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What can I start? Yes, I think it should be fine starting her. Okay, um eso this is, um, the third lecture that I'm giving on fluids. We talked about the consequences of miscalculating by giving fluids, too, until patient. Either too much or too little. We talked about the physiology of venous return, which is often poorly understood, but it's absolutely vital. And so now we're going to try and understand how you actually make an intelligent, I guess, an educated guess as to well, whether the person will person who needs fluid whether they respond to it or not. Okay, so here we go. So what we're going to talk about today is Let me decide this. Yeah, this this floating panel keeps coming up all the time, So Okay, so why is it important to assist someone's fluid status? What is the goal of optimization of fluids We're we're trying to achieve. How do we predict this is the keyword predict? If someone's someone who requires improved cardiac output, where the Iraqi get that improvement through fluids or not, that's really important. Uh, we want to know what works and helping you predict what doesn't work because They're a lot of things that we think work and they don't and how to give fluid in intelligent manner to be able to assess whether what you're giving is working or not. Sounds very prosaic. It sounds very simple, but in fact it's amazing how often we badly do this. So why is that important to assess fluid status. So here we start off again with these are all true clinical case is none of these are made up. This is This is typical. By the way, when I was in intensive care, I would get this all the time. So this one was an 82 year old lady who was admitted to the accident in emergency department. She had a past medical history that was kind of typical of that age, you know, skimming car disease. On top of that was heart failure. Probably secondary to the skin, McCarty's and diabetes type two diabetes. She came in short of breath, and when the registrar listened to her trusty hurt, Crepitation is in her chest, so he saw right away. Oh, this must be heart failure. Well, not necessarily. And he had a dry mouth while she was breathing fast, so that's that makes sense as well. Her BP was a bit low. Temperature was a bit high. She was found to be an acute kidney and your acute renal failure. And the question was, Is this woman overloaded? Hence the crepitation, where she under filled dry mouth temperature lowish BP and not passing a lot of urine. This is absolutely classic temp, so classic and almost always when this sort of case was referred to me in the intensive care unit, Um, the registrar, whoever was looking after this patient would either give fluids or not based on either crepitation is hence heart failure. We mustn't get fluid or not passing urine. Then we better give lots of food. And almost always when I asked, how did you assess this? It was always They didn't say it was. So they did. It was basically heads or tails, took a fluid or not so totally, totally guessing. And that's not really the best way to to work. So why is it important to predict if this person would respond to fluid when I say what's part of fluid? I mean, if their BP is low this case, it was that you were not that slow in this case, it was. How do I know whether fluid will help them get better or not? Well, we all know, and again I do apologize. I don't apologize, actually, going back and back and back to the starling curve because this is gonna be the that the pillar of what you're going to be using, theoretically to determine what you're going to do. So the starting curve? Well, no, you have that pre load on the bottom, which is the pressure in the heart distending the heart. And we talked about how it how it distends the heart. And it separates the active in my side of the acting fibers so that you have the maximum contraction as you a stretch the heart more and more until you get to the plateau and it doesn't work anymore. You don't get increasing cardiac output. We get a large increased pressure, and that's you don't want There's another curve that a lot of people don't know about. This is a really important curve, and this is the lung would occur with the extra vascular love water curve. Very few people that. Have you heard of this? And if you look at it carefully, you'll see where the previous patient while guessing, was not a great idea. So if he was in renal failure because she was lucky and fluid because you had a temperature, it was breathing fast. Wasn't able to swallow, For example, could he was so breathless. Well, maybe she was on the very steep part of her starling and needed fluid, In which case, if you gave her fluid, if that was the case, you'll see that there's very little is a big increase in cardiac output. It was a very little increase in love water. That's fine. But as you get more and more fluid, if she had been on the top part of her starling curve the flat bit. So if those crepitation is were due to heart failure now, you see if you give fluid, you're not gonna get much of an increase in cardiac output. That's not gonna help her. But you're gonna get a large increase in lung water. And if you did have pulmonary d m A, you're gonna make it a lot worse. So that's why it's important not to guess. At least in this case, you can see that if you are guessing right, you have dinner. Uh, some. You dinner some good. If you get strong, you could make her primary demon worse. So that's one of the reasons why it's important to guess. I'm just going to briefly recap in one slide what we talked about of the first lecture on fluids. And that was what are the of complications if you under recess, state with fluids or if you overuse estate flutes? So here you have the line of fluid and complications. If you under assess it a tieu cause organist Kenya. And for those of you who we were at the lecture, if you recall, we've showed that if you, um if you under assess it, it's someone. The first organ it suffers is your four good. In this case, it's your stomach and the and your your small intestines, which allowed translocation of bacterial products and that I fabrics like your guts proponent intestinal fatty, acid binding protein. So it's not like it's a marker that your gut is suffering. You can see if you give too little fluid. And then we talked about the experiment where they bled volunteers. And you could see the I felt going up so that the gut was suffering and that for you get skinny A you get translocation of bacteria and you get cytokine release. Basically, that's not good. If you give too much, you have two problems because you get organ a Dema. You get that back perjury talked about. So you get like the Cardiorenal syndrome or cardiac cirrhosis or again a a gut that is suffused with blood. And therefore you again get translocation bacteria both bed. And we had talked about the famous glyco. Okay, Alex, which I hope you found is exciting as I do. And you could see that too much fluid causes a release of atrial, naturally peptide from the heart that is being over distended. And we know that atrial metric peptide destroys the glyco. Okay, Alex, that all important blocker care looks So there's two reasons to make his battery, but basically, we're saying is too little. Too much is not good. Do you want to be in the middle if possible? And we also know and there's lots of lots of studies that show the same thing if you guess wrong and give too much fluid and almost always when you look at studies in severely your patients and and falling over a few days. Almost all the studies show that we have a 10 cc over load patients with fluid, and those that get overloaded had a lower chance surviving. Now there is an association, but I think there's biological plausibility that the fluid itself is harmful and it's independently associate it with mortality associated necessarily costed. That probably has caused it. And as we asked before, and this is a question on throughout to the audience, what percentage of severely, Oh, patients, whether it's in the accident Urgency department for in the wards or in the eye to you will respond by improving their cardiac output fluid. So you're not sure what to do. You get fluids, guessing what percentage of people will respond. Anybody want to take a guess? What do you feel less than 10% Anybody else? We've got a few people saying 50 in the chocolate. Well, that's what we said last time. There's been lots of studies and there's just a selection of studies 50%. So when I said you're literally putting your hand in your pocket and pulling out a coin and flipping it and going heads or tails. That's basically what you're doing. And the case I just told you about the light lady who was with reputations but who also was lucky and maybe lacking fluid. Maybe an overloaded so often I mean so. So often. When I asked the the person sending the patient, how did you arrive at that decision? They might have been right. But how did you arrive at that? Can? Almost always. It was