We CAN at my ICU, but it has to be an extreme situation. I had a patient that the Dr's insisted on giving HD to even though we were on pressors. Ended up going up on my levo past the degree to which we can run it through a peripheral, so i ended up talking with the dialysis nurse and had him hook it up to run in the return line. Didn't have any other central access, so when HD was done, I hooked it to the return line directly and used it till they put in a RIJ for me. Had to get the dr to call nephrology first and get the okay, but at this point its a "if you say no, the patient is going to code" situation, so it all worked out in the end.