Dialysis is a treatment for kidney failure that helps filter waste products from the blood when the kidneys are not working properly. Peritoneal dialysis (PD) uses a membrane in the abdomen (the peritoneal membrane) as a natural filter to clear wastes and extra fluid from the body and to keep chemical levels in the body as close to normal as possible.

Peritoneal dialysis does not require travel to a dialysis center. The dialysis process (called an exchange) can be done at home, often at night, during sleep, but must be done on a continuous, everyday basis.

The first step in peritoneal dialysis is called the Fill, in which the dialysis solution enters the peritoneal cavity. The second step is the Dwell; while the solution is in the peritoneal cavity, extra fluid and waste from the body travel across the peritoneal membrane into the dialysis fluid. The final step is the Drain, in which the dialysis solution is drained after a few hours and replaced with new solution.

There are three types of peritoneal dialysis:

• Continuous ambulatory peritoneal dialysis (CAPD) is the form of peritoneal dialysis that most people use. During CAPD, the dialysis solution stays in the belly for about 4 to 6 hours. Most people do 3 or 4 exchanges during the day and one in the evening that stays overnight. During the dwell time, the person is able to go about normal daily activities.
• Continuous cycling peritoneal dialysis (CCPD) uses a machine that automatically fills and drains the solution from the belly. The machine performs 3 to 5 exchanges while the person sleeps. In the morning, one exchange is left in the belly. Usually one exchange is done in the middle of the day.
• Intermittent peritoneal dialysis (IPD) also uses a machine, but it is usually done in a hospital. Treatment sessions may last up to 24 hours and are done several times a week. This type is rarely used anymore.