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Optimizing renal replacement therapy in the ICU
5 Plays1 year ago
Acute kidney injury is a frequent complication of critical illness, and a subgroup of these patients will require renal replacement therapy. In this episode. Dr. Sergio Zanotti discusses optimizing renal replacement therapy in the ICU. He is joined by Dr. Michael J. Connor, Jr., a practicing intensivist and nephrologist. He is a professor and senior physician of critical care medicine and nephrology at the Divisions of Pulmonary, Allergy, Critical Care, & Sleep Medicine and Renal Medicine at Emory University School of Medicine. In addition, he is the director of critical care nephrology at the Emory Critical Care Center at Grady Memorial Hospital.
Additional resources:
Delivering optimal renal replacement therapy to critically ill patients with acute kidney injury. Wald R, et al. Intensive Care Med 2022: https://pubmed.ncbi.nlm.nih.gov/36066597/
Initiation Strategies for Renal-Replacement Therapy in the Intensive Care Unit. AKIKI Study Group. N Engl J Med 2016: https://pubmed.ncbi.nlm.nih.gov/27181456/
Effect of Early vs Delayed Initiation of Renal Replacement Therapy on Mortality in Critically Ill Patients with Acute Kidney Injury. ELAIN Trial. JAMA 2016: https://pubmed.ncbi.nlm.nih.gov/27209269/
Timing of Renal-Replacement Therapy in Patients with Acute Kidney Injury and Sepsis. IDEAL-ICU Investigators. N Eng J Med 2018: https://pubmed.ncbi.nlm.nih.gov/30304656/
Timing of Initiation of Renal-Replacement Therapy in Acute Kidney Injury. STARRT-AKI Investigators. N Engl J Med 2020: https://pubmed.ncbi.nlm.nih.gov/32668114/
Comparison of two delayed strategies for renal therapy initiation for severe acute kidney injury. AKIKI 2 Trial. Lancet 2021: https://pubmed.ncbi.nlm.nih.gov/33812488/
Books and Music mentioned in this episode:
The Invisible Life of Addie LaRue. By V.E. Schwab: The Invisible-Life-Addie-LaRue
Moon Music. By Coldplay: Moon-Music-Coldplay
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
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To learn more about our programs and career opportunities, visit www.soundphysicians.com.
00:00:26
Speaker
And now your host, Dr. Sergio Zanotti.
Introduction to Dr. Michael Connor
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Acute kidney injury is a frequent complication of critical illness, and a subgroup of these patients will require renal replacement therapy.
00:00:40
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Today's podcast, we will discuss on optimizing renal replacement therapy in the ICU.
00:00:46
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Our guest is Dr. Michael Connor, a practicing intensivist and nephrologist.
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He is a professor and senior physician of critical care medicine and nephrology, the divisions of pulmonary allergy, critical care, sleep medicine, and renal medicine at Emory University School of Medicine.
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In addition, he is the Director of Critical Care Nephrology at the Emory Critical Care Center at Grady Memorial Hospital.
00:01:06
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Dr. Conner's clinical and academic interests are focused heavily on critical care medicine and especially acute nephrology issues in the critically
Optimizing Renal Replacement Therapy in ICU
00:01:13
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ill.
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Dr. Conner is an internationally recognized expert on acute renal replacement therapies, acute kidney injury, antimicrobial dosing and AKI, volume management and hemodynamic support of the critically ill, intra-abdominal hypertension and abdominal compartment syndrome,
00:01:28
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acute acid-based arrangements, and extracorporeal blood purification techniques, including extracorporeal membrane oxygenation or ECMO.
00:01:34
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Michael, welcome back to Critical Matters.
00:01:37
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Hi, Sergio.
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It's so great to join you again.
00:01:40
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Thank you so much for this invitation.
00:01:42
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Absolutely.
00:01:43
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And I would like to start with just a big question.
00:01:46
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Why is this topic important for clinicians in the ICU?
Understanding Renal Replacement Therapy
00:01:52
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Yeah, well, it's a great question.
00:01:54
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So depending on what flavor of ICU that you work in, anywhere from 10 to 30 percent of patients will end up requiring dialysis at some point in the ICU, whether that's for end stage kidney disease, you know, support for those patients admitted with end stage kidney disease.
00:02:12
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but more commonly for acute kidney injury.
00:02:14
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And I think we all know when we work in the ICU that, you know, AKI is a very common diagnosis that affects 50 to 60% of the patients we see in the ICU.
00:02:24
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So, and a not small number of those one that requiring dialysis.
00:02:31
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And so I think it's really important that when we are thinking about providing dialysis to these patients, we have to remember that it's a form of life support
00:02:39
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And just like many of the other therapies of life support that we use in the ICU, we have to make sure that we are using the support measures to try to accomplish specific goals while minimizing the potential harm that the dialysis could introduce to our patients.
00:02:57
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Growing up, I guess, or being educated through the internal medicine ranks, I obviously was very involved and exposed to patients with chronic kidney disease and stage renal disease on
When to Initiate Renal Replacement Therapy
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dialysis.
00:03:08
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And it always was interesting to me, the tension between initiation of RRT in the chronic setting versus initiation of RRT in the acute setting in the ICU, right?
00:03:19
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I mean, one, you try to wait as much as possible.
00:03:22
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And then the other for many years, it seemed that some people would argue the earlier, the better.
00:03:26
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But ultimately, when we talk about timing of RRT in patients with acute kidney injury in the ICU, what really kills these patients and how should we start thinking about when is the right time to initiate dialysis?
00:03:40
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Yeah, it's a great question.
00:03:41
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So let me just back up and just to your point about end-stage kidney disease.
00:03:46
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You're absolutely right that in the outpatient chronic kidney disease progressive CKD patient population, we really do want to wait to initiate dialysis until...
00:03:57
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some sort of symptoms develop, not just based on a purely GFR number, but, you know, some sort of symptoms of end-stage kidney disease that we cannot manage without dialysis, generally speaking.
00:04:10
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But in acute kidney injury, this timing of when to start dialysis, you know, remains quite perplexing.
00:04:15
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We know from several really excellent studies that the patients that have advanced AKI certainly are at an increased risk of death compared to patients who don't have AKI in the hospital or in the ICU.
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And depending on which study you look at, patients who have sort of advanced stage three AKI by the KDGO criteria, which means an increase of 300% from baseline,
00:04:42
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have an increased risk of death of around eight to tenfold compared to patients who don't have AKI in the ICU.
00:04:51
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And when we look further into that, what really kills these patients is not the AKI itself, but it's really the complications associated with AKI with the three
00:05:03
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Three big ones being fluid overload, hyperkalemia, and metabolic acidosis.
00:05:09
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And so the idea is, can we use dialysis or how should we use dialysis to mitigate and minimize the risk of death from those complications?
Major Trials on RRT Timing
00:05:19
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Because to me, if we haven't started dialysis in a timely enough fashion and a patient dies due to complications of fluid overload, we may have missed the boat on that.
00:05:30
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So I'm sure you probably want to discuss a little bit some of the timing trials that have been done.
00:05:35
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But the general question has been, you know, if we start dialysis sort of preemptively before the patients develop really any specific symptoms, the creatinine has gone up and they may not be making quite as much urine.
00:05:49
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Do we provide a benefit from that patient from starting sort of preemptively or early to mitigate or avoid the fluid overload hyperkalemia and metabolic acidosis?
00:06:01
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And in terms of the literature, you did mention, obviously, I think over the last couple of years, there's been a series of large trials that have tried to answer this question, right?
00:06:11
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There's, I think, several questions around, obviously, renal replacement therapy in the ICU that have been studied.
00:06:18
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But in terms of initiation of dialysis, what does the literature say today?
Dosing and Timing Based on Trials
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Yeah, so great question.
00:06:26
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So first of all, the two main areas that have been really researched extensively is the dose of dialysis.
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How much dialysis do we need to give somebody when they're in the ICU?
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And then more recently is this timing question, which is really
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perplexed us for about the last decade.
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And there are five main big randomized control trials on this.
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And I'll just list them for your readers to sort of go back and pull if they want to.
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But there is the Akiki trial, the Ideal ICU trial, the ALANE trial, something called the Stark AKI trial, and the Akiki 2 trial.
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And all of these trials attempt to look at
00:07:09
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sort of starting dialysis before symptoms develop at some level of increase in creatinine.
