My concerns with the wearable artificial kidney

Last week the Wearable Artificial Kidney reached some sort of new benchmark and a bunch of press ensued. I stumbled across this one.

And I tweeted:

This was a popular tweet 

but not a popular opinion. Most people say that it is great to see out of the box thinking in nephrology. They advised me not to look at the technology as it is today but envision where this technology could go.

I appreciate the technology and can totally see how something like this:

Could undergo a transition analogous to this:

My concern is not the size of the equipment, though by the looks of it, they still have a formidable chasm to cross. My concern has to do with access. This is hemodialysis. It still needs a way to get blood out of the body, into the machine, and back into the body, reliably, continuously and safely. This is not a trivial task and tunneled catheters have a high rate of infection and mortality. 

Persons using catheters had increased risk of all-cause mortality (RR=1.38, 95% CI=1.25–1.52), fatal (RR=1.49, 95% CI=1.15–1.93) and nonfatal (RR=2.78, 95% CI=1.80–4.29) infection, cardiovascular event (RR=1.26, 95% CI=1.11– 1.43), and hospitalization (RR=1.51, 95% CI=1.30–1.75) compared with those individuals using grafts. From Ravani, JASN 24:465-73, 2013.

They are public enemy number one in dialysis units and this technology depends on them. Vascular access is the weak link of hemodialysis, whether it is in-center, home or a WAK. And adding mobility, continuous use, and patient error to the equation probably will not help.

I look forward to sheepishly reading this post one day in our WAK future, but I suspect that future is populated by hover boards and self tieing shoes.