Dr. Josh Cohen discusses the structure and function of PA catheters with a review of the hemodynamics and describes indications and complications.
I am honored to be here, happy to always do this kind of teaching. Um, my goal today is to give you guys a little bit of an introduction on. Uh, either PA catheters or hemodynamics. I actually used to give this talk to the, um, the internal medicine residents and the first year cardiology fellows and fellowships, so I kind of modified it just a little bit. My goal is to stay basics. I'm sure, I'm sure some of, um, some of you guys know this stuff. I'm sure, or, or, or even most of you guys, um, but it's nice to kind of go back and be formal about it and just kind of understand what this means when we interact with people who have, um, invasive human dynamic numbers kind of on a daily basis, and I think this is, um. Pretty essential to our daily practice and trying to figure out what's going on with people. So Let's keep going here. Um, so the objectives here, understand, uh, what, what is a PA catheter, um, or Swan Ganz catheter. What are the indications and contraindications? Uh, what does it look like when we put these in, uh, and where's the posi, you know, positioning on, on routine imaging? Um, what are the potential complications? I think we all, you know, just think, yeah, we'll get a right heart cath or, oh, we'll get a right and left heart cath, whatever it is, um. But you know, no matter how uh minor or how infrequent, there's still things, uh, if you do enough of them like uh like we do, um, there are complications you will see and then, and then basic human hemodynamics, which should be kind of, uh, hopefully what you get most out of this lecture. So just a quick picture here, this is uh Doctor Swan N Ganz, and this is kind of where that name comes from, right? You'll say someone say, hey, just float a swan or put in a swan, uh, or swan them. Uh, it's a Swann Ganz catheter, but, but really just a, a pulmonary artery catheter, and that's where that term comes from. So what, what is it, um, this is kind of your formal swan. This exists in various forms. You may not have an accessory, you know, med infusion port, or sometimes you don't even have thermo uh, or thermister connections, but in a, in a formal way this is what, uh, a Swan Gaines catheter is. And so if you see the labeled parts here, um, you have a small 1.5 cc syringe that's for the, you know, quote unquote when we say, hey, can you wedge them, um, and understand what the. Uh, wedge pressure is that's because you're putting this into, you know, deep into a pulmonary artery and then reaching the um. The distal end of that uh capillary bed and then you'll inflate 1.5 cc's of air to occlude that and then get an estimate of the downstream pressure and that's your wedge pressure. B is your accessory infusion port. This is usually for meds or someone who's super sick in the ICU and you need multiple points of access for meds. You have a distal port, which you see, which is for your pressure measurement. That's, that's what's measuring the pressure at the tip of the catheter. So as you're advancing and you're looking at different wave forms, um. That's uh where you're measuring your pressure, your CVP or your RA port. Normally you'll notice if, if someone has a swan in the unit, um, they have an RA pressure and then you see their, uh, their PA pressures as well. So the way you see those simultaneously is because you have a CVP or an RA port, um, and then you have your thermoster connector, and that's if you're running thermos, right? We've all kind of heard, uh, you know, cardiac output by thick or by thermo dilution, um, two separate methods. We won't talk a ton. About them, but they're calculations we should be familiar with, at least on the fixed side. Thermos is, is really just injecting, uh, a cold solution, uh, usually saline, and, um, essentially measuring the area under the curve in terms of timing for how long that takes to get through the, the, the heart. Um, and when you do that, you can get an estimation of cardiac output. There's some back and forth on. You know, what is a more accurate method. FCC has a lot of assumptions. Thermo has some slightly less assumptions. I think overall when they look head to head, they're fairly similar. Uh, when people have severe TR, they think that thermo's, uh, uh, maybe less accurate, and the reason is because instead of the blood glowing through the heart, it goes backwards. Um, most of the time I think here we use, we use F sometimes in the, uh, advanced heart failure lab we'll kind of do both. That's, that's how we did it in fellowship is if there was a real need for, uh. Index and output assessment, we would kind of just run both at least at the time of indexed right heart cath, and then more so kind of when you're putting them in, but you know when you're looking at this, the small lines here are 10 centimeters each and so if you have 4 of them, they're 40, once you get to the big um or the bold kind of dots here, it's 50 centimeters. This is just to understand where you are. That's important with day to day positioning and seeing if the catheter has moved along with the pressure wave form. So indications and contraindications, um, undifferentiated shock, cardiogenic shock, or tailored therapy, right? Put them in the unit and try and understand what's going on, um, and then when you do understand what's going on, can you titrate medications both from, from a preload, afterload, uh, and inotropy