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Trial Shows Feasibility of Wearable Dialysis Device

Wearable artificial kidney
Wearable artificial kidney prototype (Stephen Brashear, University of Washington)

3 June 2016. An early clinical trial shows a wearable device can provide the same dialysis functions as conventional stationary equipment for people with kidney failure. A team from University of Washington in Seattle and Cedar-Sinai Medical Center in Los Angeles reported results of the trial in yesterday’s issue of the journal JCI Insight.

The occurrence of kidney failure — also known as end-stage renal disease — is increasing in the U.S., as the population ages and becomes heavier, leading to high blood pressure and diabetes, the two leading causes of kidney disease. According to National Kidney Foundation, some 26 million people in the U.S. have kidney disease, leading to 47,000 deaths per year, making it the 9th leading cause of death. Men, African-Americans, and Hispanic-Americans are more likely to get kidney disease.

Once kidneys fail, dialysis or a transplant is needed. National Kidney Foundation says about 450,000 people in the U.S. are on dialysis, requiring 3 visits a week for hours at a time. In addition, some 185,000 Americans have a transplanted kidney, but fewer than 17,000 per year will receive a transplant, despite a waiting list of 122,000. About 12 people a day in the U.S. die waiting for a kidney transplant.

The wearable artificial kidney tested in the trial is the invention of Victor Gura of Cedar-Sinai Medical Center, the study’s lead author. The wearable device is designed to be much more efficient than conventional dialysis equipment, thus allowing it to be smaller and portable. It features a pulsating pump that combines blood and impurity-removing chemicals in the same flow. That flow is then filtered through hollow fibers that treat the transferred solution, while a membrane around the filter removes waste and excess fluids.

The wearable kidney allows the person to be mobile during the blood clearance process, rather than tethered to a fixed piece of equipment. The device itself weighs less than 10 pounds and operates on 9-volt batteries, while using less than 400 milliliters of fluid. It connects to the patient with a catheter, attached in an outpatient procedure using local anesthesia.

The clinical trial tested the wearable artificial kidney in 7 individuals with end-stage renal disease at University of Washington Medical Center in autumn of 2015, where the participants wore the device for 24 hours. The results show the device cleared the patients’ blood of phosphorus, urea, and creatinine, while also taking out excess salt and water. During the test period, the participants’ blood remained stable, as indicated by their levels of electrolytes and hemoglobin. In addition, no serious adverse effects were reported.

The researchers did encounter some glitches. The team originally planned to enroll 10 participants, but stopped the trial after the seventh patient reported carbon dioxide bubbles forming in the dialysis solution, as well as variations in the blood flow and dialysis solution. This experience suggests design changes are still needed in the device.

Participants in the trial reported more satisfaction with the artificial wearable kidney than conventional dialysis treatments. In addition to greater mobility and freedom afforded to dialysis patients, using the wearable device enabled patients to have fewer dietary restrictions, while maintaining stable levels of electrolytes in the blood.

Despite the glitches, results indicate the wearable kidney device is capable of providing dialysis functions for people with kidney failure. And while design modifications are still needed in the device, the researchers believe the technology can be developed further into a viable alternative to conventional dialysis.

The Wearable Artificial Kidney Foundation in Hollywood, Florida funded the trial, with Blood Purification Technologies Inc. in Los Angeles that provided the device. Gura is the company’s chief medical officer.

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