just a guess. So maybe right half the time. But the problem is which have Okay, So what's the goal, Doctor? Well, we already said this before that you're on, they're starting curve again. And if you are, if you're needing an improved cardiac out, but but once again, all of us on the steep part, like starting curve where that little dot is and I presume all of us are relatively healthy, so we don't need an improved cardiac output. But if I were to give any of you or myself uh, a bolus of fluids and measured my cardiac output, it would go. Uh huh. maybe not to the top, but I would go up. I have improvement card account. So a you need your assist. The person there's severely ill you. You assess them and you say, Hey, that person needs that improved cardiac output. So how do we How do we get that? First I try and optimize your film, and that's getting to close the top of the strong curve. But what's there on the flat part of strong turf? There's no point in getting more fluid, so get no more cardiac output improvement. But I'll get a large, increasing pressure, and that's not good. So the next thing you want to do such fluids phone is down a steep part and the not flu responsive. There's no point getting more fluid. You'll cause harm. So then what you do is you came to the starling curve. How do you do that? You use pine trips, heart studio and what are we trying to treat with this cardiac out? What is our gold? Well, first we want to treat on it. Effective cardiac output. What we mean by that is the cardiac output. That is, uh that is adequate for your metabolic needs. So someone who's sitting quietly or someone who's actually a decent size. For example, if someone's cold type of thermic someone's very hypothermic, you can actually stop their circulation for, you know, for about an hour if you have a temperature of 18 degrees. We used to do that. We used to operate on Children recent, so we used to operate on Children, and we would We would stop their circulation for specific procedures and and that would allow us for a Knauer toe because your metabolic changes so low. On the other hand, if you have somebody who say I've seen this before where someone's very septic, they had a cardiac output and eight liters a minute, which is much higher than normal, but it wasn't enough for their medical needs. So you want to get you want to marry their cardiac output to their their metabolic needs. You want adequate BP cause without BP. You don't have slow and you want an adequate macro and micro circulation, and that's something that is often for God. It's called a circulating coherence because it's coherent between macro and micro. So we're not assessing blood volume. We heard so many times before, people will say, Oh, assess if this person is hypo really maker, hyperbole maker and basically saying is, see how their with their volume status is. I mean, for example, when I talk to you about this next time. Um, one of the approaches to hyponatremia, low sodium in the blood in the serum is, um is to to divide people up into a normal Olynyk hypovolemia and hyperbole. And I totally reject that because it's absolutely impossible to guess what someone's rolling. Because we can't actually assess someone's blood drawn. Well, you really want to know this is their cardiac output adequate? That's not always easy to determine, but it's not always difficult, either. If it's not well, they improve with fluids. And what you really want to know is, is this person fluid response. It really respond to fluids with an increase of cardiocap, so we know you're not going assessing blood going clinically. This was a study that was done in 2020 and this was looking at I to patients. They took six I two patients at different times of their stay, so it's somewhere staying for two out two days seven days 11, 13, 14 and 20 days. And they had a technique of radio labeled albumin, which gave a very accurate. This has been validated, very accurate assessment of someone's blood drawn, and they want to see how far they deviated from the ideal blood draw that was calculated. So they asked senior doctors to to estimate guest of me. That person was hypo hyper would normally take. It's the clinical estimate made by some senior doctors. Was this number patient was number on The second day was hypo. Another patient on seven days was hyper when was usually make hyper hyper hyper. And what did the actual maker, blood volume, using this fairly fancy tools show that they were almost always wrong, and only in one case where they correct out of six. And most studies are maybe not exactly the same result, but they're pretty close. So we're not very good. It says it going. So we remember. Another thing is, yes. You want to absolutely resisting someone to their macro. He mowed and ideal. So in other words, if someone's BP is low there, heart rate's fast. They're tacky. Kartik, whatever. Whatever you're measuring the kind of thing. The nurses will come up to you and say, Oh, is looking good. So what we're gonna do, I have to correct that. There's no discussion about that. But you don't stop with that because you may correct ones macro chemo dynamics. So you correct them to the point where the nursing staff are happy because you've you've given the write orders and it's working fine. That's not enough. You have to also consider the micro circuits. So this was a very interesting study, I thought 2020. So this is all very recent. These were patients who were assessed using a laser Doppler, their skin blood flow so the tool itself doesn't matter. It's just a way one of many ways. Fact of assessing someone's blood, micro circulation, their peripheral circulation. And what they found was that was what a normal volunteers blood folks look like. That's that's That's what your control a patient would look like. And what they found was this and those that survived as they were resuscitated. They're micro circulation assessed by this laser doctor was improving in the second group who didn't survive. They're micro circulation, stayed poor or got worse, but it was fascinating about this study was if you mix the two together, the two groups together, they all had the same normal systemic hemodynamic. So in other words, they're all resuscitated initially to what we would consider adequate macro hemodynamic. So their blood pressures look fine. Their heart rates came down everything. Risperdal rates were back to normal again. So we're saying he's fine, right? The nurses are happy. We're happy. But in fact, if you if you had assessed there microsecond when you see they weren't and if you believe this, they were more likely to die. So how do you assess the micro circulation? Well, there are a lot of fancy tools, a very simple tool. First of all, I would always make sure the lactate to start with. But after that, if it's abnormal, especially, I would then continue following the patient up using a very simple tool. We use this all the time now. Daily practice is capillary refill time. That's important to do that correctly. What's even more important, doing it correctly is to do it in a systematic way. Everyone does the same uses the same, take me. They're different techniques different parts of the body to look at finger tip, sternum, kneecaps. It doesn't I don't know if it matters, and I really don't know the answer to that. But I do know it's important that you do the same throughout your unit because if someone does, uh, presses for 15 seconds on your finger and then when presses on five seconds on your sternum, you may get different results, and you can't compare them and be comparing apples and oranges. So this study looked at How did the two, the lactate versus properly refill time compare and there was your elected and how it related to mortality over time. And there's peripheral profusion assessed by CRT capillary refill time. And they were both to say, In fact, some people would say today you're really refill times even better, because lactate tends to improve quickly, and then second is a second phase where 10 Stick of Wild got about a two hour half life to improve where it's curly refill is about 20 minutes, so it will respond quicker to a successful a cystic. So it's very simple. I mean, you could easily do it not not complicated, and here I think it would show you this before using fancy tools. Just if you want to visualize. This is what, uh, professor I to physiology and Astrodome in 10 Interest sent me these videos. That's a normal capillary circulation. It's just another example where never over one Looks like this. Someone septic shock. You could see the roast difference. I've got lots of these videos you ever want to see. Okay, So how do we predict if someone can or will? It is likely to improve their cardiac output with fluid, What works and what doesn't work. So here's untrusting clinical case again, This is what I will never forget. So this was a 68 year old man, and he was He had a past history of multiple sclerosis. He lived alone, and he was He was neglected. One thing about him, I remember