Dialysis is a treatment that does some of the things done by healthy kidneys. It is needed when the kidney loses about 85 to 90 percent of its function. Hemodialysis is a kind of dialysis where an artificial kidney (hemodialysis) is used to remove waste and extra chemicals and fluid from the blood. To get the blood into the artificial kidney, the doctor needs to make an access into the blood vessels. This is done by minor surgery to the arm or leg

Sometimes, an access is made by joining an artery to a vein under the skin to make a bigger blood vessel called a fistula

However, if the blood vessels are not adequate for a fistula, the doctor may use a soft plastic tube to join an artery and a vein under the skin. This is called a graft

Occasionally, an access is made by means of a narrow plastic tube, called a catheter, which is inserted into a large vein in the neck. This type of access may be temporary, but is sometimes used for long-term treatment