Dr. Natalia Ivascu on Fluid Management in Cardiac Surgery for Acute Kidney Injury

Hills and Valleys is a podcast that uncovers stories from leaders in healthcare, tech, and everything in between. Straight from the heart of Silicon Valley, we give you a look at the good, the bad, and the future, one episode at a time. Brought to you by Potrero Medical.

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About Dr. Natalia Ivascu

Dr. Natalia Ivascu is an Associate Professor of Clinical Anesthesiology. She cares for patients as a Cardiac Anesthesiologist and Critical Care Intensivist in the Cardiothoracic Surgical Intensive Care Unit. Dr. Ivascu is the Director of the Cardiothoracic Surgical Intensive Care Unit (CTICU).

Dr. Ivascu completed her undergraduate studies in Cellular and Molecular Biology at the University of Michigan, in Ann Arbor. She went on to earn her medical degree from Wayne State University School of Medicine in Detroit, Michigan. She began her career at NewYork-Presbyterian Hospital/Weill Medical College as a resident in Anesthesiology. Dr. Ivascu completed an additional year of fellowship training at Cornell, in Cardiovascular Anesthesiology. She then spent a year at the Columbia University campus of NYP as a fellow in Critical Care Medicine.

Dr. Ivascu is board certified in Anesthesiology and Critical Care Medicine. She is also a Diplomate of the American Board of Echocardiography, with certification in Advanced Perioperative Transesophageal Echocardiography and Special Competence in Critical Care Echocardiography.

Follow Dr. Ivascu on Twitter @NIvascuMD

?       Interviewer: Omar M. Khateeb, Director of Growth at Potrero Medical

?       Interviewee: Dr. Natalia Ivascu

Khateeb: Hi, everyone. I’m Omar M. Khateeb, the director of growth over at Potrero Medical and we are in Chicago at the fantastic Society of Cardiac Anesthesiology meeting and we’re joined by Doctor Natalia Ivascu. 

Thanks for spending some time with us. You’ve been quite a popular person. It’s hard to get ahold of you, so I’m glad we’re able to get you for a little bit. Welcome. 

Ivascu: Thank you. I’m honored and really pleased to have a chance to talk to you too. 

Khateeb: Great. Before we jump into things, tell us a little about yourself. Where’d you grow up? Where did you go to med school? And, how did you go from the Natalia Ivascu to Doctor Natalia Ivascu? 

Ivascu: Well, I grew up in the Detroit area. My family is of Romanian origin. My father was an immigrant when he was 12 and my mother was born in the Detroit area also, but her parents are Romanian. We grew up in that sort of community and I went to the University of Michigan for undergrad.

So that was as far as I…

Khateeb: Go blue, right?

Ivascu: Go blue, absolutely! And from there, I decided about midway through college to pursue medicine and apply to medical school. So, I first got into Georgetown and the first thing out of my mother’s mouth was: “This doesn’t mean you can’t go to Wayne State, right?”, which is where my sister was in medical school in Detroit.

I ended up also being admitted to Wayne State and it was really the best decision ever. I entered medical school there, not so far from home. It was an economical choice and especially now with all the pressure on positions, dealing with post graduate debt. I was really pleased that I chose a state school in the end.

From there, I applied to residency, and I wanted to go to a city and get further than 45 miles from home, which is as far as I had really gotten up till that point. [Laughs]

Khateeb: Oh, it’s a really good idea.

Ivascu: I really fell in love with New York when I came to do interviews, so I chose Cornell New York Hospital at the time to do my residency. I picked it in part because I knew I wanted to do cardiac anesthesia and they had a really strong department of cardiac surgery and cardiac anesthesia division within the department of anesthesiology.

I stayed there for my fellowship in cardiac anesthesia, then I ended up deciding to pursue critical care. I spent a year at our sister institution of New York Presbyterian Columbia University, Uptown. I did critical care and then resumed my practice at Cornell and I have been on faculty for 12 years.

Khateeb: Fantastic. I’ve got to go back a little bit. So, you said that halfway through college you just decided to become a pre-med. What did you start out thinking you were going to do and what made you change? 

Ivascu: Well, I thought I would be a lawyer and even in our pre-conversation you picked up that I like to talk and it’s easy for me to have a conversation.

So, I guess that was my general impression of what I might go into. The turning point was that I had a lot of friends that are pre-med. Everyone comes into college or last people come into college pre-med. 

Khateeb: I feel like everyone starts out as either pre-med or pre-law and very few stick it out.

Ivascu: And you know, even though I had been a strong student, I really held physicians on such a high pedestal. We didn’t have doctors in my family. It was just something so important. I think I had the impression that, well, maybe I’m not smart enough to do that and so in my sophomore year of college, I took organic chemistry a real “weeder” course as they say.

