How artificial kidneys and miniaturized dialysis could save millions of lives
After decades of slow progress, researchers are exploring better treatments for kidney failure — which kills more people than HIV or tuberculosis.
Kidney in a backpack
One of the big problems with modern dialysis is that the machines require vast amounts of water: 120–180 litres for each 4-hour session, Himmelfarb says. “Obviously nobody can carry that around them because it would weigh tons.” There are a few in-home models marketed as portable: Fresenius sells a device that it says gives patients more mobility. It weighs 34 kilograms and can be used with a home tap, as long as the water meets certain quality standards. But the first priority in making dialysis more convenient is to remove the need for an external water supply.
In Seattle, CDI researchers have developed a technique that pushes the used dialysis solution through a cartridge that uses light to convert urea — a key toxin targeted by dialysis — into nitrogen and carbon dioxide, so that the solution can be recycled3. The method can remove 15 grams of urea in 24 hours, sufficient for most people with kidney failure, and requires only 750 millilitres of solution, Himmelfarb says.
The team’s standalone haemodialysis device could be made compact enough to fit inside a rolling case, Himmelfarb says, weighing no more than 9 kilograms. Ideally, patients would use it daily, he says.
Another group trying to downsize dialysis was recently formed by the Dutch Kidney Foundation, the medical-devices firm Debiotech in Lausanne, Switzerland, and non-profit insurers. Its latest prototype, which it hopes to make available to patients by 2023, weighs about 10 kilograms and will require only 6 litres of solution, according to Ton Rabelink, a nephrologist at Leiden University Medical Center in the Netherlands who is on the medical advisory board of the company, called NextKidney. The device, which could be used at home, limits the quantity of dialysis solution needed by using an absorbent material to soak up the toxins, Rabelink says.
In Singapore, researchers at the medical-technology company AWAK have been testing an even lighter device, one that weighs no more than 3 kilograms. It’s designed for peritoneal dialysis, a technique that uses a catheter to send dialysis solution into the abdominal cavity, where a lining (the peritoneum) filters out toxins from the blood so they can drain, along with the solution, into an empty bag.
The AWAK device relies on a pump and a cartridge to absorb toxins from the used solution so that it can be recirculated. Each daily treatment would last seven to ten hours.