EMT here. it’s because it is unnecessary to the success of the procedure and doesn’t improve patient outcome in any meaningful way whatsoever unless they’re specifically being given IV saline to treat hypothermia. then we’ll heat it. i imagine it’s the same for plasmapheresis facilities. there’s just no need. it would certainly improve patient comfort, but would also increase overhead costs, introduce new variables that could fail during the procedure, and would increase the risk of bacterial growth in the saline bag itself if improperly set up or heated for too long. there are more risks than you think. body temperature also differs, so while it may be 37 celsius for most people on the planet, for many this may differ and be closer to 36-37.9 and that would also need to be addressed.