Khateeb: It’s definitely a leader course. 

Ivascu: In the first exam I did totally average and I was like, Oh I can’t believe this. So I went to office hours and I became really interested in Biochemistry. I was like, I’m going to master this, and I did great on the next exam. 

After that, I had figured out organic chemistry, and I ended up getting an A-Plus. I didn’t know that A-Plus existed in college. As a result, I decided that maybe I’m smart enough to go into medicine and ended up heading that way. 

Khateeb: Very nice. I’m gonna edit this part out. [Both laugh]

It’s okay. It’s okay. Hey, you know, that’s the benefit of being at these conferences that people come by and say hi to you and everything. I don’t think I’m going to edit this part out. I think it’s good. 

Ivascu: Well, that’s an old friend that was at Columbia when I was a fellow.

That was 13 years ago, and we’ve never worked together since, but we see each other at conferences. He’s actually now in UCLA on the other end of the country and conferences are so great with networking and making connections that you just wouldn’t have without them. It’s still worth making the trips and coming in person 

Khateeb: Nice. When you were in medical school, what made you say, “I’m going to go into Critical Care”? 

Ivascu: I wasn’t really sure what I wanted to pursue. I feel like the first decision in choosing a medical specialty is deciding if you like clinic work or hospital work because they’re very different jobs.

You know, I always think it’s interesting especially those of us who went into medicine that didn’t have family members in the field that have a very glossed overview of the idea of the profession. We think all doctors are doctors like it’s all the same job, but there’s a huge difference. For instance, it’s completely impossible to see pediatrician, radiation oncologist and general surgeon like the same kind of a job. They have different hours, different responsibilities, and different pressures. It’s just something that I didn’t really appreciate as I was doing my clinical rotations. 

I quickly realized that I liked being in the hospital. I liked the intensity of it. I like the organization in particular. Most of all, I think I like the teamwork. I think being alone in a clinic just doesn’t suit my personality. I’m more of an extrovert teamwork kind of a person. 

Being in the hospital is going to lend yourself to being in the surgical half of the hospital. The hospital is really divided in half between medicine and surgery and many times, the two don’t meet. The people in medicine may never encounter what’s happening in the surgical corner of the world. The most organized and predictable in terms of day-to-day operations is really in the surgical side. So that kind of kind of spoke to me. 

From there, I wasn’t quite sure. My sister was a year ahead of me in medical school and she actually is a trauma surgeon. She does both trauma surgery and critical care. I saw similarities and differences in our personalities. In any case I considered surgery, but to be perfectly honest, I think the one thing that bothered me the most about surgery is that some patients are going to have complications and they were going to be at my hand. That’s just an interesting thing about surgery. 

Patients get diseases and we try to give them treatment?medical treatment or surgical treatment. When medical treatment doesn’t work out, well, as doctors you usually think to yourself, What happened to the patient? What did their disease do? On the surgical side of the world, when the treatment doesn’t necessarily give the results we’re hoping for the first instinct is What was done wrong?

I think I just had that fear of being in that position of thinking someone didn’t do as well as they could have in my hands and I thought I’d be better being part of the team than having that kind of role on the team. So, I found anesthesiology and stumbled into it. We didn’t have a formal rotation even in my medical school that was required and so I stumbled into it. We had a really great pediatric anesthesiologist. She was known for finding people that might be interested in anesthesia and encouraging them when we were on our surgical rotations. We’d be in the operating room and if you came early, she’d walk you through the anesthetic care and helped you participate in it. This sparked that interest within me.

Khateeb: Did she serve as a mentor for you? 

Ivascu: A little bit. Actually, other anesthesiologist who were in surgery were always the doctors saying: “Oh, you should do this job. It’s much better than the surgical job.” In general, I got to find out that they seemed like happy people. Then I did a rotation in cardiac anesthesiology as an elective in my fourth year.

That’s where I really solidified my decision that this is what I wanted to do. Not just anesthesiology but cardiac anesthesia in particular because there was a lot more to it than just the anesthesia. 

Khateeb: It’s a very high stakes environment. 

Ivascu: High stakes environment, yes; with lots of procedures too. Having to place an arterial line, to measure the blood pressure, to place a line in the neck, to be able to monitor the heart pressures as well as giving medications. Then the transesophageal echo. It’s such a particular role for the anesthesiologist that we provide this inter-operative examination that gives information to the surgeon that either solidifies or finds new information related to the cardiac disease. We often get better pictures if they only had a transthoracic echo preoperatively, the transesophageal echo being that the probe is in the esophagus right next to the heart.

