Preparation for hemodialysis starts several weeks to months before your first procedure. To allow for easy access to your bloodstream, a surgeon will create a vascular access. The access provides a mechanism for a small amount of blood to be safely removed from your circulation and then returned to you in order for the hemodialysis process to work. The surgical access needs time to heal before you begin hemodialysis treatments.

There are three types of accesses:
Arteriovenous (AV) fistula. A surgically created AV fistula is a connection between an artery and a vein, usually in the arm you use less often. This is the preferred type of access because of effectiveness and safety.
AV graft. If your blood vessels are too small to form an AV fistula, the surgeon may instead create a path between an artery and a vein using a flexible, synthetic tube called a graft.
Central venous catheter. If you need emergency hemodialysis, a plastic tube (catheter) may be inserted into a large vein in your neck or near your groin. The catheter is temporary.

It's extremely important to take care of your access site to reduce the possibility of infection and other complications. Follow your health care team's instructions about caring for your access site.

What you can expect

In-center hemodialysis. Many people get hemodialysis three times a week in sessions of three to five hours each.

Daily hemodialysis. This involves more-frequent, but shorter sessions — usually performed at home six or seven days a week for about two to three hours each time.

Simpler hemodialysis machines have made home hemodialysis less cumbersome, so with special training and someone to help you, you may be able to do hemodialysis at home. You may even be able to do the procedure at night while you sleep.

The procedure

During treatments, you sit or recline in a chair while your blood flows through the dialyzer ― a filter that acts as an artificial kidney to clean your blood. You can use the time to watch TV or a movie, read, nap, or perhaps talk to your "neighbors" at the center. If you receive hemodialysis at night, you can sleep during the procedure.

Preparation. Your weight, blood pressure, pulse and temperature are checked. The skin covering your access site — the point where blood leaves and then re-enters your body during treatment — is cleansed.

Starting. During hemodialysis, two needles are inserted into your arm through the access site and taped in place to remain secure. Each needle is attached to a flexible plastic tube that connects to a dialyzer. Through one tube, the dialyzer filters your blood a few ounces at a time, allowing wastes and extra fluids to pass from your blood into a cleansing fluid called dialysate. The filtered blood returns to your body through the second tube.

Symptoms. You may experience nausea and abdominal cramps as excess fluid is pulled from your body — especially if you have hemodialysis only three times a week rather than more often. If you're uncomfortable during the procedure, ask your care team about minimizing side effects by such measures as adjusting the speed of your hemodialysis, your medication or your hemodialysis fluids.

Monitoring. Because blood pressure and heart rate can fluctuate as excess fluid is drawn from your body, your blood pressure and heart rate will be checked several times during each treatment.

Finishing. When hemodialysis is completed, the needles are removed from your access site and a pressure dressing is applied to prevent bleeding. Your weight may be recorded again. Then you're free to go about your usual activities until your next session.
In hemodialysis, a machine filters wastes, salts and fluid from your blood when your kidneys are no longer healthy enough to do this work adequately. Hemodialysis (he-moe-die-AL-uh-sis) is one way to treat advanced kidney failure and can help you carry on an active life despite failing kidneys.