Need Help for 6 month old with fluid after heart surgery

I have a 6 month old that had heart surgery 12 weeks ago. He has had fluid draining sincw thwn. It started in the chest tubes then the did a procedure on his lung and it switched to his other lung then  they did the same procedure on this one. His fluid then went throuhout his body. They did dialysis to help with this and his extra fluid went away. They left his pd cath in and it still drains about 300-400 cc a day. The drs here are telling us they have done everything they can think of. and that we need to decide if we want to take him off the vent. Is there anything that can be done to help this fluid. They have tried almost all meds and procedures to his heart and lungs. Do we have any other options????