This way, we get much more detailed and sharper pictures so we can understand the pathology better. There was a clear dynamic of teamwork and partnership such that the anesthesiologist role I felt in the cardiac O.R. was different from what I observed in the general O.R. where they seem to be much more siloed. In the cardiac room there was a lot more interaction and involvement between the team. Then after the surgical repair, there needed to be some evaluation to make sure that it was adequate and so forth. So, there’s a lot of give and take in conversation about the management. 

Khateeb: Yeah. At least from my times that I’ve gone into cardiac cases, between anesthesiology and surgery, if there’s anything that is an analogy for a grand symphony, I feel like it’s the cardiac O.R.

The cooperation between the prefusion team, the surgical team with anesthesiology and nursing is insane. Another thing I’ve noticed coming from Silicon Valley as a technologist is that I don’t think much has changed from the picture of a critical care room in the ‘70s till now. Also, I don’t think much has changed in the cardiac till now because while I’m walking, I have to either be looking down, so I don’t trip on anything or looking up, so I don’t run into anything. So, there’s a lot of stuff going on.

Ivascu: Yes, a lot of stuff going on. There are definitely some improvements. Like all technology there’s growth. We may be using similar equipment but it’s certainly better equipment. We were just joking yesterday about how the T.E. machines looked when I was a resident.

Someone asked me, Do you remember when there was a VCR tape? and I was like, Yeah, that’s how it was when I was in training that you had to record the echo which was a digital recording of it. So, you put it in the VCR tape, and you recorded all of your clips live. Then you can go play it in the VCR to review it.

Khateeb: RadioShack could have been a medical device company if they’d thought about it the right way. 

Ivascu: Exactly. Now, it’s all of course digital clips and the processors are amazing, and we can do all these technologies we couldn’t do. When we first changed the VCR level to the next generation, I remember it was so frustrating to go back. I used to say I have to slow my brain down to be able to use this machine because the rate at which you could take pictures was so much slower you’d get this sort of choppy picture as opposed to a really nice continuous picture.

The quality has improved and some of the technology has improved in that way. There are some differences in what’s happening in the critical care environment in that we’re doing more things. We have more ways to keep people going. And one thing I think we are struggling with in cardiac surgery, cardiac anesthesia, and cardiac critical care is finding that right line of knowing what’s heroic that’s likely to have a good outcome and what’s heroic that’s probably not. So, where is the line of “too much”? 

Khateeb: I wanted to ask you this. You gave a lecture on a very interesting time about training residents, especially with transesophageal echo. Can you dive into a little bit about having the residents and the ethics around training them with, of course, the third party being the patient?

Ivascu: Yeah. I really love being an academic anesthesiologist because we get a chance to work with trainees and they challenge you they come up with new ideas. There are a lot of benefits to having them around the care of a patient. However, there are some challenges that we have to think of as well.

We can justify training by saying there are some added benefits like it makes you have another person involved. They are another set of eyes and may find things no one else noticed. They’re another skilled person and somewhat educated person involved. There’s also the ability for the attending senior person to be in more places at once so you can expand care in that way.

In other words, having trainees can improve or allow care for more patients. So, there are some plus sides. The thing that we have to keep in mind, however, is in two parts:

One is making sure that the things we teach residents, especially the technical tasks and invasive procedures, are done in a way that is appropriate. The tasks need to be appropriate to the level of the resident or else needs to be appropriate to the preparation that they’ve made. Simulation has changed the way we train residents. We don’t have to literally do the common saying in medicine: “See one, do one, teach one”. It was quite literal in a lot of ways which I’m sure is horrifying from a patient’s perspective that you would see a procedure, do a procedure and then all of a sudden, you’re the teacher but it was pretty close to that. 

Now, we have wonderful simulation that allows us to be able to bring learners along to learning basic tasks so that when they get to the patient, it really isn’t the first time they’re doing it. Maybe everyone’s going to have the first time they’re doing it on a real person, but they’ve already had appropriate exposure and experience in a training situation. As a result, they have the correct knowledge along with some dexterity and manual ability that makes it much safer.

Transesophageal echo is something that’s unique to our specialty in terms of intraoperative teaching. It exists in a couple of other areas like transplant liver transplant in particular has a high use of intraoperative Echo and some other surgeries may use intraoperative Echo. However, on a routine basis, if you wanted to learn transesophageal echocardiography go to the heart room because that’s where it’s being used every day.

So, it’s an opportunity for education. Again, it’s a good place to be able to teach this. I think of it like getting in a car with a student driver. If you’re going to get into the car with a student driver, the student has to learn but it’s a safe environment, because there’s an expert right next to them.