perspective to, to best optimize people with cardiogenic shock, uh, severe valve disease, we do this all the time, uh, to try and understand the effect. Of disease valves on, uh, filling pressures and, and cardiac efficiency, um, shunts, so formal shunt runs and running sats at different levels, uh, of the heart can be very helpful in understanding, um, shunt flow, and you'll hear the term like QPQS, um, and then evaluation of pulmonary hypertension as well, right? You can get direct measurements of, um. The pulmonary system and try and understand the etiologies of pulmonary hypertension again, which we'll, we'll talk about contraindications, so absolute contraindications if you have an RVAT in place, you can't put in a swan, um, right-sided endocarditis, tumor mass, this has been done before, but you know, most would argue that that's an absolute contraindication because you don't want to, uh, mess with whatever is there or potentially embolize whatever is there. Relative contraindications, uh, left bundle, we do, we do swans on people with left bundles all the time. The point to know there is that, you know, if you tap the septum too hard, you can induce a right bundle and, and, and induced, uh, complete heart block. That's kind of a, a classic board question. Um, usually that's temporary, uh, but I've seen where it is, uh, more prolonged and people actually require, uh, temporary pacing and, and it's an urgent type of thing. Um, severe TR relative contraindication. Again, all of our TR patients get right heart cath, so I, I wouldn't be too worried about that. TS pulmonary stenosis, meaning, is there any obstruction to where you're going to put this catheter, um, and just being careful about that. Severe pulmonary hypertension, there's, you know, there's theoretical risk of, of rupturing, uh, pulmonary artery or injuring the pulmonary vasculature, uh, when you wedge. In patients who have, you know, significantly elevated PA pressures. Prosthetic tricuspid valves or, or pulmonic valves, again, you're gonna have to cross those valves. Uh, it can be done, but, but just have to be careful about it. And then coagulopathy and thrombocytopenia, again, these are kind of for any procedure. Um, most of the time when people are very sick, uh, you know, venous access or large bore venous access can be accomplished anyway. So insertion, uh, you know, so all of us as fellows, uh, put in a, a bunch of swans at the bedside, um, and in the cath lab in a more controlled setting and fellowship, and really what you're doing is you're, you know, uh, getting good venous access, making sure you're using ultrasound, of course, um, in the old days they didn't always do that, um, and then. Advancing the catheter and understanding the wave forms as you go and so you'd, you'd put the catheter in and then you'd have, you know, your nurse or someone writing down your, your pressures as you did that, um, so you get into the RA just like a central line you see a a RA um. Did someone have a question or something? And, and by the way, please feel free to stop me if anyone wants to interject or has a question, um, and then we'll have time for questions at the end. I don't know if someone's mic was on or if they had a question. All right, we'll keep going. Um, so when you advance, um, you know, at the start, you're in the RA, you get an RA, uh, pressure wave form, um, which is pretty similar to your, your CVP form. You have your A, your C, and your V waves, which are all about atrial filling and, and contraction. Um, this can be important in assessment of, uh, things like, uh, constriction and tamponna and, and, and whatnot. They're very specific wave forms which we won't really touch on today. Um, but looking at things like rapid Y descent and rapid X descent. And uh then you push that catheter further, you get an RV pressure tracing curve. So your systolic pressure goes up here uh and then down back to the RA pressure. You then get into the PA uh and you lose that dip back down. You now have a dicrotic notch, kind of like an aortic pressure, but lower pressure system in the pulmonary artery. And then you get out to, um, you get out further and you wedge the catheter, meaning you blow up that balloon, you occlude flow and you get a um. An indication of left atrial pressure tracing or your wedge uh pressure tracing, which we use as a surrogate for left atrial pressure tracing. Um, similar, uh, in look to an RA pressure tracing curve, uh, but just usually at a slightly higher number if that makes sense. All right. So what, what does the position look like when you guys are rounding in the ICU or, or get a call at night or something like that? Um, this is a quick thing if there's a, you know, a lot of this these days, um, has been taken over by critical care, either critical care APPs or critical care docs, um, and even when we're the team that requests putting in a swan. Um, oftentimes we're not actively managing the swan itself, um, but as a fellow this was, this was like your minute to minute in an ICU when, uh, you know, 15 of your patients had swans and you get called that the pressure tracing is different or it's an RV pressure tracing. So you gotta know, you know, do you pull back, do you push forward, uh, what's going on based on the pressure tracing. So, um, when there's a question of position, you gotta look at the chest X-ray or get a chest X-ray. And then in general you should be in the middle third of the thoracic cavity on, on X-ray, right? So you kind of see if I've divided