00:07:17
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There's a little bit of heterogeneity in these studies about what do they consider the creatinine cutoff to start dialysis early versus do we wait to a more conventional timing to start dialysis?
00:07:32
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So either the creatinine continues to increase, it's been several days, or they have some new onset of symptom.
00:07:39
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And there really has been no fantastic difference that has been shown.
00:07:47
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One trial, the ALANE trial, which was a single center study done in cardiac surgery patients primarily, did show that maybe an early initiation was superior to waiting.
00:07:58
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But the AKIKI, the IDEO ICU, and most importantly, the START AKI trial
00:08:03
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showed no difference when you look at the study populations at large.
00:08:11
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And the START-AKI trial was a multicenter global trial done in, I think, well more than 30 countries that enrolled 3,000 patients, which is one of the largest nephrology studies that was ever done.
00:08:25
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And again, the headline result was that it showed no difference between starting in an accelerated or early fashion
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or in a more conventional fashion.
00:08:35
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And if I recall, sorry, go ahead.
00:08:38
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No, I was just going to say that it is important though to recognize that there might be also, if you dive into the details of these studies, there might be a bit of a harm signal from waiting too long to start dialysis.
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And there is a follow-up trial that was called the AKIKI-2 trial that randomized patients to sort of the standard approach or an even more delayed approach.
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And in that study, the even more delayed approach appeared to be harmful, which
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sort of confirmed that there might be also this or reinforce this potential harm signal of waiting too long.
00:09:20
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So it's a bit of a U-shaped curve.
00:09:22
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We can probably start too early and then put some patients on dialysis that may not have otherwise been destined to need dialysis that may have recovered if we waited a little bit longer.
00:09:35
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But clearly, I think most people agree that we can also wait too long.
00:09:40
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And if we wait too long, the sort of horses left the barn.
00:09:44
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It's hard to recover from a lot of the complications that the AKI has already induced.
00:09:52
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Yeah, so like many things, obviously in our practice, that U-shape or that sweet spot is the elusive target, right, that we have to really think for each individual patient.
00:10:01
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Because what I was going to ask you, Michael, is my recollection is that, and I don't remember which one of the trials, but there was also a signal that if you were started early, you would have to be able to do it.
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you were more likely to stay on dialysis.
00:10:14
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And that seems to indicate that you're condemning people to more long-term life support or chronic life support that they may have not needed.
00:10:21
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Is that correct?
00:10:24
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There was a little bit of a signal in the START AKI trial that recovery rates may have been a little bit slower in patients who were in the accelerated arm of that trial.
00:10:37
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I will say that the community that focuses on this question is not really sure what to make of that because they're, you know,
00:10:51
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provided we provide dialysis in a thoughtful and careful way, it's not clear how the dialysis itself would be quote unquote nephrotoxic or preventing recovery, provided we're not causing a lot of intradialytic hypotension or other additional sort of insults.
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So it's a little bit unclear.
00:11:13
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And that question, though, is an important question that needs further evaluation.
00:11:20
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Perfect.
00:11:21
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I wanted to ask you a little bit more before I hear kind of your approach at the bedside as a summary.
Biomarkers and Predicting Dialysis Need
00:11:28
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What is happening with biomarkers these days?
00:11:32
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Are those really just research or are there biomarkers that are helping us make this decision?
00:11:39
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Yeah, so it's a great, another great question.
00:11:43
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So biomarkers are coming.
00:11:48
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In the United States, there are two that are FDA approved at this point.
00:11:53
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Something that is a combination biomarker, I'm not reporting for brand names, but it's easier to talk about brand name in this case, which is called NephroCheck.
00:12:02
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It's a combination of two biomarkers called TIM2 and IGFBP7.
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That is an early warning biomarker of a patient who is at risk for AKI.
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And then we also now have, at least for the pediatric patient population and young adult patient population, FDA approval for using urinary NGAL, which is more of a tubular injury or ATN marker.
00:12:29
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Perhaps the best bio, neither of these two biomarkers are really validated yet to predict patients who will need dialysis, but they certainly can predict patients who have AKI and can identify patients who have AKI before creatinine starts to go up.
00:12:47
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Perhaps the best biomarker, in my opinion, right now to help us understand who's at risk for needing dialysis is the biomarker called the furosemide stress test.
00:12:59
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I realize that's not a lab test, but we like to think about it as a biomarker in the AKI space.
00:13:06
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And this is this concept that if I give furosemide to somebody, they should have a response to that diuretic.
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And so if you give somebody a prescribed amount of Lasix, which is one milligram per kilo in a Lasix-naive individual, or 1.5 milligrams per kilo bolus in patients who are chronically on diuretics,
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then you want to look at the amount of urine they're making over the course of the next two hours.
00:13:37
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And if they make more than 200 cc's of urine in the first two hours, they're considered to have passed their furosemide stress test.
00:13:45
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And if they make less than that, they're considered to have failed.
00:13:47
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And in study after study, patients who pass their furosemide stress test as a
00:13:54
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predictor tool, generally speaking, have low risk of needing dialysis during that episode of AKI.
00:14:03
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It's not zero risk, but it's a low risk, whereas patients who fail their FST have quite a high risk of needing dialysis.
00:14:12
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And the area under the curve to predict the need for dialysis
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is around 0.85 to 0.9.
00:14:21
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So it's quite a strongly predictive tool to help us understand.
00:14:25
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So that is what I tend to recommend that we use at the bedside to help us understand, is this patient somebody who's destined to need dialysis and maybe starting early is better, as opposed to the patient who responds very briskly to diuretics, maybe I can hold off and they might recover without needing dialysis.
00:14:46
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Excellent.
00:14:47
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And quick question, Michael, on the FSD.
00:14:50
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I guess it would be the equivalent of a dynamic, a hemodynamic evaluation, right?
00:14:55
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But is there a timing consideration?
00:14:58
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Could I do it too early and have a false positive or false negative, a false positive?
00:15:04
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Yeah.
00:15:07
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Go ahead.
00:15:07
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Generally speaking, no, generally speaking, no.
00:15:11
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There is no clear signal of a time as to when you can do this because the FST is also been very validated to predict if you do it very early in a
00:15:24
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who will develop advanced AKI.
00:15:27
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So it not only can predict if you do it very early in AKI, those that will go on to have stage three AKI, if you give it in stage three AKI situations, it also predicts those who will end up needing dialysis.
00:15:39
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So it's a very useful tool, regardless of what stage of AKI you're in.
00:15:43
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One of the questions that I get, Sergio, that you probably get a lot of times also is, well, I don't want to give the diuretic to this patient because
00:15:51
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Either I'm worried it's going to hurt the kidney or, you know, I'm not ready to diurese the patient, quote unquote, like I'm not ready for them to lose volume.
00:16:01
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To the first point, you know, we don't consider Lasix a nephrotoxin.
00:16:06
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It is not something that directly injures the nephron.
00:16:10
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So if the keratinine goes up after giving exposure to furosemide, it was going to be going up anyway, regardless of whether or not they got the furosemide.
00:16:20
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So that you shouldn't worry about.
00:16:22
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To the question of, okay, well, I'm still resuscitating my patient.
00:16:26
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I'm not ready to diurese them.
00:16:29
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I usually tell people, look, we're giving them diuretics to test how their kidney is responding.
00:16:36
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if they make a whole ton of urine, my first response is great.
00:16:40
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This kidney is working.
00:16:41
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I don't need to worry so much about this.
00:16:43
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And number two, if they make a whole ton of urine, but I wasn't ready for them to lose all of that volume, then I can always give them that volume back, you know, as like a replacement situation.
00:16:55
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So I don't think we should be too worried about a single dose of diuretics if we're using it as a diagnostic and predictive tool.
00:17:03
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Perfect.
00:17:04
Speaker
And so to summarize the question, when should acute RRT therapy be initiated?
Framework for Initiating RRT
00:17:10
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What's your practical kind of framework at the bedside?
00:17:15
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Yeah, so I tend to give an FST.
00:17:18
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If they make a lot of urine, then I usually will carefully monitor the patient.
00:17:23
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I'll take strategies to avoid complications from AKI.
00:17:27
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We stop giving extra volume.
00:17:29
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We're careful with exposure to potassium, and we're monitoring our labs daily or twice daily to keep a close eye on things and keeping a close sense of what our fluid balance is.