They have their foot on the safety break and they can control the situation. As you know, that’s probably okay if the passenger has to get where they’re going anyway. This is a way for that passenger to get from point A to point B. I think it’s a really justifiable way to say, Okay, you have to get there and we’re going to take you there. However, in this very safe environment with appropriate safety precautions met, we’re going to let this other person who’s not yet an expert but already has appropriate level of training to start driving. What’s tricky is when we use opportunities of convenience, the passenger doesn’t actually need to make the trip. You can justify that maybe it’s not quite as safe with a student driver as it would be if the expert was in the driver’s seat, but they have to get there anyway. It’s okay because they’re still going to get there reasonably safely. But is it just as justifiable to take a passenger and expose them to that risk if they don’t need to be in the car at all? That’s where we need to draw that fine line. 

Something that we talk about and try to examine is where is that appropriate level? This is something tricky for us in the cardiac O.R. because it’s not clear when you cross that line. So, for example, we do a lot of invasive procedures as I mentioned. I typically let my residents do those procedures or make the first attempt at it. Anyhow, I can justify it based on all the things that we’ve talked about. I’m always right there watching and making sure nothing I’m not comfortable with isn’t happening.

The echo is similar. When we have cardiac fellows, for example, and it’s time to do the exam, they may have their hands on the wheel but I’m right there next to them directing and making sure that we’re doing the appropriate clips and that they’re manipulating the probe safely.

The tricky part is that there might be an opportunity there. Since the patient’s anesthetized and the probe stays in place throughout surgery, maybe we could have another person also do a practice exam. After all, we might find something else. They’re anesthetized and the probe is there anyway, so why not? Well, I’ve given you some reasons why not already and that’s where it can be really easy not to realize that you’ve crossed the line. It’s just liked any other part of education, right?

We let the trainees be involved in all these other elements, why is this different? And when is different because maybe we’ll see something that we didn’t see the first time around while the next person’s repeating the exam. It’s not a black and white answer but it’s something I think we need to be aware of and something we need to talk to patients about. That’s where the ethics of this comes in.

We live in a society where we prize autonomy?the ability to decide what will happen to one’s body. Of late that’s become a question in some states in this country, but generally speaking you’re allowed to decide what is going to happen to your body. 

Khateeb: One thing I was going to ask is that in the last few decades, it seems that there’s been an explosion with technology and it’s a good thing in the sense that there are better solutions to approach problems in medicine. The problem though is that it’s similar to a few centuries ago when someone discovered the microscope and looked at water droplets like, Oh my God, there are millions of organisms in here!

Now with data and technology, there are new problems are surfacing. In some ways they’re solving certain things but on the other side, it’s complicating a lot of things. How does this affect the way you train residents? 

Ivascu: Well, it’s becoming an overwhelming environment for residents. In particular, it  makes me think of working in the ICU with a tremendous amount of data that comes up on patients every single day which we have to consider; whether it’s laboratory data, radiographic data, X-rays, EKGs, trends on their urine output patterns, their heart pressures or any other markers of their cardiac performance. It’s a lot to manage for people who do it all the time, but it’s even harder to manage when you have rotating residents who are going to be changed every couple of months with a new resident coming in that has probably never been there before.

So, it’s this perpetual state of orientation. It is a little bit sub-specialized from what they do in other areas and that’s something that poses a challenge to us. I do think there are limited great solutions of which one is to have advanced practice providers like physician assistants and nurse practitioners that are there on a more regular basis and would have more of the “usual routine” in mind. The downside there is the physician input; you do have a different type of training for those providers. There might be some advantages and disadvantages.

However, that’s where I do hope that the burgeoning artificial intelligence and predictive technologies are going to be really significant in the ICU in particular because trends are really important and you can get caught up in the fog of war, so to speak. You can get caught up in all the things happening that you could easily lose sight and it’s that subtle trend that I think is most important for patients. 

We always make an inaudible joke about being a black cloud and there is some truth to the fact that everyone’s more of a black cloud when they’re a junior. I’m sure they just don’t see it coming. And as you become more and more senior, your cloud gets less and less dark because you are more likely to sort of see things coming. You have both the experience and instinct.

I think it could be very useful in terms of streamlining and making it a little bit more standardized.

Khateeb: Interesting. On the topic of intuition, we checked out. Dr. Perry at the University of Minnesota. He had to talk on the use of technology and how that could essentially help free up physicians so they can get back to utilizing more of their intuition and it seems that with all the technology and data points, you have no choice but to start using your intuition to pay attention to what’s important at that moment because there are so many different inputs.

How do you how do you decide what to rank as more important than something else with all these data points especially in the cardiac suite with all these different monitors going on? 

