once the edema starts to settle, or the ileus resolves the bowel shrinks. And when it shrinks now you've got a hole because you've, you've impaired the healing and you've, you've, if you think about it, you've stretched it really wide and then when it goes down, it's going to go down like that. So you're going to end up with a hole there, there's your leak, ok? Not going to happen to every patient, but you know that you increase the chances of, of them having a leak by over fluid them and why? Because you get, you do your operation, you go home, the house offer is on at night. The nurse rings and says, oh, so and so's BP is low or his urine outwards dropped. They come in, prescribe a liter bag, go back to sleep or carry on with their job because they're really busy. Yeah, all they want to do is stop getting bleak. In the meantime, the nurse gives the, the fluids and they start this whole pathological process going. Ok. And essentially the, the end of all of this is increased postoperative complications, you increase mortality and you increase the acute kidney injury rate and the need for renal replacement therapy. That that's the, the learning point from this. So that's abnormal cell line is what I would call it. So these nice guidelines came in. So originally in 2013 and then they tweaked it in 2017. So you're saying that patients need to have, if they need to have a prescription, you need to be thinking about what you're giving. When you give, let's say morphine to a patient, you think very clearly about the concentration of morphine you give to somebody and how much you give it. I bet you nobody thinks about the concentration of what's in the fluids that they prescribe patients. They just shove it in because it's just fluid, but it is a drug. It is not something that is normal to the body that you are giving to them. OK? And that is something you need to be aware of. Um So you can see the 2007 17 standards changed. Um But please feel free to read this. I am not going to sit here and read this for you. What I need you to take away from. This is this bit in red, OK. Maintenance requirement. This is not resuscitation, this is not replacement. This is your normal guy sitting in bed happy. OK? He requires 30 mils per kilogram per day of water, some kind of fluid, one Milmo per kilogram per day of potassium of sodium and chloride and about 50 to 100 g of glucose to prevent starvation, ketosis. OK? If you, if you smell the breath of of patients that are um nil by mouth, you get this sort of sweet smell, that's aldehyde that comes from the breakdown of, of the fats. OK? That, that, that is telling you that they are in ketosis, they're acidotic. OK? So that this is what you need to give to prevent it. So here's a nice guidelines. Nice little picture from there. Looks horrendous. Yeah, I agree. So let's take each bit. So first thing you do, you assess the patient, you do your ABCDE, you find out they need, they're hypovolemic or not, they need fluids. So you are going to follow your algorithms. They either need resuscitating, they're unwell. OK? They're hypotensive they're tachycardic. They look horrendous. You need to give them something or they are losing large amounts of ng fluids or they've got a high output stoma. They need, um, replacement. Ok? You need to replace the fluid that they're losing or they just need routine maintenance fluids. They're ok. They just need a bit of support. Ok. They might be just post straight, um, POSTOP. Just a bit dry. Not feeling well enough to drink. You know, let's say a lap coli, you know, the, the, the day after they're a bit ropey, you give them a couple of bags of fluid to settle down to go home, done and dusted. That's your routine maintenance. Um So fluid resuscitation, what we're gonna do. So you need to figure out what's going on with the patient. Is it because they're just dry? Are they bleeding somewhere or they're just horrendously septic? Because each of those will have a different treatment. So if they're bleeding, they're actively bleeding, you need to give them blood throwing in more. Um fluid is not going to make them better or turn off the tab. And you know that process is different. I'm just talking about resuscitation here. You've got a pancreatic patient as our example, he is unwell. He's got, so that is um systemic inflammatory response. Capillaries are leaky fluids, losing out urine output is dropped. He's looking really horrendous. He needs fluid replacement to get his tissues working again. Ok? And why? Because the blood carries oxygen to the tissue. If you don't have the blood volume and the BP, the oxygen doesn't get to the tissues, the tissues goes into an aerobic respiration produces more lactic acid gets more acidotic. And that is a cycle that you need to prevent. Because once the cells become acidotic, you destroy the mitochondria and once they're destroyed, they will not, that's it. The cells dead. Ok. So if you think of one cell, you need to save that cell because all the, the