00:17:40
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if they don't make a lot of urine and they're otherwise seem like they are unlikely to recover in the next few days then i usually balance and i usually assess sort of what is the capacity of the kidney and what are we asking of the kidneys to do and if there's a big gap between the capacity of the kidney and the demand on the kidney then i tend to start dialysis and don't delay at that point um
00:18:07
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Am I, did that make sense?
00:18:10
Speaker
Yep, yep, for sure.
00:18:11
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And I think that it's important, right, because I think a lot of times non-nephrologists always have an opinion, right, of when things should be started.
00:18:22
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And I think that understanding the thought process, the literature helps us work and collaborate a little bit better with our nephrology colleagues.
00:18:31
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Now, once you made a decision to start, right, you have options.
RRT Modalities in ICU
00:18:35
Speaker
So can we talk a little bit about RRT modalities and maybe start with a basic overview of the modalities available to us in the ICU?
00:18:44
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Yeah, sure.
00:18:47
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I think it depends a little bit of what hospital you're working at, right?
00:18:50
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Because not all hospitals necessarily have access to all modalities of therapy.
00:18:56
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So first and foremost, when we're practicing, we have to know what's available at our facility.
00:19:03
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And if we don't have all modalities available, we also may need to know when do we need to think about transferring a patient because a specific modality is clearly better in a certain situation.
00:19:17
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So I think that's really important.
00:19:20
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Theoretically, the menu includes sort of three blood-based forms of dialysis.
00:19:26
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We have your traditional intermittent hemodialysis that, as you know, we do for three to four hours.
00:19:32
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We have our continuous modalities, CRT, CVVH, CVVHD, CVVHDF, which have obviously, as most people in the US at least are aware, has really grown exponentially over the course of the last 20 years.
00:19:47
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to the point that it's becoming more and more rare that hospitals don't have CRT options.
00:19:54
Speaker
And then we have these hybrid modalities that used to be called SLED, but are increasingly placed under the umbrella term of prolonged intermittent renal replacement therapy or PERT, which are eight to 12 hour sessions that can be performed with a variety of different machines, either traditional intermittent hemo machines
00:20:14
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or CRT machines or some machines that have been specifically developed to try to use this sort of middle ground of prolonged intermittent renal replacement therapy.
00:20:26
Speaker
I do think that we still have
00:20:31
Speaker
these debates, I'm sure that you run into this in your facility sometimes as well, where people are saying, well, there's, you know, are there any studies that CRT is better than HD or HD is better than CRT?
00:20:45
Speaker
And I think that that's really the wrong question.
00:20:48
Speaker
These are not competing modalities.
00:20:50
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These are complementary modalities of therapy.
00:20:53
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And if you have access to all of them in the ICU at your facility,
00:20:58
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you have to realize that some modalities are better at certain things than other modalities.
Strengths and Weaknesses of RRT Modalities
00:21:03
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For example,
00:21:05
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We all know that intermittent hemo is very efficient.
00:21:09
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It removes things very, very quickly.
00:21:12
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On a minute-by-minute basis, it's far more efficient at removing things than CRT or PERT is.
00:21:19
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So if you have a problem that of where time is really the essence, you know, the K is 9.5 and the EKG looks like a sine wave,
00:21:28
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or they drank a bunch of methanol or other sorts of issues that require very brisk correction, then you may have to think about intermittent hemodialysis in the near term because you need to resolve that problem quickly.
00:21:44
Speaker
Conversely, CRRT is clearly better at fluid removal.
00:21:48
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It's clearly better at avoiding intradialytic hypotension, which has been shown, those two things have been shown in many, many studies,
00:21:57
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to be superior with CRT compared to intermittent hemodialysis.
00:22:01
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So rather than comparing, oh, survival is clearly better in one mode versus the other mode, these are complementary therapies that have strengths and weaknesses.
00:22:10
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And which one we select really has to depend on what we're trying to treat.
00:22:15
Speaker
What is the goal for dialysis for the next few hours or for the next day?
00:22:21
Speaker
What is the goal?
00:22:22
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And from there, we can design what therapy we're going to use.
00:22:26
Speaker
It goes, it also, we should be, we would be remiss if we didn't mention, Sergio, that acute PD is a viable option as well.
00:22:34
Speaker
We don't do that a lot in the United States.
00:22:36
Speaker
It was done some during the pandemic when we were short of dialysis machines and dialysis supplies.
00:22:43
Speaker
But throughout a lot of the rest of the world, acute PD in resource poor environments is the way that dialysis is done in the ICUs.
00:22:54
Speaker
And on the PD question, Michael, if you have a patient who's chronically on PD and presents with acute on chronic or some other cause of critical illness, do you continue PD or do you usually switch to hemodialysis?
00:23:10
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Yeah.
00:23:12
Speaker
So the short answer is, no, we should never change somebody's modality that they're doing as an outpatient if it can be avoided.
00:23:19
Speaker
Now, if somebody has had their diaphragm compromised for some reason, they had thoracic surgery, they were in trauma, they had a diaphragmatic rupture,
00:23:29
Speaker
whereby the PD fluid is going to navigate or move from the intra-abdominal compartment up to the thoracic cavity, that would be a potential reason why somebody can't do PD in the near term.
00:23:41
Speaker
Or if they've had some sort of intra-abdominal surgery that might limit the success of PD in the near term, they may have to wait.
00:23:49
Speaker
But for the garden variety, patient who's home on PD who comes in with a STEMI or who comes in with sepsis or who comes in
00:24:00
Speaker
due to, you know, a pneumonia, those patients could very well and should be maintained on PD rather than switching modality in the near term.
00:24:11
Speaker
Excellent.
00:24:12
Speaker
Well, we were talking before we started that really the goal of today's podcast was really inform intensivists and clinicians at the bedside in the ICU of how they can better collaborate to optimize the care of patients with AKI who require RRT with our nephrology colleagues.
00:24:34
Speaker
Most of our intensivists don't have both hats like you do, although there's a growing number of critical care
00:24:41
Speaker
physicians who do have nephrology training.
00:24:43
Speaker
But in terms of optimizing RRT in critically ill patients, you've talked about six steps.
Six Steps to Optimize RRT
00:24:51
Speaker
Can we dive into those?
00:24:54
Speaker
Yeah, absolutely.
00:24:55
Speaker
So thanks.
00:24:57
Speaker
And I think this is a really vital topic because
00:25:01
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Regardless of who is prescribing the dialysis, we are working together, be that the ICU team, the nurses, the nephrologists, the pharmacists, the rehab services, we're all working together to try to help our patients survive and recover.
00:25:18
Speaker
And not just recover kidney function, but survive and leave the ICU.
00:25:23
Speaker
And so just like everything else in the ICU,
00:25:26
Speaker
You know, care is around dialysis is a team sport.
00:25:30
Speaker
We have to work together.
00:25:32
Speaker
We have to collaborate.
00:25:33
Speaker
We have to work.
00:25:35
Speaker
And even though we may not be the person who is writing the prescription, the CRT is going to or the HD or whatever we're doing for dialysis, it's going to impact.
00:25:46
Speaker
all aspects of the care of that patient.
00:25:48
Speaker
And we need to work together rather than just trusting our nephrologists are going to be paying attention to all of this.
00:25:54
Speaker
So I like to think about it as sort of a six steps.
00:25:58
Speaker
The six steps is how we sort of successfully provide dialysis and optimize the chance for recovery.
00:26:06
Speaker
And those those steps, if we can just outline them very briefly, is number one is we need to closely collaborate between our various teams.
00:26:13
Speaker
We need to talk and continue to talk every day.
00:26:17
Speaker
The second step is we need to establish a goal for dialysis.
00:26:21
Speaker
What are we using the machine to accomplish today?
00:26:25
Speaker
Why are we doing dialysis today?
00:26:27
Speaker
Because how what we are using the machine for what we're using dialysis for is going to inform
00:26:34
Speaker
how we should prescribe dialysis.
00:26:36
Speaker
So I alluded to this before, if we need to correct, you know, an ethylene glycol ingestion, then I'm going to prescribe dialysis differently than if I am just sort of trying to remove fluid.
00:26:49
Speaker
And if we don't have a goal for the day, if there's no reason to do dialysis on that day, that might be a day to think about a temporary therapy, a break or interruption, for example.
00:27:01
Speaker
The third step is we need to keep the machines running, especially the CRT machines.
00:27:07
Speaker
We don't want circuit downtime if we can avoid it, and that requires a great vascular access, and we need to be using anticoagulation of some form as an opt-out, not an opt-in.