very clearly he was extremely independent. He was kind of admire him for that. He was a very, very much like, you know, stay out of my life. Um, I live the way I want to, and I don't want to be bothered by anybody. I don't want to bother anybody. And he loved his way he wanted to live. But he, um he was neglected, though he didn't look like he was very clean. And he was found down by a neighbor who didn't hear any noise from his apartment for a walk. And they found the police came in and found that he was unconscious. He was taken to the accident emergency department, and he had rhabdomyolysis. So his creatinine kinase is over 20,000 just high, and his creatinine was rising and his urine output was very poor. And as you probably know, the treatment of rhabdomyolysis the by far the most important treatment is to flush out the kidneys, flush out the myoglobin and all the stuff that is released by the damage. My oh, sites, all the intracellular stuff. Toxins. They're released. So you want to flush your kidneys out? That means get them during it. E 203 100 miles an hour. So lots of fluid you to start with. No, that day are intensive. Carrying it was very full. Were very, very good. And so we sent our outreach. Nurse, These air I two trainers is to go up to the board, see this patient and they advised while they're waiting for a bit and I to you but they don't necessarily need to. Right away was to give fluids, as we just said, to treat that urine output of between 102 100 mL an hour. That would be classic treat. You want to flush those kidneys out? Well, that those toxins after about three after several five or six hours, Actually, I finally went upstairs. We finally got a bed, and to my horror, I discovered that the nursing staff of the words I don't know what they were dreaming of, what they given this man over that four or five hour period. Actually, about 15 mL. Not not five leaders. About 50 mL in the story any. Of course, nothing happened. So we took him to I t u s. We found out of bed and we immediately getting three liters of fluid, had no effect on his urine up. And we're assuming now that it's too late. His kidneys are already damaged to bills have been clogged up with these toxins mild globin and the like, and that basically, we've lost its not think about this for a second. This is what really I thought was so dramatic. This man is unbelievably independent. If he loses his kidneys and requires dialysis, that means three times a week you'll be taken by an ambulance. She doesn't have a car, that's for sure. He'll be taken by an ambulance to the dialysis center and for four hours, at least every every session he'll be sitting there hooked up to a Dallas so his week now will be basically devoted to dialysis. That'll be a disaster for him and his lifestyle, and it will cost the community in absolute fortune. So that was really I was so upset because they just didn't even give the basic care. So what would you do now? Did you give us now even more fluid? Anybody? Dallas is maybe well, if we dialyzed him to see the point is that we're trying to save his kidneys. Dialyzing will not save his kidneys. What we'll do is it may make him metabolically better, but we're afraid that his kidneys were gone. If his kidneys were gone, that's that's going to late anyway. Hold that thought. Think to yourself what I give this man fluid or not, we'll come back to Mississippi. It's the flu or not. Well, we could either give him a bolus. That's what we do in the real world. Okay, Not not specifically to this patient, but in general, if you have somebody, you're not really sure whether to get fluid or not in the real world, Yeah, give him a reasonable bolus between one to leaders and watch the response. If you use relatively small volumes, Yeah, you're probably safe as long as they haven't got, you know, impending pulmonary d. So, again, you know, this idea of how you can make an educated guess is useful. But in the real world, to start with giving some money a bolus is fine. If someone's those obviously been bleeding. So someone has coming from trauma. I'm not gonna be assessing guessing. They obviously need the fluid. So I'm in there right away. But it's like if I'm not sure if it's too risky or five already tried giving a bolus, as in the case of this man who had three liters, you can try and predict how he's gonna respond. Yeah, No. Before I go on to how the tools were used, you've got to understand some of the essentials of venous return physiology that we talked about last last trip picture because their key to understanding how these tools work. So I'm gonna very briefly very briefly summarize just for those that you that might have been he didn't understand it would forgot it or weren't there. So we're gonna talk about this again. It's venous return. Any flow. Any flow on this planet requires upstream pressure that's 100 than a downstream pressure. And you get flow of water going from the mountain to the sea. If the greater the Grady int, the greater the difference in pressure, the greater the flow if you have less great and you have lower flows and if you have no Grady in so everything is equal, there's no flow. So you're up stream pressure that will. You're that's going to determine your venous return is gonna be outside your thorax in your capillaries and your vineyards, and that's called the mean, systemic feeling pressure. We talked about it last time. Downstream pressure is your CP or your right atrial pressure. That's the pressure in your heart and your right heart. So blood's going to go from the periphery and your venous and capillaries. That's the high pressure. The upstream pressure and the downstream pressure is just EDP okay, and we said, also, that's often not understood. People think that the heart left heart generates a BP, say 1 20 over a forces blood around the circuit. That's not true. The energy of that you getting from the left ventricle is disappeared by trying to get the blood through the the arterials. There's a high resistant areas. All your resistance is in your arterials. You can see not graph your energy. It's seen in the pressure the systolic diastolic, which is all dissipating as it goes through the arterioles. So your means distinct feeling. Pressure is actually write down there, and your CTP is right there. So the great idea is really small. It's not 1 20/80 back to your right heart. It's very low. 8 10 and your videos and papillary. Okay, so what determines your upstream pressure? Your mean systemic feeling pressure? Well, I use the analogy of an air mattress when you're starting out. It's completely flat. There's no pressure on the inside. The walls of the elastic Caremark Tris are totally flaccid. If I start to pump it up? Yes, you'll get it to fill to its maximum capacity initially, but he tried to sleep on it. You can't because it's not got any stress in the walls. Theological Xarelto being stretched. Yet If you try to sleep on it like this guy, you're gonna go right to the floor. So the pressure inside that means stomach feeling. Pressure is going to be zero now. If you keep pumping it up, it's going to get really someone once said bouncy. It's gonna get really tense because the the the elastic fibers are being stretched, and now it can. It can uphold your weight. And so the volume you put in once you make you read that maximum capacity is called the stress volume. The one you used to fill the air mattress to its full capacity is called The Stress for You and everything you add after that to stretch the walls. It's called the stress fight that creates that mean stinging feeling, pressure and the downstream pressure. As we said, Well, that's your CTP and as we said, your heart is full of fluid blood and you have the thoracic cavity that surrounds your heart and you surround by their interest rest of fresher and normally, when you breathe your breathing from you expire your pressure around the heart. Zero. When you take a breath in, you're sucking air in. So it's negative pressure, so minus three minus four minus five. So all your life you've been breathing spontaneously and your pressure goes from zero to my history's your itemized five. You give a cough plus 10 plus eight. If you blow hard on trumpet, you could get a pressure is we said last time. I will ask you to guess because you heard this before it could go to 1 57 years of water. Someone got appeared to be for this, by the way. And so if you were to squeeze your heart, we stopped about a syringe full of air. You could compress it, but a syringe. It's kept full of fluid water or blood. You can compress it, but you can raise the pressure dramatically. And that's exactly what happens. If you do a valsalva maneuver, you bear down and you try doing that. You can see this is a weight lifting is doing about salmon over and you could see all the Nixon is the veins in his neck or standing out because he's compressing his heart and he's raising his CP, and you could do that in front of a mirror. You can see it yourself in front of your own mirror if you