OK, so it actually takes up the entire belt at the moment… but given a few more years of miniaturization the Wearable Artificial Kidney could end up no bigger than the holster for your cellphone:

A miniaturized dialysis machine that can be worn as a belt, the WAK concept allows patients with end stage renal failure the freedom to engage in daily activity while undergoing uninterrupted dialysis treatment.

Worn as a belt, the device weighs just ten pounds (4.5kg), including the two nine-volt batteries that power it. The compact design, unlike conventional dialysis machines, will leave patients free to engage in the activities that normal kidney function would ordinarily allow them to enjoy. Walking, working and riding a bike can all be actively pursued without restriction while undergoing gentle, uninterrupted treatment 24 hours a day, seven days a week.

This really brings home the rapidity of progress for me; a teacher at my secondary school used to have to undergo dialysis treatment for kidney failure, and once a year he’d do a show-and-tell with the machine, which was roughly the size of a three-drawer filing cabinet. That was back in 1992… he was a PE teacher, too – no quitter, this guy – so he’d have loved the idea of the WAK.

How many more organs might we be able to replace with belt-worn machines? They’re probably not an ideal long-term solution, but this technology might keep people alive and active during the long wait for suitable transplant organs to come available. Or perhaps we’ll just go the route of the Mechanists – why wait for a biological organ if you can swap it out for a mechanical device that offers a greater degree of control? [image borrowed from linked article]