Do you recommend scheduled potassium phosphate dosing during PIRRT to avoid hypophosphatemia in patients with acute kidney injury requiring renal replacement therapy?

I would only do this once it has been documented that the patient developed hypophosphatemia with PIRRT. If hyperphosphatemic to start, certainly not.

I don't. It should be based on serum phosphorus concentration. However, I have a low threshold to start it, and, of course, one needs to give enough. Ideally, the best option would be to add it in the right concentration to the dialysis fluid, but that is not always possible.

PO4 removal is highly time dependent more than some measure of total clearance. PO4 and K replacement are almost understood with CRRT (24/7).

While the need in PIRRT is unusual, we check it but not as often and do not automatically have an administration regimen.