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Fluid Overload in the ICU
19 Plays5 months ago
Fluid overload is a common problem in critically ill patients. In this episode, Dr. Sergio Zanotti discuss recognizing and managing fluid overload in the ICU with guest Dr. Michael J. Connor, Jr., a practicing intensivist and nephrologist. Dr. Connor is a Professor and Senior Physician of Critical Care Medicine & Nephrology at the Divisions of Pulmonary, Allergy, Critical Care, and Sleep Medicine and Renal Medicine at Emory University School of Medicine. Additionally, he serves as the director of critical care nephrology at the Emory Critical Care Center at Grady Memorial Hospital.
Additional resources
European Society of Intensive Care Medicine Clinical Practice Guideline on fluid therapy in adult critically ill patients: Part 3- fluid removal at de-escalation phase. Intensive Care Med 2025: https://pubmed.ncbi.nlm.nih.gov/40828463/
Optimizing Fluid Therapy in the Critically Ill. International Fluid Academy website – 2025: https://www.fluidacademy.org/2025/01/17/optimising-fluid-therapy-in-the-critically-ill-introduction-to-7d/
Fluid overload in the ICU: evaluation and management. R. Claure-Del Granado and R. L. Mehta. BMC Nephrology 2016: https://pubmed.ncbi.nlm.nih.gov/27484681/
Books and music mentioned in this episode:
Think Again: The Power of Knowing What You Don’t Know. By Adam Grant: https://bit.ly/4gZvz9c
RUSHMERE. By Mumford & Sons: https://bit.ly/473FzKc
Recommended
Transcript
Introduction to Critical Matters Podcast
00:00:06
Speaker
Welcome to Critical Matters, a sound podcast covering a broad range of topics related to the practice of intensive care medicine.
00:00:14
Speaker
Sound provides comprehensive critical care programs to hospitals across the country.
00:00:19
Speaker
To learn more about our programs and career opportunities, visit www.soundphysicians.com.
00:00:26
Speaker
And now your host, Dr. Sergio Zanotti.
Understanding Fluid Overload in ICU
00:00:31
Speaker
Fluid overload is common in critically ill patients.
00:00:35
Speaker
Although it's a frequent finding, a better understanding of its potential harms has renewed interest in properly managing fluid overload in the ICU.
00:00:42
Speaker
Today's podcast will focus on this topic.
Guest Introduction: Dr. Michael J. Conner
00:00:45
Speaker
Our guest is Dr. Michael J. Conner, a practicing intensivist and nephrologist.
00:00:50
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He is a professor and senior physician of critical care medicine and nephrology
00:00:54
Speaker
at the Divisions of Pulmonary, Allergy, Critical Care, and Sleep Medicine and Renal Medicine at Emory University School of Medicine.
00:01:02
Speaker
Additionally, he serves as the Director of Critical Care Nephrology at the Emory Critical Care Center at Grady Memorial Hospital.
00:01:09
Speaker
Dr. Conner's clinical and academic interests are heavily focused on critical care medicine, particularly acute nephrology issues in critically ill patients.
00:01:17
Speaker
Dr. Conner is an internationally recognized expert on acute renal replacement therapies, acute kidney injury, volume management, and hemodynamic support of the critically ill, intra-abdominal hypertension, abdominal compartment syndrome, and extracorporeal blood purification techniques, including extracorporeal membrane oxygenation.
00:01:36
Speaker
Dr. Conner has been on our podcast in previous episodes, and today we welcome him back to Critical Matters.
00:01:42
Speaker
Hi, Michael.
00:01:42
Speaker
How are you?
00:01:44
Speaker
Hi, Sergio.
00:01:44
Speaker
It's so great to be back.
00:01:46
Speaker
Thank you so much for having me.
00:01:48
Speaker
I really always value and enjoy these conversations that we've had together.
00:01:53
Speaker
And I learned so much from you and from your audience.
00:01:57
Speaker
So I hope I can share a few things.
00:01:58
Speaker
Same here.
00:01:59
Speaker
And today we chose a topic that I know is of great interest and passion for yourself, but also happens to be a very common occurrence.
Why is Fluid Overload Critical in ICU?
00:02:10
Speaker
And sometimes I think people kind of don't pay it as much attention as they should.
00:02:17
Speaker
But in your words, why is this topic of fluid overload important for clinicians in the ICU?
00:02:23
Speaker
Yeah.
00:02:25
Speaker
Yeah, you know, this is a topic that has evolved so much over the course of the last 20 years.
00:02:32
Speaker
And please don't get me wrong.
00:02:35
Speaker
I believe very much that, you know, we should be resuscitating our patients.
00:02:39
Speaker
But the question then becomes, you know, how do we manage the fluid moving forward after that resuscitation and when do we remove it?
00:02:47
Speaker
And, you know, we have a wealth of data now that fluid overload is very harmful for our patients.
00:02:54
Speaker
It prevents
00:02:55
Speaker
our patients' recovery.
00:02:58
Speaker
It limits and slows the recovery of our organ function and our overall survival, not the least of which is that it also contributes to organ dysfunction.
00:03:11
Speaker
So we as intensivists are in the business of trying to help facilitate our patients' recovery.
00:03:21
Speaker
And as you know, Sergio, right, there's the sort of reality of critical care medicine is that aside from treating infections and sort of addressing the primary problem,
00:03:36
Speaker
We provide life support, but the patients ultimately have to fix themselves.
00:03:40
Speaker
And there's not a lot of stuff that we can actively do that can really help foster recovery.
00:03:47
Speaker
But managing fluid overload properly and resolving fluid overload is one of those things that we can actually do on a day-to-day basis that does actually improve
00:03:59
Speaker
our patients' chance of recovery.
00:04:02
Speaker
So I think it's a really important topic that we can't just accept that fluid overload is sort of the consequence of critical care these days.
00:04:10
Speaker
We need to work to resolve it and return our patients to uvolemia as soon as possible to help foster their recovery.
Causes and Commonality of Fluid Overload
00:04:20
Speaker
Perfect.
00:04:21
Speaker
Michael, could you tell us about the overall frequency and the pathogenesis or how do patients become fluid overload in the ICU?
00:04:33
Speaker
Yeah, well, let me take the first one because I think it's pretty simple that pretty much it's unusual that a patient is not fluid overloaded at some point during their ICU stay.
00:04:46
Speaker
I think the data has been pretty clear that
00:04:52
Speaker
We tend to, as a side effect of our resuscitations, make everyone sort of fluid overloaded.
00:04:58
Speaker
We're rapidly expanding volume status in almost every critically ill patient when they arrive in the ICU to resuscitation.
00:05:07
Speaker
Maybe a few neurologic indications for ICU admission.
00:05:12
Speaker
Maybe patients don't get as fluid expanded, thinking of the seizure patient or the stroke patient.
00:05:19
Speaker
But almost every other indication for ICU admission generally requires us to do some form of resuscitation.
00:05:27
Speaker
And so, you know, the frequency, the incidence is quite high.
00:05:32
Speaker
It's going to vary from patient, from population to population, and different ICUs are going to have different cultures surrounding this.
00:05:40
Speaker
You know, easily 50% of our patients, if not significant more, will have some period of time in which their fluid overloaded, you know, following admission.
00:05:51
Speaker
Why it happens, you know, the mechanisms are sort of, I would say,
00:05:58
Speaker
twofold.
00:05:58
Speaker
The first is, you know, we're giving resuscitation volumes to patients, whether that's crystalloid, colloids, blood, you know, patients are being resuscitated and we can't really necessarily avoid that.
00:06:09
Speaker
I know that, you know, we might not really get into this too much, Sergio, but I know that, you know, many of your audience and you have probably seen these various, um, studies that have looked at a more conservative approach to fluid resuscitation, like in sepsis, um,
00:06:25
Speaker
And I don't really want to get into debating, you know, the merits of conservation of fluid when it comes to resuscitation right now, but that's a big reason.
00:06:35
Speaker
But, you know, there's other studies that really talk about that a lot of the fluid accumulation and fluid overload is really fluid creep.
00:06:44
Speaker
You may have heard that term before, Sergio, but, you know, we get a lot of fluids through, you know, various medications, all the antibiotics we're giving, all the, you
00:06:54
Speaker
carrier fluids for all of our drips, all the infusion volumes, you know, all of that really sort of adds up.
