 Okay, so let's move forward, our last speaker for a faculty program, Dr. Kim Buzinski, an aphrologist at the university, was able to be on the hospital service this morning and come over and meet with us this afternoon. So assessing kidney function, how much do you really need and how to preserve what you have. Thank you. Okay, can you hear me? Yes. All right. So I'm an aphrologist and that means my job is to deal with how the kidney functions. No glamour. I can't carry your tumor, I can't knock it out with ultrasound or some waves, I don't have the skills to cut it out and I don't give radiation and I don't give chemotherapy. So I get the dregs when everything is left over and my job is really to preserve the kidney function that you have. And the key thing is that if your kidney is normal aside from the tumor, you don't need me. So the real problem comes in is if you have some other underlying kidney disease. And what I want to talk to you today is how we assess kidney function, try to give you some idea of how much you really need. And so I've got some specific, if this is working here, sorry, objectives, I want to tell you what the kidneys do. And I want to talk a lot about how kidney function is measured because you're a smart group and nowadays people get their labs and they look at it and they try to interpret it. And I can tell you the way we measure kidney function can be pretty scary on what's in those reports. So I want to tell you why this has come about and how to interpret them a little bit and then I want to talk a little bit about how to preserve the kidney function that you have. So just for orientation, very simple. You know you got two kidneys, they sit in the back, the kidneys make urine and you know they make urine all the time and it drains down these tubes called ureters and collects in a bladder. And if you look at the diagram here, the blood coming out of the heart through the aorta goes through this renal artery. And when I say renal, all I'm really meaning is kidney. So if I use those terms interchangeably, don't be confused. And so the kidney, as I said, works all the time making the urine. And I think the bladder, even though I'm a kidney doctor, it doesn't get enough attention because imagine if you didn't have the reservoir to collect that urine. You would be just continually dribbling all the time. And so you've never thought about it but you can drink something here today, get on an airplane and then you can take your urine across country and deliver it. So you've got this wonderful transport system that never gets any credit. But we're going to focus on the kidney and I want to talk first about what kidneys do and it's very simple. Kidneys are blood filters and they are designed to remove waste. And the waste that they remove is in food. So you get the chunky stuff out in your stool, right? But the food that you absorb, your body doesn't need all of it and so the kidney goes through and gets rid of that waste. The kidney filters out drugs and it filters out old body parts. The cells that you have now are not what you were born with, they are turning over. And somehow you have to get rid of that waste and the kidney takes care of that. And the kidney is equipped with very specialized sensors and regulators. And this is a list of what they regulate. They regulate the fluid in your body. And if you drink a whole lot, you're going to pee a whole lot. They regulate how much fluid you need. They regulate what I call body salts. And salts in a general means are just positively charged ions such as sodium. You've heard about table salt, potassium, which is a common salt substitute, calcium, phosphate, magnesium. The kidney senses how much your body has, what you need and whether or not it should hang on to some or just get rid of it in the urine. The kidney also controls blood pressure. And the idea is the kidney, if it doesn't think it's getting enough blood to filter, it releases this hormone called renin. And this renin in turn goes and releases some other hormones and this brings the blood pressure up because the kidney really wants to filter your blood. And if it doesn't get enough blood flow, it's going to try to bring more to it by raising your blood pressure. Good or not, kidneys are responsible for red blood cells in many ways. Now the red blood cells are made in the bone marrow, but if that kidney doesn't think that it is getting enough blood, it puts out a hormone. It's called erythropoietin. And this erythropoietin is a growth hormone for red cells. So it goes to the bone marrow, it says make more red cells. So people who are anemic, that's where erythropoietin will come in to make sure that you correct it, anemia, just being that you have low red cells. And the kidney is very sensitive to bones. You probably didn't figure out that the kidney regulates your bones, all right? A lot of times it's trendy, measure your vitamin D, you need vitamin D for your bones. That vitamin D is not going to do you any good if your kidneys don't work. The kidneys actually have to convert it to an active form. And there's other hormones, such as the parathyroid hormone and calcium and phosphate, all of which the kidney regulates. And a final thing that it senses and regulates is the acid in your system. Our bodies like to run at what we call a very neutral pH. And most of our food has a lot of acid, and so the kidney is responsible for getting rid of that acid. So the kidney does a whole lot. So how does it filter to do this? Well, we have these filtering units in the kidney called nephrons. I'm called a nephrologist because I care about nephrons. They named them after us. And so the idea is that