Peritoneal Dialysis

Peritoneal dialysis is usually self administered. In both hemodialysis and peritoneal dialysis, the blood is cleansed. However, in peritoneal dialysis the process takes place within the patients own body, in the peritoneal or abdominal cavity, rather than outside the body in a machine. The peritoneum is a thin membrane which covers the instestines and other contents of the abdominalcavity. During dialysis, the dialysate is introduced into the abdominal cavity, allowed to stay in for some time, and then drained out. The peritoneum basically functions the same as the semipermeable membrane used in the artifical kidney machine. Since it contains a whole network of tiny blood vessels called capillaries, the peritoneum is constantly able to provide a new supply of blood to be filtered. As blood flows through the peritoneum, waste products are filtered (through diffusion) and excess fluids are removed (through osmosis). The wastes flow into the dialysate which remains or dwells within the abdominal cavity for a variable period of time. At the end of this period the dialysate is drained from the abdomen and fresh dialysate is introduced.

Access for Peritoneal Dialysis

Access for peritoneal dialysis is gained via a flexible hollow tube, called a catheter, which is surgically implanted through the wall of the abdomen into the abdominal cavity. This catheter is usually permanent, but may be replaced as needed. A potential problem with peritoneal dialysis is peritonitis, an infection of the lining membrane of the peritoneal cavity. The exchanges of dialysis fluid must be performed using sterile technique in order to prevent this type of infection. Depending on the way peritoneal dialysis is performed it is described in two different ways:

* Continuous Ambulatory Peritoneal Dialysis (CAPD)
* Continuous Cycling Peritoneal Dialysis (CCPD)

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