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 helps your body maintain the proper balance of chemicals such as potassium, sodium, calcium, and bicarbonate, the NIDDK says.

During treatment, the blood travels through tubes to the dialyzer, which 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 a surgical procedure to create an access to the bloodstream. This access provides 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 a fistula made by connecting an artery directly to a vein, usually in the forearm.

Each treatment lasts at least three hours. People undergoing dialysis must remain near the dialyzer, but they can read, watch TV, talk, or doze during treatment.

Although hemodialysis is usually done at a dialysis center with specially trained staff, it also can be done at home, with a partner's help. The person undergoing dialysis and the partner both 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 uses 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. Eating too much potassium can be dangerous, even fatal. This mineral is found in salt substitutes, bananas, oranges, vegetables, chocolate, and nuts. A person on hemodialysis also must avoid sodium, which is found in salt and many canned and frozen 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, and 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 three types of peritoneal dialysis. One type (continuous ambulatory peritoneal dialysis) requires no machine and is done several times during the day. Continuous cycler-assisted peritoneal dialysis uses a machine and is usually done at night while the person sleeps. The third is a combination of the two.

This can happen if the place where the catheter enters the body becomes infected. The infection is called peritonitis and must be treated promptly with antibiotics.

The diet for peritoneal dialysis requires more protein. The restrictions 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, the NIDDK says.