Mobile Dialysis Machines Under Development

Dr. Victor Gura

Dr. Victor Gura

Researchers are developing a Wearable Artificial Kidney for dialysis patients, reports a paper in the Clinical Journal of the American Society of Nephrology (CJASN). “Our vision of a technological breakthrough has materialized in the form of a Wearable Artificial Kidney, which provides continuous dialysis 24 hours a day, seven days a week,” comments Victor Gura, MD (David Geffen School of Medicine at UCLA).

Economist calls it “A Clean Break: Kidney Machines Go Mobile” In its Article Economis calls it “The Clean Break”

Dialysis has been referred to as one of the most painful medical procidures but it lifesaving without which one would surly die. Dialisis involves being hooked up to a huge machine, three times a week, in order to have ones blood cleansed of wastes that would normally be extracted by the kidneys in form of as urine. Research now suggests that daily dialysis is better which is probably the most unpleasent news. No one wants to be tied to a machine in a hospital or a clinic for several hours every day for the rest of ones life.

Dr. Victor Gura hopes to solve this problem with an invention that is now undergoing clinical trials. By going back to basics, he has come up with a completely new sort of dialyser one you can wear he calles it an artificial Kidney.

A traditional dialyser uses around 120 litres of water to clean an individual’s blood. This water flows past one side of a membrane while blood is pumped past the other side. The membrane is impermeable to blood cells and large molecules such as proteins, but small ones can get through it. Substances such as urea (a leftover from protein metabolism) and excess phosphate ions therefore flow from the blood to the water. The good stuff, such as sodium and chloride ions, stays in the blood because the cleansing water has these substances dissolved in it as well, and so does not absorb more of them.

Both water and blood require a lot of pumping. Those pumps are heavy and need electrical power. The first thing Dr Gura did, therefore, was dispose of them. The reason for using big pumps is to keep dialysis sessions short. If machines are portable that matters less. So Dr Gura replaced the 10kg pumps of a traditional machine with small ones weighing only 380 grams. Besides being light, these smaller pumps use less power. That means batteries can be employed instead of mains electricity—and modern lithium-ion batteries, the ones Dr Gura chose, are also light, and thus portable.

To reduce the other source of weight, the water, Dr Gura and his team designed disposable cartridges containing materials that capture toxins from the cleansing water, so that it can be recycled. The upshot is a device that weighs around 5kg and can be strapped to a user’s waist. Indeed, at a recent demonstration in London, one patient was able to dance while wearing the dialyser—for joy, presumably, at no longer having to go to hospital so often.

Correspondence: Dr. Victor Gura, Cedars-Sinai Medical Center, Associate Clinical Professor of Medicine; UCLA, the Geffen School of Medicine, 9100 Wilshire Boulevard, Suite 360W, Beverly Hills, California 90212. Phone: 310-550-6242; Fax: 310-276-4276; E-mail: vgura@cs.com

The study entitled, “Technical Breakthroughs in the Wearable Artificial Kidney (WAK),” will appear online at http://cjasn.asnjournals.org/cgi/content/full/clinjasn;4/9/1401
http://cjasn.asnjournals.org/ on August 20, 2009, doi 10.2215/CJN.02790409.