you have that blood coming from the aorta into the renal artery, and it goes out through smaller and smaller blood vessels into this little structure here. That is a filter. And in this filter is where the magic happens. And urine is actually made, and it's collected through a series of pipes that comes out to the ureter and goes to our friend the bladder. So you can deposit it wherever you want. And this filter is called the glomerulus. Glomerulus, a big kind of word there that's sometimes hard to say. And every little filter is hooked up with a series of tubes. And it's the tubules that really sense how much fluid do you need? How much of those salts do you need? How do I get rid of that acid? And so this combination of a glomerulus stuck to a tubule is called a nephron. You get two parts to your nephron, the filtering. You gotta collect the urine that's actually being made as the blood is filtered. And you have about half a million of these in each kidney. They go down in age, sorry to say, but they kind of wear out. And to show you how important it is, every time your heart beats, 20% of that heartbeat goes to the kidney. So my kidneys are these tiny things. I have legs, I have this whole rest of my body. But 20% of the heart output from the heart is having to be filtered. So it says that these filters are pretty important organs for the body. And nephrons go down with kidney disease. And for you, if you lose a kidney, you lose half the nephrons you have. All right, just a nephron loss. Now we're gonna talk about this filter unit, which I've depicted here. And this is the tiny blood vessels where the filtering is happening. And I've got a diagram over here. And the whole idea is you take unfiltered blood through these vessels. These red dots, if you can see them up there, are the cells. And then you have these little particles, we'll just call them waste molecules. Whether they're body parts that are old food that's not needed, whatever. And they go through this filter unit where there's some tiny holes. And I'll actually show that to you in a minute. And what happens is that you make the urine. So the small molecules can pass through the filter. They come out in the urine. And the large molecules like red blood cells, not a molecule, but cells and protein will leave the kidney and they don't come through in the urine. So you have the filtered blood that comes out of the glomerulus. Now if we take a little picture right here through that blood vessel. Here's that blood vessel here, it's got a cell kind of holding it. And inside the blood vessel are red cells and proteins and little waste molecules. And if I slice through this and look down here, you see all these tiny holes. Like a colander that you're washing fruit. And it's the idea that the waste molecules will go through these tiny pores in this filter. Whereas these larger structures, protein that I've depicted in green and the red cells, should not go through the filter. And the rate at which these waste molecules go through the kidney is called the glomerular filtration rate, GFR. And so when you're asking yourself, how is your kidney function? Like people would want to compare their cholesterol, you should ask, well, what is your GFR? Because that's how we actually determine what kidney function is. By the rate at which the waste is filtered through the glomerulus and these tiny holes. And you can imagine then, one sign of kidney disease. If I start seeing blood and protein in my urine, that means I've got some problem with my filter. These holes may be larger and damaged. And so the cells can actually get through the filter. Now, kidney function is measured by this glomerular filtration rate. And it's got a funny kind of definition. It's the volume of blood that is completely clear to some substance that's filtered. And quite frankly, it is very difficult to measure. It's very hard to put little probes into those little filters and actually measure what comes through. Although historically we used to do that with rats. So rather than measure it directly, we estimate it. And we estimate it by something called creatinine. Now, creatinine is just a breakdown product of muscle. So muscles are always being formed and broken down. And the creatinine that comes from the broken down muscle goes into the kidney, and it is filtered out and comes in the urine. And what you can do is measure the blood creatinine. And then you use a formula to estimate glomerular filtration rate. Or what you can do is collect all of the creatinine that comes through your urine, like in a 24 hour urine collection. And you can get an estimation of your glomerular filtration rate as what they call creatinine clearance. So the idea is that if you have some sort of kidney disease, something is injured here, the kidneys aren't working. Creatinine will go up in the blood, and you don't eliminate it in the urine. And the key thing to remember is that creatinine is just merely one marker of the many waste products that the kidney gets rid of. But it's one marker that's acceptable. And so this is what you're actually going to see if you're looking at your lab reports is this creatinine. But it's representative of hundreds of other things that the kidney actually removes. So let's look at a lab report. And this is a standard lab report from the University of Washington where I work. And we've listed several labs here. And you notice that there is a creatinine, all right? And you see this GFR, glomerular filtration rate. So now you kind of know what that is. And where does that come from? It comes from a formula. They took the creatinine, plugged it into a formula, and they spit out a GFR. Now you