want to try it. So what that does is that raises your CTP that reduces your greatest. Okay, now let's talk about how you predict if someone's gonna respond to fluid. Remember the man who it's trying to determine? Do we give this man fluid or not? Okay, so how do we predict fluid responses? Well, they're static measures, and they're often talked quite a bit about. Sadly, none of them are useful in predicting fluid responses. Static measures do not work now. I don't get me wrong. Those things that are on the staff members with CP Echo or what it called global and I stuck in next story about that's a fancy term for a invasive monitor reuse they. They are useful tools. They're useful for other questions that you're trying to answer, but they will not in themselves answer the question. Will this person respond to fluid up and yet very often. In fact, I was brought up like most of my colleagues, to measure the CDP. Whatever the number was would tell you. Yes, you know, it's going to tell you whether he should have fluid or not. It doesn't work. There's been lots of evidence showing it doesn't work. That's that's that one's. Put the bed. Forget it now it doesn't mean that I don't think CPS useful it is, but not for this question. Another dynamic measures and to understand a dynamic measures. That's why you have to understand that causes of venous return. So what about looking at CVT now again? This is an important one because so many of us have been brought up since we're a little Children, almost to resuscitate somebody based on the CVP. And this was an interesting study where I thought they did this very clearly. They took patients who required a resuscitation, required an improved cardiac output. They gave fluid. They so half of them are some of them resisted who are such a response to the fluid, and someone did not and look backwards at the CP and they said with the CCP have helped me and here's what they found so those that responded to fluid, that's what they're seeing. People and those that did not respond to fluid. That's what they looked like. Not a lot of difference and was interesting is that some of the responders had a high CCP this stuff again. These are the see peace Before they were giving fluid because he look backwards, that what happened And look at these guys. These are guys who would, uh, who didn't respond and yet would have been getting fluid cause they don't know CDP, so it didn't help. And if you understand well, I explained to you about venous return. It makes perfect sense because what determines whether someone will improve their venous return and hence the cardiac output Because venous return in cardiac output and saying things that we said is the difference is an improvement in the Grady. In between the mean systemic feeling procure the upstream pressure and the CVP, which is the downstream pressure. It's got increased ingredient together, increase in venous return. So in those responders before infusion, that's what the Grady it looked like the difference between us to see a a message be in the city be after infusion, you can see the grading improved. They've got an increase in Grady intense more flow. Hence more venous return. It's more cardiac output. So we worked and the patients who didn't respond before infusion they look like this, just like in the previous graft. But what happened with these people is they didn't improve their Grady into the CP might have will have risen and but still the main systemic feeling pressure equally so there's no increase in Grady in. And so there's no increase in venous. Return is not recent flow. Hence, if you measure the CDP, it's not gonna tell you about the grading. Just gonna tell you about the downstream pressure That's always gonna tell you won't tell you if the great aunt's got bigger. So it makes sense of the CP Doesn't really help you. Yeah, so what? It out? I just don't like me to use our dependent on heart lung interactions, so they're two kinds of situations. Someone's breathing spontaneously so you could look for a drop in CVP, so I didn't say CDP was news. What's it? The absolute measure, The absolute value, which is what we're often taught doesn't help you. But the changing CDP to breathing spontaneously may be helpful. And especially people that eventually and when you're ventilated, you can look for cardiovascular. It's CV variations. Within spring, you'll see why I'm sick and of the variations you can look for either stroke volume stroke volume. Is this the cardiac output per beat of your heart? Okay, so you know what? You're still volume. Is it multiplied by the heart rate and you get your card. It help, but because we're gonna look at Perbet, we'll talk about stroke so you can look at the stroke going to be Or you could look at a surrogate, something that you can substitute for the stroke and pulse pressure is one of those stroke volume is he just said you could look at systolic pressures and see in a second you can even look at a pulse oximeter. We'll see how interesting is. So let's go back to our gentleman and we talked about Yeah, uh, I need to this guy I want to get a game away here. So, uh, then we just do one more time. Sorry. I was trying to make this into a surprise with didn't work. Okay, so we brought the guy down to I to you. He's had three liters of fluid. No effect. We decide. So ask you, would you get this man fluid or not? Any more fluid or you think he's had enough? Just not gonna work. You're gonna You're gonna give him pulling a demon. If you get any more fluid, that's the risk. Would you get this man more food or not? If not, what would you do? Just put him on dialysis, giving more fluid or just try something different? You're not. Give some more fluid, you would give you more fluid and also giving minor Trump's well, you know, I'm the trucks is really not going to help his kidneys. I don't think I think it's basically you're coming down to Is a question of do I give him more fluid? Hoping starts to pass urine again, but he's already had three leaders. Or do I just put him on dialysis? It's a tough call. It's difficult questions. Well, what happened was we decided to put him on dialysis. We thought he's already had enough fluid. We thought it's too late. You should have had this early on when he came in. It's not five or six hours after he came here, and they they didn't give me enough fluid on the words they gave him. Nothing said essentially and we were really annoyed at this. We getting three leaders, we thought, it's not gonna work. It's too late. It is not responding to three years at all. So we're just gonna put him on dialysis. And what was really fascinating was this. The registrar was putting in Central Line for a dialysis dialysis catheter, and he said, Hey, look at this. And he showed me the ultrasound he was using to to determine where the internal jugular vein was, where he's gonna put his catheter, and you could see it when he took. This man was breathing spontaneously. He wasn't mentally every time I took a gentle breath is, Is internal jugular just totally collapsed, totally collapse you breathe out it, open up. He take a sudden you suck air in it collapsed. That will be the same. Is seeing a CD. Keep dropping if your breathing quietly or you can even just look at the extra jugular. And sometimes I've noticed when I put a catheter in someone central internal jugular vein. If they're very dry, you can almost not almost you can feel the catheter being squeezed by the regular vein is you're trying to advance it, so it's very it's very noticeable. So this man basically was telling us he needs a lot more fluid. And so what do we do? Well, in this case, we gave him a lot more fluid. And guess what? He started passing your So we never got the Iowa Dialyzed and he went home and he lived when home and has lived his life. So he had his life saver in the sense that he had his own freedom of independence back and the community didn't pay a fortune, for that was a really a nice winter. And it was only because that register our saw that this man internal jugular vein was was collapsing. So does the CP cane can see p work of your breathing quietly spontaneous, and you sleep, and this is one study looked at it. Yes, people that had a fall on CP responded fluids, and those that didn't have a phone CP did not respond to fluids, and I would say, Maybe in best issues ultrasound. Now there is a bit of controversy about this because some people say it doesn't work as well as we say. But I'll tell you something. I've seen this. If someone's very dry, you can see it beautiful. Whether it's ultrasound, we're even just looking at it. No, even when you could feel your putting a catheter in. So it probably does work. Spontaneous, disagree, not dynamic missions. How does the cardiovascular system respond to the positive pressure you get when you ventilates? Now? Remember, when you ventilates somebody you are. For the first time in your life, I presume putting not negative pressure to suck air into your lungs. You're using positive pressure