this up into thirds, the arrow here you see the distal tip of the, the PA catheter. So this catheter comes all the way down here. Around and into the right PA and this is in the, in the middle, again, middle third of this chest X-ray. If it's out much further, you think you're probably, you may be wedged at baseline. Um, or just too far out. If you're kind of here, you may be in the main PA. If you're all the way back here, you're probably in the RA and then you're using the pressure wave form, right? Because you have a, you should have a wave form from where the distal tip of this catheter is. And so if you're kind of in this area and you say, well, that looks kind of proximal, and it looks like a PA tracing, um, or even an RV tracing, uh, we probably have to advance the catheter, OK. What are some complications of swan? So again, we do this all the time. We don't see many of these, um, commonly, but when you start to look up rates of complications and they're 1 in 1000 or 1 in 10,000, um, you do enough of them and these will happen. Um, most of the time they're, they're not a huge issue, but when they do happen, um, they can be serious and so. Um, you know, infection or thromboembolism, that's possible. Those are usually people who are sitting in the unit for weeks on end with a swan in place. If someone's going to really have a swan for, for that period of time, you should probably be exchanging it every couple of days, or every, let's say 5 days or something like that, similar to kind of any kind of central line. Um, arrhythmias, right, depending on if you're tickling the RV or the septum, um, conduction abnormalities, again, you can induce a right bundle branch block. Usually not a huge issue. If they have a pre-existing left, you can induce complete heart block. Um, valve apparatus injury, uh, depending on how it's placed, how aggressively it's placed, uh, if it's placed under fluoro or not, sometimes these are just done at the bedside. You don't really know what you're getting into sometimes. Um, you can injure the tricuspid valve or the pulmonic valve. Uh, pulmonary artery infarction and pulmonary artery capillary rupture, that's kind of the big one, the, the, the board tested one, and, uh, what happens if you, you know, have brisk, brisk hemoptysis, you know, after wedging a balloon or something like that. So what does that mean? That's essentially where you, you know, rupture or lacerate the pulmonary artery from, from blowing up a balloon in it. This is a highly morbid thing. I've seen this once, um, in, in fellowship with no real rhyme or reason, it seems. Um, sometimes if people get, uh, fairly aggressive, they may put different wires up to be able to get a swan up and, and there can be an injury from a wire rather than just a balloon. Um, but I've seen this once, um, in, I don't know, let's say 5 years of, of fellowship at a fairly high volume place doing tons of swans, um, you know, and once kind of including all of my medical school and residency, so let's say in 12 years I've seen the swans, um. But, uh, brisk hemoptysis, so this is like people start coughing up a ton of blood, they become very unstable. The, the way you treat this, if you're gonna get to it or if you're gonna treat this patient is you leave the balloon inflated to try and tampon on it by itself. You place the patient on the affected side down, OK, so they won't necessarily flood the other lung too, and you call cardiac surgery and interventional radiology as fast as you can. Um, oftentimes they can try and embolize this, same as like, you know, a rapid GI bleeder or, or something like that, um, and then as soon as you can, you reverse anticoagulants or antiplatelets. Um, this is pretty profound when you see it, um, and, and quick action is important. All right, so this is what I really kinda wanna get to. So we put the, the swan in, uh, we're worried about a patient or we're just evaluating them in the outpatient setting. What do we do now? Let's keep going forward. Um, OK, so first, let's just talk about normal filling pressures. Um, has anyone, and, and we don't have to talk so much, but has anyone seen this? You know, you'll see this go around in internal medicine and cardiology. People say, you know, I can't, I can't remember the filling pressure. I can't remember normal pressures. You look in the textbook and the RA should be less than 10 or it should be less than 5 or it should be 2. Like what do we use? The, the absolute values are not so important, but I would have a general kind of gestalt about, um. About what numbers to use, so this is a kind of a nice way to remember nickel, quarter, dime, dollar, right? So nickel, 5, quarter, 25, dime, $10 100, and if you look at the, the heart picture on the left, right, so your RA pressure and, and again we usually use means for the kind of RA and wedge, um. But in RI pressure less than 5, again, a lot of us will say 5 to 8 or less than 10, some of this is just where, where does real clinical medicine fall with like, where does a perfect value fall? This doesn't account for, you know, is there a whip in the catheter? Are you leveled on all of your, um, lines before you take these measurements? And so I would say, you know, remembering 5 is fine, but if the RA pressure is 8, like, are you, are you going nuts? Probably not. Um, so 5 RV pressure 25/5 again now you have a diastolic pressure there. Um, PA pressure is 25/10. LA pressure 10. Again, sometimes you'll hear us say 12 or less than 15 or right? Um, but again, that's just