Transcript
Speaker: Welcome to Critical Matters, a sound podcast covering a broad range of topics related to the practice of intensive care medicine.
Speaker: Sound provides comprehensive critical care programs to hospitals across the country.
Speaker: To learn more about our programs and career opportunities, visit www.soundphysicians.com.
Speaker: And now your host, Dr. Sergio Zanotti.
Speaker: The Fongans catheter or pulmonary artery catheter was commonplace in intensive care units and closely linked to the growth of critical care as a specialty.
Speaker: Over time, it fell in disfavor and its use became very rare in most ICUs.
Speaker: In today's podcast, we will revisit the role of the pulmonary artery catheter in our critical care practice.
Speaker: Our guest is Dr. Steven Hollenberg, a critical care and cardiology physician.
Speaker: Dr. Hollenberg is a professor of medicine at Emory University School of Medicine and director of the cardiac intensive care unit at the Emory Heart and Vascular Center.
Speaker: He has participated in guideline development in both critical care and cardiology,
Speaker: including the Surviving Sepsis Campaign, the AHA-ACC Guidelines on Percutaneous Coronary Intervention, Heart Failure and Chest Pain, as well as chairing an expert consensus decision pathway on assessment of trajectory and risk in hospitalized heart failure patients.
Speaker: His research interests relate to microvascular myocardial function with emphasis on the pathophysiology of shock.
Speaker: Clinical interests include septic and cardiogenic shock, acute heart failure, and acute coronary syndromes.
Speaker: A mentor and a true friend.
Speaker: Steve, welcome back to Critical Matters.
Speaker: Thank you.
Speaker: It's a pleasure to be here.
Speaker: Well, I think that we have definitely seen the arc of this topic over the years, and I probably, without aging any of us, put my first PA catheters with you.
Speaker: So we'll see where we stand today in 2024 and moving forward.
Speaker: But as an introduction, maybe you could give us your thoughts on why is the pulmonary artery catheter an important topic for today's practicing intensivist?
Speaker: So I think that it's a look into hemodynamics and in particular a way of measuring serial hemodynamics.
Speaker: And I think throughout this conversation, I'm going to try to make the case that there are at least some clinical situations in which that's useful.
Speaker: for diagnostic purposes, but also to guide therapy.
Speaker: So I think there is still a role for a PA catheter.
Speaker: And I sometimes like to say that the position that you're never going to need a PA catheter makes no sense.
Speaker: The position that you'll always need a PA catheter makes no sense.
Speaker: So that somewhere in between is that once in a while you might find the PA catheter useful.
Speaker: And then the question is when?
Speaker: Excellent.
Speaker: Could we start maybe with giving some of our listeners who might not be as aware a little bit of the historical context?
Speaker: I mean, why is it called Swan Gantz?
Speaker: Where did this start and how it was related to really the growth of critical care as a specialty in the early 70s?
Speaker: Yes, so the legend starts with Jeremy Swan in Santa Monica, who says that he was looking out at the water and he saw the sailboats and the idea came to him that if he attached a balloon to a catheter,
Speaker: it would sail along with the blood flow and go into the right ventricle and pulmonary artery.
Speaker: He was working with Willy Gantz, who had come over from Poland with, you know, a dollar in his pocket maybe, but had done some work with actually thermodilution and putting things on catheters.
Speaker: And so Swan came up with the idea, and Gantz did most of the rest of the work.
Speaker: And so they developed this catheter.
Speaker: They did show that they could float it into the right ventricle and the pulmonary artery.
Speaker: And over at Cedars-Sinai, along with James Forrester, they began to use it in patients in their intensive care units, which at the time were pretty much exclusively patients with acute myocardial infarction.
Speaker: And so they
Speaker: So they floated these catheters and they defined the sort of four subsets in myocardial infarction.
Speaker: They looked at wedge pressures and cardiac output, and you could either have low filling pressures and a normal cardiac output, which was normal, or you could have
Speaker: high filling pressures and a normal cardiac output, which is pulmonary edema.
Speaker: And then there were groups with a low cardiac output.
Speaker: And if you had a low cardiac output and a high filling pressure, you had cardiogenic shock.
Speaker: So they defined these subsets.
Speaker: They showed that the patients with cardiogenic shock had the worst outcomes.
Speaker: And they began to treat patients on the basis of these hemodynamic subsets.
Speaker: So part of the other context is that at the time,
Speaker: The CCU had the best physiology in the hospital.
Speaker: So the CCUs evolved from places where they shocked people out of ventricular tachycardia and saved their lives to places where not only did they do that, but they treated patients with heart failure after myocardial infarction.
Speaker: And so you could actually see the physiology and treat the physiology and watch it get better.
Speaker: And so
Speaker: That was, in a biased sense, the best place, the most fun you could have in the hospital.
Speaker: I guess the surgeons would argue differently, but at least for the medicine people, the CCU was the place.
Speaker: So that's where it started.
Speaker: And people began putting in PA catheters, and they spread out of the CCU into operating rooms and intensive care units and such, and it went from there.
Speaker: Excellent.
Speaker: And I think that obviously there was a proliferation, like you said, of PA catheters.
Speaker: And if you were an internal medicine resident, I mean, it would be a badge of honor when you got to put your first PA catheter.
Speaker: And eventually a lot of people went into critical care or pulmonary critical care or cardiology critical care.
Speaker: And PA catheters were really not uncommon when you were on call.
Speaker: Putting in PA catheters for patients was something that I think was routinely, routinely done.
Speaker: However, like everything in medicine, we get very enthusiastic.
Speaker: We start doing a lot of things and then people start doing studies.
Speaker: And there is a very famous paper I remember, I think came out in the mid-1990s, 1996.
