Overview of Peritoneal Dialysis
Peritoneal dialysis cleans the blood without it being removed. Dialysate is injected into the peritoneal space in the abdomen through a two-way catheter (the Tenckhoff catheter). The membrane that lines the abdomen (the peritoneum) allows waste and fluid to pass from the blood into the dialysate, which is pumped out. Peritoneal dialysate, made up mostly of salts and sugar (glucose), encourages ultrafiltration through the peritoneum.
About 2 weeks before dialysis begins, a Tenckhoff catheter is surgically inserted with one end in the peritoneal space, and the other extending a few inches away from the skin. This is done with general or local anesthetic, depending on patient tolerance. It remains permanently in place and is accessible any time. When not in use, the external end of the catheter is sealed.
Two Methods Of Peritoneal Dialysis
Continuous ambulatory peritoneal dialysis (CAPD) exchanges roughly two liters of dialysate while the person is active, three to six times a day. The patient connects a bag of dialysate fluid to a catheter in the abdomen. After the dialysate filters for 4 to 6 hours, the patient exchanges it for fresh fluid.
A machine exchanges the fluid while the person sleeps during continuous cyclic peritoneal dialysis (CCPD), or automated peritoneal dialysis. The abdominal catheter is connected to the machine at bedtime. Over an 8 to 12 hour night, the machine exchanges fluid four to eight times.
About 10 liters are exchanged during the night. Upon waking, the patient's fluid is exchanged and used throughout the day. Some patients require a mid-day exchange. Peritoneal dialysis must be performed everyday and fluid must be in the abdomen at all times to clean the blood adequately.
Peritoneal Dialysis Complications
Complications of peritoneal dialysis include the following:
- Abdominal infection
- Amyloidosis (stiffening of kidney due to protein deposit)
- Diabetes (requires blood sugar monitoring)
- Infected catheter
- Peritonitis (caused by bacterial infection of peritonium or scarring)
- Vitamin and mineral deficiencies
Some patients develop an infection an average of every 12 to 18 months and are treated with antibiotics. If the infection persists, the catheter must be removed and the patient must switch to hemodialysis. An inadequate peritoneum membrane may be unable to sufficiently clean the blood. This condition usually warrants hemodialysis.
Some patients develop diabetes mellitus or obesity from the large glucose (sugar) content of the peritoneal dialysate.