where does, where does real clinical medicine fall in. And then, um, LV pressure 10 100/10, OK? And this, uh, you know, when you go over 10 and over 5, this should always really kind of be pretty similar to what that proximal chamber is. So 25/5 here, uh, and 10 for the, the left atrium. Um, unless there is a significant inflow obstruction, um, meaning if there's, you know, TS or MS or something like that, that will create a pressure gradient where those, those pressures then shouldn't be the same if that makes sense. Um, Let's keep going. So this is this slide maybe didn't come out totally right, but this is in my mind if there's any slide that you should take, it should be this one. So we're gonna bring in all these numbers because they came in in a funky way. These are the questions I ask myself when I look at every right heart cath, OK? And it seems kind of daunting, but you'll end up doing it in your head without needing any of this. So let's just. Let's take a second and go through it because in my mind this is the meat of the talk and the, the one slide you're gonna want to remember. So the four questions you, you get a pulmonary artery catheter in whether it's again in the outpatient setting or in a sick patient in the unit, um, and instead of looking at the report that will say whatever it says, I, you know, I don't know, it may be accurate, it may not be accurate, you may get the ones that auto populate from the cath lab that are almost inherently always wrong, um, and so it, it'll be important for you to assess that for yourself, and I think it's important to understand hemodynamics and how we end up treating people, so. Swan's in. First question is, are the filling pressures elevated? OK. Second question is, what is the cardiac output or cardiac index or what are the surrogate measures we use to understand if we think that the index or output is, um, normal or abnormal. Third question, is there pulmonary hypertension? If so, what is the ideology of that pulmonary hypertension? And then for general markers of how is the RV doing as well, OK? Um, so let's go through these one by one. Are the filling pressures elevated? If the answer is yes, now let's just go back for one sec, uh, we won't go all the way back, but the, the pressures that I showed you on that chart, right? So within reason, if you know the RA pressure is 14 and the um wedge is 22, the answer is yes, right? So are the filling pressure is elevated. Yes, if that's the case, we say that the patient's wet, right? These are kind of colloquial terms, but you'll see their hemodynamic profiles of, of heart failure or cardiogenic shock that you'll hear warm and wet commonly, you'll hear cold and dry, right? All these things. So filling pressures are elevated, patient's wet, OK? And that's the, you're, you're talking about congestion. Are they wet or are they dry? Are the filling pressures, uh, normal or low? If they're normal or low, you say no, they're, they're dry, OK? Um, and then the question that comes after that, uh, is, is it just the right-sided filling pressures that are elevated? Is it just the left-sided feeling pressures that are elevated, or are the biventricular filling pressures elevated? So right, left, or both. And if the patient's dry, it's not to say they don't need a swan or hemodynamic assessment, but is it necessary? Does it have to stay in, all that kind of stuff. That's as you're evaluating people day to day for it to stay in. OK. So, second question, what's cardiac output or index? So if you're gonna do, again, there's thick and thermodilution. Thermodilution, you, you inject saline and you get a number back, OK? Um, thick is a calculation. There's a lot of automatic calculations, a lot of assumptions as well. It assumes your VO2, uh, or your, uh, metabolic consumption of oxygen. That's reasonable, but if you just think for, you know, 10 seconds about who's in the unit, um. You know, you may have a, a 5' 120, 5' 100 pound female, and you may have a 6'2, 250 pound man, and we kind of estimate it the same way in a lot of people. So in some of the other places I practiced, we would actually measure it, a measured oxygen consumption, use that in the equation. The, the, that's a little less important other than to understand that there are some assumptions. But we use mixed venous sats as a as a surrogate because that's one of the main players in the equation for FI and in general if that's above 60 or 65, we think that that that will generally correlate to a cardiac output or index that is uh index above about 2 or 2.2 and we kind of say that the perfusion is normal in that sense. So what's the cardiac output either with with a mixed venous or with a formal thick or thermo and if the output and index are normal. Then you say that that patient is warm if the output and index are low, you say that patient is cold, OK? So first question deals with congestion. Second question deals with perfusion, and then you get to your third question, is there pulmonary hypertension? So, uh, historically that's a mean PA pressure above 25. More recent WHO guidelines have made that 20, um, but just kind of understanding where that cutoff is. If the answer to that is yes, then you're trying to understand, is it pre-capillary pulmonary hypertension, meaning are these are kind of true. Uh, Group one PH patients, they have, uh, significant elevation of pressures in their pulmonary system that is not related to something on the left side of the heart. Versus is it postcapillary, meaning is it