look at this, and you say, oh, they're non-Blacks or they're African-Americans. And you get two different numbers for your GFR. So what's all this about? Well, it turns out that back in 1999, there was a group of investigators, and they were trying to find ways of estimating glomerular filtration rate. So they did some experiments, and they were experiments done with people who had some kidney dysfunction and looking at diet. And to get a real glomerular filtration rate, we have to inject you with a radioactive substance. And then we watch it go through the kidneys by counting that radioactivity as it comes out your urine. It's called isophthalmate. So they did that to this group of patients. Half of which were white, and half of which were black, and they were all Americans. And so what they found when they did this is they went back then and tried to figure out how can I get a glomerular filtration rate by an equation. Let's derive an equation that gives me this value I actually measured. So they have this complicated equation that has a bunch of exponents. But what they found is that it was different if you were African-American, or if you were Caucasian-American. So that's why you get two different numbers here. Now heaven forbid that you're Asian, heaven forbid that you're old, heaven forbid that you were young, and you weren't one of these study populations. Doesn't matter, this is where the equation came. And it actually has been quite frightening because it means that most of us who are over 60 are all sort of destined to have kidney disease when you plug this in. So there's been some real problems in doing this. But this is out there in the labs, and it started to come out probably within the last decade or so. So you have a creatinine, but they're translating it to you by GFR by using an equation that's based on your creatinine and your age. Now why would anybody do this? I mean, this is just really silly. Well, we went out with good intentions and there's always this idea you have good intentions and then something goes awry. And the problem we had here is that we wanted to have providers, physicians recognize that when your creatinine goes from 0.8 to 1.2, say just a small change of 0.3, look what happens to your glomerular filtration rate. It goes down a whole lot, right? So what happened is that most providers were ignoring these small changes. And that means that people were developing kidney disease and nephrologists weren't seeing them till way late in time. So that's why they decided to also put out a glomerular filtration rate to alert people that are looking at labs that there may be a problem going on. And you'll also notice here is the older you get for the same creatinine, your GFR is less. So the idea here is small changes in creatinine show a significant loss of kidney function, that's why we went to GFR. And even though the equations may not totally be applicable, they're out there and you're gonna see them and they can be somewhat frightening. And as I go up higher in my creatinine, my GFR goes down. It's actually kind of funny that when you go from a bigger change in creatinine when it's higher, there's actually less loss of glomerular filtration rate. So up here is normal, and everything down there is a little less than normal. So what has happened, even though this estimated glomerular filtration rate by this equation may not be the best thing to have in there, that hasn't stopped us from using it. To give you sort of the normals, if you have normal kidney, your creatinine, this marker for toxins should be less than one. And your estimated GFR is about 100, that puts it really easily. If you make no urine and your kidneys are shut down, your estimated GFR is zero. And we say that you just have in-stage renal disease and you need some form of replacement to survive, dialysis or kidney transplant. But then what my colleagues did is they decided to assign stages of kidney disease. And sometimes you're gonna see these on your labs, and that can be kind of frightening as well. So he said we had five stages. The first couple stages, the glomerular filtration rate is still pretty good, but they've got some protein in your urine. So that means that filter's gotten leaky. And as you go higher in your stage, your glomerular filtration goes lower. And when you get here is when you start having problems eliminating the waste and the fluids and all of a sudden you get anemic because you can't make red blood cells and your bone metabolism gets all off. So this is when the nephrologist is really heavily involved. Although if there's a problem, we'd like to see it here. So we don't go this way. Okay, and just if you're curious for a kidney transplant, if your estimated GFR goes below 20, you can actually be listed for a transplant at that time. That's sort of the tipping zone, even though you're not necessarily needing renal replacement then. So what will cause kidney disease? These are our main causes, diabetes and hypertension in the US. And you read through this list. Notice it does not say renal cancer. There is no kidney cancer up here. So the fact is that if you don't have diabetes, hypertension, or one of these other disorders, the chances are that the kidney that you have is normal once they take the tumor out. Now, the issue is if you have one of these diseases, then there's a chance that the tumor, the non-tumor tissue in your kidney may have a problem as well. And that gets to be a concern. So diabetes and hypertension are major causes of kidney cancer. If your heart doesn't work, if your liver doesn't work, you can't get enough blood flow to the kidney and that causes problems. Certain chronic