00:27:20
Speaker
Rather than waiting for trouble and then starting anticoagulation, we need to use some form of anticoagulation unless it's contraindicated.
00:27:28
Speaker
And then the step four, five, and six are sort of how we can
00:27:34
Speaker
avoid harm from the dialysis machine.
00:27:36
Speaker
And that step four is we need to address medication dosing.
00:27:40
Speaker
So as we make changes to the dialysis plan or the dialysis modality, we need to make sure that we have addressed the medication impacts of this so that our patients are not subtherapeutic on their antimicrobials, for example.
00:27:54
Speaker
We need to ensure that they're receiving appropriate nutrition support.
00:28:01
Speaker
If we do dialysis frequently, either daily HD or CRT, we're going to be removing a lot of amino acids, a lot of vitamins, a lot of micronutrients.
00:28:12
Speaker
And so these patients oftentimes need an augmented and artificially high amount of nutrition support, especially as it pertains to protein, amino acids, and vitamins and micronutrients.
00:28:23
Speaker
And then we need to avoid other complications such as hypophosphatemia, hypotension, bleeding, and some other rare complications along the way.
00:28:31
Speaker
So those are the six steps.
00:28:34
Speaker
Close collaboration, establishing goals, keep the machines running, addressing medication, dosing, ensuring appropriate nutrition support, and avoiding dialysis-related complications.
00:28:45
Speaker
So that is, I think, a great framework to think about at the bedside as critical care clinicians.
00:28:52
Speaker
And what I would like to do, Michael, if it's okay, is to dive maybe a little bit deeper in each one of these and ask you a couple of questions related to those six steps.
00:29:01
Speaker
Absolutely.
00:29:02
Speaker
So in terms of a team effort, it always strikes me as something we talk about on a regular basis, yet there's tremendous opportunity to do better, right?
00:29:14
Speaker
I really believe that truly high functioning teams are not as common as we think they are.
00:29:21
Speaker
Right.
00:29:22
Speaker
And there's a lot of opportunity there to work better, not only within the ICU team, but when we're collaborating on a specific organ failure and organ support like we would with the nephrology team, that includes obviously not only sometimes the nephrologist,
00:29:38
Speaker
but also might include the dialysis nurses or other team members that are interacting with us.
00:29:44
Speaker
So what do you think, other than obviously the obvious of talking on a daily basis, but what do you think are good questions for intensivists to ask our nephrology colleagues, or what are things that we should try to settle in terms of as we plan to care for these patients?
00:30:04
Speaker
I wish I could give you a clear answer on that one, Sergio, but you're absolutely correct that high-functioning teams, I do think, is less common than we like to think that it is.
00:30:14
Speaker
It is hard.
00:30:15
Speaker
These are, you know...
00:30:18
Speaker
People like to use the analogy of high-functioning teams like pilots in an airplane.
00:30:25
Speaker
And while I like that analogy in general, I think that it falls short at some levels because flying an airplane should theoretically be a very predictable event with predictable...
00:30:41
Speaker
things that occur, whereas our ICU situation is so unpredictable and the patients vary so much from patient to patient to patient.
00:30:50
Speaker
When the pilot gets in his, you know, Airbus A320, each Airbus A320 is the same.
00:30:56
Speaker
Our patients vary so differently.
00:30:59
Speaker
They have different problems.
00:31:00
Speaker
They have different genetics.
00:31:02
Speaker
They have different issues.
00:31:03
Speaker
And so it's really hard, I think, to have high-functioning teams.
00:31:08
Speaker
I think one of the most important questions that we should be asking as intensivists with our nephrology colleagues is,
00:31:15
Speaker
We need to we need to work together to define what the goal is.
00:31:19
Speaker
Why are we using it today?
00:31:21
Speaker
What are we doing with the dialysis today?
00:31:25
Speaker
And and make sure that that's the most important thing that we discuss.
00:31:30
Speaker
And then from there, you know, it's.
00:31:34
Speaker
you know, are there going to be any changes to our dialysis for that goal today?
00:31:39
Speaker
I think if you start with those two questions, you know, then the collaborative discussions can flow from there.
00:31:45
Speaker
Um,
00:31:46
Speaker
Perfect.
00:31:48
Speaker
In terms of establishing the daily goal of renal replacement therapy, what you talked about, which I think is an important point for our audience, about answering the question of how quickly do I need to remove something and clearly showing that intermittent hemodialysis might do a better job in some cases than CRRT.
RRT Dosing Insights
00:32:08
Speaker
And I think that that is important consideration because I do believe that with the goal of simplifying things, often intensivists think the sicker the patient, the more likely they're going to be on CRT.
00:32:22
Speaker
But you can be extremely sick, like you said, and require immediate removal of a toxin.
00:32:28
Speaker
And in that case, probably intermittent hemodialysis would be the way to go.
00:32:31
Speaker
So I think that's very important.
00:32:32
Speaker
But when we think of dialysis dose, which I think is also one of the goals, right?
00:32:38
Speaker
So even though that's going to be prescribed by the nephrologist, how should we think about that?
00:32:43
Speaker
And what have the studies showed on the dialysis dose?
00:32:47
Speaker
Because I think as human beings, we tend to think that more is better usually, and that might not always be the case, right?
00:32:54
Speaker
Yeah, and that has been researched and shown in general, right?
00:32:59
Speaker
That when we talk about, just for your audience, just to remember, when we're talking about dialysis dose, we're talking about how efficiently and how aggressively are we removing things, okay?
00:33:14
Speaker
um so in other words um are we are we doing are we removing things you know as briskly as possible or are we backing down a little bit and how much a dose they get how aggressive that removal is throughout the day and throughout the week is sort of what we talk about when we talk about dose it's a fairly straightforward concept in crt in hd it gets a little bit complicated and and some very um
00:33:40
Speaker
uh, esoteric and nerdy nephrology formulas and stuff like that, that, that we won't necessarily need to get into, but there have been a several large randomized controlled trials that have looked at sort of, um,
00:33:54
Speaker
a sort of moderate dose of dialysis or a higher dose of dialysis?
00:33:59
Speaker
Do we provide higher exposure to CRT, thinking that maybe more is better at controlling things like acid base or potassium?
00:34:10
Speaker
And without a doubt, there is not a huge benefit or any real benefit to doing higher doses of dialysis.
00:34:19
Speaker
for extended periods of time.
00:34:20
Speaker
And I think that's the key point here.
00:34:23
Speaker
Dose is not static and should not be static.
00:34:27
Speaker
What these randomized control trials looked at was exposure to high dose dialysis versus sort of standard or more moderate dose dialysis throughout their entire course in the ICU.
00:34:41
Speaker
It didn't ask
00:34:43
Speaker
should this patient be on high dose dialysis for five hours?
00:34:47
Speaker
It said, if we look at their entire journey through the ICU,
00:34:53
Speaker
where they randomized to high dose dialysis or low dose dialysis.
00:34:57
Speaker
And remember, if we're doing high dose dialysis, we might be removing a lot of bad things, you know, like urea, uremic toxins, potassium, correcting acid base disorders, but we'll likely also be removing a lot of good things like medications, nutrition,
00:35:15
Speaker
phosphorus, other sorts of stuff like that.
00:35:17
Speaker
So we can't really have our cake and eat it too.
00:35:19
Speaker
We can't selectively increase the removal of bad things while leaving the good things behind.
00:35:26
Speaker
So at this point, the way that we generally conceptualize this or recommend that people conceptualize this is to say,
00:35:36
Speaker
Once the patient is sort of at steady state, they should be at a standard dose of dialysis, which for CRT, we talk about the total effluent dose.
00:35:47
Speaker
So their replacement fluid, their convection and their diffusion, their dialysate and replacement fluid flow rates.
00:35:54
Speaker
adding up to around 20 to 25 mls per kilo per hour so if they weigh 60 kilos that means the crt effluent flow rate should be somewhere between 1200 and 1500 mls per hour if they weigh 100 kilos it should be somewhere between 2000 and 2500 that doesn't mean that when they first start
00:36:17
Speaker
They don't necessarily need to be on a higher dose for 12 hours to correct that pH of 7.
00:36:22
Speaker
But once the pH is sort of more acceptable, the dose should be decreased to that sort of standard dose.
00:36:29
Speaker
And I think that's an important distinction, right?