00:07:01
Speaker
And, you know, regardless of sort of what study you look at, there is generally in the adult patient population, around two to two and a half, up to three liters of obligate intake every day between infusion volumes and medications and, you know,
00:07:21
Speaker
and carrier fluids.
00:07:23
Speaker
And it's really this fluid that really leads to the sort of inexorable gain of fluid if we're not sort of actively managing it, if we're not really sort of paying attention.
00:07:35
Speaker
And we're not, you know, so these are the fluids that we really have to pay most attention to.
00:07:39
Speaker
It's these sort of hidden fluids that we don't think about, you know, our non-bolus fluids.
00:07:46
Speaker
Analogy that comes to mind immediately, Michael, is what happens with sedation often, right?
00:07:52
Speaker
It's more likely over time or especially over a night shift that sedation go up as opposed to go down unless we actively intervene and have an intentional approach to reevaluating and bringing that down.
00:08:05
Speaker
So like you mentioned, this is very common in the ICU situation.
00:08:10
Speaker
It is unlikely that somebody who's been in the ICU for several days is not going to be fluid overloaded, and we just need to manage that a little bit better.
Sources and Impact of Hidden Fluids
00:08:20
Speaker
Yeah, and, you know, I think that you're absolutely right, and there have been some studies that have really tried to, in a very granular way, look at the sources of fluids for patients throughout their time in the ICU, and
00:08:36
Speaker
and had been able to sort of, and then sort of create like a pie graph as to where these sources of fluids come from.
00:08:45
Speaker
And by far the biggest portions of those pies
00:08:49
Speaker
are the sort of hidden creeped fluids.
00:08:53
Speaker
In these studies, they oftentimes even look at how many of the pre-filled flush syringes are being used for patients.
00:09:04
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And you can see that it's really, the piece of the pie that's the resuscitation volume in most patients
00:09:15
Speaker
is somewhere around a third to 40% of the fluid.
00:09:19
Speaker
But the majority of the fluid ends up being all of these other hidden areas.
00:09:24
Speaker
And if we're not cognizant of that, if we're not being mindful of those, then our patients become fluid overloaded quite easily.
00:09:34
Speaker
You know, just to piggyback one quick thing, one, you know, one common, you know, scenario is, is, you know, you need to provide your patients some dextrose.
00:09:44
Speaker
So people order, you know, D5W or D5, you know, something or other.
00:09:49
Speaker
when we could easily just disorder D10, or if they have a central line, D20, at which point we're decreasing the volume of fluid by twofold or fourfold compared to D5, yet still providing the same amount of sugar.
00:10:05
Speaker
So it's small little things like this that can really make a huge difference when you look at the arc of our patients' time in the ICU over the course of a week or 10 days or God forbid longer.
Mortality and Fluid Overload: Cause or Indicator?
00:10:18
Speaker
I would like to talk about the consequences of fluid overload in our patients.
00:10:24
Speaker
And maybe we could start by talking about the general impact of fluid overload on patient outcomes, specifically mortality.
00:10:31
Speaker
What do we know today, Michael?
00:10:33
Speaker
What have we learned over the last decade or more that maybe has changed our approach to fluid overload?
00:10:41
Speaker
Yeah, well, I mean, Sergio, I think it's pretty well known now that there have been many, many prospective and retrospective studies that have demonstrated that there is a very strong association between
00:10:57
Speaker
The development of fluid overload, depending on how you define that, of course, each study defines a little bit differently.
00:11:03
Speaker
We can get into the definition in just a couple of minutes, but there's a very strong association between the development of fluid overload and, for that matter, the persistence of fluid overload.
00:11:15
Speaker
and mortality in the ICU.
00:11:17
Speaker
Now, I'm very much on record as saying that, you know, I think it's very clear from other studies that we can talk about, you know, over the course of the next few minutes, that this isn't just an association of fluid overload with worse outcomes, it's actually causative of worse outcomes.
00:11:37
Speaker
And we can talk about, and we will get into, I think, in a little bit why that is.
00:11:42
Speaker
But
00:11:43
Speaker
even when you look at this association, many people will come to me and say, well, this is just a marker of disease severity, Dr. Connor, that the more sick you are, the more likely you've gotten a lot of fluid, you've gotten a lot of resuscitation volume.
00:12:03
Speaker
And there have been several studies that have
00:12:06
Speaker
sort of demonstrated that that is not entirely accurate, that the severity of illness does not correlate very strongly with the amount of fluid that people accumulate, and that in several studies in which they look at
00:12:21
Speaker
SOFA scores or Apache scores or other sorts of severity of illness retrospectively, oftentimes they are either equally as sick between the two groups or sometimes the fluid overloaded patients actually have lower SOFA scores and lower Apache scores.
00:12:39
Speaker
And so there really is no correlation between the severity of illness and how much fluid that people are accumulating.
00:12:45
Speaker
So
00:12:46
Speaker
Fluid overload is not just a marker of more sick patients.
00:12:51
Speaker
There is clearly something, there's clear mechanisms by which this venous hypertension and fluid overload causes organ failures.
00:13:02
Speaker
And we can get into that over the course of the next few minutes.
00:13:09
Speaker
Just if I can put on one other quick hat, which is to say that patients who have acute kidney injury, this is a particularly profound effect that fluid overload is really fatal in patients who have acute kidney injury.
00:13:23
Speaker
And we need to work to mitigate that as much as possible.
00:13:28
Speaker
If I may, let me just take your audience for one second and say we need to define what fluid overload is.
00:13:35
Speaker
There are many ways to do that, but increasingly the most accepted way to do that is to calculate a percent fluid overload.
00:13:47
Speaker
In other words…
00:13:49
Speaker
You know, are you 10% fluid overload, 5% fluid overload?
00:13:53
Speaker
And the way that we do that is you take your current weight minus your admission weight and divide that by your admission weight and multiply that, you know, by 100 then to get a percent.
00:14:03
Speaker
So in other words, if you are...
00:14:07
Speaker
If you are currently 77 kilos, your admission weight is 70 kilos, then you are 7 over 70.
00:14:17
Speaker
You are 10% fluid overloaded.
00:14:19
Speaker
Does that make sense?
00:14:20
Speaker
It does.
00:14:21
Speaker
And it's an objective or more objective way for our clinicians to think at the bedside.
00:14:27
Speaker
And what I would imagine, based on my own experience, is that once in a while when you do calculate that, you'll be surprised, right?
00:14:34
Speaker
Like, whoa.
00:14:35
Speaker
Yeah.
00:14:36
Speaker
Yeah, I mean, it wasn't that long ago that I had a patient transfer or lateral into my ICU who was 50% fluid overloaded.
00:14:46
Speaker
Like literally, they had gained 50% of their weight with volume and they were obviously not doing well.
00:14:58
Speaker
And studies have looked at that percent fluid overloaded both as a dichotomous value, you are above or below a certain benchmark, 5% or 10% fluid overloaded, but it can also be looked at as a continuous variable as well.
00:15:15
Speaker
So 2%, 5%, 7%, 10%.
00:15:16
Speaker
And different studies have taken a little bit of a different approach.
00:15:22
Speaker
And this concept of percent fluid overloaded, I do want to really give credit to the people that came up with this because this was really our pediatric colleagues in both pediatric critical care and pediatric nephrology that really have been on the vanguard over the course of the last 20 to 30 years, recognizing
00:15:39
Speaker
how important and how much morbidity their pediatric patients experience from fluid overload.
00:15:49
Speaker
And they're really the ones who have taught us as adult doctors how important this topic is.
00:15:56
Speaker
And I think credit should be given to our pediatric colleagues on this concept.
00:16:00
Speaker
And they really invented this idea of percent fluid overload.
00:16:04
Speaker
And it really has held true between both pediatric and adult literature.
00:16:09
Speaker
You mentioned the impact that fluid overload has on outcomes in patients with AKI.
00:16:16
Speaker
There's also been similar studies in specific populations such as severe sepsis, septic shock, ARDS, respiratory failure, and post-op patients.
00:16:26
Speaker
What I would like to do instead of reviewing that literature is to go a little bit more into the mechanisms and to talk about the specific impact fluid overload has on organ systems.
00:16:39
Speaker
Yeah, well, so first of all, you're absolutely right.
00:16:41
Speaker
I mean, I don't know a patient population.
00:16:43
Speaker
I haven't seen a report of a patient population who does better with fluid overload.
00:16:50
Speaker
It holds true in trauma, ARDS, sepsis, cardiac surgery, abdominal surgery, AKI.