Ivascu: Something I actually like to emphasize with the residents is that the very essence of being a doctor is making the diagnosis not fixing the numbers. 

The electronic medical record is another big driver because so much of a resident’s life is chained to the computer to enter orders, modify orders, discharge orders, and reinstitute orders. Each click does take a large portion of their day.

So, there’s this urgency when there’s something wrong. For example, if the patient’s blood pressure is low, there’s an urgency to quickly add some blood pressure medication to raise the blood pressure and fix the problem. Unfortunately, in the process of rushing to fix the numbers, I’d like to say we miss the opportunity to make the diagnosis. This is my saying all the time, so I feel like I’m an echo. Once you make the diagnosis, you can Google the treatment. Everybody can Google the treatment. Being a doctor is about making the diagnosis, not fixing the numbers. 

I think that having some cognitive unburdening as you described?by helping the numbers to be processed to be able to raise alerts, allows that physician to come in. And, you know, I hesitate to use the term intuition because in a world of evidence-based medicine, we get a little bit farther from the idea of the art of medicine or the creative piece to it.

I think that the quote art of medicine isn’t so much that you go with your gut or even your experience, because that’s what research is supposed to be giving us evidence based. It’s that you have the time and cognitive energy to be able to process the information in order to see which of your evidence-based information is applicable or if there is no evidence.

Sometimes it spurs some future investigation; however, it can also give an alert of something that’s going on here and we’re not sure if we know the right treatment for this. So now more attention has to be paid here instead of drawing those resources. 

Khateeb: So doctor, one of the interesting things is that once you start getting more evidence on certain syndromes and diseases, it does have the potential to shift paradigms and change the way you diagnose a patient, One of the things that we focus on here at the podcast is Acute Kidney Injury.

It’s kind of a black box disease and a syndrome that no one really knows much about because technologies didn’t really exist to either understand it or monitor it, but that’s changing. You published an interesting article that I’ve never read anything like it. It was about what you call congestive kidney failure and more specifically how central venous pressure is a very powerful indicator of Acute Kidney Injury in the cardiac suite. Can you tell us a little bit more about that? 

Ivascu: Sure. So, you obviously read that the kidney is so important and it’s a really smart organ. It tells us when we…

Khateeb: We got two of them, right? [Both laugh] So that’s the importance. 

Ivascu: That’s right. It tells us a lot of information on how a patient’s doing in heart surgery the realm in which I work. I’m particularly interested in the kidney because first of all, if the kidney doesn’t function well, the fluid management in the body will be dysregulated and that can lead to heart problems which is, of course, our main concern. And conversely if the kidneys aren’t functioning well, it might be an indication that there is a heart problem causing the kidneys not to produce urine in their usual amount because they’re not seeing enough blood flow. That’s a marker that there’s a perfusion problem or a blood flow problem in the body. So, we pay a lot of attention to the kidney a lot of time and the urine output. 

The concept of the congestive kidney failure is that if, for example, the right atrial pressure and the central venous pressure is elevated?and it can rise for different reasons?that’s reflected back to all the organs from the lower extremities that would normally drain to the heart.

Both from the upper body as well as the lower body, the blood all drains back to the right atrium and then passes to the lungs for oxygenation. This is all a passive downhill flow of blood. So, if that pressure becomes elevated on the right side of the heart, then it gradually becomes a more uphill rise for blood to return. In doing so it engorges all of the organs and doesn’t allow them to drain normally. 

The perfusion pressure of the kidney, meaning the blood flow to the kidneys, will be reduced by this back pressure or engorgement because the organ is not able to empty the venous blood adequately. That can lead to dysfunction, decrease in urine output and decrease in clearing all of the toxins for which the kidney is responsible. So, it becomes a vicious cycle because as you’re not making urine, it’s likely your fluid overload continues to rise, and that central venous pressure will get even higher. This is why it creates a vicious cycle. 

And as I say in cardiac surgery in particular, patients are so vulnerable for having heart issues particularly related to fluid management in the perioperative period so it’s something that’s of a special importance to us. 

Khateeb: That’s interesting. Historically, decreased perfusion to the kidney either by ventricular pump failure or vasoplegia is one of the main hemodynamic determinants of AKI but, one thing that I read in your papers was that you found that this is really being challenged by the concept of increased central venous pressure, which is becoming more of a powerful determinant than arterial pressure.

Why central venous pressure over arterial pressure? 

Ivascu: Well, they’re both important because certainly the organ (kidney) like any organ needs arterial perfusion. The best way to think of arterial perfusion is the very simple goal of the entire heart and lung system, which is to bring oxygen to the cells.