related to left-sided heart disease. The vast majority of what we see is post-capillary or mixed, right? We, most of the pulmonary hypertension people will see some of these, uh, more rare kind of autoimmune mediated or connective tissue mediated disease where you're pre-capillary, but most of what we see is postcapillary, and what that means is left sided, essentially that the left-sided heart disease, the elevation. Um, and disease state of the left side is what is affecting or what is driving the high pressures in the lungs, OK? Um, and the way that you kind of understand that is we, we use multiple metrics. So for you to say that something is precapillary, meaning kind of inherent to the pulmonary vasculature, the wedge has to be normal, right? And so again, I know we just talked about a wedge that was less than 10 being normal, but let's, let's just say somewhere between 12 and 15, right? So if the wedge is 5 and your PA pressures are super high, you have pre-capillary pulmonary hypertension, right? And then same thing on the postcapillary side, you have to have an elevated wedge to say that the elevated right sided pressures or elevated pulmonary pressures are actually a result of, or in some fashion a result of, of, um, left-sided heart disease. The other two things you'll. Thrown around are transpulmonary gradients, TPG and diastolic pressure gradients or diastolic gradients. Most commonly, I think at least used here is transpulmonary gradient, and the calculations for that are here, TPG DPG. That's a PA mean minus your wedge, pretty easy calculation. And essentially what you're trying to figure out is, is the difference between these two very high, meaning that your wedge is likely low and your PA mean is very high. A high TPG, so greater than 12 to 15, will tell you that this is mostly pre-capillary. A low one, meaning your wedge is very high and your mean is lower in correlation, would mean that this is likely post-capillary etiology, OK. And then it's the same, just a slightly different calculation, diastolic minus your wedge. Same thing for this, and these are the published numbers 7 and 7, OK? And then a lot of disease we see is mixed, right? You have a high wedge, you have a high transpulmonary gradient. You can't say it's only inherent to the pulmonary vasculature when your wedge is high as well, right? So then we call that mixed, mixed disease. And then next question here, how is the RV? OK, there's lots of, and, and some of the advanced heart failure, um, APPs know this, there are lots of metrics that we use. There's even more than, than this, um, but as I'm, you know, as a clinical guy at the bedside when I'm trying to make a decision about like do people need. Support? Do they need isolated, uh, isolated RV support? Do they need BV support? These are kind of things you're keeping an eye on. And so in general, right, when we looked at that chart, the RA pressure was 5, the wedge was 10, right? So that ratio is 1 to 2 or, or half. OK. When your RA, RA to wedge pressure is greater than half, you have to start to at least consider that there may be right-sided disease, right? So if your RA is 10 and your wedge is 10. That, that's not totally normal, right? If your RA is 2 and your wedge is 8, OK, great, um, so just a simple RA to wedge ratio can kind of clue you into RV dysfunction, OK? And then the other thing that's kind of probably the most well studied is something called a PAPI or pulmonary artery pulsatility, um, index, and all that is, is it's the PA pulse pressure, so systolic minus diastolic over your RA. OK, and if that number is less than 1 or 1.5, again, you should be concerned that there's, uh, an, an element of RV dysfunction. Pay is most well studied in, in VA patients, um, and predicting RV failure post that. But, but again, used pretty frequently clinically to understand. Um, how well, how well the RV is doing, OK? And the same way, like again as a correlate, if you see someone who's in cardiogenic shock, you think they're in cardiogenic shock based on physical exam and their, uh, blood pressure is, you know, 100/75, that's a low pulse pressure, right? It's a low pulse pressure. You can imagine their wedge is probably let's say 20 or so and so if you created kind of the correlate of Pappy for the left side. Um, that's what that means is there's not a lot of pulsatility in the either RV or LV at that time, right? So PA pulse pressure, not a lot of pulsatility, and your RA pressure is high. OK, the RV must not be doing well. Just trying to take you through those equations to understand what we're actually looking at. And then there's a, there's an RV stroke work index. These are complex calculations, but again, this is a, you know, a published normal value for that. So this seems like a lot, but if you kind of, if you understand these things, you can walk through these really quickly. So you get the pressure numbers, are they elevated or not? You get a mixed venous, sometimes you'll have a, uh, either a thermal or a um thick cardiac output and index right away. Are they warm or are they cold? OK? Is there pulmonary hypertension? Is it pre-capillary, post-capillary, or mixed? And what's a general sense of what the RV is doing, OK? So this is the take home slide. This is the thing that's really helpful. I literally, I, I take myself through these 4 questions every time I look at a right heart cath, but I, I can do this in 2 minutes because I've done it every time I've, I've looked at a right heart cath, um, and you guys