00:16:57
Speaker
You know, I haven't seen a patient population that that that, you know, it's beneficial for.
00:17:05
Speaker
So but the mechanism, you know, it primarily has to do, at least in my opinion, and I think the literature backs this up.
Effects of Fluid Overload on Organ Systems
00:17:16
Speaker
is that this really comes down to a blood flow problem.
00:17:21
Speaker
And I remind your audience that, you know, blood pressure is not the same as blood flow.
00:17:30
Speaker
And while we agree that we have lots of studies that we don't need to just, you know, give every organ
00:17:37
Speaker
massive amounts of perfusion.
00:17:39
Speaker
You know, we don't need to maximize delivery of O2.
00:17:42
Speaker
We do need to have organ perfusion.
00:17:44
Speaker
And the underlying physiology has to do with fluid overload leading to venous hypertension and leading to other compartment pressure problems like abdominal hypertension.
00:17:57
Speaker
And as we get venous hypertension, that impairs blood flow.
00:18:04
Speaker
So just if we step back for one second, Sergio, we, um, to sort of, you know, very basic stuff, right?
00:18:13
Speaker
Flow of anything, fluid air or anything flows from high pressure to low pressure.
00:18:19
Speaker
And that pressure gradient from high pressure to low pressure drives the, the, the, um,
00:18:27
Speaker
the, what's the word I'm looking for?
00:18:31
Speaker
The quantity of the flow, how much something flows is a function of that pressure gradient from high pressure to low pressure.
00:18:41
Speaker
And so if your audience remembers, in normal individuals like you and me, hopefully sitting here right now, we don't have a lot of venous hypertension.
00:18:52
Speaker
Our right atrial pressure, depending on where we are in our spontaneous respiratory cycle, is anywhere from minus two to four.
00:19:01
Speaker
And so our veins of our organs are basically draining into a pool in which the blood drainage has no resistance.
00:19:14
Speaker
And as our blood leaves our various organs, we've lost a lot of the pressure gradient.
00:19:21
Speaker
So in our capillaries, our mean capillary pressure is only around 12, 15, 18 millimeters of mercury.
00:19:29
Speaker
And so the pressure gradient on a normal circumstance is somewhere between 15, 18 at our venous capillary to essentially zero in our central venous circulation.
00:19:44
Speaker
And so our organs have this sort of pressure gradient of around 18 to 20 millimeters of mercury to drain out blood.
00:19:53
Speaker
And when venous hypertension develops, when CVP goes up, especially acutely from its sort of baseline, then the pressure gradient to allow the blood to drain out of the organs decreases.
00:20:09
Speaker
And then that leads to organ congestion.
00:20:13
Speaker
And as we get organ congestion, that leads to perfusion problems because we oftentimes impair the blood entry into the organ
00:20:23
Speaker
if we're unable to drain blood out of the organ.
00:20:27
Speaker
So, you know, many of your audience will have heard of things about like, you know, congestive hepatopathy, but it's the same physiology that drives kidney dysfunction,
00:20:38
Speaker
We get organ edema in our heart, in our lungs, in our brain, in our viscera, all of which leads to impairment in function of those organs.
00:20:48
Speaker
Did that crystallize it at least simply enough without being able to show diagrams?
00:20:53
Speaker
That was excellent.
00:20:55
Speaker
And I believe that it's important to reemphasize some of these specific organ failures because most clinicians are familiar with what pulmonary edema looks like.
00:21:04
Speaker
And if you give too much fluid to certain patients, they become more hypoxic.
00:21:08
Speaker
You diurese them and they get better, right?
00:21:10
Speaker
I mean, pulmonary edema is a very common complication.
00:21:14
Speaker
Let's call it a fluid overload.
00:21:16
Speaker
But sometimes...
00:21:17
Speaker
we are not as aware of cerebral edema and the impact it might have on the patient's mental status.
00:21:24
Speaker
We're not, we're not, we, I remember very vividly one of my first patients I took care as an attending is like over 25 years ago, 20 years ago.
00:21:34
Speaker
And a septic shock, ARDS, obviously massively fluid overloaded and then kind of stuck, right?
00:21:40
Speaker
Not getting better at one point off pressers, still on the vent, not responding.
00:21:45
Speaker
And we started diuresing aggressively, and you saw every single organ get better.
00:21:51
Speaker
All of a sudden, tolerating nutrition better, waking up slowly, weaning down the ventilator, renal function starts improving.
00:22:00
Speaker
And it's just a crystallization at the bedside of everything you talked about in that mechanism.
00:22:05
Speaker
And I would like to hear more about the kidney specifically because...
00:22:10
Speaker
The story of intra-abdominal hypertension and intra-abdominal compartment syndrome is an interesting one that evolved significantly over the last 20 years, and probably because we also started giving massive amounts of fluid to non-surgical patients and started seeing this more commonly in the medical ICU and elsewhere.
00:22:31
Speaker
But the impact on the kidneys is quite significant.
00:22:34
Speaker
quite special and probably much more frequent than people realize.
00:22:42
Speaker
Yeah, well, first let me just piggyback on what you said before.
00:22:46
Speaker
Every organ is impacted by this.
00:22:49
Speaker
And when you said cerebral edema, a lot of people think about pathologic amounts of cerebral edema and intracranial hypertension leading to herniation.
00:22:57
Speaker
But that's not exactly what we're talking about here, Sergio.
00:23:00
Speaker
You know, this is just subtle amounts of cerebral edema that cause delirium and cerebral dysfunction and some confusion problems.
00:23:08
Speaker
But yes, you're absolutely right.
00:23:10
Speaker
Every organ system is impacted and the kidneys are very susceptible to this for a variety of reasons.
00:23:18
Speaker
You're right that if we develop intra-abdominal hypertension or on its most severe forms, abdominal compartment syndrome,
00:23:26
Speaker
which is very common in patients that are fluid overloaded, even in non-surgical patients, that impairs arterial perfusion into the kidney.
00:23:36
Speaker
But fluid overload has a much more insidious problem on kidney function, which has to do with organ edema,
00:23:46
Speaker
and congestion.
00:23:48
Speaker
And I'm going to try my best to verbally describe this process.
00:23:54
Speaker
It's best illustrated, I think, with some pictures.
00:23:57
Speaker
So I'm going to try my best to verbally discuss this.
00:24:02
Speaker
But
00:24:03
Speaker
But as we get venous hypertension, that leads to an impairment in drainage out of the kidney.
00:24:11
Speaker
The kidney, unlike your liver, is an encapsulated organ.
00:24:15
Speaker
So it has a very tough capsule around the outside.
00:24:18
Speaker
It's similar to your brain that is encapsulated by our skull.
00:24:22
Speaker
And so acutely, the kidney cannot really swell.
00:24:26
Speaker
You can get nephromegaly over time.
00:24:29
Speaker
The kidneys can get larger over time with infiltrative diseases and slow processes like lymphoma or diabetes.
00:24:36
Speaker
But acutely from congestion, the kidney cannot really swell that much.
00:24:41
Speaker
And so as you get impairment in drainage out of the kidney,
00:24:48
Speaker
that leads to interstitial edema and an increase in pressure
00:24:53
Speaker
inside the interstitium of the kidney because the kidney can't swell to relieve that pressure.
00:24:58
Speaker
And as that pressure goes up, it starts compressing the individual nephrons because the nephrons, like the ventricles in the brain, the nephrons are the compressible structure.
00:25:11
Speaker
And so the pressure starts compressing the nephron, which thereby raises the pressure inside the nephron
00:25:19
Speaker
and the nephron is contiguous with Bowman's space, if you remember the nephron anatomy, and so the pressure in Bowman's space then increases, and that then drastically impairs our ability to filter at the level of the glomerulus, because the glomerulus filtration is driven by a pressure gradient from the glomerular capillaries into Bowman's space.
00:25:44
Speaker
And so if you can't, if that pressure gradient decreases, now your filtration gradient decreases.
00:25:51
Speaker
You're not filtering as much at the level of the glomerulus.
00:25:54
Speaker
And the patients become oliguric.
00:25:56
Speaker
And when you look at the urine, it's very highly concentrated.
00:26:00
Speaker
It has a very high specific gravity or osmolarity.
00:26:03
Speaker
The urine sediment will oftentimes be very bland, so it won't show any signs of ATN.
00:26:08
Speaker
Creatine will be increasing sort of slowly every day.
