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Rapid Exchange of Continuous Renal Replacement Therapy for Acute Kidney Injury

Children’s Mercy is one of only a handful of programs across the nation using a unique bridging technique called Rapid Exchange of Continuous Renal Replacement Therapy (RECRRT) for children diagnosed with acute kidney injury. By consistently using RECRRT, Children’s Mercy has become proficient in the bridging technique, resulting in significantly less blood exposure and therapy downtime for these critically ill children.

The technique’s primary goal is to reduce exposure to blood products for these patients.

Vimal Chadha, MD, Pediatric Nephrologist explains how this technique helps lower the risk for iron overload, transfusion reactions, exposure to infectious agents and sensitization to different antigens that could jeopardize a future kidney transplant.
Rapid Exchange of Continuous Renal Replacement Therapy for Acute Kidney Injury
Featured Speaker:
Vimal Chadha, MD
Vimal Chadha, MD is a pediatric nephrologist at Children’s Mercy Kansas City and Associate Professor of Pediatrics at the University of Missouri-Kansas City. Dr. Chadha received his medical degree at Safdarjung Hospital –Delhi University, Delhi India. He did his pediatric residency training at Medical College of Virginia and at Kansas University Medical Center. He completed a fellowship in pediatric nephrology at Children’s Mercy.

Learn more about Vimal Chadha, MD

Dr. Michael Smith (Host): So, our topic today is “Rapid Exchange of Continuous Renal Replacement Therapy for Acute Kidney Injury”. My guest is Dr. Vimal Chadha. He is a pediatric nephrologist at Children's Mercy Kansas City and Associate Professor of Pediatrics at the University of Missouri Kansas City School of Medicine. Dr. Chadha, welcome to the show.

Dr. Vimal Chadha (Guest): Thank you. Good morning.

Dr. Mike: So, this is obviously a complicated discussion, but very important one, because I know that Children's Mercy is one of the few hospitals that offers this type of rapid exchange technique, so we're going to get there. But, before we do, let's first start talking about acute kidney injury and do a nice review there. Tell us, Dr. Chadha, what are some of the more common causes of acute kidney injury, some of the risk factors, and how do we recognize it in the PIC-U?

Dr. Chadha: Sure. So, acute kidney injury, we define as a certain abrupt decrease in kidney function which happens over a short period of time and, basically, there are two common ways that the blood tests show the increase in serum ketones, or the patient's urine output decreases. Now, having said that, the acute kidney injury causes, they vary. If you are seeing the patient in the community, the most common causes might be dehydration and the causes also vary from country to country and region to region, but when they come to the ICU, the most common causes are sepsis, shock, nephrotoxic medication; so, basically, it's multi-factorial in the ICU and we do pick the kidney injury by measuring the serum ketones that have started rising and also by measuring the urine output.

Dr. Mike: Right. So, if you start recognizing that there is the onset of acute kidney injury here through some of those measurements, through the history, run us through, from your standpoint, as the specialist, what are some of the common ways that you’re going to treat this.

Dr. Chadha: So, once the acute kidney injury is recognized, the reason why we treat it, obviously, is because it's associated with the increase in mortality and when acute kidney injury is present and the complications for these patients, the length of time they stay in ICU, everything increases. So, the first is, obviously, prevention. We don't want acute kidney injury to happen, so we then identify to the high-risk patients, try to avoid the medications which can cause acute kidney injury, but, unfortunately, if it does happen, the severe acute kidney injury does happen in 11% of ICU patients, then the dialysis is required. We do have three kinds of dialysis modalities. We do use all of them. Briefly, they are peritoneal dialysis, hemodialysis, and then the third one is CRRT, continuous renal replacement therapy, which is the most commonly used in ICU because these patients are sick and unstable. So, the third modality or the CRRT is the most common modality which is used.

Dr. Mike: So, obviously, when you have to go that far, and you have to start to do dialysis in these patients, there are concerns, right? There are concerns about the exposure to blood products, iron overload, etc., etc., right? So, tell us now, then, about this rapid exchange technique that Children's Mercy is now using and why you're doing that and what the outcome has been.

Dr. Chadha: So, you know, whenever we use a dialysis machine, whether it's hemodialysis or CRRT, the machine has tubing and filters which has to be filled with the blood because if the patients are younger and smaller in size, they're less than 12 kg., there's only that much blood they have. They have less than one liter of blood and if I take out 100ml of blood going in the tubes, they're at risk of developing shock and a lot of problems. So, we have to fill the tubing with the blood. So, specifically, this rapid exchange is used for younger babies. So, previously, what was happening was, every time this machine stopped or we had to change to a new machine, so we had to get the blood from the blood bank, fill the tubing, and fill it with the new blood, and restart the machine. So, that was causing exposure to the blood and infectious agent, iron overload, a lot of problems. So, we started using this technique in 2013. So, what we do is, so we transferred the blood from one machine on which the patient is currently on to the other machine, which is done in five minutes, and during this time, the patient is off on dialysis therapy, and once the blood is transferred, the same blood, which is obviously coming from the patient, and then we re-start the dialysis just by putting the machine back on the patient. So, we don't have to get the blood from the blood bank; there is no new blood used, so everything is avoided and the patient is off therapy only for five or six minutes compared to before, the whole process took more than an hour to do.

Dr. Mike: So, with this bridging technique, what you're seeing is that there's less down time--therapy downtime--for these really critically ill children, correct?

Dr. Chadha: That's absolutely right.

Dr. Mike: So, let me ask you this. So, you've started this at Children's Mercy, you mentioned in, I think, 2013, and according to what I've researched and found, very few hospital centers are using this type of bridging technique. Why do you think that is the case and what is the plan for Children's Mercy to maybe educate more about this technique and the benefits?

Dr. Chadha: So, we are going to publish our experience, I think only three or four hospitals probably use it currently, and we presented on it in posters in the International Conference in Advancements in Critical Care Nephrology in California, San Diego, in 2016, and we also presented a poster at symposium on AKI in children in Cincinnati. So, after presenting at those two places, we are in the process of publishing our data because we have more than 15,000 hours of experience on these machines and we have changed over 300 subjects and nearly half of them by rapid exchange. So, we have a lot of experience, so I think now it's the time that we'll publish it and more and more people, when they come to know of it, I hope that everybody will start using it.

Dr. Mike: Yes, and so, and also just to kind of wrap it up, too, this technique is well-tolerated with the patients, right? I think that I read that there was only one episode of hemodynamic instability versus what? Up to like 20% with convention circuit changes, correct?

Dr. Chadha: Yes and that's the biggest advantage. Because every time you get a blood from blood bank, that blood is very acidotic and it's likely to cause problems, but now we are not getting the blood from blood bank, it is the same blood which was already running through the patient, so that's why all the hemodynamic instability, they are so less and that's one of the reasons that we even use it in older kids. So, obviously, less than 12kg, it's used to avoid blood exposure, but even older kids, where we don't have to prime the circuit with blood, we still use the rapid exchange to avoid the hemodynamic instability.

Dr. Mike: Right. That's fantastic work, Dr. Chadha. I want to thank you for what you're doing and I'm sure you're going to be very successful in getting the message out and getting more hospitals to use this technique, and thank you for coming on the show today. You're listening to Transformational Pediatrics. For more information, you can go to That's I'm Dr. Mike Smith. Thanks for listening.