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 a 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, semipermeable 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. The benefits of hemodialysis are that the patient requires no special training, and he or she is monitored regularly by someone trained in providing dialysis.