00:26:11
Speaker
And if you're inclined, I don't believe in this necessarily, but if you're inclined to measure fractional excretion of sodium, it would be very, very low.
00:26:21
Speaker
And so this is venous hypertension causing a very intense perfusion mediated acute kidney injury, what some people would call sort of a pre-renal AKI.
00:26:37
Speaker
But this is not necessarily a problem with inflow.
00:26:40
Speaker
This is a problem with outflow.
00:26:43
Speaker
And unfortunately, many, many times, this physiology of this slowly creeping up, increasing creatinine,
00:26:52
Speaker
oliguric concentrated urine, bland urine sediment is oftentimes misinterpreted as this patient must have total body fluid overload but intravascular volume depletion, when in reality this is really all just venous hypertension and fluid overload that's causing this problem.
00:27:12
Speaker
And this has been known for quite a while, several decades.
00:27:18
Speaker
And we have animal models that have shown this on kidney biopsies and such.
00:27:25
Speaker
But Sergio, as you know, you're a big proponent of POCUS.
00:27:29
Speaker
POCUS has really allowed us to prove this physiology over time.
00:27:36
Speaker
As you know, we'll get into some assessments, but we've been able to prove with POCUS that you do get sort of impairment and drainage of these renal veins, of your portal veins, and that this is venous hypertension that's causing this problem.
00:27:50
Speaker
And so, you know, we can move past this idea of association
00:27:55
Speaker
and really show that this is a causation problem.
00:28:00
Speaker
So we established that it's extremely frequent and that this is not just a marker of severity, but can actually cause problems, organ failure, and lead to worse outcomes for our patients.
Objective Assessment and Management Strategies
00:28:14
Speaker
So let's move on to what can we do at the bedside and start with the recognition of fluid overload and its assessment.
00:28:21
Speaker
You defined a little earlier fluid overload.
00:28:24
Speaker
Are there any other useful definitions you want to share with us before we talk about fluid status assessment?
00:28:32
Speaker
I think in terms of useful definitions, no.
00:28:36
Speaker
I think the percent fluid overload is a great way of being able to do that.
00:28:42
Speaker
I think obviously, you know, cumulative fluid balance and daily fluid balance is very important.
00:28:47
Speaker
I'm not going to say that they're not.
00:28:51
Speaker
There is some accuracy questions, I think, that go into all of those, you know, over time.
00:28:56
Speaker
But, you know,
00:29:00
Speaker
I think combining, you know, what is our cumulative fluid balance, how's our daily fluid balance been, combining that with these percent fluid overload definitions is really probably the best way to define this situation.
00:29:16
Speaker
How do you evaluate an ICU's patient fluid status?
00:29:22
Speaker
I think we all do it.
00:29:24
Speaker
Yeah, I mean, I think we all probably have many different ways that we do it.
00:29:29
Speaker
I think the most important thing, Sergio, if I can stress, is we have to get away from this sense of sort of conjecture
00:29:38
Speaker
or sort of feeling, you know, I feel like my patient is fluid overloaded.
00:29:43
Speaker
We need to be objective about it as much as possible.
00:29:47
Speaker
And fortunately, in the ICU, we have so many tools at our disposal that can help us move away from using intuition and objectively sort of
00:30:00
Speaker
deciding what someone's fluid status is.
00:30:03
Speaker
And that includes looking at things like fluid balance, daily fluid balance, looking at the weight trends and the percent fluid overload.
00:30:13
Speaker
That's the really great place to start.
00:30:15
Speaker
And then you can use other tools, other objective tools to help confirm
00:30:21
Speaker
what you're thinking and to triangulate information.
00:30:26
Speaker
It's not to suggest that any one definition or any one tool is perfect or infallible in all patients.
00:30:34
Speaker
We usually have to sort of triangulate assessing the volume by several different tools, make sure that they all sort of agree that
00:30:44
Speaker
and move forward from there.
00:30:46
Speaker
I'm still a big believer in physical exam.
00:30:49
Speaker
It is exceedingly uncommon for me to have a patient that is anisarkic and has 3, 4-plus pitting edema who has an IVC that's collapsible or has a CVP that's low or has a positive passive leg raise.
00:31:11
Speaker
So physical exam, I think, still remains very important.
00:31:15
Speaker
But I will say that I don't think we all agree on what these definitions of 1 plus, 2 plus, 3 plus are.
00:31:22
Speaker
I don't think there's a lot of good inner observer variability on this because many, many patients that I've been told...
00:31:30
Speaker
hey, this patient by my APPs or resident has one plus edema, you know, I go in there and I would say, you know, wearing my nephrology lens that this patient has, you know, four plus edema or anisarca.
00:31:41
Speaker
So we need to, we need to probably define these things a little bit better.
00:31:49
Speaker
But then, you know, as you know, right, we have things like passive leg raise, we have POCUS, we have chest x-rays, we have, you
00:31:59
Speaker
Things like CVP we can talk about, other forms of dynamic fluid monitoring like stroke volume variability, dynamic cardiac output assessments, all sorts of different hemodynamic monitors that look at this type of question is, is this patient fluid responsive or are they fluid overloaded?
00:32:22
Speaker
And so we need to think about using all of those different tools to help us recognize the problem.
00:32:29
Speaker
Is there anything you want to mention on labs?
00:32:34
Speaker
You know, I don't know that there is a lot.
00:32:37
Speaker
I mean, I'd be curious what your experience is.
00:32:39
Speaker
I don't think we have a real good data on any particular lab biomarker that's very reliable for this.
00:32:47
Speaker
I don't think that BNP or pro-BNP are particularly useful in the critically ill patient population.
00:32:59
Speaker
It's not to say that it's not, but I certainly don't use it that way, and I haven't seen any studies on its pro-
00:33:09
Speaker
predictive value to define fluid overload in a critically ill patient.
00:33:14
Speaker
And I'm not really aware of many other biomarkers along that pathway.
00:33:20
Speaker
Is there anything specific that you were thinking about?
00:33:22
Speaker
No, just wanted to get your impression.
00:33:25
Speaker
And I agree with you.
00:33:26
Speaker
BMP, I find it more useful when it's normal.
00:33:31
Speaker
And usually earlier in the context of my caring of a patient when they show up as opposed to a week into the ICU.
00:33:39
Speaker
Yeah, I agree.
00:33:40
Speaker
But I was just curious if there's anything out there.
00:33:43
Speaker
I know there's been a lot with biomarkers, but that's more renal function.
00:33:47
Speaker
And I was just curious if there was something that I was missing.
00:33:52
Speaker
But like you said, part of this for me is also having the...
00:33:58
Speaker
the intention of evaluating a patient as objectively as we can and utilizing all these tools at the same time to kind of inform our assessment.
00:34:09
Speaker
And then, like you mentioned, we can quantify it by just looking at the percent fluid overload because a patient who's been in the ICU for a week or two weeks did not gain weight because they're munching down McDonald's hamburgers, right?
00:34:25
Speaker
No, you're actually right.
00:34:26
Speaker
Yeah.
00:34:27
Speaker
You're only gaining weight in the ICU by getting external fixators attached to you or, you know, gaining fluid.
00:34:35
Speaker
You're not gaining muscle weight or fat weight in the ICU.
00:34:38
Speaker
That's for sure.
00:34:39
Speaker
Yeah.
00:34:40
Speaker
For those who like movies, I don't know if they saw this is the end.
00:34:43
Speaker
There's a very famous line of one of the guys caught in the rapture.
00:34:48
Speaker
They're trying to survive.
00:34:49
Speaker
And one of them is gaining weight.
00:34:50
Speaker
And there's like, oh, everybody's complaining.
00:34:52
Speaker
The
00:34:53
Speaker
The mother F is gaining weight and everybody else is losing weight.
00:34:56
Speaker
What is he doing differently?
00:34:57
Speaker
And he was, he was eating the secret stash of food.
00:35:02
Speaker
Yeah.
00:35:03
Speaker
But, you know, I think battling this problem of fluid overload, recognition is really half the battle.
00:35:09
Speaker
Um, you know, we have to look at this and, you know, I would say that, um, there are a few things I think that hand string us, you know, number one is, um,
00:35:21
Speaker
we have to insist that we have accurate I's and O's.
00:35:25
Speaker
We have to help the nurses.
00:35:26
Speaker
We have to design systems to help the nurses keep track of this easier and more accurately.
00:35:33
Speaker
Urine output is oftentimes viewed as this extra thing that people don't – it's just some excrement.