Speaker: by Connor and JAMA that raised some questions.
Speaker: Can you start talking maybe a little bit about the literature or the evidence that started pushing us away from PA catheters?
Speaker: Yeah.
Speaker: So Albert Connors, who turned out to be a cardiologist, did something called a support trial, which I believe was about psychosocial aspects as well.
Speaker: But in any case, they looked at patients with and without a PA catheter, and they did something which was
Speaker: as far as I know, more or less unknown in the literature at the time, called propensity matching.
Speaker: So they took the patients who had a PA catheter and they did this propensity matching, which at least I didn't understand it all of the time, but somehow when you compared the odds ratio of patients with the PA catheter and without the PA catheter, you looked at mortality, it found a 25% increase in mortality in the
Speaker: patients with PA catheters compared to the propensity match patients.
Speaker: And the paper itself by Connor was reasonably judicious, but some other people started to run with this paper, most famously an editorial by Dr. Eugene Robin titled, Death by Pulmonary Artery Catheter.
Speaker: And there were calls for banning the use of PA catheters by some very prominent people.
Speaker: And that sort of started an era of skepticism about the PA catheter.
Speaker: And then people said, well, maybe we should put this to randomized controlled trials.
Speaker: So there were randomized controlled trials of, and importantly, routine use of PA catheters.
Speaker: And the first thing these trials did is actually failed to show an increase in mortality with the PA catheter.
Speaker: But they also failed to show a decrease in mortality with those catheters too.
Speaker: And so there was the, in the perioperative setting, there was a trial by Sandum, there was an ARDS trial by Michard, and there was a Pac-Man trial out in England in ICUs.
Speaker: And none of them showed any effect of the PA catheter
Speaker: on mortality.
Speaker: And then came the ESCAPE trial.
Speaker: So the ESCAPE trial was a similar trial in patients with heart failure, and they looked at patients who were treated with PA catheters and patients who weren't, and what they showed is that the PA catheter didn't change mortality.
Speaker: So that study has been widely quoted as showing that even in patients with heart failure, the PA catheter doesn't make any difference.
Speaker: And it's not uncommon, I think, in our field and in medicine in general to quote studies without really reading them in detail and understanding some of the issues and what they really represented.
Speaker: And I know that offline we were talking about escape and there were exclusions in escape that I think will be quite relevant to our discussion in 2024.
Speaker: Can you talk a little bit about that?
Speaker: Sure.
Speaker: So if you look at the trial, if you had been on inotropes recently, you were excluded.
Speaker: If your creatinine was greater than three and a half, you were excluded.
Speaker: And at the time, if your physician thought you needed a PA catheter, there was no ankle poise and you were excluded.
Speaker: And if you had cardiogenic shock, you were excluded.
Speaker: So at least in terms of the patient population with cardiogenic shock,
Speaker: that is not spoken to by the ESCAPE trial.
Speaker: There's really not much controversy about that.
Speaker: And so there's a lot of, now that most of the PA catheter is coming back to cardiogenic shock, most people believe that the ESCAPE trial really isn't pertinent for that.
Speaker: So, you know, as you know, after the PA catheter use plummeted, but the ICU decided that there were some new toys that could do with the PA catheter.
Speaker: And so there's a whole set of technologies of measuring cardiac output and using pulse volume analysis and PICCO catheters and lithium dilution catheters and such, essentially new toys that
Speaker: We're going to replace the PA catheter.
Speaker: And this podcast isn't really about those new toys, but I would argue that very few of them have been subjected to rigorous analysis either.
Speaker: I was going to mention, and you're right, we're probably not going to dive into all these new hemodynamic monitoring devices, but none of them pass the higher standard than the PAC, right?
Speaker: Actually, the PAC has been studied in more situations than any of those,
Speaker: And if anything has been shown to be safe.
Speaker: So that is true how we are very selective in the requirement of data based on, I guess, on just whatever intuition or bias we have for one device or the other.
Speaker: Right.
Speaker: And I'm not trying to say those new devices don't have utility.
Speaker: It's just that they haven't been proven to be better than the PA catheter.
Speaker: That I'm willing to say.
Speaker: Yeah.
Speaker: And again, the fact that there's so many tells you that nobody solved the problem finally, right?
Speaker: So I think it's an important...
Speaker: Like you mentioned, I think that with all this data, and to give people perspective, ESCAPE is 20 years old, came out in 2005.
Speaker: So over that span, the use of PA catheters, based on the literature, based on, let's say, based on interpretation of the literature, and based on the fact that there was a proliferation and a push for so many other hemodynamic devices, some of them billed as
Speaker: non-invasive or less invasive, although a lot of them required, I mean, similar levels of invasiveness, right?
Speaker: And the reality is that residents and fellows stopped putting PA catheters, right?
Speaker: And it's almost like it slowly became a skill that was more rare in very specialized units, I would say, and even in areas where it would still be utilized, was utilized less and less.
Speaker: And I should say that the cardiologists have been doing right heart catheterizations in the cath lab for a long time, and they're still doing that.
Speaker: So it's not like the cardiology world has gone back on right heart catheterization, but cardiologists in the cath lab may or may not be comfortable with the idea of internal jugular access and floating a leave-in SWAN catheter in through a neckline.
Speaker: So it's somewhat interesting, but the cardiology world hasn't quite given up on right heart catheterization.
Speaker: It's just that the ICU stopped doing it.
Speaker: And it's also very interesting just from the perspective of if you're not a cardiologist or not interventional cardiologist, if you say right heart catheterization in the cath lab, the mental model of that is much more complex than putting a PA catheter at the bedside in the ICU, but essentially you're measuring the same things, right?