00:36:31
Speaker
The dynamic nature of ARRT versus maybe the steady state framework that we have for chronically end-stage renal disease patients.
00:36:41
Speaker
Although some of our patients might get to a steady state in the ICU as well.
00:36:47
Speaker
The next topic or step is keep the RRT running.
00:36:51
Speaker
And as we were talking before we started recording, this is a common call or problem that we will get on patients on CRRT especially, right?
00:37:02
Speaker
the filter is clotted, or the catheter is having a bad flow.
00:37:07
Speaker
So maybe we can start with establishing great vascular access.
00:37:11
Speaker
How should we think about location and type of catheter, since a lot of our listeners are probably the ones putting in these lines in the first place?
Vascular Access for Renal Therapy
00:37:20
Speaker
Yeah, so decision support tools at the time of insertion can be really helpful because expecting everybody to remember how and what a great vascular access looks like can
00:37:37
Speaker
important point, which is that vascular access is key to especially CRT, but really for any forms of hemodialysis, is that we have to have an excellent vascular access.
00:37:51
Speaker
And if your circuit is clotting frequently,
00:37:54
Speaker
Before you even start talking about anticoagulation or how to adjust the anticoagulation, we have to verify that the access is functioning properly.
00:38:03
Speaker
Because if you're getting a lot of access alarms or return pressure alarms, then your catheter is probably not functioning ideally.
00:38:11
Speaker
And every time those alarms go off, the blood pump stops for 10 seconds or 20 seconds, and the blood isn't circulating until the nurse is able to restart it.
00:38:23
Speaker
And that leads to stasis and leads to increased risk of circuit thrombosis.
00:38:28
Speaker
So the guidelines, the global guidelines in AKI that talk about vascular access are currently being revised.
00:38:38
Speaker
The ones that have been published are since 2012, and we don't think that those are particularly germane because we've had better studies that have come out since those guidelines were written that help us understand what a truly good vascular access is.
00:38:55
Speaker
So the general recommendations now are right IJ is preferred, left IJ is the second option,
00:39:05
Speaker
as opposed to femoral, which used to be considered the second option besides right IJ.
00:39:10
Speaker
And then femoral is our third choice, and subclavian should be avoided unless there's really no other options.
00:39:18
Speaker
And theoretically, it would be better to recite a central line into a subclavian to free up a site for a vascular access in one of the IJs or a femoral.
00:39:31
Speaker
And when you're using the vascular access, length is really important.
00:39:36
Speaker
So in the IJ positions, the goal is for the catheter to the tip to sit in the right atrium or at the cable atrial junction.
00:39:46
Speaker
And there had been several randomized controlled trials, but one in particular from 2012 that clearly shows that longer catheters
00:39:56
Speaker
that sit in the right atrium as opposed to in the more proximal portions of the SVC, the longer catheters function better by all metrics when you're looking at CRT or intermittent hemodialysis.
00:40:10
Speaker
So, and for most patients,
00:40:13
Speaker
for most adult-sized patients to reach the right atrium from the right IJ position, you would be using a 20-centimeter catheter and a 24-centimeter catheter from the left IJ, which is significantly longer than what a lot of your listeners may have been trained on, which was 15 centimeters in the right and 20 centimeters in the left.
00:40:34
Speaker
but clearly the studies have shown that it's better to have a longer catheter rather than a shorter catheter so that i think is a very important piece and then in the groin it's also we need to have a longer catheter 24 to 30 centimeters in the femoral position and please don't assume that your residents or your fellows know how to select this catheter so one of the important things that i tell the nephrology team is is that if they're not going to be inserting the catheter
00:41:04
Speaker
they should view themselves as the holder of the knowledge as to where the catheter selection should be.
00:41:11
Speaker
So it should be, the conversation should be with the ICU proceduralist, hey, are you going to be putting in the catheter?
00:41:18
Speaker
If the ICU team says yes, then let's talk about what site and what length of catheter we want to put in, because starting with a bad catheter is just going to cause problems.
00:41:29
Speaker
And I think that this is a super important point.
00:41:32
Speaker
And from practice in the community and talking with people, I think that the knowledge of the proper length is not as common as we might think with our intensivist colleagues.
00:41:49
Speaker
I think that a lot of IJ catheters are 15 centimeters in length.
00:41:55
Speaker
And I'm sure that a lot of the problems that people have with those catheters might be attributed or might be correlated with that.
00:42:02
Speaker
So really, unless the patient is really, really small, the 15 centimeter really doesn't have a great use.
00:42:09
Speaker
Is that a fair statement?
00:42:11
Speaker
Yeah, I completely agree.
00:42:12
Speaker
I mean, if the patient's sub five foot, then maybe.
00:42:16
Speaker
But absolutely, I completely agree.
00:42:19
Speaker
I never reach for a 15 centimeter catheter.
00:42:22
Speaker
Conversely, if they're really tall, you may also have to think about a 24 centimeter in the right neck.
00:42:27
Speaker
We had a patient like that last week who was well over six feet tall.
00:42:32
Speaker
And we knew from other central lines that were really short on the patient.
00:42:38
Speaker
that a standard 20 centimeter was just not going to be long enough.
00:42:42
Speaker
And so we inserted a long catheter in the neck.
00:42:46
Speaker
It also goes without saying that, you know, we're talking about non-tunneled catheters, but there is a role for tunneled permcasts in these patients as well.
00:42:55
Speaker
Probably not to initiate dialysis, but if they're going to be stuck in the ICU for several weeks on dialysis,
00:43:01
Speaker
We should also be having some conversations about when is it a proper time to potentially think about having our patient go downstairs to IR to get a tunneled long-term dialysis catheter in, because those perform exceedingly well with dialysis in the ICU, and they're going to be associated with a lower rate of CLABSI than any sort of other central line is.
00:43:27
Speaker
Perfect.
00:43:28
Speaker
So the second question about keep RRT running
Anticoagulation in RRT
00:43:32
Speaker
is the clotting issue, right?
00:43:35
Speaker
The anticoagulation.
00:43:36
Speaker
And you talked about opt-out versus opt-in, which I think is an important architecture choice design, right?
00:43:46
Speaker
But can you give us a little bit more overview of why anticoagulation and what are the options that we have and how you approach it?
00:43:54
Speaker
Yeah, so anticoagulation is a class one recommendation by all the global guidelines for CRT use for AKI.
00:44:03
Speaker
It really has to be an opt-out, not an opt-in, as we discussed.
00:44:07
Speaker
Your options are many.
00:44:10
Speaker
The guidelines are pretty clear that citrate is recommended, but we recognize and understand that all hospitals don't have access to citrate.
00:44:18
Speaker
anticoagulation and during this IV fluid shortage period, neither do we.
00:44:23
Speaker
That citrate use and availability is certainly a little bit lower at the current moment.
00:44:29
Speaker
But heparin is really the mainstay of therapy for patients who don't have citrate, or you could think about direct thrombin inhibitors like bivalirudin or argatroban.
00:44:43
Speaker
So, and we can get into some details if we have time on this, but suffice to say, when we're starting dialysis, we also need to talk and communicate with the people who are writing the prescription.
00:44:56
Speaker
So if we're the ICU team and we've consulted a nephrologist, we need to say, look,
00:45:00
Speaker
Okay, we're all in agreement.
00:45:01
Speaker
We're going to start, you know, dialysis.
00:45:03
Speaker
And because our main goal is fluid removal, we're going to do CRT in this patient.
00:45:07
Speaker
So how are we going to keep this running?
00:45:09
Speaker
I don't have any concerns about bleeding.
00:45:12
Speaker
So I would be okay with heparin in this patient or...
00:45:15
Speaker
you know, this patient doesn't have any contraindications to citrate, so let's use citrate in this patient.
00:45:20
Speaker
That needs to be the sort of follow-on conversation and not just assume that the nephrologists know what the risks are in that situation.
00:45:28
Speaker
So again, another area for close collaboration and communication.
00:45:33
Speaker
And just, I think, a lot of hospitals do have this sort of practice pattern where they wait for trouble and don't start CRT immediately.
00:45:42
Speaker
with anticoagulation unless there's problems.
00:45:45
Speaker
We don't recommend that because a lot of times teams aren't very attuned to all the circuit changes that may be happening.
00:45:52
Speaker
And so if you don't know on day shift that the circuit was changed twice overnight, you may not know that you necessarily need to start an anticoagulation or that you're having trouble.