toe force air into your lungs, and that's going to raise the pressure around your heart. So let's see. I'm going. Eventually it somebody classic ventilation. I'm gonna give them a little bit of positive pressure with the called Peep. Positive and experience. Pressure stayed up 57 years of water. So instead of starting at zero as you and I would be when we're breathing out, we're going to suck air in. We started plus five and then instead of sucking in state minus five, we're going to give up to 20 centimeters of water because we're now going to have to put the lungs and the thoracic cavity to expand them, Teo to force air into the threats a cavity. So we're totally flipping the physiology. And I said so instead of going when you're breathing quietly spontaneously from zero to a minus 502 minus three, you're going from plus five to start with and then up to 20 plus 20 plus 25. So all that time you're squeezing your heart and because your CTP is going to go up just like that syringe full of water that you're trying to squeeze, it's gonna raise your CTP when you put that positive pressure. And so every time you put a pulse of gas into someone, store X rays, the intra-alveolar pressure, the intra thoracic pressure, you're squeezing the heart racing the CP. By raising the CCP, you're going to be reducing the Grady it we talked about and by reducing the grading between that means systemic feeling pressure which is outside outside your thorax, and the CCP, which is inside your thorax that greedy gets temporarily reduced with the pulse of gas going in your thigh or ex. That's positive pressure. Hence your venous return drops and your cardiac output drops. And so whatever you're measuring stroke volume or any of the Seroquel, it's post pressure variations. Any other variations you're going to see it's going to change as you put gas going in. Gas coming out? Yes, going it, Yes, come here. So let's look at this. Those little green bars is when you're putting a pulse of gas and your ventilating someone with positive pressure of insulation. So what happens? Let's look at these. This is on the top. That's your systolic pressure. You can see it going up and down like a like a roller coaster, Right? What's that? Blue lines, it apnea. That's what it would be if you have Nogas going in. We called Delta up so it goes up. Then it goes down swinging all over the place. And the other thing. You may notice that systolic pressure guardianship the top of those those peaks, that systolic pressure on the top, diastolic on the bottom. So it's going up and down, up and down when you see swings like that. You know that person is going to respond to fluid. You may also notice if your drink a clever and look at this carefully. The difference in systolic and diastolic also gets bigger and smaller, bigger and smaller. That's pulse pressure as pull stretch. Very so whatever surrogate of stroke volume going to be using, you're going to get a positive response. We're not. A positive response in this case is very positive. You can see the stocks going up and down, up and down, and you could see the pulse practically bigger and smaller and bigger and smaller. That tells me that that person's definitely gonna be responding to fluke systolic pressure. Very speedy. But you have to eventually it it for this. And you want to be in science for their ways around that anyway. So you look again at the starling curve now, so this is what it would look like. This is a person that's more saying you're on the steep party or starting curve. Hence you are fluid. Responsive. That's the question we're asking. Are you fluid response? It Will you improve your cardiac output like giving fluid? And if you're on the steep part of your starting curve and your fluid. Responsive. You're going to get those swings and those swings could be either pulse pressure variations. Just so systolic pressure variations as you just saw or stroke volume variation. If you're measuring stroke voting there, was it doing? If, on the other hand, you're on the flat part of starting curve, those variations that we're looking for are not really gonna, you know, be present. Not, you know, there's a way of separating, and there's it's not quite a simple to sing it yesterday, though. There's they're different thresholds, but basically that's we're talking about. So one case, there's flu, responsive lot of sweet things, a lot of very interesting with the V stands for and your hands. You're not a full response, and what's interesting is you could even use a pulse oximeter. A pulse oximeter doesn't just give you the oxygen saturation. It sends a flow signal and gives you flow, and the flow signal actually looks like a pressure signal. It's not pressure, it's whoa. Okay, so you tell me which of those two is the signal from a heart Erie. A catheter And which of those two is the signal of a flow signal from a pulse oximeter that you put on someone's finger. Any idea? And I I think that's the point, Isn't that Yeah, they work the same. Do it exactly once the arterial curve and one's the fourth is a graphic curve. And don't forget to pull. This isn't a graphic curve. You don't need any fancy tools. Just put a clip on someone's finger. And in fact, some of the new manufacturers now are coming up with something called a profusion index, which is a way of quantifying the the flow in your in your foot is, um, a graph not be coming to a theater near you very soon. And so on the upper one, you had what they called arterial pulse fracture, which is a surrogate for stroke alone. The bigger the pulse picture the biggest struggle early for me, the pulse oximeter give something called the pop the pulse oximetry with his ma graffiti, and you can look at the maximum minimums just like you can look at the variations and pole specially to look at the variations in the pulse. Oximetry listen for this model for your pop so you can look at the maximum minimum and the more the swings er are are impressive. Great of swings, the more likely you are to be fluid, responsive. Both get curves, get similar information. So it's quite easy if you know how to look at this. Now, this is, um I just brought this up because I thought this is a This sounds very theoretical, but my God, this was useful. So I was involved with the first wave of cove it and we were told by, um, by various learned body's how we should respond. Now I have to be honest. It was it was new was a new illness. It was very scary. It was quite, you know, we're all pretty desperate and but we didn't stop thinking and we were told these people have a RDS and we looked at these patients. They said they have inflamed lungs. They were very stiff. The classic what we call as cute mus pretty distressing. Just very stiff lungs full of ah Dema Oh Exudates, etcetera, etcetera. And we looked at these papers. There are a lot of things that just didn't look right. Didn't look like the kind of pneumonitis you see in the RDS. But one of the things we we were told because they thought it was a hard es. They said We must try them out. So when they come in, get minimum fluid and give them diarrhetics to dry them out, even more thinking that that would be good for their look because you want to make them too wet. No, I have a I have an issue with that to start with. But let's forget my issue. But the one thing that we will noticed was guess well, let me. This is one of our leading experts describing that nine months after the first wave, what he said that we did wrong. We also forgot what we knew does someone was so dehydrated that they are higher hassled in order to try and improve the be able to will make for words. So we saw a much too much real failure. So what I was going to say there was that we saw because there was so many patients coming in because we had a lot of very young doctors, very scared doctors who didn't have time to put in various catheters like we just looked on the screen and saw the plethysmography swinging all over the place. And we said, I don't care what anybody says We're not going to give these people diarrhetics. We did the opposite where they told us that if we gave him fluid and try and reduce those swings and guess what we had half of the renal failure that most other units had in London. And if you get renal failure, recording dialysis, you're gonna more. Your mortality increases by a roughly three or five times pending on the studies, but definitely not good for you. But let's say three times your mortality is increased and after they stop doing this, the renal failure recording dialysis went from 28% to about 12%. So what you just heard they're in that video was again. I must. After this, this was a you know, let's look back and still a postmortem of what we did wrong. And what I can say with a little bit of pride is that we didn't do that wrong because we knew what we're looking for. Where this what you're teaching you tonight is exactly what we knew. We talked ourselves Well, I've been taking. We've been teaching ourselves. And we saw this. If you looked, it wasn't