Speaker: Yeah, although often you're doing them in the cath lab, you're often doing them from the leg.
Speaker: Okay, and on the floor.
Speaker: So that's commonly an in-out PA catheter.
Speaker: If you want the cath lab to do a leave-in PA catheter, you're asking them to go away from the leg and go to the neck.
Speaker: And they know where the neck veins are.
Speaker: They can do this, but it takes them a little bit longer.
Speaker: And I remember once in a while we had to put a...
Speaker: a PA catheter through the leg in the ICU.
Speaker: And that was really just an endeavor of hope.
Speaker: Right.
Speaker: And if you got lucky, it got in.
Speaker: And if you didn't get lucky, there's nothing you could do.
Speaker: That's about right.
Speaker: And every once in a while you can, you know, you can go to the cath lab, put a wire in the catheter and do it under fluoro.
Speaker: But, you know, that's a road trip and all that.
Speaker: Awesome.
Speaker: So let's talk about the the the.
Speaker: So first, I guess I'll throw a piece of trivia that I found out as I was preparing for this podcast.
Speaker: The original intent was to call it revenge of the PAC.
Speaker: kind of thinking of my Star Wars original trilogy.
Speaker: And then I did a little bit of reading, and the original name of the third movie was Revenge of the Sith, but it was changed to Return of the Sith... I'm sorry, Return of the Jedi, because George Lucas thought that a Jedi couldn't want revenge.
Speaker: And I said, well, maybe...
Speaker: A diagnostic tool that is intended to save lives wouldn't want revenge either.
Speaker: So we went to return to the PAC.
Speaker: So in terms of the return of the PAC, something that's quite interesting, I think, has also fueled this discussion today, Steve, is that CCUs have changed.
Speaker: What we see in CCUs have changed.
Speaker: And actually, I would say that we are on the verge of a rapid increase of a new type of patient in critical care, right, with MCS and other types of support.
Speaker: Could you talk a little bit about that?
Speaker: Yeah.
Speaker: So I think that's absolutely right.
Speaker: So, you know, it used to be that CCUs were places where there were MIs, right?
Speaker: And so they were the province of cardiology.
Speaker: And then in a paper by Jason Katz that published in Critical Care Medicine, they looked at the evolution of CCUs and began to realize that the patients were getting more complicated in terms of multi-system disease.
Speaker: There were more patients on mechanical ventilation, more patients with
Speaker: renal failure, some patients immunosuppressed and you had to worry about infection.
Speaker: So there's a much greater role for critical care in in ICUs and CCUs.
Speaker: And then with mechanical support, the cardiology aspects became much more prominent.
Speaker: So the selection of mechanical support, weaning mechanical support, thinking about the goals, whether you are going, what your escape strategies are, and the use of hemodynamics to titrate mechanical support and figure out what you needed has sort of made the ICUs much more hemodynamic and much more places where cardiogenic shock is involved.
Speaker: And as you're going to hear, I mean, once you get some mechanical support,
Speaker: you have to have a hemodynamic assessment.
Speaker: If you're going to do a transplant evaluation, you have to have a hemodynamic assessment.
Speaker: And you know, in theory, you could do that as an in-out catheterization laboratory, and sometimes you do in healthier patients.
Speaker: But in your patients in the CCU, in whom you either have mechanical support or are considering mechanical support, you just have to have a PA catheter.
Speaker: And so
Speaker: ICUs that don't necessarily see mechanical support may not have a need for PA catheters, but CCUs that do have to have familiarity with the PA catheter.
Speaker: And this has sort of made a little bit of divide between, say, the cardiology critical care types that take care of patients with mechanical support, who sort of say, you have to have PA catheter, and ones who don't who say, well, we don't really see much need for it.
Speaker: And I do think it's also important to mention that the use of mechanical secretory support is really growing everywhere, right?
Speaker: So clearly there are certain ICUs, like you said, cardiac ICUs, who might be very heavily invested and have...
Speaker: a whole bunch of ECMO, of Impella's 5.5s and other devices.
Speaker: But I do think that these are proliferating everywhere now because they're easier and easier to put, right?
Speaker: I mean, and I think interventional cardiologists and communities now are starting to put them.
Speaker: And I think that my anticipation is that it is more likely that more intensivists will be exposed to these types of patients.
Speaker: And hence, I mean, the topic that we're talking about today.
Speaker: Yeah, and you know, I mean, if you're in a hospital, if you're in an outside hospital and you think your patient might be a candidate for hemodynamic support, the criteria are largely hemodynamic.
Speaker: So you might find some utility in actually measuring hemodynamics and calling your referral hospital with hemodynamic data in hand, saying, here are the hemodynamics, this is why I think we need mechanical circulatory support.
Speaker: Absolutely.
Speaker: What has changed in the literature?
Speaker: I mean, have there been other studies, I mean, maybe more focused on particular populations?
Speaker: So yes, with mechanical support came a host of, maybe not a host, but at least some observational studies.
Speaker: And so the Cardiogenic Shock Working Group, which is a multi-institutional group, put out a paper in 2020 in Jack Hart failure in which they looked at patients with mechanical circulatory support.
Speaker: and they looked at patients who got PA catheters before mechanical circulatory support, and then they compared them to patients who didn't.
Speaker: And that observational study showed decreased mortality in that group.
Speaker: And they also looked in that study at what they called complete hemodynamics, right atrial pressure, pulmonary artery, systolic and diastolic pressures, wedge pressures, mixed venous oxygen saturation, and cardiac output.
Speaker: And the patients with complete data with a PA catheter did better than patients who didn't quite have all those data with PA catheter.
Speaker: So that started in mechanical support.
