Keep in mind that an Art line has a continuous flow of fluid INTO it from a pressure bag. A dialysis needle has to have the ability to withstand the continuous PULL of blood through the needle at a rate of 400-500 ml/min and maintain the pressure of that pull at less them 200 mm. Most plastic IV catheters with walls thin enough to not damage the vessel will collapse at that amount of suction. Pushing fluid down the catheter of an Art line or Central line will prevent the walls from collapsing. By the time the wall is strong enough to withstand the pressure it is very thick and/or very stiff. It seems it is not possible for needles to have both thin; smallest possible hole; and strong walls that don't collapse under pressure. Also, dialysis needles are not always placed going in the direction of the blood flow. The Art needles may need to be placed facing "downstream" or retrograde. The amount of pressure in the vessel would have a softer plastic catheter bending back on itself. Temporary dialysis catheter placed in the acute unit for short term dialysis are EXTREMELY stiff catheters that could go through the back wall of a vein quite easily. Heck, I had one that went through the wall of the heart and into the pericardial sac. Pericardial effusions don't dialyze well, no the pt didn't survive and yes the CXR had been read as good placement. I told the Doc when I started the treatment the blood didn't look right and the art pressure numbers were wrong. He told me he read the CXR himself and it was good placement.
But back to the orginal question about incont NH patients. Not only is the lack privacy, supplies, staff, time an issuse in cleaning a pt up but there is also the risk to the other people in the room. Dialysis chairs are very close together. Keeping stool contained within a diaper, within clothes is much better then risking bacterial infection in the catheter of the patient in the next chair that is within arms reach. Not that the next person would reach over and play in the mess; though some would; it would be very easy to accidently brush against their chair, table, supplies, or belongs and not even realize it.
It is hard to realize that the decision if someone lives or dies is based on if they can preform the simple act of personal toileting.