body is just full of cells. So that, that you, your job is to prevent the mitochondria from swelling up and dying inside the cell. So that, that's what you're trying to do, get the oxygen to the tissues. And so let's talk about routine maintenance. Ok? You've, you've got your, your, your patient, they are for theater tomorrow, ok? They're nil by mouth. You that if they are going to go to theater tomorrow, it means they are going to have a massive trauma because that is the effect of you sticking your knife in the patient. The the body doesn't know the difference between getting stabbed and the surgeon cutting. OK. So if you remember, you've got this ebb and flow phase of trauma. So the e face is that that first phase where the body is trying to, to preserve OK? And the flow phase is where it, it, it breaks down and it tries to repair so that your, your patient needs to get to theater in a well hydrated as healthy and as stable as possible position. So he can go through that horrendous trauma that your, your, the surgeon is going to put him through, not just the surgeon but the, the in as well. You're gonna shove in loads of drugs into that, that is not normal. They need to be broken down, they need to be got rid of and the liver and the kidneys are gonna be working pretty hard, ok? They are going to go through horrible trauma, which means adrenaline is gonna be pumped, the heart's gonna be working hard. So your your job that night before for that patient is to make sure that they get their 30 millimoles per kilogram per day of of of fluid. They get their one Milmo of sodium, they get their one Milmo of potassium, they get a little bit of glucose. So you're sending them there in the most optimal way so that they come through their surgery as, as, as best as you can manage for them. OK? Remember that we all prescribe to this and it is above all, do no harm. So sitting by and not doing anything is also doing harm. So you need to think and you need to prescribe and need to give the right things to the right people. OK? So all of that was quite complicated. We look at that. Yeah. So Professor Lobo has kindly turned all of that into this. Ok. Your patients are going to be in resuscitation, replacement or maintenance or they're heading down to the oral maintenance and out the door kind of state. So you, you, you need to and, and you can see what happens. You, you don't replace enough. Ok. Electrolytes get deranged, inadequate replacement. They'll end up here, then you end up having to resuscitate. You have your maintenance patient and they, they have ongoing losses. You don't replace it. They end up being needing resuscitation or, or they your maintenance patient, you can drive them all into, into areas where you need to work hard to get them back into here. And the whole point is that you go and stand at the end of the bed and look at the patient and say, am I resuscitating you? Am I replacing you or am I maintaining you? And then depending on that, you need to think clearly and prescribe the right stuff. Ok. So resuscitation, what is it that's happening? Are you bleeding? Have you got a, a bleeding um duodenal ulcer or you've got a varices or whatever? What do I need to do? I need to put blood into you to resuscitate you because anything else will be wrong. Because if you put too much fluid into a person that is bleeding, you will dilute the clotting factors in the blood. You will reduce the quality of the clot, you might increase the BP enough to actually blow off the clot. And then at the same time, dilute the clotting factor. So they can't clot again properly and you will drive them towards death from, from there. Ok. So you need to understand what it is that you are doing for the patient. You know, initially you come there, you're not a genius, you're not going to know that they're bleeding so you can give them a bolus bang. Let's find out what's, you know, hold off. Give me a chance to think, let me do something. OK? This is what is going to treat the patient now. Replacement. So you've got your Hartmann's plasma light, whatever. Yeah. So why this because you need the, if you're replacing it, you need that intravascular volume to fill up. And if you put in dextrose into there, it's, it's just going to spread out. It's not going to hold the BP. And here if you don't want to push them from the replacement to the resuscitation, ok. You've got a patient with a high output stoma. If you do not replace correctly, one, you're going to knock off the kidneys because um from acute kidney injury, the electrolytes get deranged horribly, you're going to get cardiac arrhythmias. You know, you, you can imagine the, the downward spiral they're going to go if that isn't thought off properly. Ok? And maintenance dexalone, why, why dexalone? I would? Right. So we said the patient needs 30 millimoles per kilogram per day of fluid. Now, if you take a 70 kg adult, that's 73 is a 21 that's 2.12 let's say two liters of fluid that that person needs. They need one Milmo