Speaker: And then the Cardiogenic Working Group, some years later in 2023, published a paper in the Journal of Cardiac Failure looking at just patients with cardiogenic shock
Speaker: and also found, it's a thousand patients or so, found an odds ratio of 0.68 with the PA catheter compared to patients without.
Speaker: And then a different group, the Cardiac Critical Care Trials Network, which is another large group, it has about 5.
Speaker: 35 institutions.
Speaker: We actually participate in that.
Speaker: Did an observational study, and they also showed that the PA catheter was associated with decreased mortality and shock with an odds ratio of 0.79, or about a 20% decrease.
Speaker: And the last piece of data is there's something called the
Speaker: National Readmissions Database, and this is a big administrative database with all the challenges of using coding to make a diagnosis.
Speaker: But suffice it to say, that observational study also showed an odds ratio of 0.69.
Speaker: So there are a bunch of observational studies that suggest that use of a PA catheter is associated with decreased mortality.
Speaker: Of course, you could argue about whether that really means it's the PA catheter or whether it's associated with the sort of people and the sort of environments where they're putting in PA catheters.
Speaker: That's probably at least part of it.
Speaker: But at least there's a set of observational data now that suggests benefits.
Speaker: And I think that, like you mentioned, I mean, is it causal or correlation with something else?
Speaker: But I think that the point there would be that the familiarity with managing and utilizing the hemodynamic data that the PA catheter provides probably improves the team caring for that patient in other ways, right?
Speaker: So one way or the other, it would seem that now when we're going to more of a focused approach, which I think is always important,
Speaker: the key in medicine, right, is choosing the right patient.
Speaker: I mean, same argument we could have with TPA for pulmonary embolism, for ECMO, for ARDS, right?
Speaker: It's about patient selection.
Speaker: So in 2024, like you said at the onset of our podcast, Steve, you wouldn't say everybody or nobody, but you would say if you have cardiogenic shock,
Speaker: If you are thinking of MCS, a PA catheter probably would help, right?
Speaker: And it's probably best practice.
Speaker: Are there any patient populations that you think, I mean, benefit today of a PA catheter as well?
Speaker: Yeah, well, so, I mean, I think, so we start with cardiogenic shock, and not just every cardiogenic shock, but when you start talking about pressors and potential mechanical circulatory support, they have been used in pulmonary hypertension, right?
Speaker: right, you know, the standard of care for pulmonary hypertension is right heart catheterization.
Speaker: If you're going to be treating pulmonary hypertension in a unit with pulmonary vasodilators and such, it makes sense to measure those pulmonary pressures and the cardiac output.
Speaker: So that's a population.
Speaker: And the other use that I think a lot of us have done in the past, and maybe the critical care people have gotten away, but, you know, if you have uncertain hemodynamic status,
Speaker: and you aren't responding to empiric therapy.
Speaker: So if you have, if your patient is getting better, you're giving some therapy and they're getting better, fine.
Speaker: But if the patient isn't getting better and you don't really know what their hemodynamics are, then measuring hemodynamics makes a certain amount of sense.
Speaker: And there are those of us who will at least consider a PA catheter and have experience of sometimes being surprised.
Speaker: Wow, the pressures are really much lower than I thought they were.
Speaker: Or alternatively, the cardiac output is different or something like that.
Speaker: So I think that's still a population.
Speaker: And sort of a subset of that is the concept of the in-out swan in somebody who has renal failure.
Speaker: You don't know whether they're wet or dry.
Speaker: You really don't.
Speaker: You can't figure it out.
Speaker: You put in a PA catheter and settle the issue, and then you just take it out.
Speaker: because now you know, and now you know what to do.
Speaker: You don't necessarily need to leave that catheter in, but it is a reasonable diagnostic procedure in that setting, at least in my opinion.
Speaker: And, you know, I think you get
Speaker: The other thing to say is I think you get some data from PA catheter that you can't get from other things.
Speaker: So you could argue about the hemodynamics and the ability to obtain hemodynamic parameters with a good echo, with a Doppler, etc., etc.
Speaker: But I think the mixed venous oxygen saturation is something that you have to measure.
Speaker: I personally think a mixed venous oxygen saturation that is from the right ventricle or pulmonary artery is better than the central venous oxygen saturation, but that's my opinion.
Speaker: But that's an index of the adequacy of cardiac output.
Speaker: Cardiac output is just a number, but if you take that along with the mixed venous oxygen saturation, you can get a sense of the adequacy of cardiac output.
Speaker: And I think that's something that you don't get with other techniques.
Speaker: Excellent.
Speaker: So a lot of our listeners either need a refresher on the basics or maybe did not get exposed to this sufficiently during training.
Speaker: And as we said, we're seeing in more and more environments that all of a sudden we were asking, we put a PA catheter, and I've heard intensivists say, well, I haven't put one in X amount of years, or I haven't put one in training.
Speaker: And I think that obviously that depends on
Speaker: the pattern of your practice and types of patients, but it is a growing, I think, trend.
Speaker: So why don't we do a little bit of a pulmonary catheters one-on-one 2024 edition or 2025 edition as we're ending the year and start with some very basic refresher of indications and contraindications.
Speaker: Right.
Speaker: So, you know, I think you, you know, the indications, the indications are when you think it will help cardiogenic shock,
Speaker: Pulmonary hypertension in some settings, although with severe pulmonary hypertension, you have to be a little careful with the catheter.
Speaker: Those are the ones with very high pulmonary pressure.
Speaker: Those are the ones that you might get in trouble with.
Speaker: And as I said, uncertain hemodynamic status.
Speaker: You are putting the catheter into the right ventricle.
Speaker: And it used to be said that if you had left bundle branch block, you could induce right bundle branch block and thus have complete heart block when you were putting in the PA catheter.