difficult. You saw. And you thought, No, this is not right. And we did. We got half of what everyone else got. Terms of renal failure. Unless more town. So, you know, don't be afraid to use your your knowledge. How do you get fluid? So how do you fluid load? Well, let's say I say this person, I think these fluid Okay, How are we gonna do it now? Again? It depends on where you are. You can give a small volume, but you've got to get it quickly. The smaller the volume, the quicker is gonna be. And you look at the response that you got to get the right response and you look at it quickly. You can't come back in half now and see what? What? You know, the response is you gotta look at it within a minute or five. Okay, But how do you fluid load? This is how we do it some of the night to you, for example. But you don't always have to be a night to you because we have more and more monitors coming on the mainstream now that are non invasive. We're semi non invasive. They're all kinds of monitors, and I haven't got time to talk about them all. But we go from the noninvasive, always the invasive, and you give a small bolus of fluid after having measured the stroke volume. And you see how that person struggle on response that fluid and again when you give the bolus to give a small volume but quickly so if you give a small volume, say, 202 150 mL over five minutes and you see an increased by 10% of the stroke volume, you know you're going up, the stolen her Do it again. 10% keep going. You're getting less than 10%. You know, you've reached the talk. You're starting to stop. That's how we give fluid. We test and we give it in a controlled fashion. So we're not gonna go away over the top of the starting that works quite well, or there's something else you could do. You can raise the legs. So how does that work? Well, if you raise the legs, you get an auto transfusion of about 300 mils more or less depends on certain factors. Um, but the good beauty of this is if you do that, and you make your either stroke volume or a surrogate of stroke volume, and you have to quickly, so it's not the within about a minute or so. You know that that person's responding. If you do it and there's no change in struggling, you just put the legs down and you haven't overloaded that. Not a problem. It's reliable. It works both in spontaneously bleeding patients, and those are not. But you've got to measure the right tool. Stroke volume or pulse. Pressure was, they said it was a surrogate of stroke volume, or you could use a puff is up mammography, and there are other things you can use as well. But you mustn't use the BP. That's what a lot of people make the mistake. It's like, Oh, look at the BP is going up or it's not going up doesn't tell you what you want to know, and you can. Even as I said, you can use it on spontaneously bleeding patients as well as a ventilator and and I to you, you don't always have. This is to get the most blood. So hence the greatest. The stimulus if you like. If you're sending recumbent night to you, which is what you should be and you do that you bring the thorax down and the legs up the same time. But if you can, if you're lying flat, you just lift the leg. You get less blood because you're not. You're not and training the splanchnic vessels, but it's still, you know, it's good. It works well. I do not use BP is a surrogate for cardiac output. Well, this is one of many studies that look at this on the X axis. You have the BP on the Y axis. You have the cardiac index, and you see what happens when you give. But somebody fluid. There's no correlation. BP to go up and ex card. It can't go Look. If you could stay the same and cardiac index and go up, pressure can go up on the cardiac index goes down. So it's not all over the place. There's no real correlation to to surprisingly, perhaps, And what about lifting them? Lift your legs is great. What about head down, You said Okay, so there are not a table tilt head down. Right? What doesn't work? This was one study that was looking at the right atrial transmural pressure when we talk about transmitting pressure was the bag of lettuce. They got bigger. It's a stretch. Is the pressure Grady in between the inside of the heart and the outside of the heart. But in the thorax, that's what causes the stretch of the heart. That's what is going to determine how hard your heart contracts that star are. Things look okay, Well, they looked at head down and legs up alone. So one's head, one's head down with legs up because you're doing the trendelenburg. You're tilting the table so the legs go up on the head goes down and the other just lift your legs up. You with the rep stays horizontal, and you can see the transmittal pressure goes up. You put legs up, but it doesn't get put them head down. What about the cardiac index? Strangely turned. Changes in cardiac index again legs up, it goes up, head down doesn't go down. And the reason is because, yes, you will get more blood going back to the heart if you put them head down. But you're gonna also increase the pressure in your thorax because all your guts are gonna be pushing up on your diaphragm and you're going to raise the interest. Arrest pressure's the radiant between the inside of the heart and the outside. The heart is not going to increase. So the CT people go up with the outside of the heart is not gonna get get any bigger. So you don't want to put them head down. You want to lakes up. So here's a patient. We had two story again. Remember this very well. Ah, a man who had upper drive, a major, a poetry out. Lied. He went for and ask me as an emergency. We didn't know about him at that time. We suddenly get a focal go downstairs cause there's a cardiac arrest. And then he was continuing to believe during the procedure, we were told, and they called the cardiac arrest E. And that was, uh so And we were We went downstairs and we said, um, rapidly putting fluid. The cartridge must appear to be ineffective, that we assess that on several parameters but the most important. We looked at the entitled Oh two. What and you had you was dropping. Fluid infusion. Big foot fluid infusion wrap include infusion. Well, he's obviously has an empty circulation. He's been bleeding and he's carrying on bleeding to the point where there's a cardiac arrest. They're confusing with fluid, and the cardiac massage seems to be ineffective. There's no entitled. There's no so two coming out of his energy. Kill two comedians that was getting no flow going to his right heart. Well, I would say the reason would be Anybody want to take a guess? You Who is the mean, certainly compression. Okay, let's Let's hold on. Hold on that for a second, okay? And what should you do? Cooled on it. So here's another similar story. This has been known for years. I did trauma for several years, and we know one thing that someone who comes in after trauma when they're high Covalin they make and have a cardiac arrest. They almost always die. You know why? Same reason the reason is, and what should you do? The reason they do they die is because they're massaging your heart. That's empty. If your heart is empty, you could pump all day. There's nothing to pump, so why do they not succeed? The previous case didn't work. They weren't getting any success because they were wrapping, but yet they were rapidly infusing fluid. The reason was was because it takes way too long to rapidly infuse food rapidly infusing fluid at the best. If you use a pressure bag or, you know one of these fancy pressure systems, you'll get about 200 mils in and minutes. That's way too slow. So what did I do with the case? That previous case, because I was involved in that, created this case and I did something. And immediately the the massage got better. So two from his skill, too improved. It came up. Which means that I was getting blood full of Coatue circulating to his lungs and he actually went home. What did I do? Raise the legs? Yeah, I raised the legs immediately. Is 0 to 1 up, and that gave them time to. Then they give him some vino from be know, pressors, and secondly, it came time to keep filling him, but I just raised the legs that would hopefully fill the presumably filled the heart. So now they have something different side. So if you ever get in a situation like that, never forget. Just raised the legs. It's very quick and it doesn't cost you. Okay, here's, ah, their clinical case. And see what? Like a cataract on this one. So there's a 72 year old male past history of just hypertension, not a big deal fever for a couple of days. And then he has a lower urinary tract. Symptoms of a UTI tract infection symptoms. Now he's confused. He's modeled, so it's perfect. Profusion is terrible. Is temperature's very high. He's got a very painful rectal examination. So you probably got prostatitis Is respect to rates a little bit fast. Heart rates a little bit fast. Blood pressure's low and saturations. Okay, Would you test this man for fluid? Responsive. We have students in the trouble saying guess Okay, let me ask you a question. What