will, uh, be able to do the same or, or should be able to do the same, OK? Um, great. All right, so this is where I may ask for a little bit of help on the line if anyone is willing, um, and this is not to trick you, it's literally just to walk through what we just went through so that you can kind of do it in practice, um, so sample human dynamic interpretation. I, I think I, it is, it's been a while since I've given this talk, but I'm pretty sure I just took this from a random patient's chart in the unit. Um, all right, so we have an RA mean of 17. We have an RV pressure of 38/16, uh, a PA pressure of 36/23 with a mean of 27, a wedge or pulmonary capillary wedge pressure of 20, a mixed venous of 56, and I'll even, I'll give you the thick cardiac output and index, uh, output is 38, index is 17. OK, so what I wanna do first is let's just, let's just walk through some of these numbers and maybe if someone, if anyone on the line, and if you don't, that's fine, I'll, I'll pick it up, but. If anyone on the line wants to just go through this, so, um. Here are our questions. So let's go through them one by one. So are the filling pressures elevated? First question is yes or no. So filling pressures elevated, yes or no. Anyone wanna chime in? Uh, yes, it's Sarah. Have a good day. Hey Sarah. Um, great. So yes, filling pressures are elevated. Uh, let's take a stab, right, left, or both? Both, both good. All right, so we're through question one, right? And again, most of the time I'm looking here at this RA and your wedge kind of for that, that question, right? So our feeling pressures elevated and just to be even more concrete about this, right? So let's just say RA less than 10 would be normal, OK? There's some, there's some variability there, right? So you may see like if that were 11, you may see mild elevation or right sided pressures, right? But it's everything's on a spectrum here. So, um. This, let's say less than 10 would be normal. So RA is elevated wedge, let's say, you know, less than 12 or less than 15, whatever the 12 is probably an appropriate number. So 20 elevated, great. So our feeling pressure is elevated? Yes, both. OK, next question, what is the cardiac output? Is it normal or is it low? Low, good. OK. Cardiac output should be around 5 L a minute. Cardiac index should be generally greater than about 2 or 2.2 L per minute per meter squared. OK, so cardiac output is low. Is there pulmonary hypertension? Yes. Yes, and what makes you say that? Uh, slightly elevated pulmonary pressures, yeah, and, and so to be more specific, a mean PA pressure again that this is more recently changed greater than 20. Um, and I think that's to be more sensitive, meaning to catch more people who may have pulmonary hypertension. 20 is not super high, so you'll see that a lot, but let's, let's stick to somewhere between 20 and 25. That's why I made this 27. But if your mean PA is 27, your pulmonary pressures are, again, maybe not crazy elevated, but mildly elevated, so there is pulmonary hypertension. OK, great. And now we get to a little bit of a harder question. What is the etiology? Is it, uh, pre. Post or mixed. Not exactly sure. I wanna say pre or um potentially some mixed. OK, good, um, and then let's, we'll come back to it because I'll, I'll go through it again because I, that, that's always a sticking point for everyone, um, but just remember some of the things we're looking at when we do that are, um, is the wedge elevated if the. You, you can kind of do this two ways, but if your wedge is elevated, it can't be isolated pre, if that makes sense, right? Pre, we're saying there's disease and remodeling purely of the pulmonary vasculature that has nothing to do with the left side of the heart. So if the left sided filling pressures are elevated, you, you can't have isolated pre. You can either have post or mixed, um. And so wedge being 20 takes out pre and then we use that transpulmonary gradient which is your PA mean minus the wedge and if that's less than about 12 or 15, we say that that that usually these PA pressures are elevated in proportion to the elevation of the left side. And so this is likely post-capillary. OK, we'll go through the calculation and I'll show you. Yep, yep, yep, you got it, which is, which, and, and you guys know this, right, because we see this every day, that is the vast majority of what we'll see that or, or mixed where and you know the, the thing that's well defined is that. Over time, over years of elevated left-sided filling pressures, you do get remodeling of the pulmonary vasculature and you start to get people who have a component of precapillary pulmonary hypertension. That's why we call it mixed, um, but really what that is, is that's long-standing left-sided heart disease that has now induced pulmonary vascular remodeling to to create kind of both of these things. Um, OK, great. So, yes, there's pulmonary hypertension, we'll talk about the calculation for pre-post mixed, and then what's the general status of the RV here? Remember, we can't, well, let's, I'll let you guys say and then we'll go through it. Um, not terrible, but the RV pressures are slightly elevated. Good, OK, and so this is, and this one's a little bit more obscure in the sense that like. For me, I'm usually like let's look at the echo and let's look at these things, um, and most of the time they correlate but not always, um, and so again we'll look at, let's let's look at some of the numbers for that, but the big things I look at, I'm looking at the RA pressure in