Speaker: And actually they built some of the PA catheters, they built something called a pace port swan, where you could actually pace through the catheter.
Speaker: There was a port where you could drop a pacing wire through the port
Speaker: And then there were pacing swans where the pacer was actually on the swan GANS catheter.
Speaker: I have to say, I've put in a lot of PA catheters, including in patients with left bundle branch block, and I have not induced a complete heart block.
Speaker: And if you do, you just pull the catheter out.
Speaker: So that's probably not a contraindication.
Speaker: I think that the patients to be careful about are people with other sorts of lines, people with
Speaker: a bunch of complicated pacemaker leads.
Speaker: You ought to at least think twice about trying to do this blind, because if you wrap a PA catheter around an indwelling catheter, you have to make an embarrassing call to your interventional radiologist to help you out.
Speaker: So you can do it, but you at least in that setting, you at least ought to think about whether that might best be done under fluoroscopic guidance rather than blind at the bedside.
Speaker: Could you tell us a little bit, Steve, of some placement techniques, maybe some pearls and pitfalls to avoid and maybe some troubleshooting tips?
Speaker: Sure.
Speaker: So, you know, I think you have to remember that.
Speaker: And even I, you know, so I put in a lot of PA catheters, but I'm not an expert with the actual setup as how you plug the transducers in and this and that.
Speaker: So you want to know that that setup is working.
Speaker: So the first principle is that,
Speaker: you need to know where the tip of the catheter is at all times, and it's guided by the waveform.
Speaker: So you have to have a waveform that you can believe, you have to be able to see that waveform, and you have to be confident on the basis of the waveform that you know where the catheter is.
Speaker: So before you put the catheter in, so you set up the catheter, you flush the catheter,
Speaker: before you put the catheter in, you take the catheter, you look at your bedside monitor, and you move the tip of the catheter up.
Speaker: You move it up, you know, 10 or 20 centimeters.
Speaker: When you do that, your pressure that your transducer is measuring ought to go up by 20 centimeters.
Speaker: So when you move that thing up and down, you ought to see a tracing go up and down.
Speaker: If you do that, you have reasonable confidence that your
Speaker: monitoring system is picking up changes in pressure at the tip of the catheter.
Speaker: If that doesn't happen, you should sit and troubleshoot until that does happen.
Speaker: You should ask your nurses or technicians to look at that, make sure the stopcocks are all in the right direction, et cetera, et cetera, et cetera.
Speaker: So I think that that's, and you should also, that's another chance to look at the scale.
Speaker: So if you're trying to put a PA catheter in with a pressure of 40 and your scale goes from one to 10, you aren't going to be able to see the top of the of the waveform.
Speaker: So I think before you start, you want to be confident that your monitoring system is measuring the pressures that the other the other tip is is.
Speaker: that I think you'd like to, after you put in the PA catheter and you'd like to write a note that says a couple of things.
Speaker: It's useful to write the initial hemodynamics and not make somebody go hunting through the chart to figure out when you put in your PA catheter and what the numbers were when you put it in your daily note.
Speaker: Write a procedure note.
Speaker: And that includes two things.
Speaker: How far is the PA catheter in when it wedges?
Speaker: That's a useful piece of information because if it stops wedging, it's nice to know where it was wedging in the first place.
Speaker: And what were the initial hemodynamics when you put it in?
Speaker: I think that's useful.
Speaker: sort of the last tip is to look at the correlation between the PA diastolic pressure and the wedge pressure and look at it for the first couple of measurements because it's usual.
Speaker: There are some situations where there's a big gap or something, but usually the wedge pressure is pretty close to the PA diastolic pressure.
Speaker: So if you're leaving that catheter in for a while and the catheter stops wedging,
Speaker: then I think the part you don't necessarily have to gyrate to measure a wedge pressure.
Speaker: You can sometimes just look at the correlation between the PA catheter and the wedge pressure and use the PAD diastolic instead.
Speaker: Excellent.
Speaker: And in terms of access, obviously, you mentioned earlier, Steve, that in the cath lab on the floral, most access is usually through the femoral.
Speaker: In terms of putting in the ICU, if everything else is equal, is there a preference?
Speaker: Is there an access that gives you a straighter path?
Speaker: Yeah, so the other thing I didn't mention is that you want the curve of the catheter to follow the path that you want to go.
Speaker: So sometimes you might even coil the catheter.
Speaker: So you want the catheter to point toward the left side.
Speaker: The internal juggler is really a straighter shot.
Speaker: And it's the straightest shot and probably the preferred access.
Speaker: You can use the right internal juggler.
Speaker: You can use the left internal juggler.
Speaker: It'll go that way.
Speaker: You can use a subplavian artery and assuming those will float.
Speaker: But the right IJ is probably the easiest way to get your catheter where it needs to go.
Speaker: And so you sort of check the orientation of your catheter as you put it in to try to make sure that it's going in the right direction.
Speaker: Perfect.
Speaker: Could you tell us a little bit before we talk about actual management, any potential complications, real complications?
Speaker: I know that there's been reported.
Speaker: Like you said, I have not seen a ton of complications with PA catheters, but they are reported.
Speaker: And I think it's always important for people to be aware so they can recognize them when they do happen.
Speaker: Sure.
Speaker: I mean, it's a central line with a bigger introducer.
Speaker: There's an infection risk.
Speaker: You can get arrhythmias, not so much heart block, but when you bang around the right ventricle, you can have ventricular tachyarrhythmias.
Speaker: Occasionally, you'll put somebody in atrial fibrillation, although that's not very common.
Speaker: The real worry is pulmonary artery rupture and a PA bleed.
Speaker: And that happens.