So every cell as an obligate anaerobe must have oxygen. Therefore, the arterial pressure is important because that’s going to bring the oxygen which allows the organ to function normally. However, some of the reason why there is increasing attention in this realm is because there’s also increasing attention on the right heart itself which we used to call the “Forgotten Ventricle”.

I think that’s aptly named because the right heart is actually a remarkable thing in that the right heart is much thinner walled. It’s not the big powerhouse muscle like you’d describe the left heart. 

Khateeb: The left heart I guess definitely has much better marketing around it. [Ivascu laughs] Yeah, it’s better marketing on the left side.

Ivascu: Absolutely. The right heart has got a new PR agency because right now, it’s starting to get some notoriety in that realm. In particular when we have patients, for example after heart surgery, their right heart is a little bit more vulnerable.

Khateeb: Why is that? 

Ivascu: Almost all patients that have heart surgery will have a period where the heart is stopped. I mean, we stop all blood flow to the heart in order to be able to operate on it. It’s a remarkable thing. In fact, it is really what revolutionized the ability to do heart operations back in the 1950s. The stopping of the heart is protected. We give a medication called cardioplegia that protects the heart, meaning it reduces the metabolism of the heart to be able to tolerate this period where there’s no blood flow. However, that period of time which we call the “aortic cross-clamp time” is actually the “myocardial or heart muscle ischemic” time.

It’s the time that there was no blood flow to the heart during the surgery. There are other medications used to reduce the need for oxygen but there was still no presence of oxygen and as a result there will be some inevitable?maybe not permanent but at least temporary?injury to the heart and the right heart is particularly vulnerable.

It’s not as thick-walled as the left heart. Although the whole heart is cooled down, it doesn’t have that thick internal refrigeration hence it’s a little more vulnerable to warm back up to room temperature, which is why we try to get it below 10 degrees Celsius. Obviously, the room is much warmer than that. So inevitably, it could warm up. 

Also, those hot surgical lights. There’s this movie version of a surgeon’s forehead being dabbed. That’s doesn’t happen in reality, but it can be quite warm under those lights. Since the right heart is what’s most anterior in the chest, it may be a little more vulnerable to losing some of the benefit of the protective techniques. 

Then the third thing is there’s a lot of extra fluid in the body and so there’s an inflammatory response, there’s a need for fluids… 

Khateeb: I guess all the ECMO being done has an effect as well. 

Ivascu: You mean the heart and lung machine? 

Khateeb: Yes. 

Ivascu: Yeah, because they’re on the heart-lung machine during surgery that causes an inflammatory response. They tend to need some more fluids and their total body volume goes up. They may need blood transfusions or other factors. 

Khateeb: And I guess that’s what causes the central venous hypertension? 

Ivascu: Exactly. It’s either one thing or another. If the ventricle is not working well or even in a normal ventricle, if you give it enough volume the pressure will start to go up and then you can run into those kidney problems. 

The kidney also has a stress of going through surgery. We know that surgery itself is a risk factor for post-operative Acute Kidney Injury. One of the main taxes on the right heart and those first few days is that as that fluid which may have become extravascular from the inflammatory response starts to get intravascular again, that right heart is vulnerable to not being able to keep up. And if the right heart can’t pump it to the left heart, then it can’t get to the kidney and it can’t be turned into urine and excreted by the body.

Khateeb: Yeah and then it becomes this whole cast kick. That segues into another question that I have. In the paper, you’d mentioned that postcardiotomy AKI is grossly underestimated. I’m guessing it’s because of this reason that you just stated. 

Ivascu: Yeah. We watch very closely to some extent, but we use traditional markers of creatinine to look at kidney function. There’s definitely emerging evidence that there may be some biomarkers that may give us an indication sooner.

However, all too often the dye has already been cast.  This exactly happens in the operating room and what we can do though is to avoid further fluid overload or be more aggressive in fluid removal and be on guard for it. 

Khateeb: When you’re in the operating room, what do you look for to give you an idea about how those fluids are being managed and everything? 

Ivascu: There are a variety of ways to do it. In our institution, we typically use a pulmonary artery catheter also known as a swan-ganz. That catheter sits in the heart and gives us the continuous central venous pressure as well as the pulmonary artery pressure?the pressure that the right heart is generating. We also have the echo. We use these things to help guide our fluid management so that the fluid we’re giving is only to the extent that we want to optimize the stroke volume which is the amount of fluid that’s ejected with each heartbeat, but not more than that. If not, that’s going to add to this total fluid overload, which could become problematic in the days after.

It’s still a moving target but certainly many different areas of medicine have looked at evidence concerning goal-directed fluid administration and that’s something that we continue to do as well. 

Khateeb: In this process, where does urine output fit? Is that a factor?

