Hemodialysis is a procedure that cleans and filters your blood. It rids your body of harmful wastes and extra salt and fluids. It also controls blood pressure and helps your body keep the proper balance of chemicals such as potassium, sodium, and chloride.

Hemodialysis uses a dialyzer, or special filter, to clean your blood. The dialyzer connects to a machine. During treatment, your blood travels through tubes into the dialyzer. The dialyzer filters out wastes and extra fluids. Then the newly cleaned blood flows through another set of tubes and back into your body.

Before your first treatment, an access to your bloodstream must be made. The access provides a way for blood to be carried from your body to the dialysis machine and then back into your body. The access can be internal (inside the body -- usually under your skin) or external (outside the body).

Hemodialysis can be done at home or at a center. At a center, nurses or trained technicians perform the treatment. At home, you perform hemodialysis with the help of a partner, usually a family member or friend. If you decide to do home dialysis, you and your partner will receive special training.

Hemodialysis usually is done three times a week. Each treatment lasts from 2 to 4 hours. During treatment, you can read, write, sleep, talk, or watch TV.

Side effects can be caused by rapid changes in your body's fluid and chemical balance during treatment. Muscle cramps and hypotension are two common side effects. Hypotension, a sudden drop in blood pressure, can make you feel weak, dizzy, or sick to your stomach.

It usually takes a few months to adjust to hemodialysis. You can avoid many of the side effects if you follow the proper diet and take your medicines as directed. You should always report side effects to your doctor. They often can be treated quickly and easily.

Hemodialysis and a proper diet help reduce the wastes that build up in your blood. A dietitian can help you plan meals according to your doctor's orders. When choosing foods, you should remember to:

Eat balanced amounts of foods high in protein such as meat and chicken. Animal protein is better used by your body than the protein found in vegetables and grains.

Watch the amount of potassium you eat. Potassium is a mineral found in salt substitutes, some fruits, vegetables, milk, chocolate, and nuts. Too much or too little potassium can be harmful to your heart.

Limit how much you drink. Fluids build up quickly in your body when your kidneys aren't working. Too much fluid makes your tissues swell. It also can cause high blood pressure and heart trouble.

Avoid salt. Salty foods make you thirsty and cause your body to hold water.

Limit foods such as milk, cheese, nuts, dried beans, and soft drinks. These foods contain the mineral phosphorus. Too much phosphorus in your blood causes calcium to be pulled from your bones. Calcium helps keep bones strong and healthy. To prevent bone problems, your doctor may give you special medicines. You must take these medicines every day as directed.

Each person responds differently to similar situations. What may be a negative factor for one person may be positive for another. However, in general, the following are pros and cons for each type of hemodialysis.

• Treatments are scheduled by the center.
• You must travel to the center for treatment.

• Helping with treatments may be stressful to your family.
• You need training.
• You need space for storing the machine and supplies at home.