of sodium per kilogram per day. So that's 70 millimoles of sodium. They need 40 sorry, 70 millimoles of sodium, 70 millimoles of potassium and about 100 g of glucose. OK? You're not going to get that from MS, you're not going to get that from plasma light and you're not going to get that from 0.9% sodium chloride. OK? You're going to get that from this because if you take 4% dextrose which has got 30 millimoles of um sorry uh 30 31 millimoles of uh sodium in it, put 20 millimoles of potassium into it and you get a second bag with the same with 40 millimoles of potassium. That's 60 millimoles of potassium, 60 millimoles of sodium two liters. Bang, you've done your job. That's the correct thing. So here replacement. What do you do? You, you've got your Harmans helpful er to give you that um high osmolarity but I would I tend to use that. I put Dextro Saline for replacement. OK? Um and why? Because I need to make sure that I don't knock off the kidneys if you've got, if you've got your guy with um high energy output, let's say he's got over a so high stoma output more than a liter is considered high output stoma. So he needs two liters of fluid plus he needs another liter because he's lost out of his stoma. OK? That stoma output small bowel and gastric contents quite rich in potassium. So you need to be replacing your 70 millimoles of potassium and probably at least another 20. So, so that's 90 milli of potassium. You need to stick back into the patient plus three liters. And that is easily done by the dextrose saline because you're not resuscitating, you're replacing. OK. Here, definitely Harman's plasma light because that, that you are resuscitating. You need that intravascular volume to fill up so that you can oxygenate the tissues and you can stop the apoptosis of uh cells because the mitochondria been destroyed. Ok. So um I just want to go through one more thing here. The other thing is that people don't think about it at all is magnesium. It's uh I don't think it's hardly ever checked by anybody. Magnesium is mostly absorbed in the, in the upper um small bowel. It is an absolute necessity for the function of all your cells. OK. It is the hidden electrolyte. That's what it's called. If your magnesium is low, no amount of fluid resuscitation will ever get the sodium and the potassium back to normal again. OK. They are required for intracellular function. The the the systems within the cell are dependent on magnesium it. And which is why when you have patients with short bowel syndrome, your um nutrition team will always want to know what the magnesium and phosphate levels are. They are always checking magnesium and phosphate levels for TPN patients. Because if the intracellular volume isn't correct, you're not going to get the extracellular stuff to um study. And what will happen is if you've depleted the intracellular electrolytes by not correcting it or not giving regular maintenance or replacement. When they start eating, they get insulin in, you get an insulin drive, it will drive the potassium phosphate magnesium, all of it will get driven into the cells and you get re feeding syndrome and you are going to get a very sick patient. OK. So this is a few of the papers I used to put together that um presentation. I just want to quickly go through this. How we doing. We got an hour. Um I will be quick with this. I think we've got two hours. So if I can use some 20 minutes, I think this will be very useful. Um So very good paper. New England Journal of Medicine. Yeah, 2018, recent enough, I think. So they, it was a huge trial done in the states between balanced crystalloids and saline in. This is important non critically ill patients. This is your average patient that you go down to. Ed, you see, you know, they've got cholecystitis, they've got appendicitis, you know, whatever these are, the patients you're bringing up to the ward. This is your daily, daily patient. Ok. So they studied Saline versus, um, lactated Ringer's lactate as we call it. And it was a single center study, looked at it over a reasonable time and all of the patients were randomized to either lactate or a Ringer's lactate or Saline. Ok. Um, they had to, and they had to have, sorry, that's more than 18 years of age who had received more than 500 mils of IV fluids and were subsequently hospitalized. They didn't go to ICU, they did not have endstage renal failure and they weren't receiving renal replacement therapy. So those were the more than 18 years. So adults who did not have kidney dysfunction and weren't sick enough to go to ICU and the intention to treat analysis of all the randomized patients. We have a primary outcome looking for the number of hospital three days um within the 1st 28 days of presentation to Ed. So it's, it's looking at them from Ed to them leaving the hospital and from the point of coming into Ed to leaving, they either had Ringer's lactate or not 0.9% sodium chloride. Ok? And then secondary events were, you know, kidney events, death and look at