Ivascu:  Well that’s a huge part of kidney function as well. The creatinine gives us some objective data, but the urine output is definitely an indicator of kidney function.  That’s one of the things I mentioned in terms of subtle trends which I think can be really helpful. Let me give you an example. A pretty common post-operative complication of heart surgery is atrial fibrillation. Many patients will tolerate atrial fibrillation very well. Their pressure may not change or may only change subtly. 

Khateeb: Unless they have a bunch of comorbidities, right?

Ivascu: Forget about all the other things going on. Just looking at their heart and their blood vessels, some people will tolerate it pretty well. It is dependent on some subtle factors, but sometimes their blood pressure may still be okay. They will, however, notice that there’s a big drop-off in their urine output and that tells us that the blood pressure’s only one marker of knowing that the heart is able to produce enough blood flow. The other is if the amount of blood flow actually going is enough to meet the demands of the body. I’d say the kidney is smart, especially in patients that don’t have pre-existing kidney disease. 

Khateeb: The nephrologists will appreciate it. [Ivascu laughs] 

Ivascu: I do it all the time too. The smart kidneys will tell you when there’s something going on because it’s not making blood flow for a reason. We may use diuretics and things like that to augment it but if the kidney doesn’t respond to the diuretics as we’d expected it, there’s probably something happening.

It may have to do with that forward blood flow, so they may have a primary heart issue. and atrial fibrillation could be that reason. So, it may look like they’re tolerating it from the perspective of their blood pressure; but were you to not be aggressive about restoring normal sinus rhythm, they may start to suffer early kidney injury because maybe this will be a second hit from their initial cardiac intraoperative stress. 

Khateeb: The urine output seems like a point-of-care measurement that can indicate something’s happening upstream that you need to intervene on. 

Ivascu: That’s right. 

Khateeb: I heard this, but I don’t how true it is. Can urine output be a tip-off to a cardiac anesthesiologist as to how healthy the cardiac output is?

Ivascu: Absolutely. The urine output tells us a lot about the cardiac performance in general. In patients that are at a higher risk for Acute Kidney Injury, a one-to-one analysis may not be that a low urine output definitely means there’s a heart problem. It might be a primary kidney problem.

That’s one of the subtleties I think is important to know when taking care of cardiac patients postoperatively because there are occasions where patients have Acute Kidney Injury that’s significant from the operating room. Maybe there’s a pressure reason. Maybe there was a lack of appreciation of decreased kidney function going in. Again, we only have rudimentary numbers looking at just the creatinine. 

Maybe there wasn’t as much kidney reserve as we thought and so they come out with kidney failure or kidney injury at least very early postoperatively. We have to use these other monitors to distinguish whether it’s a heart problem or a primary kidney problem.

This is something that’s really important which we’re actually working and studying right now. Based on my personal experience, if it turns out that there’s a good heart function and you therefore by deductive reasoning assume that this is a primary kidney issue, it’s very important to not be afraid to give aggressive diuretics. This will help make sure the kidney doesn’t stop making urine. It also ensures that it makes enough urine that can help to start bringing down the CVP which may help the recovery of the kidney but also prevents the heart failure.

If the kidney is failing primarily and you do nothing, you’ll go into heart failure too. This is because the fluid will start to immobilize and the body won’t be able to produce urine. Now you have a second hit on the kidney meaning you will have started with an injury from the surgery, let’s assume. And now, because the heart’s not functioning well, the forward flow out of the heart is not good. So, the kidney by implication is getting starved oxygen because it’s not getting enough blood flow from the heart. That second hit is what we know causes even more kidney injury and predisposes to renal failure needing dialysis.

So, whenever we see kidney injury, we’re sometimes nervous about giving diuretics thinking it could actually cause more harm. However, in fact in this one particular various specific case in heart surgery, we know if we don’t aggressively manage fluids, we may predispose and risk causing a secondary heart problem, which will only injure the kidney further.

Khateeb: That’s really eye-opening. I don’t remember reading about this back in medical school, but I never realized that in the US alone, there was a paper that showed that there’s about 300,000 death just from Acute Kidney Injury. However, you stating that a lot of times when this kidney injury happens, it backs up and it’s going to end up causing heart failure. So, I wonder how many of those cases?probably thousands of them?are listed as heart failure and AKI is not even thought about. 

Ivascu: Interesting question there. 

Khateeb: You gave me this “Aha!” moment. [Ivascu laughs] Again, that’s why we do this podcast where we love speaking to physicians like you. That’s really interesting. So, what do you think makes a great cardiac anesthesiologist? Because it sounds like being able to look through a jungle of data points instead of focusing on the really specific ones that give you an idea of the physiology and tip you off, right?