Speaker: That's why you want to check the position of the catheter.
Speaker: You don't want it to be too far out.
Speaker: You want to make sure that after you blow up the balloon to wedge the catheter, when the balloon goes down, that the tracing changes to a PA catheter tracing because you don't want it in permanent wedge.
Speaker: That's when the trouble happens.
Speaker: As I mentioned, people with pulmonary hypertension are at
Speaker: somewhat higher risk and you might actually decide that maybe you don't really need to wedge the catheter often in those patients.
Speaker: I should mention that you put the catheter in, it's room temperature.
Speaker: And when it sits in the body, it then goes to body temperature, it softens up.
Speaker: So in general, the PA catheter might migrate out a little further from where you put it in.
Speaker: And you can tell that sometimes by x-ray and sometimes you have to pull it back to keep it out, to keep it from being too distal and increasing the risk for pulmonary artery rupture.
Speaker: It's a rare complication, but it can be dangerous when it happens.
Speaker: You mentioned earlier that, for example, a mixed venous from the right ventricle or from the pulmonary artery is a unique feature of the PA catheter compared to other hemodynamic monitoring devices.
Speaker: Are there other things that the PA catheter does better than other devices?
Speaker: Well, I think, you know, at least in my world, I mean, so you can get those data.
Speaker: One of the things that the PA catheter naturally does is allow you to do serial hemodynamic measurements.
Speaker: And there are other devices that do serial hemodynamic measurements.
Speaker: But, you know, people talk about echocardiography as an alternative to the PA catheter.
Speaker: And you can get hemodynamics from a good echo with Doppler and all that.
Speaker: But serial measurements require you to do another good echo with Doppler and all that.
Speaker: And another one and another one.
Speaker: So it's a convenient way to get serial measurements.
Speaker: Not the only way to get serial measurements, but it's more convenient than many of the other techniques.
Speaker: Perfect.
Speaker: How do you use PA catheter data, hemodynamics in your actual management of patients?
Speaker: And I think that we could maybe think about it, Steve, from figuring out what to do with the patient as their cardiogenic shock gets worse, how to manage hemodynamic support, and maybe even how to wean them eventually from some types of support.
Speaker: Yeah, so I think that, you know, you're getting two, maybe two, maybe three main pieces of data.
Speaker: You're getting filling pressures on the right side and the left side.
Speaker: You're getting cardiac outputs, whether that's an assumed fit cardiac output or a thermodilution cardiac output.
Speaker: And I think that helps you with management of the patients.
Speaker: If you're dealing with elevated filling pressures, then filling pressures are what you want to look at.
Speaker: And if you're dealing with low cardiac output, then you want serial measurement of cardiac output.
Speaker: with manipulation of hemodynamics and support devices and such.
Speaker: And you also, the other thing that has become clear in the cardiogenic shock world is that biventricular failure is not uncommon.
Speaker: And the way to diagnose right heart failure is hemodynamically.
Speaker: And there's a
Speaker: There's something called a PAPI, which is basically an index of the pulmonary artery pulse pressure, that is the PA systolic minus the PA diastolic divided by the right atrial pressure.
Speaker: So if you think about it, what you'd like is a—and the pulse pressure on both sides actually is an index of stroke volume.
Speaker: So what you'd like is a high pulse pressure and a low right atrial filling pressure.
Speaker: If the pulse pressure is low and the right atrial pressure is high, then the PAPI is low.
Speaker: And that's something that particularly in mechanical circulatory support, you can use as an index of right ventricular contractility and right ventricular function.
Speaker: So I think that it's a little hard to be to to.
Speaker: you're going to use it differently in all sorts of different clinical situations, but I think that's really what you're thinking about.
Speaker: What parameter am I titrating to?
Speaker: And it goes to the same thing when you wean the catheters.
Speaker: So when you're ready to wean mechanical circulatory support,
Speaker: You want to say that the filling pressures are low, that the indices of right ventricular performance are good, and then if you put it in to support cardiac output, then you're going to measure cardiac output.
Speaker: You can often turn down the support and measure hemodynamics again to see what happens when you give less support.
Speaker: And if the patient maintains his or her hemodynamics, then you have some confidence that it's a good time to wean the support.
Speaker: Perfect.
Speaker: So I think as a general principle, probably, like you mentioned, is the serial measurement in response to therapies and the changes to that therapy is what really helps us.
Speaker: I think that many years ago, residents would have this conception that a high wedge equals pulmonary edema, and that was really kind of a summary of what the PA catheter gave you.
Speaker: But really what we're looking today is
Speaker: new measurements like the poppy, trying to see what the response is on that wedge pressure, filling pressures, but also on the cardiac output to the things that we're implementing over time.
Speaker: Excellent.
Speaker: The other question I was going to ask you is for diagnostics,
Speaker: So you wrote a lot of board type questions for reviews and for the actual boards.
Speaker: At one point, I used to joke that there were certain things related to the PAC that you only saw when you took tests.
Speaker: But from a physiological standpoint, I think there's always some interesting little nuggets to learn there.
Speaker: Are there any patterns in particular that are kind of classical or very instructive?
Speaker: Well, you know, I think that there are a lot of sort of hemodynamic patterns in the cath lab.
Speaker: So there's all this.
Speaker: You can look at the X descent and the Y descent and a blunted Y descent suggests tamponade.
Speaker: at preserved X and Y descent suggests pericardial constriction, and those are right heart findings.
Speaker: The thing about testing is it's classic cardiovascular physiology.
Speaker: It's something that critical care people are supposed to know that other people don't know.
Speaker: So it's, if you will, unique to critical care, and it's testable.
Speaker: And the other thing that you want to think about is you want, it depends a little bit, you want to know when to measure the PA catheter.