the number of patients, you know, you're not talking small numbers here. So the outcomes from this I think is, is um important. So you can look at the balanced crystalloids in your saline and you can see it's almost equal. So you got median age of 54 median age of 53 you know, 3500 females on that side, 3300. So you can see race, white, black other. Um and oops sorry whether they went to medicine. Equal amounts, cardiology, neurology, general surgery, trauma. The the numbers were were fairly equal. OK? Which which is great because the comparison actually holds some meaning and look at what happened to the the sodium levels. So this is intravascular sodium between arrival and day three of patience who were given normal saline shot rate up. We expected to balance crystalloid is keeping within a a reasonable range, still a bit high but not bad. OK. Chloride ions, the saline group. So if you remember there is 100 and 54 millimoles of sodium and 100 and 50 millimoles of uh chloride ions in normal saline, it it peaks quite high. And if you remember at those kind of levels, the afferent arterial is going to start squeezing quite a lot. Yeah. Uh but the balance crystalloid is gonna keep that open much more and you've got a much more steady. That means the kidney is working well. It's it's keeping things pumping the blood urea nitrogen. You can see they, they both. So remember these patients aren't healthy adults, they, they have apathy. So you're gonna have certain inflammatory response going on within the body. Um but you know, after a couple of days they start diverging, you know, the the the sodium, the normal, the no 0.9% sodium chloride is definitely having a a more of an adverse effect on on the patient and the potassium levels of patients. Well, unsurprisingly, the potassium level by day three is fairly steady and reasonable. Whereas the saline patient is dropping, we talked about the intra cellular potassium being driven out of the cells because we're not replacing it. Yeah. So you can see what's happening to it here and bicarbonate levels. Yep. Same again. So that ABG you know your, your blood gasses, you're going to see a a difference here. Uh you're going to get a metabolic acidosis. Yeah, and creatinine level. So that's uh that is essentially kidney function, isn't it? And you're going to say that your, your, your kidneys are more damaged essentially because the creatinine levels have gone up. And that's your, your those two together is what you use to compute the A K. So what happened to these people? Let's see, median hospital three days, 25 days, 25 days. Not really a big difference. Ok, major events, kidney event within 30 days. So 315 people had some kind of kidney event. 370 had some kind of kidney event. So these were balanced patients. They were pretty much the same patients across the board of all the specialties yet, you have got fairly significant difference in the amount of patients. So 4.7% of patients had a, a kidney adverse event from your ringer's lactate and 5.6% in that. So, if you know you're talking out of every 100 people, essentially, you're going to injure six people as opposed to five people by choosing the wrong fluid. If you can put it down to basics and death, 94 versus 102 or 1.4 to 1.5 looks like small numbers. But you know, you really want somebody to die because they were given the wrong fluid. So if you can do something to get that to this much better, I think those people that required renal replacement therapy at the end of this, you know, that's, that's a 0.3 to 0.5% difference still quite high if you take 1000 patients. Yeah, 30 to 50. That's big numbers. Big hospital, that's a small number of patients, 1000 patients is nothing. The hospital I work at has got 1500 patients in it at any one time. So you know that that 30 patients requiring renal replacement as opposed to 50 is quite a significant number. Um Final creatinine levels definitely bigger and the number in in hospital deaths I think is also quite significant. I know those low numbers 1.6% I would think most people would say Yeah, it's nothing. But then if you multiply that by 10, 14 patients as opposed to 16 patients, ok. It's two extra deaths but two extra deaths that may have been preventable by having used the right fluid. So it's two lives that were unnecessarily lost, maybe. Ok. So let's go to here. So this was the death rate. A new renal replacement therapy that was needed between the balanced crystalloids and the saline group and the persistent renal dysfunction. You know, long term renal dysfunction. That's quite a significant number. I know. Yes, 4.75 0.6. But if you take a whole population, you're looking at like, you know, 20 million people, those are now big numbers of people that require continuous hospital support to live. OK. So this is what I would like you to take away. I would like you to stand at the end of a bed. Look at a patient and say which corner of the triangle is he or she in? I need to give them the right fluids. I