The only case i know of a client receiving "involuntary" dialysis was a severely intellectually handicapped man who was getting haemodialyisis 4hr X 3 a week. a family member was required to be with him at all times as this client had no concept of the whole deal. After this poor soul had endured about half a dozen dialysis treatments a family meeting was called and the consensus was that no more dialysis was going to be of any benefit to anyone (particularly the client). The renal staff as a whole gave a sigh of relief.
Initially the family were offered dialysis as a treatment for the client but once they realised that they would have to be present for minimum 4hrs 3X week, the reality sunk in and they decline further treatment after good honest advice.
This person died a few months after ceasing treatment but at least this person died in their own home instead of a large facility.
I know of clients with mental health issues that only sporadically attend dialysis but it is up tho them. If they are in our area we only set up for them when we see them (eg eyeballing!)
It would be a tough one dialyising an acutely unwell mental health client. i don't think it would be authorised where i work due to the danger to staff and the distress to other clients (who would be present by nature of being dialysed at the same time). I can be certain that ICU dialysis would not be permitted for such a client.