Speaker: So you really want to measure it at end expiration when the pressures equilibrate between the left atrium and the pulmonary capillary, the wedge.
Speaker: the pulmonary artery, and there's no flow at end expiration.
Speaker: So there's classically the question of when should you measure the wedge, and of course the respiratory pattern changes whether you're in spontaneous ventilation or whether you're on a ventilator, but you do want to go to end expiration to measure the pressures.
Speaker: So those are sorts of things that are kind of testable, and then
Speaker: The waveforms and whether the catheter has too much whip, whether the catheter is appropriately transduce and whether it has too much whip is sort of one of these cute questions that people ask.
Speaker: Even I can't remember how to do it.
Speaker: But there are a bunch of questions.
Speaker: I will say that some of those questions have been left over from when Dr. Perillo was writing questions, and they still perform well on the test.
Speaker: That is, they discriminate the people who are passing from the people who are not passing.
Speaker: And so I don't take the blame for all the PA catheter questions.
Speaker: Fair.
Speaker: Awesome.
Speaker: So as we move forward and looking ahead, are there any upcoming trials or new technology that might be associated with PA catheters that you're excited about?
Speaker: Well, so there is a trial ongoing called the PAX trial.
Speaker: Pulmonary artery and critical care, something like that.
Speaker: But that's a trial looking at the PA catheter and cardiogenic shock.
Speaker: And it randomizes people between early PA catheter placement, that is less than six hours versus delayed PA catheter placement, that is
Speaker: either no PA catheter at all or delayed past 48 hours.
Speaker: And you have to have cardiogenic shock, low ejection fraction, elevated lactate, hypotension or vasopressors, or clinical evidence of heart failure or mechanical support with a balloon pump.
Speaker: So mechanical support with other devices is excluded.
Speaker: It's an adaptive trial.
Speaker: That is, they're looking for outcomes, and it will be somewhere in between 200 and 800 patients, and the primary outcome is in-hospital mortality.
Speaker: So that trial is ongoing.
Speaker: You can imagine that that may not be the easiest trial to recruit for, so we'll see how long it takes, but there is a randomized trial of PA catheterization ongoing, and I think everybody is looking forward to those results, although
Speaker: one wonders exactly how many mines that's going to change no matter which way it turns out.
Speaker: Because I've already said you have to have PA catheter for mechanical circulatory support no matter what.
Speaker: But nonetheless, I think randomized data is always good and we're looking forward to the results of that trial.
Speaker: Perfect.
Speaker: As we close, I always...
Speaker: I'd like to say that the main goal of education is not knowledge but action.
Speaker: And part of the discussion today was to help colleagues who are all of a sudden faced with perhaps there's patients in my practice in whom a PAC, a pulmonary catheter would be very helpful and there's evidence to support that as opposed to where some people were for many years is that we don't use those things anymore.
Speaker: So any recommendations for critical care clinicians at the bedside to develop or regain that expertise with PACs?
Speaker: Yeah, I think that if you're going to put in a PA catheter, you don't want to put it in once a year in a very sick patient.
Speaker: If only for your entire operation of the unit, your nursing staff, your technical staff, your trainees, everybody, you want your unit as a whole to have some familiarity with PA catheters, which I think means that you're going to have to put some of them in.
Speaker: So I think in virtually all, except for mechanical circulatory support, but in any individual case, you can make an argument that you can get away without a pulmonary artery catheter.
Speaker: It's not like there's somebody who absolutely has to have a pulmonary artery catheter, but I do think they're helpful, and I think it's worthwhile to sort of dip your toe in the water, try to find a patient in whom you might get some data with a pulmonary artery catheter, and put a couple in, make sure you have...
Speaker: have a chat with your nurses, say you're going to want to do it, get used to the protocol and how to do it and then do it.
Speaker: And you might want to start just putting them in and this isn't the only place to start, but you could essentially say, if you have a patient with renal failure and you don't know whether they're wet or dry,
Speaker: There are other ways to do this, but if you're not putting a PA catheter, the usual technique is to give a bunch of fluid, and if that doesn't work, give a bunch of diuretics.
Speaker: So you might argue that it may actually have lower morbidity to measure filling pressures and then decide whether what you need is fluids or diuretics.
Speaker: So that might be one situation in which...
Speaker: You don't necessarily need a PA catheter, but you could imagine that it might be useful.
Speaker: And those patients tend to be relatively stable.
Speaker: So that might be one place to start.
Speaker: And, you know, the other thing is that you can get some help.
Speaker: Call your interventional cardiologist and say, look, I want to do this at the bedside.
Speaker: Would you mind coming and talking me through it?
Speaker: I think that would be a good way to start.
Speaker: Excellent.
Speaker: So you've been on the podcast before, Steve, and you know, we like to close with a couple of questions unrelated to the clinical topic.
Speaker: Last time we spoke about books, but are there any books that you've read since we last spoke that really impressed you?
Speaker: So there's one book that I like and I really like to recommend.
Speaker: I don't know if you've read it.
Speaker: It's a book called I Contain Multitudes.
Speaker: It's by a guy named Ed Young, who's a science writer for The Atlantic magazine.
Speaker: And it's about the microflora.
Speaker: It's about bacteria and the microbiota.
Speaker: And as you probably know, we have more bacterial DNA in our bodies than human DNA.
Speaker: And it talks about not only our microbiota, but the way that microbiota finds ecologic niches and the way in which those niches work often in synergistic ways.
Speaker: fashions and help not only host for the microbiota, but help the host organism in a number of ways.
Speaker: And you could argue that our microbiota do that for us.
Speaker: It's an ongoing area of investigation.
Speaker: I think that's, it's a really fascinating book.