do you notice that his BP. What? Strike two. It's very low. What's very low? Diastolic is very low. Yeah, No good man. That is great. Glad they gave that answer is diastolic BP. That tells me a lot We're gonna talk to you. Want us to serve? This was I sort of add this on to the end, but I think this is so very important. Let me quickly tell you. Ah, Anamika Dota story that really breaks my heart were obsessed with diastolic pressure. I work and you could see so much. Just looking at someone is nice because most everybody ignores but we went to We had a mortality and morbidity meeting one day between the pediatric team that we had one in our hospital and the eye to you. And there were excellent doctors and they talk about one of their cases we we don't know any about. And it was a 10 year old girl who had been in their care for a couple of days, and she was very own. Well, previously, help you. And they couldn't figure out what was wrong with her or how sick reports. But he wasn't getting better. They took her downstairs for a CT scanner and well, he was in the CT scan, but he had a cardiac arrest and she died 10 years old previously. Help truck Anyway, they put on the screen all her parameters over the last day or two and without wanting to be. I told you so are smart Alic. One thing I noticed was that for the last day and a half, two days had a really low dose salt pressure. They hadn't even noticed that. And that immediately told me something. Give me a lot of therapeutic and diagnostic information and they didn't even look at that guy. Stop pressure. So I'm gonna I don't want you to make that same mistake. So I'm gonna tell you briefly about how incredibly important you diastolic pressure. So what does it do? It helps with diagnosis, and it helps you a treat. And the diastolic pressure depends on two things. It depends on your peripheral resistance, which determines the slope of going from systolic to diet. So it's like a ski slope steeper the ski slope, the faster you're going to go down, and that means your dilate it. The less flat it is, sort of flatter is not steeper. The flatter is you're going to go down a lot less with on a ski slope, and that means your constricted. So someone who loses blood the first thing that happens is there? Diastolic pressure goes up because they're vasoconstricting. When you're dilate it, you're gonna have a low diastolic pressure. Okay, So what happens for the same heartbeat? Okay, we're not going to change your therapy yet. You see, you get a steeper slope if you're dilate it and you drop diastolic pressure drops. So what are the causes of a drop in your peripheral resistance? Anybody commonest one by far? People impression. So hypertension, No attention doesn't raise your doesn't drop your BP. What drops your diastolic pressure. So he's a dilation. Yeah. What causes that? What's the commonest course? Um, like big point. Anybody want Teo intoxication causes from? Yeah, sepsis. But why the the to commonest cause that we see sepsis by far. 1st, 2nd, 3rd receptions. And also cirrhosis the liver. But sepsis causes massive vasodilatation. The previous case that you saw when I asked you what would you do? Would you do a fluid? Responsive or not? I'm say, Know why? Because the diastolic pressure was low right away. This man office was septic. If he's septic with a low BP, low diastolic pressure. Well, the first thing I do when I'm resisting him. Yeah, I'll give him some fluids. Definitely. Give it some venous. Oprah is a swell because he's massively dilated when we talked about the size of your mattress. So I'm gonna try and make that they're mattress small. I'll give you some fluid, but I'm definitely gonna give him some vans. Oh, some venous pressures and the reason I know that because I saw his load, I stopped. Okay, so that's one of the things that determines you don't stop pressure and the other is your heart rate. So for the same slope, if suddenly go from a 60 beats a minute to 100 beats a minute, I'm going to get a rise in my diastolic pressure. So the little girl I was telling you about who was 10 years old, who died in the CT scan, what struck me wasn't just that she had a vote. Very low diastolic pressure. That number with the number was it was very low. But the other thing that struck me was that he had a really fast heart rate was very tachycardia, which means the tachycardia should raise her diastolic pressure. But it was still very, very low. It means that you must been massively dilated. Okay, So again, going back to that, it's like it's like a the steep. You want to think that was a ski slope? If you make the ski slope, uh, steeper and you have a seat, you have a minute to go down the ski slope. You're gonna go further down than if the ski slope is found. It flatter for over a minute. Let's see. Okay, so the fake same time. But on the other hand, if you have the same ski slope But I say now, instead of going down for a minute, you're only going down from 30 seconds. Then you're gonna go down less far for the same slope. So those two things are going to affect how you what your diastolic pressures. So last question. Patient a patient be heart rates 1. 30 are 8. 70 and they both have the same diastolic pressure. What do you think about the arterial tone of these two patients? Well, we're more worried about the diastolic inpatient. A right? Why? Because the high heart rate should be raising their diastolic. So if they have the same heart race patient be with much be much lower Exactly that we have with the girl. She was a young girl, 10 years old. He had a low diastolic heart rate. So that means he was massively message. He dilated. He was so something that hurry. It was only one thing I would do. That was sepsis. Well, as you said, you get the right answer. I'm sorry. It's Is he more depressed for the exact reason you gave Bravo? That was really good. So to recap this quest number one is the cardiac output adequate? But we're okay, so yeah, but it's no. Then you want to get to the top, you're starting curve with fluids, and you want to predict if they respond to food or not, unless it's really obvious. Or you give a small bullets and they don't respond if they're ventilated or if there's continously breathing. If they're ventilated. You want to look at those variations? We talked about the breathing. You would look for a drop in the CD pee or you want to look it with ultrasound. Look at the internal jugular, or in both cases, you can use passive leg raising, so please raise the legs to see how they respond. And if they respond well, you get fluid. If they don't respond well, when you use on the troops and you re assess again, can you want to make sure you get a reading on a fluid Too little, too much or bad for you? You want to be optimal gossip. Remember, half of the people you're gonna be treating who are sick gonna respond. But half of them are not. So basically, don't guess because you were looking up calling if you guess you'd be right half the time. Maybe you want to see where you are on the starting curve by looking at those variations when you're ventilated. Don't forget the venous return physiology that's gonna help you understand how these techniques work. Don't forget you have to assess the peripheral circulation. Once you retrieve your macro circulation, don't go. Don't go off for a cup of coffee. You assess their micro circulation. Maybe the capillary refill time you can use leg raising. That's a very good technique, is a diagnostic but also therapeutic. Remember, people that have empty heart will not respond if you don't. Giving fluid through an intravenous line is too slow. You want to raise the legs and then when you buy time, then you start getting were coming to me. Don't forget the diastolic pressure. That really helps a lot. I find it's really useful. People often just totally ignore it so we can check. Last thing. The question you want to ask you is Are you fluid responsive or not? Don't Symbicort. And that's it. So if you have any questions, I'll be delayed an answer. We do have a couple in the child on someone has raised their home. Um, I bought a If you'd like to meet yourself, you can ask the question. Yeah, I know, but if you're trying to speak, we can't hear you. Um, could you just check you if you're Michaels liking? If no, I think done. If you'd like to go ahead. Um okay. Um so when you're using the StarLink of, um, obviously it's kind of a spectrum when you're in that middle portion about whether they are fluid to responsible. No. And are you gonna be more eager to get fluids and what we may consider non responsive if you're trying to preserve, say, kidney function? Or do you do you tend to stick to your 10% rule all the time. You know, these air just, um general rules. You obviously look at the patient. You have to assess the situation. I think one of things I didn't kill you once was Sometimes you are in a situation work. For example, I have somebody who comes in with really severe pneumonia and they're saturations are very agree. No parlous, the