relation to the wedge. So remember that kind of 1 to 2 ratio normally. So if this were like 10 and this were 20, I'd say OK, that's a pretty normal ratio. The RA mean of 17, like this is almost 1 to 1, so I'm a little concerned maybe there's some element of RV dysfunction. Um, and then remember we talked a little bit about the PAPI PA systolic minus diastolic, so let's say 13 over your RA means 17, so that's less than 1. So that makes me concerned that there's some evidence of RV dysfunction, OK? So normal ranges again and again this is a nice slide to just maybe keep to understand what we looked at. So normal range is 0 to 10 RV 25 over 0 to 10, remember this, these numbers should be the same, uh, PA pressure of 25/10 to 15, wedge of 5 to 12, and a mixed venous of greater than 65. OK, so interpretation here, like we said, I believe, if not we'll, we'll go back and look, but elevated biventricular filling pressures, and this is, this is how I write, not that I do write heart caths anymore, but, um, this is how I would write my report and I do it in the same way that I almost asked myself the question. So elevated biventricular filling pressures, low cardiac output index, mild pulmonary hypertension, that is postcapillary etiology, hemodynamic evidence of RV dysfunction based on a pay of 0.8. Oftentimes you won't see this in a report, but I, this was more like in my head when I'm asking myself those questions. This is how I would then turn that into a, a palatable report to kind of understand and put everything together. Does that all make sense? Are there specific questions that anyone has about just this sample or what we're looking at when we say certain things, um, or this kind of sample, um, you know, question based way of interpreting a right heart cath? OK, we'll keep going. Um, and so that's the kind of the meat of the talks. This is where there's a very old chart. I forget where it's from, but this is in all of the, the cardiology textbooks, and it's just describing the hemodynamic profiles of heart failure. This is what the AHF APPs do all day every day, um. So when you're seeing a patient, it is important to try and understand where they fall in the spectrum, and a lot of this can be done on exam, right? So the vast majority of the people we see are, are in, in a profile B state, right? So wet and warm, elevated filling pressures, cardiac output, cardiac index are preserved. These people need diuresis, diuresis and after low reduction, but, but diuresis, OK. Um, dry and warm is, is, is normal. It's profile A, but it's, you know, potentially someone who's had congestive heart failure in the past, but they're well compensated. Um, but dry and normal is, you know, hopefully what we all are right now, OK? And then cold and dry, this is this interesting profile of, of low output heart failure. It's called profile L, and these are people who don't have elevated filling pressures but also have a low cardiac output or index and the kind of classic teaching. Is that you should warm them up first and and that may be with vasodilators or or something like that or leave them alone and they they're just advanced in their stage and they need something else. Cold and wet is kind of the typical cardiogenic shock profile that we see that's see, right? And these are people who have significantly elevated filling pressures and low cardiac index, low cardiac output, right? That's the vast majority of kind of what you see in probably the ICU setting. Warm and wet is what you see, you know, mostly in the, uh, either. Acute care or um you know inpatient setting that we're actively diuresing cold and wet again classic teaching is warm them up, then dry them out. Different centers have vastly different ways of treating this. I'll tell you when I was at Mass General, uh, these people got inotropes and a little bit of diuresis, and then when I went to Cleveland, they are, there is sodium nitropresside in the water, and these people actually got nitro pressuside, um. And diuresis and did just as well without kind of the negative implications or effects of inotropes. Doesn't say you never had to use inotropes, but, um, this was something I didn't really believe in just giving aggressive IV afterload reduction, uh, when I first got to Cleveland and then you do it 2000 times over the course of your fellowship and see, see these people get better and you start to believe in it. So just depends kind of where you train and what the thinking is of the people who kind of lead hemodynamics and heart failure at your center. Um, and what the comfort level of the ICU is, um, but this is typically a profile that either requires isotropes or aggressive, um, uh, afterload reduction. All right, basic equations you guys have seen this a million times and, and so far in this, um. Study, but I, I, in this lecture, but I think it's important to kind of, kind of just every time what's a normal CVP, what's a wedge, what, you know, what should the index be because then when you see it in a report or see it when you're talking to somebody about it, you at least know what's, uh, what's normal, abnormal without having to look it up. But what are the basic targets, right? So your CVP should be in, in close to a normal range, so less than 8 to 12. Your PA diastolic, which we didn't talk a lot about, but we use as a surrogate for the wedge, OK, um, so your PA diastolic. Anywhere from about 18 to 20 or 16 to 20 is, is reasonable. Um, you'll see like in the ICU we don't, we don't necessarily wedge everyone