Speaker: I have not, the only multitudes I read about was in Leaves of Grass.
Speaker: So I would definitely will, will, will read this book.
Speaker: Sounds very interesting.
Speaker: And I think it's always one of those things that I tell people is reading about things that you have no expertise over or that, that doesn't come in your daily work is usually very enlightening and opens your mind to new ideas.
Speaker: So yeah, definitely.
Speaker: What I did want to ask you though, is I used to ask if you were stuck on an island, but now I've added or isolated with a new pandemic, where there'd be any, what are two musical albums and I'm old school vinyl.
Speaker: So I say albums, although I hear CDs are also coming up, making a comeback these days that you would want to have with you.
Speaker: Yeah.
Speaker: So I, I, I thought about this.
Speaker: I think, I think I might go with a Miles Davis kind of blue.
Speaker: It's a, you know, as you know, it's a classic jazz album, but it's one of those albums that you hear a different thing every time you listen, and you recognize a little more of the genius every time you listen.
Speaker: It's really a great album, and I think I could spend a while listening to that one, too.
Speaker: And then, you know, maybe a classical album.
Speaker: My favorite classical piece is actually the Brahms Requiem.
Speaker: Perfect.
Speaker: And we'll add links to all these in the show notes.
Speaker: So the next question, Steve, is could you share with us something you changed your mind about over in the last couple of years?
Speaker: Yeah, so I think I've, I'm thinking about this.
Speaker: I've sort of changed, I don't know that I've changed completely, but I've kind of changed my attitude about the concept of, of why not try an unproven therapy when you don't know what to do, particularly if you think that unproven therapy is relatively safe.
Speaker: And sort of, you know, what could it hurt?
Speaker: And I think we saw a lot of this in the COVID pandemic.
Speaker: And we saw a lot of people trying a lot of things.
Speaker: They tried vitamin C, they tried ivermectin, they tried hydroxychloroquine, and the argument was, well, they're probably not harmful.
Speaker: And
Speaker: They probably weren't harmful, but they weren't helpful.
Speaker: And to me, that really hindered the effort to figure out what works because it just complicated things.
Speaker: So to me, when you don't know what to do, you should at least have some plan to study what you're doing.
Speaker: And that doesn't mean that you have to only do things that are proven in randomized clinical trials.
Speaker: But if you're going to try something, then you want to know, you want to at least have some sense of,
Speaker: what would say that that particular therapy was working and sort of measure it, try to figure out whether that particular therapy is doing what you think it is doing, whether that's an observational thing or whether that's a...
Speaker: participation in a controlled trial is sort of up to you.
Speaker: Controlled trials are preferable, but there may not be there.
Speaker: So I've kind of gotten a little harder on, you know, don't just do something, stand there.
Speaker: And I also think along those lines that we in the scientific and the medical world need to be advocates for that approach.
Speaker: We need to say that science works and that we need to study things and try to
Speaker: figure out what works in a scientific fashion rather than letting everybody choose an empiric therapy that makes sense to them.
Speaker: I agree.
Speaker: And I think that on that note, obviously, two things that come to mind immediately, Steve, are our best to action.
Speaker: Right.
Speaker: We always think that doing is better than not doing.
Speaker: And I think that gets us into trouble many times.
Speaker: But the other mental model idea or concept that that I think applies and I've been thinking a lot, a lot about a lot lately is opportunity cost.
Speaker: Every time we do something, we are paying an opportunity cost to maybe do something that was more valuable or better.
Speaker: And I think it's worth thinking, right?
Speaker: I mean, I think that all the energy, time and money spent on all these trials and all these to try to prove or disprove these worthless therapies were wasted because there probably was better scientific arguments to go in other directions.
Speaker: Right.
Speaker: And, you know, the other thing is that what you give may be safe, but what you don't know is whether that safe therapy is making something else stop working.
Speaker: And you don't know that unless you test it.
Speaker: So, you know, imagine doing a trial in COVID where half the patients are on hydroxychloroquine and half of them aren't.
Speaker: That just introduces unnecessary complexity into the interpretation of a trial.
Speaker: For sure.
Speaker: So the last closing question is, what would you want every listener to know?
Speaker: Could be a parting thought, a quote, or something else.
Speaker: So I thought about this.
Speaker: I've decided this is my new favorite quote about medicine.
Speaker: And the quote is, and I didn't invent it, but I heard it once.
Speaker: I can't even remember who said it.
Speaker: But the quote is, good judgment comes from experience, and experience comes from bad judgments.
Speaker: So this is not, I don't read this as a call to have bad judgment, but I think it really stresses the concept of continuous learning.
Speaker: Try to figure out when something doesn't work,
Speaker: try to figure out what you could have done differently, how that could have gone differently.
Speaker: And there are processes within the hospital, but even in your own practice, when things don't work.
Speaker: And even when you do something and get in trouble, why did you get in trouble?
Speaker: What were you seeing that was deceiving you?
Speaker: Or what did you not see?
Speaker: And sort of how can you try not to have that happen the next time?
Speaker: So that's my new quote.
Speaker: I think that's a perfect place to stop.
Speaker: Steve, thank you for sharing your time and your expertise with us once again.
Speaker: Look forward to have you back and to talk about other topics.
Speaker: And always good to learn from you.
Speaker: Great.
Speaker: It's been a pleasure.
Speaker: And thank you for having me on.
Speaker: Thank you for listening to Critical Matters, a sound podcast.
Speaker: Make sure to subscribe to Critical Matters on Apple or Google Podcasts and share with your network.
Speaker: Sound's transforming the way critical care is provided in hospitals across the country.
Speaker: To learn more, visit www.soundphysicians.com.