00:35:45
Speaker
Why do I have to measure this or why are people so caring about this?
00:35:48
Speaker
I mean cardiac ICUs are religious about documenting urine output.
00:35:52
Speaker
you know, all ICUs need to be religious about documenting urine output.
00:35:56
Speaker
It's not just because urine output can give you an insight into the development of AKI, which I'm, you know, obviously a big believer in.
00:36:04
Speaker
But if we're not measuring the urine output, where there's no way we're going to be able to keep a sense of, you know, how we're doing on an eyes and nose perspective, we have to look at the graphs, right?
00:36:14
Speaker
Every EHR system
00:36:19
Speaker
not only tracks ins and outs, but can actually display it for you on a daily basis on graphs, what my cumulative or what my daily net fluid balance is.
00:36:29
Speaker
And so if you have many days in a row where your net balance is positive,
00:36:34
Speaker
That's important.
00:36:35
Speaker
And I think a lot of times in the new era of critical care, at least in the US, where there's a lot of shift work, you know, people don't, we might not have people who have had three or four or five days straight with the patient where they know, oh yeah, three days ago, we were also positive.
00:36:51
Speaker
Five days ago, we were also positive.
00:36:54
Speaker
So when we're rounding and reviewing things, we have to look at those graphs, you know, more carefully.
00:37:01
Speaker
And then we have to use these tools.
00:37:04
Speaker
So we say, hmm, I think my patient might be fluid overloaded.
00:37:07
Speaker
They look like it on exam.
00:37:09
Speaker
Their I's and O's are positive for many days.
00:37:13
Speaker
Their weights are up.
00:37:14
Speaker
Now let's confirm this by some other mechanisms.
00:37:19
Speaker
Let's look at our POCUS.
00:37:21
Speaker
Let's look at our VEXUS.
00:37:23
Speaker
Let's look at our
00:37:25
Speaker
you know, our CVP.
00:37:27
Speaker
CVP is not predictive of who is fluid responsive, but it certainly can tell you what the venous pressure is like.
00:37:34
Speaker
And if the CVP is 15 or 18, then it's either fluid overload or your right heart has failed, you know, either way.
00:37:42
Speaker
So, you know, I think we have these tools that we can use, but we should use them to help confirm what we're already thinking by reviewing the data.
00:37:52
Speaker
Let's talk about fluid overload management.
00:37:55
Speaker
And we could start with some general concepts.
00:37:58
Speaker
I still recall the first time I heard somebody talk about de-resuscitation.
00:38:04
Speaker
And it was 20 years ago, Dr. John Marshall, who's a surgical intensivist from Toronto, he was talking about this concept.
00:38:13
Speaker
And I was like fascinated because at that point,
00:38:16
Speaker
we would just abide by the rule that to get well, you have to swell and we would give tons of fluid and then see what happens.
00:38:23
Speaker
But I know that that thought has evolved and now people talk about rows or other frameworks in terms of fluid management.
00:38:32
Speaker
And maybe we could start with a general overview of those concepts.
00:38:36
Speaker
Yeah, you know, I agree.
00:38:39
Speaker
I mean, I think there's a lot of debate about what's the right term, de-resuscitation, evacuation.
Phases of Fluid Management: ROSE Model
00:38:45
Speaker
You know, I personally like the word de-resuscitation because it implies that we have to actively do something as clinicians.
00:38:54
Speaker
Yeah.
00:38:55
Speaker
And I think what's clear is that in the absence of actively doing something, patients just gain weight.
00:39:02
Speaker
And I'll come back to that in a second.
00:39:04
Speaker
But we really have been a proponent for the last 10, 12 years with this concept of phases of fluid management or this ROSE model, resuscitation, optimization, maintenance, or stabilization, and then evacuation or de-resuscitation.
00:39:23
Speaker
And this was first, I would say, conceptualized by the Acute Disease Quality Initiative, the ADKE group of critical care nephrologists and intensivists that created a consensus around this concept.
00:39:42
Speaker
With the idea being that when our patients come in, in the first few hours or days, most of them are gonna be resuscitated.
00:39:47
Speaker
We should be rapidly increasing our volume status.
00:39:52
Speaker
But that at some point in the first 12 to 24 hours, resuscitation and optimization should end.
00:40:00
Speaker
And we should transition into a state of stabilization in which the entire goal is to no longer accumulate volume for the patient.
00:40:11
Speaker
That the patient may have developed and accumulated three, four, five, six, seven liters, but the goal at that point is to no longer continue to accumulate volume.
00:40:22
Speaker
And then at some point, you transition to a period of time after you've plateaued here to a period of time in which you're actively evacuating or de-resuscitating the patient's volume through various means.
00:40:37
Speaker
And so this model should look like a steep rise, a plateau, and then a fall with the various slope in the volume over time.
00:40:49
Speaker
What's clear is that if you're accumulating volume very quickly in this resuscitation phase and you continue to just rapidly accumulate volume because you can never transition out of the resuscitation phase and the patients just rapidly develop really profound fluid overload, those are the patients that are just likely going to die because you've never really been able to
00:41:13
Speaker
you know, exit your resuscitation phase.
00:41:17
Speaker
Resuscitation does not mean like transitioning to stabilization does not mean being liberated from vasopressors.
00:41:23
Speaker
It just means that you have achieved an appropriate fluid balance and the patient is no longer fluid responsive.
00:41:31
Speaker
You know, they have an appropriate cardiac output and such.
00:41:37
Speaker
But what's equally as seen is that if you do not transition into this plateau period, but you do sort of exit out of resuscitation, you sort of get into stabilization phase of illness,
00:41:54
Speaker
but that the fluid balance just sort of continues to go up and up and up, you know, very slowly throughout their course in the ICU.
00:42:00
Speaker
These are the patients that end up with a lot of morbidities like prolonged time in the ICU, disability, failure to recover, tracheostomy insertions, post-intensive care unit syndromes.
00:42:12
Speaker
And so really we need to transition very quickly.
00:42:15
Speaker
We need to actively make a decision as a team, okay,
00:42:20
Speaker
This patient is no longer needing resuscitation.
00:42:23
Speaker
Our goal for today, for tomorrow, for the next day, you take it on a day-by-day basis.
00:42:28
Speaker
Our goal is to no longer accumulate volume.
00:42:31
Speaker
We want ins equal to outs.
00:42:33
Speaker
And then at some point, we transition into taking that fluid away and giving the patient a net negative fluid balance.
00:42:41
Speaker
And I think that this sense, this concept of
00:42:46
Speaker
of phases of fluid can be really helpful and is something that I really advocate a lot, is that we need to actively have these conversations on rounds as to what our fluid balance goals are.
00:42:59
Speaker
The problem is, Sergio, is as you know, most people, at least in the U.S. and for that matter around the world,
00:43:09
Speaker
oftentimes discuss patients and review patients in this sort of systems-based approach in which we talk about the brain and then the heart and then the lungs, and then most people jump to the GI system.
00:43:22
Speaker
And so by the time they start getting into kidneys and fluid…
00:43:26
Speaker
our attention has sort of waned.
00:43:28
Speaker
And I think that's part of the reason why we end up not conversing and having clear discussions about what we want to accomplish as much as we should.
00:43:36
Speaker
So, you know, please continue to prioritize fluid management, you know, high up in your talk.
00:43:43
Speaker
And I think you'll in your discussion about the patients every day.
00:43:46
Speaker
And I think you'll see that a strategy focused on fluid management and fluid evacuation will improve your patient's outcomes.
Evacuation Phase and Use of Diuretics
00:43:55
Speaker
And clearly, as you stated, there is active interventions that we should be implementing in the R, the O, and the S phases to try to control this and improve the outcomes of our patients.
00:44:10
Speaker
But I would like to dive in further into the E or evacuation phase of our fluid management.
00:44:16
Speaker
When you get to that point and you say, okay, it's time to evacuate some of this fluid, I'm seeing some of the effects of fluid overload.
00:44:23
Speaker
And my patient now is probably being hurt by this fluid overload as opposed to help by the fluid we gave him in this phase of his disease.
00:44:32
Speaker
How do you start by setting some goals and explain to the team how you will monitor efficacy and safety?
00:44:39
Speaker
And then we can go into the actual interventions.
00:44:42
Speaker
Yeah.
