Dialysis is a process that removes waste products and excess fluid that accumulate in the blood as a result of failure of the kidneys to function. Dialysis is not a cure for kidney failure. It only substitutes for some functions of the kidneys like removing some waste products and excess water from the body. When the kidneys have ceased functioning permanently, they will not resume functioning again no matter how many dialysis treatments are given. The patient with permanently damaged kidneys (ESRD) will therefore need dialysis treatment for the rest of his life unless he has a successful kidney transplant. Hemodialysis This is a process in which blood is passed through a special filter, an artificial kidney, which contains a special membrane. This membrane is made of a type of cellophane. The membrane contains millions of tiny holes or pores through which waste products and excess fluid are removed. Before hemodialysis can be done, a doctor must make an entrance, called an access, into the patient’s blood vessels. This is done by minor surgery in the leg, arm or sometimes neck. The best access for most patients is called a fistula. Minor surgery is performed to join an artery to a vein under the skin to make a larger vessel. If no vessels are suitable for a fistula, the doctor might use Dialysisa soft plastic tube called a vascular graft to join an artery and vein under the skin. For temporary dialysis in the hospital, a patient might need a catheter implanted into a large vein in the neck. Once the access is made and healed, two needles are inserted in the fistula or graft, one on the artery side and one on the vein side. Blood drains into the dialysis machine to be cleaned. The machine has two parts, one side for blood and one for a fluid called Dialysate. A thin, semi–permeable membrane separates the two parts. As dialysate passes on one side of the membrane, and blood on the other, particles of waste from the blood pass through microscopic holes in the membrane and are washed away in the dialysate. Blood cells are too large to go through the membrane and are returned to the body.