Ivascu: Yeah, there’s definitely some multitasking. This is definitely a characteristic. As I mentioned there’s a lot going on and as you mentioned, it’s a dynamic high-stakes environment. There’s a lot of data coming in, there are a lot of monitors, there’s the echo, and there is the aspect of looking at the patient. Intraoperatively, there’s definitely the ability to multitask and in our post-operative critical care I think it’s similar. 

I think the other big piece is teamwork because we do have to function in this greater team. We’re really unique in that were there from the very beginning to the very end.  As a result, I think that we have a real opportunity to be leaders when it comes to teamwork. 

The president of one of the leading cardiac surgery organizations once said in his presidential address that “Cardiac surgery is hard; and when it’s not hard, it’s really hard.” I think that’s really apt. [Laughs] It still presents a lot of challenges and we often can be real leaders in keeping everyone moving in the same direction. 

Khateeb: We want to be very mindful of your time, but I have one more thing I want to touch on. You have a talk coming up in the next hour which is really interesting. I want to read the title. It’s “When doctors slam the door: Addressing the disruptive physician in the cardiac O.R.”.

What a surprise! So, there are disruptive, angry physicians in the cardiac O.R.? I wouldn’t have guessed. [Laughs]

Ivascu: Well, you know as an anesthesiologist it’s easy for us to throw the surgeons under the bus and say it’s always the surgeons. That’s not always the case, but it may be more common that we get aggressive personalities on the other side of the team.

Khateeb: Why do a talk on this? 

Ivascu: Well, we have this upcoming panel and we’re really interested in some of these sorts of issues that come up for us that aren’t just hard science but are actually other things that we really face. The disruptive physician really got attention over 10 years ago. The Joint Commission made it a requirement that we address disruptive behavior and the hospitals have a process for handling it. 

There are three things I hope I’ll be able to accomplish in the talk. One is introducing the concept of disruptive physicians and how it can really indicate some serious underlying pathology that may need professional help. So, referring it may be in the best interest of the person you’re referring as well as in the greater team. 

And again, this is where we can be leaders by being the first one to say that didn’t go as well as it could have, speaking of how we can handle that differently. Let me just reflect back to how the rest of the room, took your attitude today.

I think we have to be mindful of these things so that we can avoid inappropriate behaviors because ultimately that can compromise patient care. In the end we’re all on the same team and that’s the patient’s team.

Khateeb: Absolutely. I think this feeds back into your main point that there are different things that each physician can do to make themselves a great physician, but it’s a care team, right? 

Ivascu: Absolutely.

Khateeb: And so, if the team fails, it’s going to be a failure for the patient.

Ivascu: Absolutely. We are only as strong as our weakest link and we have to help each other be strong so that we can present the best care possible. 

Khateeb: Before we let you go; I’m sure many people are going to be curious how they can connect with you. Do you have a social media handle online?

Ivascu: I do. I’m kind of new to Twitter. So I’m more of an observer than a participant. 

Khateeb: Welcome to the internet. [Both laugh] You can reach me @NIvascuMD. 

Khateeb: Perfect. Are there any other any other social platforms that you have? 

Ivascu: [Laughs] That’s all I have for now. I’ve just broken into social media about six months ago.

Khateeb: How does it feel?

Ivascu: Good. I’m still a little shy I’ll admit, but I’m growing. I think I have 95 followers. [Laughs]

Khateeb: That’s great! One last question. We do have a lot of medical students, pre-medical students and residents who listen and residents. Do you have any suggestions on a good book? Whether it’s on in leadership or medicine, what’s a book you often give to others?

Ivascu: Again, I think it’s obvious since my passion is cardiac surgery. So, I have two books; one is in the cardiac surgery realm and the other is in general. The first is called King of Hearts and it’s really about the origins. It’s the story about Dr. Lillehei, who is a pioneer of heart surgery. I like it because it’s actually a lot of medical history and it’s fascinating to hear how heart surgery began.

It’s something that you probably couldn’t start today. I mean, they had deaths left and right and they went back into it the next day and tried it again, because it was a frontier that there was really nothing else to help some of these patients. I think that book is actually really fascinating from the evolution of medicine point of view.

There’s another book if you do like medical history?called Genius On The Edge. It’s the story of Halstead who is a surgeon known for his clamp. [Laughs] It also takes place in, I guess, early 1900s in New York city. So, I feel like the New York City’s history mixed in with early medical schools. It’s just like one or two medical schools. It’s a pretty good as well. 

Khateeb: Very cool. Thank you so much for taking time to sit and speak with us. We’re looking forward to checking out your talk. 

Ivascu: Thank you very much. Happy to be here. 

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