00:44:43
Speaker
So first of all, we have to recognize, Sergio, that oftentimes given our patients have an obligate intake of, you know, say two and a half liters a day between meds and nutrition and other sorts of stuff, we actually oftentimes have to start thinking about active strategies to evacuate fluid, even when we just want to keep them net even.
00:45:05
Speaker
So even before we actually want them to be net negative, we oftentimes have to introduce some
00:45:13
Speaker
assistance to the patient to even just keep them net even.
00:45:18
Speaker
And I think this is a really important concept because many, many times, especially in ICUs that care for younger patient populations, be them pediatric patients or trauma ICUs, where
00:45:32
Speaker
The patients tend to have a skew younger.
00:45:36
Speaker
Even when the kidney function looks normal, the creatinines are low, the patients are urinating, it's very easy to overwhelm the kidney's ability to excrete salt and water.
00:45:52
Speaker
And I have, you know, you hear this all the time where someone says, well, I wasn't giving a diuretic because their kidney function was normal.
00:45:59
Speaker
I assume their kidney could do this on their own.
00:46:03
Speaker
And the reality is, is that even kidneys that are quote unquote healthy or normal,
00:46:10
Speaker
can easily be overwhelmed and will struggle to excrete that salt and water.
00:46:16
Speaker
I remind your listeners that every one liter bag of 0.9% quote unquote normal saline contains around 3.6, 3.5 grams of sodium.
00:46:30
Speaker
That's the same amount of sodium as in one and a half pounds of Ruffles potato chips.
00:46:35
Speaker
And you can understand that our kidneys are not designed to be able to excrete three grams of sodium in
00:46:45
Speaker
You know, especially if we give five liters of fluid in that day, you know, now we've given, you know, 20 grams of sodium.
00:46:53
Speaker
Our kidneys are not designed to be able to excrete all of that.
00:46:57
Speaker
And so oftentimes, even just to maintain a net even fluid balance, we need to start thinking about not only decreasing our intake, but how can we augment the output to keep the patient sort of net even.
00:47:12
Speaker
But switching directly to the evacuation phase, as you discussed, you know, most patients are going to end up needing some sort of help for this.
00:47:22
Speaker
It is the exception rather than the rule that spontaneous urine output alone can help evacuate the volume.
00:47:31
Speaker
The most common situation where spontaneous urine output alone might be able to do this is
00:47:36
Speaker
is like a patient who might be polyuretic when they're recovering from an ATN episode, or if we have demonstrably improved cardiac output.
00:47:47
Speaker
We've started somebody on ECMO or we inserted an Impella or something like that, and now cardiac output and perfusion has increased significantly.
00:47:56
Speaker
And the kidneys that, you know, might be able to then suddenly say, wow, I can get rid of all of this volume now.
00:48:02
Speaker
But it's really the exception rather than the rule that our patients are sort of spontaneously polyuretic and spontaneously net negative.
00:48:10
Speaker
So we have to establish, we have to discuss what is our goal going to be.
00:48:14
Speaker
is it the right time to start evacuating?
00:48:17
Speaker
And then if we're going to evacuate, how are we going to do this?
00:48:20
Speaker
In the overwhelming majority of patients, we should initially think about, you know, making them urinate more and potentially augmenting their urine output with diuretics.
00:48:33
Speaker
And then, you know, we'll consider other strategies for fluid removal if augmenting urine output is unsuccessful.
00:48:42
Speaker
In terms of helping them with active medical interventions, obviously, you already mentioned diuretic therapy.
00:48:50
Speaker
Can we talk more about this?
00:48:52
Speaker
Which drug?
00:48:53
Speaker
Is there really a difference?
00:48:55
Speaker
Is there a delivery mode, bolus versus continuous, that you prefer to use and why?
00:49:00
Speaker
And how we should think about these diuretics?
00:49:02
Speaker
And maybe we could start with something I've heard you say multiple times.
00:49:06
Speaker
Diuretics are not nephrotoxic.
00:49:12
Speaker
Yes, diuretics are not nephrotoxic in the classic sense of the word.
00:49:17
Speaker
So I just, you know, it's a matter of nuance here, but nephrotoxic agents are agents that are directly toxic to the tubules or the glomerulus.
00:49:28
Speaker
They directly cause cytopathies.
00:49:31
Speaker
Diuretics do not do that.
00:49:33
Speaker
Under very, very rare circumstances, most of our diuretics contain a sulfamoiny, and there will be some patients who can develop an interstitial nephritis due to our exposure to the sulfa of diuretics.
00:49:50
Speaker
But that is really very rare.
00:49:52
Speaker
I cannot recall the last time I diagnosed interstitial nephritis quite frequently in my ICU.
00:49:58
Speaker
I cannot recall the last time I have blamed a diuretic as the cause of that.
00:50:03
Speaker
So in the classic sense, diuretics are not nephrotoxic.
00:50:07
Speaker
But it is – I am –
00:50:11
Speaker
I recognize that when we give a diuretic, you know, that that can cause people to be a little bit nervous, especially when there is some change in creatinine concentrations that occur when we give diuretics.
00:50:23
Speaker
But I remind most of your listeners that, you know, as we give diuretics, if we're successfully removing volume from the patient,
00:50:34
Speaker
we're going to be lowering total body water.
00:50:37
Speaker
And since creatinine is dissolved in total body water, there will be a concentrating effect in that situation.
00:50:44
Speaker
So if we have three liters less water, but the same amount of creatinine, concentration will have to go up.
00:50:50
Speaker
And so we have to be a little bit more nuanced when we see the creatinine going up and we're giving diuretics.
00:50:59
Speaker
The creatinine could be going up because they have ATN and the kidney function hasn't gotten any better.
00:51:04
Speaker
The creatinine could be going up because we're concentrating the creatinine down.
00:51:09
Speaker
The diuretics are almost never to blame for the situation.
00:51:15
Speaker
It is very hard to have overdiures the patient.
00:51:20
Speaker
You will have other signs that you've overdiures the patient.
00:51:24
Speaker
So that's the first thing is diuretics are generally, you know, no nephrologist views them as nephrotoxic.
00:51:34
Speaker
We also have to remember that kidneys that are sick, in other words, whether they have AKI or even if they are sort of have subclinical AKI, kidneys that are unwell will need more diuretics.
00:51:47
Speaker
And there are some patterns of care that have been looked at that tend to suggest that as kidneys get less well, many ICUs prescribe less diuretics.
00:51:57
Speaker
And really, they should be potentially using more diuretics, not less diuretics.
00:52:03
Speaker
So generally, I teach that in the overwhelming majority of patients, diuretics are safe.
00:52:10
Speaker
They're very efficacious.
00:52:12
Speaker
I'm not going to stand here and tell you one type of diuretic, you know, furosemide is better than bumetanide or this or that.
00:52:20
Speaker
What matters is whether or not it's effective and meeting your goals.
00:52:25
Speaker
And we should be dosing the diuretics to achieve certain goals.
00:52:29
Speaker
We shouldn't just say, let's give Lasix twice today, 40 milligrams twice today, and then we'll follow up tomorrow and see how they did.
00:52:37
Speaker
No, we should be giving diuretics to achieve a certain goal.
00:52:41
Speaker
So the discussion on rounds should be, let's give Lasix, you know, to have our patient net negative two liters by tomorrow.
00:52:50
Speaker
And you start with, you say, I'm going to try, this is the first time we're exposing a patient.
00:52:55
Speaker
I don't, you know, I think they're going to need 80 milligrams of Lasix.
00:52:59
Speaker
And then you look and see how well did they respond to that 80.
00:53:02
Speaker
And that will then make a decision as to what your second dose or your third dose is going to be.
00:53:07
Speaker
There have been lots of studies that have looked at bolus versus continuous, Sergio.
00:53:11
Speaker
I think you probably are aware of these.
00:53:13
Speaker
That generally speaking, there is no clear benefit to a continuous infusion of a diuretic over high-dose bolus-dose diuretics.
00:53:26
Speaker
That being said, there are a couple of situations where I might lean more towards a continuous as opposed to a bolus, but these are sort of more nuanced situations, specifically surrounding mechanical circulatory support.
00:53:42
Speaker
If I give a bolus of a diuretic, the patient may make one liter of urine in an hour,
00:53:49
Speaker
And that might lead to some dynamic changes in intravascular volume as we are re-recruiting volume from the third space back into the intravascular compartment.
00:53:59
Speaker
And that could disrupt the function of maybe my mechanical circulatory support device or my ECMO device.
