Peritoneal Dialysis (PD) is a dialysis process that involves using a person’s peritoneal membrane. The peritoneal membrane is a vascular lining inside the abdominal cavity that covers some of the major organs and the intestines. A small catheter, called a Tenkchoff catheter, is inserted through the skin of the abdomen, usually to the left or the right of the naval. The catheter is tunneled under the skin and into the peritoneum. A portion of the catheter is left outside the person, so the person can perform their PD treatments.
The treatment takes place by infusing PD fluid through the catheter in the abdomen. The fluid is made of dextrose and other electrolytes, which allow the dialysis process to occur in the peritoneum. The process occurs through diffusion, the movement of solutes from an area of higher concentration to lower concentration, through a semipermeable membrane, and osmosis, the removal of fluid from an area of higher concentration to lower concentration. This procedure takes place by doing several PD exchanges every day. The person connects him/herself to the PD fluid apparatus by using the catheter in his/her abdomen. He/she drains the fluid from the last exchange and puts new fluid in. The period of time the fluid stays in the peritoneum is called the dwell time. Depending on which type of PD the individual is doing, the dwell time is anywhere from 2–6 hours. During the dwell times is when the actual dialysis occurs.
There are basically two types of PD. The first type is called CAPD. This stands for Continuous Ambulatory Peritoneal Dialysis. This procedure requires 4 or 5 exchanges every day, 7 days a week. All of the exchanges are evenly spaced apart. The major benefit of this type of therapy is the patient does not have to be attached to a machine. The patient connects, completes the exchange, and detaches him/herself. Each CAPD exchange only takes about 30 minutes.
The other type of PD is called APD, Automated Peritoneal Dialysis. With this treatment the patient hooks him/herself to a machine at night and the machine does the treatment for them. The patient is usually attached to the machine for 10–12 hours a night, while the patient sleeps. Most times, with this therapy, the patient only has to do one treatment in the middle of the day. Most pediatric dialysis patients perform this therapy as well as working adults.
The benefits of PD over hemodialysis are the following:
- The patient controls his/her care
- The treatments can be performed in the patient's home
- Traveling is much easier
- The treatments are much more gentle, because dialysis occurs everyday, instead of three times a week
- The diet is much more liberal
- Clinic visits are only once a month after the initial training
The disadvantages of PD are:
- There is greater risk of infection
- The patient must be able to perform their own treatments (trained family members can help)
- Not all patients are candidates for PD (example: multiple abdominal surgeries)