Hemodialysis Access

The kidneys normally remove waste products and excess water from your blood. When the kidneys fail, the waste products build up in your blood, and this is called "renal failure". If the kidneys fail completely, you pass into a coma and die within a few weeks if something is not done to cleanse the blood.

"Dialysis" is the process of removing waste products from the blood by artificial means. It is used in many millions of renal failure patients every year. Most of these people are able to live relatively normally even though their kidneys have failed. There are two methods of dialysis: hemodialysis and peritoneal dialysis.

Hemodialysis means "blood dialysis" . It is done by removing some of your blood, running it through an artificial kidney machine which removes the waste products, and then giving the blood back to you. This is usually done with two tubes, one carrying blood to the machine, and the other carrying it back to you. Each dialysis treatment takes about three hours. Most people need three treatments each week. The dialysis is usually done at a dialysis clinic. Some people have a dialysis machine at home and give themselves dialysis treatments with the help of their family or a visiting nurse.

In order to get the blood out of you and back in, a special "access" , or place from which a lot of blood can be drawn very rapidly must be created. There are several types of access for hemodialysis:

1. Fistula: a connection is made between an artery and a vein in your arm or leg with a minor operation. The blood flows rapidly from the artery to the vein; over a few months, the vein enlarges and thickens, so that needles can be placed into it for each dialysis treatment. This is the best access for hemodialysis, because the fistula tends to work for a long period of time. Unfortunately, in many people, the vein does not grow enough after the fistula is created.

2. Graft: in people whose veins are too small, or scarred from having iv's or blood tests, an artificial vein made of soft plastic can be inserted under the skin of the arm or leg. One end of the graft is connected to the artery, and the other end to a large vein deeper in side the arm. The blood then flows rapidly through the graft. Once the arm has healed (about two weeks), needles can be placed into the graft in order to do the dialysis. This generally works well, but grafts do not last as long as fistulas do. Blood tends to clot on the plastic, so the grafts often clot off after one or two years of use (sometimes sooner). When this happens, an operation must be done to fix or replace the graft.

3. Catheter: sometimes dialysis needs to be done immediately, or in someone without a fistula or graft. In these people, a "dialysis catheter" can be temporarily or permanently inserted. The catheter is a flexible tube which is usually placed through the skin into the large vein underneath your collarbone. The tube has two openings at its tip; the tip is positioned right next to the heart, in the largest vein in your body. Blood can be rapidly drawn through one of the openings and replaced through the other. The catheter comes out through the skin on your chest, and is connected to the dialysis machine during the treatment, and covered by a dressing at other times. This access is convenient, but the catheters require constant care and dressing changes, and often become clotted and sometimes infected, in which case they must be removed and replaced. Catheters work well for temporary dialysis access, but can be troublesome if they are needed for long periods of time.

Peritoneal dialysis is completely different from hemodialysis. This treatment involves periodically putting about two quarts of a special solution directly into your abdomen through a soft plastic tube, which has been surgically implanted. The fluid bathes the intestines and the lining of the abdomen, and absorbs the waste products and excess fluid from your bloodstream. After a few hours, the fluid is allowed to run back out through the tube, and is discarded. This treatment is repeated three times a day, and only takes a few minutes each time. Most people can do it without any help. Peritoneal dialysis is explained further in a separate pamphlet.