00:54:06
Speaker
And so sometimes, not always, but sometimes...
00:54:11
Speaker
in my ECMO patient, I might lean a little bit more towards a continuous diuretic just to sort of smooth out the hourly variation in the fluid removal as opposed to the sort of up and down that you get with bolus dosing.
00:54:26
Speaker
But outside of those sorts of more
00:54:29
Speaker
nuanced mechanical circulatory support devices, there's really no demonstrable difference clinically between bolus versus continuous.
00:54:38
Speaker
And certainly bolus is easier and generally speaking cheaper and generally speaking associated with a lower total daily dose of diuretic needs.
00:54:50
Speaker
In terms of monitoring your therapy, obviously, you're going to look at the urine output.
00:54:55
Speaker
You're going to continue to look at the weight and calculate the percent fluid overload.
00:54:59
Speaker
You mentioned CVP, obviously, as an example.
00:55:03
Speaker
Another tool that I have read about in the literature, and I wanted your input, is we talk a lot about fluid responsiveness.
00:55:12
Speaker
And when somebody's being resuscitated or somebody's fluid responsive, it doesn't necessarily tell you that clinically they need more fluid.
00:55:20
Speaker
But patients who are fluid overloaded technically would not be fluid responsive.
00:55:24
Speaker
So if you recover fluid responsiveness by any way that you measured, is that a good sign?
00:55:29
Speaker
Is that a good goal?
00:55:33
Speaker
You know, that's a great question.
00:55:36
Speaker
I'm not aware of any problems.
00:55:38
Speaker
of any prospective studies that look at the reacquiring fluid responsiveness as a endpoint for when you've evacuated enough fluid.
00:55:52
Speaker
Does that make sense?
00:55:53
Speaker
I'm not aware of any studies that look at that.
00:55:56
Speaker
I am aware, however, of a number of studies that have looked at the absence of fluid responsiveness
00:56:06
Speaker
as being a predictor of patients who are ready to have fluid removed.
00:56:14
Speaker
Does that make sense?
00:56:15
Speaker
Yep, perfect, yeah.
00:56:16
Speaker
So in other words, if you do a passive leg raise before you do a session of intermittent hemodialysis, for example, if they do not respond on the passive leg raise,
00:56:31
Speaker
they tend to tolerate their session of intermittent hemodialysis without generating interdialytic hypotension in the ICU, as opposed to the patients who have a positive class of leg raise at the start of hemodialysis are more likely to get interdialytic hypotension with fluid removal during dialysis.
00:56:52
Speaker
There's a few other studies that have sort of looked at that.
00:56:55
Speaker
So, you know, I don't want to get too far
00:57:01
Speaker
off tangent, Sergio, because we could, you know, I don't, I'm not espousing, I need to come back to have this discussion, but, you know, you could have a whole podcast on hemodynamic monitoring, right?
00:57:14
Speaker
And, um, and there's so many different tools like change in end tidal CO2, passive leg raise, um,
00:57:21
Speaker
cardiac output.
00:57:22
Speaker
But what I think is important for your audience to recognize is that when we are testing somebody's fluid responsiveness, we're not looking at whether or not their blood pressure is going up in response to the challenge.
00:57:36
Speaker
What we care about is whether their cardiac output is changing.
00:57:41
Speaker
Okay.
00:57:42
Speaker
And so when you test any of these things, you don't really want to test and just look at blood pressure because that does not predict patients who need more volume.
00:57:52
Speaker
Change in blood pressure does not.
00:57:54
Speaker
What matters is a change in cardiac output.
00:57:58
Speaker
So I tend to, I tend to just to finish that thought, I tend to look at some of these tools.
00:58:04
Speaker
For example, if we're diuresing somebody and we happen to have a dynamic, a pulse wave or stroke volume variability tool, hemodynamic monitor that we're using, and let's say we are taking fluid away by diuretics or by dialysis, and we see that the patient at the start
00:58:28
Speaker
had a stroke volume variability of 7%.
00:58:31
Speaker
And now we're taking fluid away and they've become more hypotensive and their presser needs have gone up.
00:58:36
Speaker
Well, if we have over-diurese them or if we've evacuated fluid too quickly with CRT,
00:58:43
Speaker
We should see, therefore, if it is related to low intravascular volume, we should see that the stroke volume variability is going up and that cardiac index and cardiac output are going down because preload is going down.
00:58:58
Speaker
And many, many times you'll see that the pressure needs might have gone up, but there's been a slightly, but there's been no change at all in any of these other objective measures of preload.
00:59:10
Speaker
And in that situation, I would say that we haven't overly done this too quickly, and we just need to keep taking volume away.
00:59:18
Speaker
Perfect.
00:59:20
Speaker
That makes a lot of sense.
00:59:23
Speaker
I would like to ask you about extracorporeal therapies, Michael.
00:59:28
Speaker
When do you bring them to the bedside for your patients with fluid overload?
Extracorporeal Therapies: Last Resort
00:59:32
Speaker
Okay.
00:59:33
Speaker
Yeah, this is a great question, because I think that increasingly I recognize that there is a little bit of controversy, and some of this comes around some of the question of timing of dialysis.
00:59:44
Speaker
But, you know, there is pretty good consensus globally within the nephrology community that we should not be starting dialysis with
00:59:57
Speaker
for the indication of fluid overload absent any other indication for dialysis.
01:00:02
Speaker
We should not be starting dialysis purely to manage fluid unless we cannot achieve
01:00:10
Speaker
our targets, our goals, of fluid balance goals with non-dialysis means.
01:00:18
Speaker
So we have no data that suggests that dialysis is superior to spontaneous or augmented urine output.
01:00:29
Speaker
And there has been some
01:00:32
Speaker
increasingly this sort of sense of, oh, I don't want to use diuretics.
01:00:36
Speaker
I'm just going to put my patient on dialysis.
01:00:39
Speaker
Dialysis comes with CRT, you know, but any form of dialysis comes with its own set of complications and risks.
01:00:49
Speaker
You and I discussed that in our most recent podcast about, you know, diala trauma and, and, and insults to patients that dialysis itself causes patients.
01:01:01
Speaker
And so we really should never introduce that unless we cannot achieve the goals for that patient by urine output or some other means.
01:01:14
Speaker
But if I've given high-dose diuretics, if I'm doing these things and I'm not reaching the goals that we need to reach, then it's very reasonable to introduce dialysis in that situation.
01:01:31
Speaker
Excellent.
01:01:32
Speaker
And as you mentioned with hemodynamic monitoring, renal replacement therapy could be another series of podcasts.
01:01:40
Speaker
And we did discuss this topic earlier in a previous episode.
01:01:45
Speaker
So I will definitely link that episode to our show notes so our listeners can refresh their memory on that.
01:01:52
Speaker
As we move towards our closing moments,
01:01:54
Speaker
Michael, could you summarize some pearls and pitfalls about fluid overload for our clinicians before we move to non-clinical questions?
Conclusion: Proactive Management of Fluid Overload
01:02:04
Speaker
Yeah, well, can we start with the pitfalls?
01:02:06
Speaker
I mean, I think the pitfalls is that we don't recognize this.
01:02:10
Speaker
We assume that it's cosmetic instead of being causative of a lot of bad outcomes for our patients and that we have a lot of, I think,
01:02:24
Speaker
pass down a generational dogma that leads us to be less aggressive than we should.
01:02:33
Speaker
There is this dogma that we swell to get well.
01:02:36
Speaker
Well, we need to probably think about, we need to, as one of my former pharmacy residents said, we need to pee to be free of the ICU.
01:02:46
Speaker
And we need to give diuretics.
01:02:48
Speaker
We need to think about using diuretics.
01:02:50
Speaker
I think most intensive is due, but we need to not be afraid of diuretics as a means to achieve fluid goals.
01:02:59
Speaker
From a Pearl's perspective, you know, I think we covered a lot of them.
01:03:03
Speaker
The first is, you know, make sure that you're objectively assessing the volume.
01:03:07
Speaker
Use the tools that you have available.
01:03:09
Speaker
Don't use intuition.
01:03:11
Speaker
Talk about it every day.
01:03:12
Speaker
Establish what every day's fluid balance goal is going to be once you leave that first 12 to 24 hours of resuscitation.
01:03:19
Speaker
It needs to be a key part of the conversation.
01:03:24
Speaker
And then, you know, think about how we're going to evacuate and monitor how well it's being tolerated.