infections can cause problems. Pylonephritis is a kidney infection, osteomyelitis of infection of the bone. Certain blood problems like myeloma and amyloid. Certain drugs can cause kidneys not to work. You think that the anti-inflammatories, ibuprofen, naparicin, and large doses aren't so good. You can have diseases that are just within that filter unit. You can have genes that will give you kidney disease. You can have narrow blood vessels. So again, you can't get the blood to the kidney. And if you can't get your urine out of the kidney and it backs up, that will also cause kidney problems. Now, this estimated glomerular filtration rate, that's what this E stands for, is used to stage kidney disease. So I just said if you don't have a kidney, if you don't have full kidneys, you may have a low GFR, but that doesn't mean you have kidney disease. And the lab does not distinguish that. So you go in and you get a blood draw. They give you a cramping and they assign you this estimated GFR. And here were those stages of kidney disease. And if we look at what kind of level of kidney you function you have after an ephrectomy, you start off when you got two kidneys. Your estimated GFR is 100. Totally normal here, right? If you happen to not be able to be eligible for one of these partial removal procedures and you'll have to lose a whole kidney, your glomerular filtration rate goes down to 50. And lo and behold, the lab is going to tell you just based on your creatinine and your estimated GFR that you have kidney disease. Stage three, and that's really not true at all. You just have one kidney. If you happen to be the unfortunate person who had one big tumor and they had to take out a kidney and then you developed another tumor and they had to take out another little bit. So that you now have just half of a kidney, half of one kidney, your GFR goes to 25. Well, that puts you at stage four kidney disease on these lab reports. But really you don't have necessarily stage four kidney disease. You just have one nubbin of a kidney that may be working very well. So I go over this because one of the things that happens is since we introduced this system within the last decade, people who are knowledgeable like yourself start looking at your lab, start interpreting it, and it makes you very nervous. And I can tell you that even some physicians who are outside the kidney world don't know really how to interpret these. Because we also get a lot of referrals from other primary care docs saying, hey, I have this lab report now, what do I do with it? Because it says that this poor person has kidney disease, which they may not have at all. They may just have a partial kidney. So how do you know if you have kidney disease other than a kidney cancer? There I think there has been discussion here trying to minimize the amount of tissue that's removed. But if you have an nephrectomy, there is non-tumor tissue that comes with that that can be very valuable. So this is a kidney that was cut out and they opened it up. We call it bivalve, like a clam. And this is the tumor down here, right? It's opened up and here's the other part of it. And this is your normal kidney tissue up there, all right? And here's another example that you're very kind. The urologists are always nice, they take out as much fat as possible. So you get a little bit of an extra work here. This ink around it just shows us the margin of the tissue that's taken out. Here's your tumor right here. And here's all this normal non-tumor tissue. So if you want to know, if you have any kidney disease, all you have to do is look at what they took out from you. And they can put it under the microscope and say whether or not there's any disease there. And so if you're someone who, say, has high blood pressure or diabetes or some other kidney problem, then what they should do is just look at the non-tumor tissue and you get a pretty good idea whether or not you're gonna have a problem down the road from a kidney disease. Sometimes we forget about that. And we can always go and pull out the slides and look at it. But that's useful information to have. And the pathologist just examines this for us. So I've talked to you a little bit about what kidneys do, how we measure kidney function and how frightening it can be because the numbers that you read in the labs really may not apply to this very special group. So if you have some other kind of kidney disease, something other than cancer, then you probably need to see a nephrologist. Someone like myself who works with the kidney function. And if your remaining kidney is actually very good, then we do what we call renal hygiene. And someone was asking about some of these things earlier. And these are things that are probably good for all kidneys that have some reduced glomerular filtration rate. You go on your blood pressure control. Our goal is less than 140 over 90. So if you're someone who's not controlling your blood pressure, then maybe it's worth making sure that control is good. And you never know if your blood pressure is controlled unless you check it. And you really need to check it when you're at home doing the activities that you're doing. It really doesn't matter what it is when you come and see the doctor. It's every day when you're doing your regular business. You want to try to avoid some what we call nephrotoxins. We think that ibuprofen and naprason are not the best drugs for the kidneys. But you know, if you've got bad arthritis and if you're getting a little older and now then you need a dose, it's not going to probably kill the kidney or hurt that much. You just don't want to be using them on a daily basis. We try to avoid some