00:46:03
Speaker
So the data is quite clear that anticoagulation of some form is better
00:46:09
Speaker
than no anticoagulation when it comes to CRT.
00:46:12
Speaker
So that needs to be sort of the standard.
00:46:16
Speaker
And there are some nuances to using citrate, and there's nuances to using heparin.
00:46:20
Speaker
And I don't know if you really want to get into any of those now, or if we should have a whole separate podcast on CRT anticoagulation at some point.
00:46:29
Speaker
Absolutely.
00:46:30
Speaker
And we can talk more about it.
00:46:31
Speaker
But just I think that the one thing I would want you to share with us
00:46:36
Speaker
is at a high level, what would be contraindications for citrate?
00:46:39
Speaker
I think that people are a little bit more comfortable with making a decision on the risk of bleeding as intensivist, but maybe they might not be as familiar with what would be problematic if you're using citrate.
00:46:52
Speaker
Yeah, so with citrate, the real risk with citrate is if the citrate is not being metabolized properly.
00:47:01
Speaker
So when we use citrate anticoagulation, the principle, I think most of your listeners probably know, but the principle is that we mix citrate anticoagulation.
00:47:13
Speaker
in the blood as it's out of the body and going through the CRT circuit.
00:47:16
Speaker
We mix a certain amount of citrate per blood by some ratio and the citrate binds the free circulating ionized calcium.
00:47:25
Speaker
and in the blood.
00:47:26
Speaker
And when the ionized calcium is very low, the blood can't clot.
00:47:31
Speaker
And then for the most part, a significant amount of this citrate calcium complexes are then dialyzed off as the blood travels through the CRT circuit.
00:47:43
Speaker
But not all of it is.
00:47:45
Speaker
And some of the citrate will return back to the patient.
00:47:49
Speaker
And most of the time in most patients, that citrate will just be metabolized by the muscles and the liver into bicarbonate.
00:48:00
Speaker
And that's not really a dangerous thing.
00:48:03
Speaker
That's an expected sort of normal thing.
00:48:06
Speaker
Where you get into some potential risk is if that citrate that travels back to the patient is not being metabolized properly.
00:48:15
Speaker
And therefore, you start to accumulate citrate in the blood.
00:48:19
Speaker
And that's called citrate toxicity.
00:48:25
Speaker
You would recognize that by a sort of increase in your total calcium with your
00:48:33
Speaker
your ionized calcium staying the same or going lower.
00:48:36
Speaker
So your total calcium to ionized calcium ratio is getting higher.
00:48:41
Speaker
And the patients that are at risk for that are patients who have acute liver dysfunction, not so much chronic liver disease, but acute liver disease, and or they have poor perfusion to their muscles.
00:48:55
Speaker
So the patients who have high lactate, poor perfusion to their large muscle beds,
00:49:02
Speaker
and whose liver may be suffering from some shock liver or some acute on chronic liver disease or some sort of toxic liver issue, those would be the patients that are at risk for citrate toxicity.
00:49:16
Speaker
It doesn't mean you can't use it.
00:49:17
Speaker
You can still probably use citrate, but you need to be a little bit more cautious.
00:49:23
Speaker
Excellent.
00:49:24
Speaker
So as we move on with the list of steps to optimize, the next two we could do maybe together, which are addressing medication, dosing daily, and ensuring appropriate nutrition.
Medication Dosing and Nutrition During RRT
00:49:37
Speaker
And I think that that obviously is a call for more pharmacists and nutritionists doing rounds from my perspective.
00:49:45
Speaker
But if you want to give us some high-level comments, and then we can talk about avoiding RRT complications.
00:49:51
Speaker
Yeah, absolutely.
00:49:52
Speaker
So you're absolutely right.
00:49:54
Speaker
I agree with more pharmacists and more nutritionists on rounds.
00:49:58
Speaker
But those nutritionists and pharmacists, if we're going to outsource the management of the medications and nutritionists and nutrition stuff on CRT, they have to be knowledgeable about what those impacts are.
00:50:09
Speaker
And so it's our job as the intensivist to help educate them about that so that we can outsource some of that to them.
00:50:18
Speaker
For medication dosing,
00:50:20
Speaker
Primarily, the couple of points that I just like to make is that, first of all, medications that are dializable in CRRT, the dose of CRRT is going to impact the clearance.
00:50:32
Speaker
So the higher the CRRT dose, the more of the medicine you're going to remove.
00:50:39
Speaker
And one sort of back of the envelope calculation that we can use is if we have the total effluent flow rate,
00:50:46
Speaker
so let's say they're getting three liters an hour of combination of dialysate and replacement fluid that's 3 000 mls per hour if we convert that to minutes by dividing by 60 that would be 50 mls per minute and that's a that would sort of equate a little bit to your gfr or your creatinine clearance and so when you are trying to decide how do i dose this pitazo or how do i dose this bank
00:51:14
Speaker
understanding what the effluent flow rate is, it serves as a starting point, not the final answer, but serves as a starting point for where to dose your medications.
00:51:25
Speaker
So if you have patients getting 50 mLs a minute, they need to be essentially dosed for normal renal function.
00:51:32
Speaker
The second point that I think is really important for our for listeners to know is that the membranes we use on CRT, while they outwardly look the same, microscopically, they are quite different from what we use on intermittent hemodialysis.
00:51:52
Speaker
And so therefore, especially with the modern membranes that we use on CRT.
00:51:57
Speaker
And the reason that's important is because drugs that we have, like references that we have that talk about whether a drug is dializable on HD or not, usually are looking at stable outpatients getting HD on a regular HD membrane and who have normal serum protein levels
00:52:21
Speaker
and therefore protein binding amounts.
00:52:24
Speaker
But when patients are in the ICU, we're using a different membrane that is oftentimes much leakier and is able to transport drugs much more efficiently.
00:52:35
Speaker
And the protein binding of the drugs goes down.
00:52:39
Speaker
And so therefore we have more free peptazo or more free cefepime in the blood, which is therefore
00:52:47
Speaker
more free drug able to be removed by dialysis.
00:52:50
Speaker
So we can't necessarily trust all of the resources that we have out there on dialysis dosing.
00:52:58
Speaker
We sometimes have to make some programmatic decisions about how we're going to dose Piptazo or meropenem in our patients at our facility
00:53:08
Speaker
based on what dialysis equipment we're using, what filters we're using, and what the literature sort of says.
00:53:17
Speaker
Excellent.
00:53:18
Speaker
So finally, the sixth step is avoiding RIT complications.
Managing RRT Complications
00:53:23
Speaker
And there are some complications that are more frequent and some that are a little bit more rare.
00:53:27
Speaker
But maybe we can start with the frequent ones.
00:53:29
Speaker
And I think that the three that come to mind are hypophosphatemia, hypotension, and bleeding.
00:53:36
Speaker
How do you think about these and what will be the role for the critical care clinician?
00:53:41
Speaker
Yeah, well, so bleeding, I think, you know, comes down a little bit to what sort of anticoagulation we're using.
00:53:47
Speaker
But I also lump into that is circuit failures, because if we have a lot of circuit failures, we lose a not an inconsequential amount of blood in those circuits.
00:53:57
Speaker
There's about 180 to 200 cc's of blood.
00:54:00
Speaker
So if they're not able to retransfuse the blood and the circuits have failed several times,
00:54:04
Speaker
then your patients are going to end up needing blood transfusions just from blood loss with CRT.
00:54:09
Speaker
And Sergio, as you know, right, there's a lot of literature about the potential downsides of blood transfusions in our critically ill patients, causing immunoparalysis, increasing the risk of hospital acquired infections and other sorts of stuff like that.
00:54:24
Speaker
So, you know, a bleeding, I think, is also part of circuit clotting.
00:54:28
Speaker
So we have to weigh clotting, the risk of bleeding, as we think about some of our anticoagulation options.
00:54:34
Speaker
Hypotension is oftentimes driven by our dialysis decisions.
00:54:38
Speaker
So if the patient's particularly at risk of hypotension, we probably need to be thinking more about CRT modalities, because we definitely don't want to be causing intradialytic hypotension.
00:54:48
Speaker
You know, that's just going to cause
00:54:50
Speaker
more risk of ATN or extension of any sort of tubular injury or ischemia that we've already had and may delay and will delay the chance of recovery.
00:55:01
Speaker
Hypophosphatemia is more complex.