01:03:29
Speaker
I usually show a graphic that I created where it's sort of a circle.
01:03:35
Speaker
We have to, every day we start at the top of the circle where we're strictly monitoring I's and O's and measuring urine output and documenting daily weights.
01:03:43
Speaker
Then we need to discuss every day and establish what is our daily fluid balance goal.
01:03:47
Speaker
We need to stop excessive IV fluid administration because we talked about how much mission creep there is in IV fluid exposures.
01:03:56
Speaker
We, or at least decrease excessive IV fluid administration.
01:04:00
Speaker
And then we need to stop and ask ourselves, is the patient fluid overloaded and are they ready for fluid removal?
01:04:07
Speaker
If they're not ready for fluid removal or they're not fluid overloaded, well, then we just stop and go back to the first step of measuring everything and talking about this every day.
01:04:17
Speaker
If they are fluid overloaded and they are ready for fluid removal, then we probably need to use vasopressors a little bit more liberally.
01:04:25
Speaker
What I mean by that is that we should prioritize a return to uvilemia and a liberation from the ventilator before the
01:04:34
Speaker
prioritizing liberation from vasopressors.
01:04:37
Speaker
And I think we oftentimes, as intensive as many of us think, oh, let's get off the pressors as quickly as possible.
01:04:43
Speaker
It really should be a race to liberate from the vent, which oftentimes needs us to be uvolemic, than race to liberate from pressors.
01:04:52
Speaker
And then we need to remove volume by some means and monitor for tolerance.
01:04:58
Speaker
You know, how is this patient tolerating this fluid removal?
01:05:02
Speaker
And then sort of keep going back and going through that every day, that same sort of workflow.
01:05:08
Speaker
Excellent.
01:05:09
Speaker
You've been a guest on the podcast before, so you know how we roll, Michael.
01:05:13
Speaker
And I would like to close with a couple of questions unrelated to the clinical topic.
01:05:18
Speaker
Would that be okay?
01:05:19
Speaker
Absolutely.
01:05:21
Speaker
So the first question, it relates to any books that have impressed you since we last spoke on the podcast or any specific music album that you're really into these days.
01:05:33
Speaker
Good question.
01:05:34
Speaker
Book, I will say a book that I'm very fascinated about, but I have not finished yet, is a book called Think Again.
01:05:46
Speaker
I'm trying to remember who the author is.
01:05:49
Speaker
I want to say Adam something or other.
01:05:51
Speaker
Adam Grant.
01:05:52
Speaker
Adam Grant.
01:05:53
Speaker
Yeah.
01:05:53
Speaker
Think Again.
01:05:54
Speaker
It is
01:05:56
Speaker
not light reading.
01:05:58
Speaker
It really challenges us as clinicians, I think, and as scientists to, you know, really think through things and understand how we think in our daily lives.
01:06:12
Speaker
So I really like that.
01:06:13
Speaker
I look forward to hopefully making more progress with that.
01:06:16
Speaker
Music.
01:06:17
Speaker
I've been listening a lot recently to the most recent, um,
01:06:24
Speaker
album by Mumford & Sons called Rushmere.
01:06:27
Speaker
I've enjoyed that quite a bit.
01:06:30
Speaker
Excellent.
01:06:30
Speaker
So we will definitely check them out and also share them in the show notes.
01:06:35
Speaker
And Think Again by Adam Grant.
01:06:38
Speaker
I agree.
01:06:39
Speaker
It's a great read on how we think and how the true sign of intelligence is being able to change our opinions based on new information.
01:06:50
Speaker
And reading that book, what struck me
01:06:54
Speaker
is that our colleagues and myself as physicians tend to think about our group as being scientists, yet we don't behave like true scientists.
01:07:07
Speaker
I completely agree.
01:07:09
Speaker
I completely agree.
01:07:11
Speaker
And you'll probably see the politician analogy and the preacher analogy.
01:07:16
Speaker
That seems to be much more common among physicians and clinicians than true scientists who are really humble and questioning what they believe, right?
01:07:25
Speaker
Yeah.
01:07:26
Speaker
Right.
01:07:26
Speaker
And I probably have sounded a little preachy and politic-y in going through this topic.
01:07:33
Speaker
But, you know, I think I've, I've hope, I hopefully have stimulated some ideas that, that, that this is really what I'm saying has really come out of scientific understanding that has evolved over the course of the last 30 years, that we really have gone back and looked at some of the assumptions that we made about fluid and what we had been teaching each other, you know, for decades in medicine.
01:07:55
Speaker
And that we have really changed this over the course of the last 10 to 20 years and have really evolved, I think, in a new paradigm.
01:08:04
Speaker
But that doesn't mean we shouldn't be continuing to question what we've done on this topic.
01:08:09
Speaker
Absolutely.
01:08:10
Speaker
The second question relates to the same idea of learning from our experiences and learning from failure.
01:08:18
Speaker
So if you could share with us your favorite failure and what lesson did it teach you?
01:08:25
Speaker
Well, if it's okay, I'm going to actually share maybe two.
01:08:29
Speaker
The first is that, you know, as it pertains to this topic specifically, I will say that when I finished fellowship and, you know, became and started my life as an attending 16 years ago,
01:08:43
Speaker
I very much did not prioritize return to uvilemia.
01:08:47
Speaker
It was in the era where everyone was swollen, and we didn't really think about that.
01:08:57
Speaker
And it was my own failures of my patients not getting better that really asked me to question sort of what I was doing.
01:09:04
Speaker
Some conversations I had with some colleagues of mine who worked at LTACs, you know, that really got me thinking more and more about, you know, how do we accelerate the removal of fluid and does that improve our patients outcomes better?
01:09:20
Speaker
And so my own failures stimulated my interest in this topic and my clinical care has improved greatly as I've evolved my position.
01:09:29
Speaker
But my other failure is, you know, I would say that we've all had patients that stick with us.
01:09:38
Speaker
Oftentimes, either really good outcomes that were unexpected or really unfortunate and tragic outcomes.
01:09:46
Speaker
And I think the tragic outcomes that, uh, where we failed, um, uh, or modern medicine failed, maybe not, I didn't fail, but just the Royal we failed to, um, you know, uh, foster and allow that patient to recover.
01:10:06
Speaker
Um, it really has taught me that, you know, we don't, we need not only humility, um,
01:10:13
Speaker
and a willingness to accept when we're wrong and re-explore our diagnostic or our diagnoses and make sure we don't have diagnostic errors.
01:10:24
Speaker
But we also need to accept at some level a degree of helplessness that we as intensivists have things that we can do, but there's many things that we can't do.
01:10:38
Speaker
that we can't make our patients get better.
01:10:41
Speaker
We can't make them survive.
01:10:43
Speaker
We can try to create the environment in which their body can recover, but we can't make them actually recover.
01:10:54
Speaker
And this sort of helplessness is an idea that I use and a framework I use a lot when I talk to families and to say that, you know, we're going to work very hard to create that environment.
01:11:08
Speaker
We're going to work to resolve fluid overload and provide nutrition to your loved one.
01:11:13
Speaker
We're going to try to get off sedation and help their strength improve.
01:11:18
Speaker
But I don't have any medicine that can make them get better.
01:11:22
Speaker
I don't have any medicine that can make them heal themselves.
01:11:26
Speaker
And we have to accept that there is a level of helplessness and we should not feel angry or disappointed or carry trauma with us as physicians for cases that we did what we could, but we were helpless to really allow them to survive.
01:11:52
Speaker
I think that's a perfect place to stop, Michael.
01:11:55
Speaker
I really want to thank you for sharing your expertise and your time with us in the podcast.
01:12:02
Speaker
I'd love to have you on as a guest.
01:12:03
Speaker
We'll definitely invite you back and maybe you already suggested a great topic.
01:12:08
Speaker
But as always, thank you so much for sharing your expertise.
01:12:13
Speaker
I learned a lot and really enjoyed the conversation.
01:12:16
Speaker
Well, Sergio, it is always a pleasure.
01:12:19
Speaker
You are a fantastic interviewer and such a knowledgeable colleague.
01:12:24
Speaker
I always learn so much from you whenever you and I get a chance to talk as well.
01:12:30
Speaker
And thank you so much for the honor of being a repeat guest on this podcast.
01:12:36
Speaker
Absolutely.
01:12:37
Speaker
Thanks.
01:12:39
Speaker
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01:12:43
Speaker
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01:12:49
Speaker
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01:12:53
Speaker
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