need to spend 10 minutes figuring out what their daily loss is. So I can replace it. I need to figure out are they bleeding or not? I need to figure out am I giving them the right amount of, of fluids so that I can keep them in the optimal condition for whatever is coming ahead for them? OK? If, if, if you've got a patient whose sodium potassium levels are all perfect. They're well hydrated. If they have a sudden cardiac event, their chance of surviving goes up quite significantly than a dehydrated patient. Just because a bag of fluid wasn't given overnight. Whilst they came in for surgery the next morning, they're, you know, they're a cardi, their heart rate goes up because they're dehydrated on top of which they're now scared a bit because they're about to go to surgery. Adrenaline pumps out, you know, they have a cardiac event. Well, that dehydration wouldn't have been there and that tachycardia wouldn't have been there if they'd been fluid to start with. Rare example, but still a possibility. So I know I've perhaps used some extreme examples whilst talking to you, but that's also because the damage you can do isn't every day. It's, you're not going to see it every day. Ok. It, it happens and it will, you may not see the effect of it. You, you work from Monday to Friday, you, you've not given the right fluids and by the weekend they deteriorate and things get worse, they disappear. You never know about it. They've gone, you know, they've either gone to itu, gone to another ward, you know, ended up in theater, whatever. But if you think about what the body requires, you, we are more than 70% fluid. We have a very, very fine system creating a homeostasis that keeps everything ticking along very nicely. It takes very little to derange it and just not thinking correctly and giving the wrong fluid is enough to derange it, enough to cause accumulation of damage that will either prolong the patients stay with us or end up causing them some serious harm. OK. So there you have it. So I'm done. Mm Awesome. Am I am I still, I unfortunately my friend, you are still give me a long sentence. Yeah, you're still echoing. As long as you don't say more than two words at a time. You're all right. Um Looks like I did a good job. Nobody's got any questions. Perfect. Um Oh Yes. The one that's came in before in your heart failure patients should potassium more than 4.5 without hyperkalemia. Sorry, not sure what the good to meet you. Do you understand what the requirement is there? Sa OK. Can you hear me? Yes. Um That was, that was very, very long, long and lot. Um I think so. So question and uh so um more questions. 0.99. Yeah. So yes, there is one place I do give it and it's for hypochloremia acidosis. So if they're hypochloremia and you need to get some chloride into them quickly, then then you would give no 0.9% sodium chloride for that. That's about the only place I've ever used it. OK. Um To uh you use um the reason Sam I got bad news for you mate. Yeah. Yeah. Do you want me to read this. So we have, would you recommend routine parenteral fluids for POSTOP patients who are drinking poorly? Yes. I mean, your maintenance fluids, you know what they require, they need 30 mil, 30 mils per kilogram per day. If they're not taking that in, they are going to deteriorate if they are drinking poorly. Um, obviously depends on, on, on your patient, your situation. But, you know, if they're in a hot country, um um, you know, I've treated patients in India if you've got 30 if you require 30 mils per kilogram per day and you're sweating buckets, you need more than 30 mils per kilogram per day. And you're going to derange their physiology if they, if they carry on like that. But I, I um I, once I I it was in India, there was a patient who had had a lab Coley. In fact, my father, sorry lap appendix. Now, my father had done it and we went to see this patient the next day and she was just flat out and just lying there. Um Not had any, any fluids overnight because obviously there you have to pay for every bag of, of um, of uh fluid that you get and we give her one bag of um I think it was deline. That's all it took within about four or five hours. She was bright as a button again. So that, that is what fluid depletion does to you. I in, in in acute scenario. Um Yes, we have uh Masud who says I used to believe the daily sodium requirement is 120 to 140 millimoles. I need a clarification on that since you said one mil mo per kilogram per day is fine for sodium and Chl Yes, absolutely. If you have a 60 kg old woman, why would you give her 140 which is twice what she needs it. You're going to really derange her um physiology doing that. It is your, your electrolyte and fluid requirement is based on body weight, ideal body weight. So if you've got somebody who's massively obese and um got a huge fat content, then you will need to um um work out or assume make an assumption on on what their body weight would be and, and give them the right amount of um um fluids electrolytes. Ah