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 it must be done on a continuous, daily 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. During the Dwell step, 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 different 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 do 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.
Anne C. Poinier, MD - Internal Medicine & Mitchell H. Rosner, MD - Nephrology
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