The more common name for the fistula is an access. Usually, this surgery is done 2 to 3 months before dialysis is to begin so that the body has time to heal. In most cases, the surgeon puts the access in the arm not used for writing. To begin dialysis, two needles are placed in the access. One is for outgoing blood, and the other is for blood returning to the body.
Blood is pumped from the arm to a dialysis machine.
One compartment of this machine holds this incoming blood. A second compartment has a specially treated solution called dialysate. Separating the two compartments is a thin membrane with thousands of tiny holes. This membrane acts like the filters in a healthy kidney. The waste products in the blood pass through the holes into the dialysate.