Definition

Dialysis is a procedure that replaces some of the kidney's normal functions and is performed when a person's own kidneys can no longer function adequately to maintain life.

Description

In the U.S. today more than 100,000 individuals undergo dialysis treatments to stay alive. Treatment with dialysis is necessary when a person experiences kidney failure, usually when more than 95 percent of normal kidney function is gone in both kidneys.

Like healthy kidneys, dialysis keeps the body in balance by:

1. removing waste products, including salt, and excess fluids that build-up in the body
2. maintaining a safe level of blood chemicals in the body, such as potassium, sodium and chloride
3. controlling blood pressure

Some forms of kidney failure are temporary and may get better. This is called acute kidney failure. Dialysis may be necessary for a short period of time until the kidneys recover.

Chronic or end-stage kidney failure is the result of an irreversible scarring process which results in kidney shutdown. Chronic kidney failure does not get better and patients need dialysis treatments for the rest of their lives, or if they are medically eligible, they may choose to be placed on a waiting list to receive a kidney transplant.

Preparation for Dialysis

Preparation for dialysis requires a team approach of physicians, dieticians, and social workers. Dialysis can be performed in a hospital, a free-standing dialysis unit, or at home. The location is determined by the patient's medical condition. The patient, working with the physician, determines the best location for treatment. The patient and family should be informed of the risks and benefits of dialysis. Risks may include infection and clot formation.

In general, there are two types of dialysis: hemodialysis and peritoneal dialysis.

Hemodialysis

In hemodialysis, an artificial kidney (hemodialyzer) is used to remove waste products from the blood and restore the body's chemical balance. In order to get the patient's blood to the artificial kidney, it is necessary to make an access to the patient's blood vessels. This requires surgery on an arm or a leg. The surgical procedure connects an artery to a vein underneath the skin. The joining of an artery to a vein creates an enlarged vessel known as a fistula. Once healing occurs, two needles are placed, one in the artery side and one in the vein side of the fistula. Plastic tubing connects the patient to the artificial kidney.

The time required for each hemodialysis treatment is determined by the patient's amount of remaining kidney function, fluid weight gain between treatments and the build-up of harmful chemicals between treatments. On the average, each hemodialysis treatment lasts approximately 3 to 4 hours and is usually necessary three times per week.

A new treatment called high flux, or short-time dialysis, is being used in some units. The exact time is determined by the person's body size, blood chemistries, food intake and urine output. It is important to stress that high-flux dialysis is not available everywhere. If treatment is available, the doctor will determine whether it is suitable for the patient.

Peritoneal Dialysis

There are at least three types of peritoneal dialysis: Continuous Ambulatory Peritoneal Dialysis (CAPD); Continuous Cycling Peritoneal Dialysis (CCPD); and Intermittent Peritoneal Dialysis (IPD).

Continuous Ambulatory Peritoneal Dialysis (CAPD) is the only type of peritoneal dialysis that is done without the use of machines. Patients perform this procedure themselves, usually four or five times a day at home and at work. The patient drains a bag of dialysate into his/her peritoneal cavity by way of the catheter. The dialysate remains there for about 4 to5 hours. After an exchange is complete, the patient drains the used dialysate back into the bag. The patient then repeats the procedure using a new bag of dialysate. While the dialysate remains inside the peritoneal cavity, the patient can go about his/her daily activities.

Continuous Cycling Peritoneal Dialysis (CCPD) is usually done at home using a cycling machine. The process is identical to CAPD except the cycle (exchange) periods are usually 1½ hours and are performed several times a night, while the patient sleeps.

Intermittent Peritoneal Dialysis (IPD) is the oldest form of dialysis and is usually done in the hospital for 10 to 12 hours, three times each week. This treatment is often done in emergency situations or as a first dialysis treatment. The patient is hooked up to a machine during treatment, as in CCPD.

Questions to Ask Your Doctor

• What form of kidney failure is it?
• Which type of dialysis is best for this particular circumstance?
• Can a family member be trained to administer the dialysis at home?
• Is high flux dialysis available locally?
• Can a person stay physically active while on dialysis?
• What are the risks and benefits of dialysis?