What Precautions Should Be Taken To Avoid Swelling In Hands During Dialysis?

Good evening, My husband goes to dialysis 3 times a week. His arm it swell after the dialysis. He has a fistula on his arm for 6 months now. Last month, when he went to dialysis they could not access the blood and send him to the doctor to get check because they think he had a clot. Now, his arm has been swelling and his hand. Any suggestion what should we do? Thank you very much!