very iffy. At the same time, they're cardiocap. It's not ideal. And the problem is, you can have to ask yourself which of the two are your more willing to risk of low risk Arctic output? We're, ah, less than perfect saturation, and someone's life is in perfect. I think. Remember, the very first talk I gave was on oxygen delivery. Don't forget, that is the ultimate goals oxygen delivery. So sometimes you have to decide. You know, what's the what's the best one to change for? So there's no absolute, you know, I must get to this point. I must get to this point. It's just what I think I'm trying to say, really, is that too often we see people who are just basically guessing and We're trying to make it worth an intelligent guess. You're roughly know where you are. That's more. Thank you. And you took that. We do have, you know. Oh, yeah. We can hear, you know, Um oh, wow. So the time I've been on so much to be here. Okay. Thank you so much, Doctor. That opportunity to, um, talk on this remarkable session Thank you for the recaps segments is. Well, um, I just wanted to say or maybe just give biggest ox is a zoo. Been any situation where by when you had raised the legs. I know. Obviously you returning not back to the heart and stuff and holding that doesn't work or anything like that. Maybe. Let's see, they have an accident and legs or the legs are fractured or things like that. Yeah. Yeah, of course. Well, you do. Yeah, that's a good question. Um, so what you could do again? This is where I really like to emphasize the venous return physiology. Because what you're trying to do is you're trying to quickly mobilize the blood that you have in your venous circulation to fill the heart. So if you're massaging, you have something to massage. Now raising the legs is pretty quick. But if for some reason you couldn't, the other thing you could do is remember we talked about the air mattress When I talked about venous return. You can give a small dose of Nordgren Elin vino constricting dose. Remember I said to you again, it's It's all you know. It's all a thought experiment. If you had, if you had that area mattress and you could suddenly make it half the size you're converting the unstressed volume that that volume of fluid or gas in the air mattress case that's not stretching the walls and you're making it stretched the world you're converting unstressed volume Too stressful you. So a very quick way of doing that is giving a small, small dose of vino constrictors like more adrenalin freeze up. Not big doses that will cause arterial constricting venoconstriction doses that's becoming more and more popular. But so that's the other thing you could easily do. Yeah, I would do both, in fact, if I could, if I couldn't live the rest of the legs, first thing I would do is give a small dose of of, you know, a strong veto constrictor like Northern. But what I'm saying, I think the point is, don't rely on just getting fluid if your air mattress is very big. Okay, so it's a venous is venous systems two dilated or it's empty. Then it's gonna take you way, way, way too long to fill it with fluid, the way we normally get fluid. You've got to get in quickly, and then you have time to do it. You can't. You have to fill that heart. The heart's empty. You're not going to thank you so much. So thank you. Doctor Muhammed asks, Is there any hazard of raising the legs? I seen he means of a sudden what? Must overload? No, no, no, that's not You know if for some reason the person didn't respond, okay, you just put him down. I don't know if you remember the case of the guy with cardio dreaming shock I told you about. He was the most dramatic case because we really thought that if we gave this man fluid were very, very likely to cause him to get worsening pulmonary edema, you know, right, we do it and that will kill him, and we lifted his legs thinking that was the best way to do it. If you doesn't get better with this lowers legs. In fact, everyone's amazement his cardiac output went up massively. So he really responded. That was a really good way of testing without taking your vital risk. I thank you. Mama is saying, can you explain the patients and b again? So I think that was regarding the, um, tachycardia and non tachycardia with the diastolic if you are able to get those slides back up. Yeah, I could do that. Yeah, sure. Uh, let's see. What is it? Okay, so it could be Look who him. Okay. Yeah. So this is just explain this again. So your BP normally is your systolics. On the top of that peak in your diastolics are the bottom. It says D A p. What determines your diastolic pressure are two things. One is the slope from the top of the systolic or the top. They're right to the bottom, and the slope is very steep. Just like a skier going down. He's got a steep slope is gonna go way down over over a minute. Let's see. Okay. And if on the other hand, the slope is flat over a minute. He's not gonna go down as far. That's obvious. On the other hand, if you have the same slope, this slope doesn't move. Okay, But what? And you suddenly say instead of going down for a minute on your skis, you're only going down for 30 seconds. You're not going to go down as fast, so you're gonna have a higher diastolic pressure. So we look at this, there's a slope that steeper. You get a drop your diastolic pressure for the same time. Okay. The other hand, if you have a shorter heart rate, you're not for the same slope. You're not gonna go down. This part of your diastolic pressure is going to go up. So in the case that we described here the week we had two people who had the same diastolic pressure, I don't know who answered the question correctly, but they did very well. They have the same gonna start pressure. So who which of the two was more? Dilate it. One patient in a has a fast heart rate. Pain could be, has a slow heart rate, slower heartbeat. So the patient with the faster heart rate or two right raise their diastolic pressure. Okay, cause fast heart rate. Raise your dose, though. Pressure, we said. And that means that if they have the same diastolic pressure 40 40 then the person in a want to have a much more dilated system because he's artificially raising his diastolic pressure. So it means he's massively dilated. If he had the same heart rate of 70 patient had 70. His diastolic pressure be much, much lower. Okay, And that helps. But yes. Um, um, if you let us know in the tract, if that's helps, that would be great. So she says, Thank you. Um, brilliant, Mohammad said. What should the target BP be when you're doing for your resuscitation? Oh, oh, boy, that's a tough one. Um, that's been debated for years. So if people ask for a magic number, I want 65 mean Okay, I don't know why they say that. There's no evidence that there's not a lot of evidence for that. I would say, you know, if you get it depends. It's very complicated, because if someone's bleeding in the ongoing bleeding, uh, you want to you know, you've heard of, Ah, permissive hypertension That's on the way to the hospital, you know, But in the hospital itself, I'd say you going for a BP that would be adequate to I would go something simple. Are they able to maintain? Are they able to, um are they perfused peripherally? Do they have? Do they put produce urine? You know, those sort of things. But if you want a magic number of people for some reason to say 65 me, I don't even know why they say that. That's what they said. That's what the guidelines. But I would take that with a big interest all Thank you. I've got one last question, which is about the Venus peripheral resistance, which we've already said. It decreases when you have basic dilation, and I'm wondering if you get fluids inappropriately. Um, it's a good venous peripheral resistance, understand? I just did, uh oh, okay. For peripheral resistance on. And if you get fluids inappropriately, um, are you gonna thin the blood to any extent that it will decrease resistance further and make the situation worse with is not Not really, that's I think you have to do it. You're right. If you're this cost is very low because you're very You've done a lot of chemo delusion. You will get a drop in diastolic pressure, but I think it's gonna be minimal compared to the you know, the the you know they are charging. You got me seeing the arterial. Don't take sorry. Don't forget somebody. Keep repeating this. Everybody gets this role. If I were to put a cannula into you to your artery and let the blood just completely pour out and it had a BP cuff on the other side. Right. Another arterial catheter on the other side of your arm. And I kept watching you bleed to death. Very first thing I would see. Very first thing I would see was your diastolic pressure would go up not down up because you're vasoconstricting to try to compensate. So vasoconstriction does the opposite tube as adults. Brilliant. Thank you very much, Doctor Vogel. Let's was very interesting and very challenging as well. Thank you for giving up the time again. Well, very appreciative. Okay. Thank you. Have a good night.