every second to get a wedge pressure, pressure, so you may just be going by a CVP and a PA diastolic. So here's a kind of target as you're starting to treat these people, a wedge pressure of, you know, less than 12 to 18 or so. Again, some of these people are so significantly decompensated or significantly remodeled that like. An LV with a, you know, end diastolic diameter of 8 centimeters is likely never gonna have a wedge of 3, right? Or, or, and again we should just clarify that a wedge is, we're kind of talking about surrogates here, but a wedge is a surrogate for your LV EDP. Right, um, and so, you know, a highly remodeled ugly ventricle is probably never gonna have a normal wedge, but maybe they came in with a wedge of 40 and you got them down to 18 or 20, and that may be a, a reasonably compensated state for them, OK? Um, cardiac index, uh, this is just your output, you know, normalized to your BSA, so greater than about 2 or 2.2 and a mixed venous of greater than 60 or 65. And then, uh, systemic vascular resistance, this is calculated. I don't often use this much, but it, it, it will come out with all your calculated numbers. Um, just the more assumptions you put into things, the less accurate they are. But anywhere normal range anywhere from about 800 to 1200, OK? Um, and then basic equations to know, and you'll, I'll, I'll include these on the next slide, but, uh, you should probably have a general understanding of what goes into the thick equation, you know, how, um, how certain factors will affect that, um, your systemic vascular resistance, your pulmonary vascular resistance, um, and then, um, just what we talked about, how to evaluate RV function and, and pulmonary hypertension with the numbers that you're given. This is a slide I printed out from one of our, we used in residency we used to have a, a white book and a red book. The red book was for the cardiac side. The white book was the medicine side, and I just, I just took a quick screenshot of this from my red book, my CICU and step down unit, um, book as a resident, internal medicine resident, um, but this has a nice kind of similar to what we talked about, but if you go through this. It gives a nice sense of what's normal and what things are in these equations. This is the thick equation. To estimate cardiac output, so it takes into account your oxygen consumption, your AVO2 difference, um, there's a constant here, um, times your hemoglobin. Um, and back to that AVOO2 difference, it tells you how that's measured, what the normal values are, um, a sample calculation. Um, it gives you the, uh, equations for systemic vascular resistance, uh, how to convert to the typical units, Dines, pulmonary vascular resistance, same thing. So you guys can look at this yourself, but I thought it'd be a, a helpful thing to include. And then again gives you targets again, right? So target cardiac index, target wedge, and you may, again, it's not to, it's not to, um, confuse you, right? Like I think I said, uh, 12 to 16 or 12 to 18, this is 1418. Something in those ranges, right? Pia diastolic, CVP, uh, normal blood pressures or maps, uh, normal systemic vascular resistance, normal pulmonary vascular resistance, uh, and a normal mixed venous. So conclusions, PA catheters can be useful, um, for sure. You'll, you'll practice in variable settings where people may not believe in them. They'll say, look, it's all about the physical exam and you know, measuring the JVP and, and all that kind of stuff. Uh, I think when you do this long enough, you realize that there are limitations to the physical exam as much as I love it, um, and it can be very helpful to understand the true invasive human dynamics of, of a lot of these patients that we see that are pretty sick. Um, or advanced in their disease, especially helpful in the CSCU and undifferentiated, uh, forms of shock, um, or just difficult to treat shock, um, hemodynamic assessment when your exam is inconclusive, we have a lot of, you know, obese and morbidly obese patients where, you know, good luck looking at the neck and good luck setting them up really well to, to listen to the lungs and, um, and sometimes people are intubated and, and whatnot, so there are things that get in your way. Valvular heart disease, we tend to include a right heart cath in most of our diagnostic workups because it's really important to understand, um, and you know, severely elevated pulmonary pressures play into risk assessment for surgery and for post-op RV dysfunction and other things as well. And then ask yourself the four questions with every red heart cath. If you start being religious about this, um, it will become second nature. You'll see numbers in a chart, and then you'll kind of know exactly where that patient sits when you're going to see them. Um, and then a little bit more for, you know, if you're actively managing the, the line itself, check the position in the wave form daily, you know, as a fellow, we would have swan rounds in the morning before the attendant came in where you'd check the position and the wave form of, of every swan every day. Um, just to, to make sure that things weren't, uh, in a bad way and that you had accurate numbers. Um, and then, as with any central line or central venous access, remove it as soon as you're able or it's no longer needed to, you know, prevent infection or complications. So that is all I have, um, and I am more than happy to take any questions or provide any resources.
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