Here's a good one. What about the use of naught 0.9% normal saline with potassium? Ok. Very, very nice question because we, we went into this whole thing where we said if you give a high chloride load without the protection of the bicarbonate or lactate from the Hartmans, you will cause vasoconstriction of the afferent arterial of the kidney. Ok. So if you give you naught 0.9% saline, you're gonna decrease the blood supply to the kidney, you're gonna increase the sodium and chloride ions in the blood. You're going to increase the potassium in the blood. Ok. And now you want the kidney to correct that for you with less blood coming into it. That's my answer. No, you, you, you, you, it'll actually make things worse. Ok. So Saline and maintenance for her in the ward, so Saline shouldn't be correct. Yes, I wouldn't. I've never used Saline dex. Saline. Ok. Dextrose. Saline with some potassium. It's not drinking, it's nutrition, everything, you know, your, your patient needs to eat and drink properly. In order to get the electrolytes, you don't get the electrolytes from drinking water, you get the electrolytes from food. So if they're not eating food, they're not getting there. Um potassium and sodium. So drinking tap water does not give you those electrolytes. So that's what your intravascular and intracellular electrolytes, which are deficient. So you use the correct main, the maintenance fluid is, is deline, you know that otherwise you will give the kidney a huge a load to work against and you will um decrease the blood supply to the kidney. Um that, that's, that's it really anymore anymore. And I will email this presentation to Sam who will send it out to all of you. Um Yeah, yeah, yeah, I'm just just Yeah, thank you. Bye. Think they, I think they, they, you cannot put OK in the, where have we got, do you then give Harmans with KCL when correcting hyperkalemia in your practice in the UK. A nurse will not put potassium into a bag of Harmans because it already contains potassium. I know it's five milli mos but that is the rule here. So that is why we use dexalone um or to, to give the potassium, you can give dextrose with potassium if you want. Um if you're just trying to replace the potassium. But you know, if, if in your country, you can get the nurse to put 20 or 40 millimoles of potassium into Hartmans, then certainly that is great. And I would say it's better than the Dexa line from a point of view of resuscitation but not maintenance. You don't, you know why load up the kidney with extra work. Because if you give two bags of Hartmans, that's 100 260 millimoles of sodium, you're giving that patient which the kidney then has to um filter out. So you're making it work harder. Um Can you please advise on 0.9% saline use in postoperative hyponatremia and AKI. Um hyponatremia is not treated by giving sodium. It's hyponatremia you treat by uh restricting fluid. That's how you treat hyponatremia. Um And with AKI. So if you've got a hyponatremic patient and AKI, what's the most important thing you need to know? It depends on how hyponatremic the patient is. That's, that's your first thing. If they are just marginally hyponatremic, the most important thing is the kidney because without the kidney functioning properly, you are not going to be able to correct any of this. Um So, you know, assess your patient and IIII I have said I don't give 0.9% Saline to anybody. Um I've used it a couple of times for patients who are hypochloremia. That's, that's it in the last 10 years. Uh What would fluids like darrow solution be appropriate? I do not know what daro solution is. Sam Dare Solution. Yeah. Dare solution. Have you heard of Dare Solution? Yeah. Um I it it um I I don't know it for you. So barrel solution contains potassium chloride 1.5 mg, sodium chloride, sodium citrate and glucose. It almost looks like a like a dexa line with potassium already in it. Um It, it needs to be in mimmo this. Unfortunately, I can only get this in in it's showing in milligrams but you know whatever solution you're going to prescribe in your country, your it doesn't matter because you're prescribing it to human beings and they will all require 30 mils of of fluid with one milli mole of sodium, one milli mole of potassium, one milli mole of chloride. That that's what they require and make sure that magnesium is correct. What's the appropriate setting for Hartman's? It's, it's resuscitative fluid. OK. It's resuscitation. You need some high um osmolarity into the intravascular volume. You give that patients have come back POSTOP, they're going to be quite dehydrated. You want to, you want to pull up the um BP or you are trying to pull up the, um, BP or urine output. Uh, because, you know, they, they've got a, um, POSTOP um, changes, then Hartman's is great there. You know, if they've got a, um, epidural in, they're going to the s flank veins are going to have dilated quite significantly, their BP is going to be low and you are needing to give something like Hartman's to help bring