00:55:03
Speaker
You know, when we dialyze traditionally, at least in the United States, we traditionally use phosphorus-free solutions on CRT.
00:55:14
Speaker
And so therefore,
00:55:16
Speaker
you know, if patients are going to be on CRT for more than two or three days, almost universally, probably 60 to 80% of patients will develop a trend towards a decrease in their phosphorus level.
00:55:30
Speaker
And we have reasonably good studies that show that development of hypophosphatemia on patients on CRT increases the
00:55:40
Speaker
risk of needing a trach and prolongs the amount of time that they need ventilation.
00:55:45
Speaker
So avoiding hyphophosphatemia is really important.
00:55:49
Speaker
The strategies for that are supplementing phosphorus, you know, checking it every day.
00:55:54
Speaker
And as it starts to be sort of, you know, normal, like it's come from eight down to five or four or three, is to start empirically supplementing enterally if they're on tube feeds.
00:56:07
Speaker
think about using phosphorus containing CRT solutions, which in the United States, there is one form of phosphorus containing solutions.
00:56:19
Speaker
And those solutions have been clearly demonstrated to basically eliminate the risk of hypophosphatemia when you use those solutions.
00:56:29
Speaker
Perfect.
00:56:30
Speaker
I had a couple of questions on the hypotension or intradialytic hypotension.
00:56:35
Speaker
So obviously you mentioned that this is an indication or this is favored with CRT, which has less intradialytic hypotension.
00:56:44
Speaker
A lot of our patients are placed on CRT because of hemodynamic instability.
00:56:50
Speaker
And if I recall correctly, there are some studies that suggest that the transition to intermittent hemodialysis, the need for vasopressors might be an important consideration.
00:57:00
Speaker
How do you think about this, Michael?
00:57:03
Speaker
How do I think about transitioning between the different modalities?
00:57:06
Speaker
Is that your question?
00:57:07
Speaker
Yeah, when you're hemodynamically or when you initiate CRT because you're hemodynamically unstable.
00:57:12
Speaker
So when is it okay to move on to intermittent hemodialysis?
00:57:16
Speaker
Yeah, I think in general, I would say that I think there is pressure a lot of times to change people sooner than they really should be changed.
00:57:26
Speaker
So that's the first thing I would like to say.
00:57:29
Speaker
How we conceptualize changing, again, depends a little bit as to what the menu of options are available.
00:57:35
Speaker
If you have an option for a PERT, like a
00:57:39
Speaker
if your facility has an option for a 10 to 12 hour dialysis sessions, you may be able to think about transitioning from CRT to PERT sort of on the earlier side.
00:57:52
Speaker
But going to intermittent hemodialysis, you know, can be a little bit more challenging.
00:57:58
Speaker
What I tend to sort of tell people is
00:58:02
Speaker
I usually recommend sort of, we think of sort of one of three reasons why someone's ready to transition off CRT.
00:58:10
Speaker
The first is they have obvious renal recovery and don't need any more dialysis at all.
00:58:15
Speaker
So in other words, they've started to make urine.
00:58:18
Speaker
and their kidneys are getting better, and we can just stop dialysis altogether.
00:58:24
Speaker
That would be number one.
00:58:26
Speaker
Number two is they're otherwise ready to leave the intensive care unit.
00:58:31
Speaker
They're fully off the ventilator.
00:58:33
Speaker
They are going to the floor.
00:58:37
Speaker
and we can't make a legitimate reason to keep them in the ICU just to stay on CRT.
00:58:42
Speaker
This does occur sometimes when you have these patients that are otherwise ready to go to the floor but have terrible heart failure, for example, and they're still super fluid overloaded, and we know that we're not going to be able to achieve or get fluid off with their tenuous heart with intermittent hemodialysis.
00:58:59
Speaker
So that patient may need to stay a couple of extra days on CRT to reach uvolemia.
00:59:04
Speaker
And then the third reason people should think about, or third time that people can think about transitioning is hemodynamically stable, quote unquote, however you want to define that, whether that's low dose pressers or no pressers, but that they are also at uvilemia.
00:59:22
Speaker
If you haven't achieved uvilemia yet, if they're still edematous and they're not otherwise ready to leave the ICU, we have lots of studies that show that it's very difficult in ICU patients to achieve
00:59:34
Speaker
uvolemia with intermittent hemodialysis.
00:59:38
Speaker
So if you change before they're uvolemic, then you're basically almost sort of committing that patient to persistent fluid overload, which, you know, for me, I don't want to send my patient out of the ICU still fluid overloaded.
00:59:52
Speaker
I'd like them to have reached uvolemia if I can before they leave the ICU.
00:59:57
Speaker
Excellent.
00:59:58
Speaker
And the last question on hypotension, what's the role of albumin for preventing intradialytic hypotension with, obviously, intermittent hemodialysis?
01:00:12
Speaker
Yeah, with intermittent hemodialysis, a little bit controversial, but the studies are pretty consistent that it does help.
01:00:20
Speaker
Now, whether that improves outcomes for the patient is a little bit unclear, but if the outcome in question, if the thing being studied is avoidance of intradialytic hypotension, then giving concentrated albumin at the start of HD sessions is
01:00:35
Speaker
or some other colloid, like a transfusion of blood if they're anemic, does help avoid interdialytic hypotension.
01:00:43
Speaker
There are some other strategies too, like chilling the dialysate and doing a few other strategies that we can do that can also help minimize interdialytic hypotension.
01:00:53
Speaker
I think the key is, is if you're gonna use intermittent hemo in the ICU,
01:00:57
Speaker
we need to use all the tricks of the trade that we have available to us to avoid interdialytic hypotension.
01:01:03
Speaker
This isn't like we're prescribing dialysis like they're at home.
01:01:06
Speaker
If they're going to their outpatient dialysis unit, that prescription is going to look very different and should look very different than if they're in the ICU because we have an AKI patient in the ICU.
01:01:17
Speaker
We have a lot of tricks that we can do on the hemo machines to help avoid interdialytic hypotension, but we need to plan those ahead of time.
01:01:26
Speaker
Michael, we talked about obviously very common complications.
01:01:30
Speaker
One that I was asking you about before we started recording was the development of euglycemic decay in some patients who receive CRT with diacetyl that has no dextrose.
01:01:42
Speaker
Could you comment on that?
01:01:45
Speaker
Yeah, so the phosphorus-containing CRT solutions that are available in the market do not contain dextrose because it's not stable in solution well enough for it to be all mixed together in the bags.
01:01:57
Speaker
So what that leads to is that the patients that are on these solutions will have a bit of a net removal of glucose from their serum to the effluent.
01:02:09
Speaker
And in far more than 95% of the patients,
01:02:13
Speaker
that's really not an issue.
01:02:16
Speaker
The patients do not develop hypoglycemia.
01:02:19
Speaker
They don't really develop any complications related to that.
01:02:22
Speaker
But the two theoretical risks of this are that you could develop hypoglycemia, and the patients that are at risk for that are patients whose gluconeogenesis is impaired, so their liver isn't working,
01:02:36
Speaker
and they are not getting any sort of nutrition or dextrose source.
01:02:41
Speaker
So that patient who comes in with like acute liver failure, who's not being fed, is not getting a lot of other dextrose sources.
01:02:50
Speaker
All their drips are mixed in normal saline instead of dextrose.
01:02:54
Speaker
That patient could be a little bit at risk for hypoglycemia.
01:02:58
Speaker
Theoretically, if you're monitoring glucose levels, which you should be doing anyway in a patient like that, you would notice that.
01:03:04
Speaker
The slightly more common risk is this euglycemic DKA situation.
01:03:10
Speaker
And I can't really tell you exactly how common it is because there have not been great studies on this, but I can just tell you that we use the phosphorus-containing solutions exclusively at a couple of my facilities that I work at, and we do occasionally see this.
01:03:29
Speaker
Why does this happen?
01:03:30
Speaker
It happens because you're removing glucose, and so therefore you're controlling the sugars a little bit better.
01:03:37
Speaker
So the patient whose glucose may otherwise have been 180, may be having a glucose of 120.
01:03:44
Speaker
And most of our insulin dosing in the ICU, Sergio, as you know, is sort of driven by what the glucose levels are.
01:03:52
Speaker
And so if the glucose is running 100, 120, 130,
01:03:57
Speaker
most of the patients are not going to be getting exposed to insulin as much as they would otherwise.