of the contrasts that she used with CAT scans. Again, it's not 100%. There may be a need for it. And there's ways we can go about giving it to you and so that it doesn't injure the kidney. Somebody asked me about sodium. I'm sorry. Low sodium is worthwhile. And not terrible. But if you start looking at packages for everything you put in your mouth, you will find that our diet is typically high in sodium. And if you're eating all your meals out and if you're not looking at labels and you're doing canned foods, you're going to find that you're probably pretty high in your sodium content. And then there's these medications that somebody else had brought to my attention that I talked about last year, the prills and the sartans. And these drugs are actually used to treat hypertension. But what they do is block this hormone called renin that the kidney makes when it thinks it's not getting enough blood pressure. But it has some other effects. And it reduces what we call hyper filtration. So here's what happens. You lose a kidney, but you still have 20% of that cardiac output from your heart go into whatever kidney you have left. So that nubbin of a kidney, if that's all you're left with or the other kidney, is going to take all that blood flow. And the problem is that it may actually filter too much. And so I've got a diagram here. This is that glomerulus I talked about. And this is what normally happens. The blood comes in, gets filtered in this glomerulus and comes out. And you make the urine that gets collected here. And if you're hyper-filtrating, you get more blood flow. And where that filter unit goes in those blood vessels, they start spreading. Think of a balloon all of a sudden filling with too much fluid. And it can pop. And if it pops, you can get some scarring. So what these drugs, called prills and sartons, do is they go to this blood vessel on the side where the blood would be flowing out of the glomerulus. And they open it up to let more blood through faster so that you're not hyper-filtering. So what happens is the blood comes in. But this area right back in here gets spread wider so you can get blood out faster. And so that's what we think. We know these drugs do that. And they help them prevent this hyper-filtration. I did not say preserving kidneys and how much water you need to drink a day. So how much do you? And it really depends on how thirsty you are. And your thirst is triggered by sodium. If you are going to eat lots of sodium, you are going to be drinking lots of water. And the key thing is, is if your kidneys are working normally to get rid of the amount of toxins that you have in your body, this is all the amount of urine you have to make each day. So this business about drinking tons and tons of water, don't do it. You can if you like to drink water, that's fine. But the reality is you don't have to be forcing leaders and leaders of water to help whatever kidney you have there. In fact, it sometimes can make it problematic. There are a couple of exceptions to this. And one of them is for the person who has kidney stones. So if you tend to form stones, we want you to drink a lot of water to dilute those salts so they won't make them stones. And another case is if you're getting hydration, say before some sort of chemotherapy or contrast. But when we say hydration, then it's just not water. It's salt and water, which is another topic of discussion. So assessing kidney function, how much do you really need? I've tried to tell you about how the kidney filters to remove the toxins, adjust your fluids, adjust your salts, that this filtration is actually measured by creatinine, but we translate it into glomerular filtration rate. So how's your kidney function today? It's like, oh, what is your GFR today? And that's what you're trying to exchange. If you lose one kidney, your glomerular filtration rate goes down 50%. Consider yourself a kidney donor. We take out one kidney from people for transplant frequently. And those people who have one normal kidney live long, healthy lives and usually have no problems whatsoever. You can get by with probably 25% of normal kidney function if you practice some good kidney hygiene, controlling blood pressure of your sodium, avoiding the nephrotoxins, and trying to prevent this hyperfiltration with some of those drugs. And with that, I want to thank you for your attention. My name is here. My pager is on 24-7. And I do respond. And I have an email. So thanks for your attention. And preserve your GFR. And with that, I'll take some questions. Yeah? I'm on a little sartan. Yes. I don't know all your other problems. But for kidneys, that would not be my favorite combination if you did it regularly. But again, I'd have to know more of your history altogether. So if your kidney function is OK, you maybe are right with that. Now, the sartans, they actually may be good for your kidney in that case if you're taking a lot of non-steroidals. So if you have really impaired kidney function, you can preserve what you have by reducing your protein intake. So I sort of line it up as you can have one steak, but don't have two or three. I don't know if it makes a difference which protein as the amount overall. Yes. The blood flow because of the way the kidney's off, it's normal. Oh, extra vessels? Not necessarily because it usually gets divided between those vessels. So some people will have a couple arteries, and you usually get the same amount going over there. And I think that's fine as long as you don't have underlying kidney disease. And if you are someone who is getting contrast, then you want to make sure that you go into it with a hydrated state is usually how we handle that.