that up. And you know, if you've got a, a freshly anastomosed patient, your, your fluid management should be, are they GCS 15 and are they producing 0.5 mils per kilogram of urine? Because if they are doing that, then that is fine. That's, that, that, that, that's how you, you work it out in that acute situation. You know, you're, you're in the middle of the night, they've had an anterior resection in the morning. Patient's urine output's dropped. They've got an epidural in, you need to get the kidney working at to not 0.5 mils per kilogram per hour of urine output. That, that, that, that's it. That's all you need to do. Um So I think I've spoken about the Hartman's use. How was the question answered? Are there normal? Are there situations where no? Oh yes, hyperchloremia acidosis, that's where normal saline is given. Um Daryl solution is high potassium containing fluid. It is to be avoided in hyperkalemia. It depends what the hyperkalemia is. If uh the 3.5 to 5 is your normal range. If it's five point I, I would say 5.5 and above, I wouldn't give potassium below that. Remember, this is an intracellular um electrolyte. You are getting a snapshot of what was in the blood. At the time, the blood was taken from the patient an hour later. It's not going to be that whatever numbers you got. It was at that point when you took it, the kidney is still working. Cells are still working. Uh you know, um the metabolism is still active, so it will have changed. So, you know, this is, this is your judgment call. You know, it's your patient. You, if they, if they are a um um patient with um cardiac um history, then I probably would be more careful because you don't want cardiac arrhythmias. But certainly your average jaw blogs a slight rise in potassium is not a reason not to give it because if you think about it, you're not injecting 20 millimeters of potassium into the patient's vein, you're giving it over at least six hours. So they are getting tiny whatnot point, not one millimoles per minute, you know, dripping in, it's tiny amounts that's coming in each in each drop. You're not, you're not throwing in 20 millimoles in one go, it's spread out over six hours. Um The sodium potassium channels in the cells are still working. Electrolytes are moving around kidneys also working moving um getting rid of um electrolytes and trying to balance things. So yeah, it, it, it's um that's my answer, you know, experience bit of theory and a bit of knowledge and bit of understanding of the patient's history. OK. Any anymore? So your aim is to give the the the 30 mils per kilogram per day of fluid plus one milli mole of sodium, one milli mole of potassium, check the magnesium, make sure it's normal and make sure they have good urine output and you are balancing the fluids. So input output balance is important. Anybody with high stoma output s biliary drains you, you need to know what's coming out otherwise you can't balance them. OK? Sam? I think we've dried up our audience. I just just, it's more, that's fine, Sam. It was, it was fine, I think. Yeah, we've, we've achieved our end. We've dried up the questions. So that that's always a good thing. Yeah. Yeah. Thank. Thank you for stay until the end. The for questions. I'm I'm trying to very, very slow. So you get what they say. Um I mean and this Yeah. Yeah, and you would get back. Thank you. Thank you. Thank you. Thank you very much. Good luck with all your careers and um we for we couples and the thank you. Thank you. Thank you. Bye bye participated and we'll call it a wrap. If you still have further questions, you can pop it in the chat box and if possible, um, I can drop my email address and you can get it across to my email address. I will then forward it to the speaker and um, you should be getting answers to them in Ducos. Thank you again. And um, I'm not sure whether I can't hear myself echo anymore, so I think the queen has gone. But yeah, um, if anyone knows what could have been responsible for that, um You can reach out just so we don't experience this anymore. I know normally it's when you've got to, to um if you've opened these um platform on two gadgets, then you can get feedback from the other, but I haven't done that. So I'm not particularly sure. Yeah. Brilliant. Someone has told me there's no more echo. So I don't know why I've been echoing all along and now that the speaker had left and I'm no longer echoing. So does doesn't mean it has to do with this pica audio interacting with mine. Well, I don't know. I need to figure that out afterwards. Thank you again. Once um more. This is um we're running a yeah, about one hour, 30 minutes. I which is a good time. And if you've got more questions, drop it in my email box and I can forward it to the speaker, which I call it a wrap. Now, uh we shall be going offline in about 10 seconds. Have a good weekend. And if you've got a bank holiday for Monday if you're in the UK and you're not working of an extended, have a good extended weekend. Thank you. Cheers. Bye.