01:04:02
Speaker
And if they don't make endogenous insulin because they have underlying insulin-dependent diabetes or they don't make sufficient endogenous insulin, then they could be insulin deficient.
01:04:15
Speaker
And if they're insulin deficient, they can go into a DKA state.
01:04:19
Speaker
So it's a little bit like what we see with some of the SGLT2 inhibitors from that regard.
01:04:26
Speaker
So it sounds like something to be aware, not very common, but I guess a great topic for a board question.
01:04:32
Speaker
Great topic for a board question.
01:04:34
Speaker
And I will tell you that you do see it if you're using these solutions.
01:04:37
Speaker
So a patient who has sort of like been getting better on CRT, in other words, their acid-base status has been getting better.
01:04:44
Speaker
They had an anion gap acidosis when you started CRT, but their pH and their gap was closing and everything was looking better.
01:04:52
Speaker
and CRT is working fine, but then like day three, day four, their gap starts increasing again, but their lactate remains low, that patient you might want to screen with like a beta-hydroxybutyrate because they could be developing euglycemic DKA in some situations.
01:05:10
Speaker
And it's very easy to fix that, Sergio, just like you would with an SGLT2 inhibitor, right?
01:05:15
Speaker
You're just going to give the patient dextrose
01:05:18
Speaker
And then some insulin.
01:05:19
Speaker
So you just say, I'm not going to stop the CRT, but I'm going to add some D10 or D20 through a separate IV, push the sugar up, and then start giving insulin to the patient.
01:05:29
Speaker
Excellent.
01:05:30
Speaker
So as we close, Michael, could you just give us maybe a summary of the key concepts you want our intensivists to take home from this discussion?
01:05:39
Speaker
And then we'll go to some non-clinical questions.
01:05:42
Speaker
Yeah, absolutely.
01:05:43
Speaker
Key points, timing of when to start is a little bit elusive.
01:05:48
Speaker
Think about capacity of the kidney versus demand on the kidney.
01:05:53
Speaker
Think about doing a furosemide stress test.
01:05:55
Speaker
If they're not making urine, then that's the patient who you might want to think about starting.
01:06:00
Speaker
If they are making urine, potentially you can hold off if there's no other real glaring need to start dialysis.
01:06:07
Speaker
The second point is think about your six steps and make sure that you're collaborating, you're deciding why are we using dialysis today, you're designing dialysis to achieve that goal, and you're monitoring how well you're doing at achieving that goal.
01:06:22
Speaker
Using goal-directed dialysis is really important, and then avoiding the complications associated with dialysis, like we talked about, I think are really the key points.
01:06:33
Speaker
So you've been on the podcast before and you know, we like to close with a couple of questions that are unrelated to the clinical
Personal Insights from Dr. Connor
01:06:39
Speaker
topic.
01:06:39
Speaker
So yeah, I love it.
01:06:41
Speaker
I love these.
01:06:41
Speaker
Let's go with those.
01:06:42
Speaker
So first, last time we talked about books and you recommended some excellent books, but have there been any books that since we last spoke that have really impressed you?
01:06:52
Speaker
Yeah, last time I gave some nonfiction books.
01:06:55
Speaker
This time I'm going to give a fiction book.
01:06:57
Speaker
It's not brand new.
01:06:58
Speaker
It's a couple of years old, but it's called The Immortal Life of Addie LaRue by V.E.
01:07:05
Speaker
Schwab.
01:07:06
Speaker
It was a fantastic book, a really interesting concept of a character.
01:07:14
Speaker
I won't give too much away who has to go through some challenges in life.
01:07:19
Speaker
So I really recommend that one.
01:07:21
Speaker
Awesome.
01:07:21
Speaker
And I wanted to ask you about music and I'm a little bit old school, so I still listen to vinyl albums.
01:07:27
Speaker
But what music would you want to have with you if you were stuck on an island or you were isolated for a new pandemic?
01:07:35
Speaker
Hopefully not soon.
01:07:37
Speaker
Well, if I'm on an island, Sergio, I hope I have electricity to listen to the music.
01:07:42
Speaker
So I may have to create my own music on coconut shells or something like that.
01:07:48
Speaker
I would say a new album I've been listening to that I really like a lot because it's quite different is this new Coldplay album.
01:07:59
Speaker
There's a lot of like instrumental pieces and other sorts of just sort of like mood music.
01:08:05
Speaker
in this new Coldplay album.
01:08:08
Speaker
So I highly encourage that.
01:08:10
Speaker
Otherwise, I'm a big fan of Beethoven and Beethoven symphonies.
01:08:13
Speaker
So I like to listen to that too.
01:08:15
Speaker
Perfect.
01:08:17
Speaker
Next question.
01:08:18
Speaker
Could you share something with us that you changed your mind about over the last couple of years?
01:08:24
Speaker
Ooh, wow.
01:08:27
Speaker
That's a harder one.
01:08:33
Speaker
not related to this in medicine, I guess, you know,
01:08:40
Speaker
One thing that I've changed my mind on is that, well, I knew this all along, but I'm changing my approach, I guess I should say, is parenting is not easy.
01:08:53
Speaker
I didn't change my mind on parenting being easy, but as I've gotten, you know, my kids have gotten older into early teenage years, I've really had to sort of change how I think about this and how we parent and sort of focus on more collaboration and
01:09:10
Speaker
And sort of mentoring and thinking about that, you know, part of parenting is like mentoring people rather than purely corrective and, you know, punitive.
01:09:23
Speaker
So I've been working to try to be a little bit more supportive.
01:09:27
Speaker
of a mentor type of approach with my kids.
01:09:31
Speaker
I'm not succeeding all the time with that, though, I can admit that.
01:09:34
Speaker
Well, it is hard, right?
01:09:36
Speaker
And I think I would push back and say that we all probably have changed a little bit in that respect in terms that when we were teenagers, we would wonder what's wrong with these people, right?
01:09:46
Speaker
How can they not get it right?
01:09:47
Speaker
And now that we are in the same position, it is very hard.
01:09:50
Speaker
Yeah.
01:09:52
Speaker
Very hard.
01:09:53
Speaker
Very hard.
01:09:54
Speaker
Yeah, I've changed my opinion on how well my parents did.
01:10:00
Speaker
And now I think they were great.
01:10:02
Speaker
For sure.
01:10:03
Speaker
So the last closing question is, what would you want every listener to know?
01:10:07
Speaker
Could be a parting thought, a quote, or a fact.
01:10:12
Speaker
A quote that I have...
01:10:18
Speaker
used before.
01:10:20
Speaker
And, you know, I should have thought ahead of time to remind myself to look up the exact nature of the quote, because the name is escaping me at a moment.
01:10:31
Speaker
So I apologize.
01:10:33
Speaker
But the quote is a long history of not thinking something is incorrect, can give it the superficial appearance of being correct.
01:10:45
Speaker
So I think this holds true for a lot of things in medicine that we've passed down for dogma for a long time, you know, that like that, you know, swell to get well or that normal saline is ideal or whatever.
01:10:59
Speaker
We never really thought that these things were incorrect.
01:11:03
Speaker
And so it sort of made it gave us the impression that they were correct.
01:11:07
Speaker
And I think over time,
01:11:09
Speaker
as we keep our eyes open a little bit more, we realize that, that maybe those were wrong things to be thinking.
01:11:16
Speaker
I think that's a very powerful idea and a perfect place to stop.
01:11:21
Speaker
Michael, always great to learn from you.
01:11:24
Speaker
And I want to thank you for sharing your time and your expertise with our audience and hope to have you back soon on the podcast.
01:11:32
Speaker
Absolutely.
01:11:33
Speaker
Sergio, it's always a pleasure to talk to you and, um,
01:11:37
Speaker
Having just recently had the chance to meet you in person, it was my honor.
01:11:43
Speaker
And I'm just so amazed at all the successes that you, this podcast, and the sound physicians have been having.
01:11:50
Speaker
So keep up all the great work.
01:11:52
Speaker
Thank you.
01:11:52
Speaker
Thank you.
01:11:54
Speaker
Thank you for listening to Critical Matters, a sound podcast.
01:11:57
Speaker
Make sure to subscribe to Critical Matters on Apple or Google Podcasts and share with your network.
01:12:03
Speaker
Sound's transforming the way critical care is provided in hospitals across the country.
01:12:08
Speaker
To learn more, visit www.soundphysicians.com.