Hi there KJay,
My mother has one of these machines installed at her place.
Although we don't use AFCI's over here, I would have some problems with a machine such as this being connected to a circuit protected by one of these devices.
First off, I would make sure that the dialyser is actually 120V, the one my mum uses is 4kW @ 230V (single phase), it heats it's own water (for the hot wash after dialysis has taken place).
There are 2 motors in the unit, the first is a small geared down thing that drives the peristaltic pump that circulates blood through the patients body.
The second is a smaller drive that operates an iron infusion system.
Bear in mind, KJay, that these machines are very sensitive to the environment around them, I wouldn't personally install one in a damp area.
Having said that, you also have to think of the welfare of the person that is going to be hooked up to this machine for possibly up to 5 hours a day, up to 3-4 days a week, I'd at least want somewhere comfortable.
These machines also require a drain with a P-trap and a supply of cold water.
Dialysis units have backup batteries in them (like all medical equipment), but having the power cut out during dialysis can be distressing for patients.
The unit my mum has, is supplied via a 6mA RCD (GFCI), the unit is regularly serviced by the health services technician, every 3 months.
Even getting in contact with one of these guys, would possibly give you all the info you need, I mean if they don't know, no-one does.
Hope this is of some help.
P.S: I'm not trying to make any sort of a social statement here, but these machines could become more prevalent in the years ahead, kidney disease is on the increase.
It is good though that we have the technology to keep people alive until a transplant becomes available.