How Much Do You Know about Dialysis?

Hemodialysis uses a machine to clean and filter your blood. The procedure also helps control blood pressure. And it helps your body keep the proper balance of chemicals like potassium, sodium, calcium, and bicarbonate.

During treatment, the blood travels through tubes to the dialyzer. This filters out wastes and extra water, the NIDDK says. The cleaned blood then flows through another set of tubes back to the body. Before a person begins hemodialysis, he or she must have surgery to create an access to the bloodstream. This access gives an efficient way for blood to be carried from your body to the dialysis machine and back without causing discomfort. The access can be a graft that connects an artery to a vein using a synthetic tube. Or it can be a fistula made by connecting an artery directly to a vein, usually in the forearm.

Each treatment lasts 3 to 5 hours. People undergoing dialysis must stay near the dialyzer. But they can read, watch TV, talk, or doze during treatment.

Hemodialysis is usually done at a dialysis center with specially trained staff. It also can be done at home, with a partner's help. Both you and your partner need special training.

These side effects usually are caused by rapid changes in the body's water level and chemical balance during a hemodialysis treatment, the NIDDK says. It usually takes several months to adjust to the treatment. To help avoid side effects, you should follow a proper diet, limit liquids, and take any medicines as prescribed.

Kidneys keep minerals in balance by working at it nonstop. When a person has dialysis to restore this balance, he or she must limit the amounts of some minerals, the NIDDK says. Potassium in the right amount keeps the heart beating at a steady rate. Potassium levels can rise between dialysis treatments and affect heartbeat. Having too much potassium in your diet can be dangerous, even fatal. This mineral is found in salt substitutes, bananas, oranges, many vegetables, chocolate, and nuts. A person on hemodialysis also must avoid sodium. This is found in salt and many canned, frozen, and prepared foods. Too much sodium can make you thirsty. But if you drink more fluid, your heart has to work harder to pump the fluid through your body. Phosphorus, a mineral found in many foods, can pull calcium from your bones if too much of it is in your blood. Losing calcium will weaken your bones, making them more likely to break. Too much phosphorus also can make your skin itch.

The lining is called the peritoneal membrane. It acts as the artificial kidney in this method. A dialysis solution of minerals and sugar enters the abdomen through a soft tube that has been placed surgically. The sugar, called dextrose, draws out wastes, chemicals, and extra water from the tiny blood vessels in the peritoneal membrane, the NIDDK says. After several hours, the solution is drained back out from the abdomen through the tube. The abdomen is then filled with fresh dialysis solution, and the cycle is repeated. Each cycle is called an exchange. There are 3 types of peritoneal dialysis. One type (continuous ambulatory peritoneal dialysis) needs no machine and is done several times during the day. Automated peritoneal dialysis uses a machine. It is usually done at night while the person sleeps. The third is a combination of the two.

The diet for peritoneal dialysis requires more protein. The limits on potassium may be different. And more salt and liquids may be allowed than for a person on hemodialysis. Because of the calories in the dialysis fluid, the number of calories eaten may be more limited. A dietitian who specializes in helping people with kidney failure can help in planning meals.