Peritoneal dialysis (PD) is based on the same filtering process as hemodialysis. But instead of using an artificial kidney as the filter, the peritoneal membrane is used. The peritoneal membrane — also called the peritoneum — is a thin membrane that lines the abdominal cavity.
Peritoneal Dialysis Access
To gain access to the peritoneum, a catheter, or flexible hollow tube, is surgically placed in the lower abdomen. It’s about a foot long, but only four or five inches of it lies outside the body. Catheter insertion is done in an operating room, often with local anesthesia.
The Peritoneal Dialysis Treatment
During dialysis, the abdominal cavity is filled with a dialysate solution. Because the peritoneum is rich in tiny blood vessels, it continually provides a supply of blood to be filtered by osmosis and diffusion. The excess fluid and toxins in the blood move toward the dialysate, which is drained and replaced periodically.
An exchange is the process of draining dialysate from the abdomen and introducing fresh dialysate into the abdomen. The length of time the dialysis solution stays in the peritoneal cavity during peritoneal dialysis is known as the dwell time.
There are two main types of peritoneal dialysis: Continuous Ambulatory Peritoneal Dialysis (CAPD) and Continuous Cycling Peritoneal Dialysis (CCPD). Both can be performed at home.
Your doctor and nurse will monitor your physical condition, diet, and medications on a routine basis. Changes in the treatment plan such as the number of exchanges, the amount of solution or length of time between exchanges will be made as needed.
Continuous Ambulatory Peritoneal Dialysis
CAPD is a type of dialysis that you can do by yourself and doesn’t require any machines. Sterile plastic tubing and a bag containing about two quarts of dialysate are attached to the catheter. The bag is raised above the shoulder and a clamp on the tube is released. Gravity causes the dialysate to slowly flow into the abdomen, where it comes in contact with the peritoneum.
The fluid is allowed to stay in the abdomen for several hours allowing excess fluid and toxins to move from the blood to the dialysate. At the ends of the dwell, the fluid is drained by gravity into a collecting bag and the same process is repeated.
Draining dialysate and replacing it with fresh solution takes about 30 minutes and is repeated four to five times every day. The last exchange of the day is done right before going to sleep, and the dialysate is left in overnight.
CAPD training takes one to two weeks. Patients learn about the different solution strengths to control fluid weight gain and practice doing exchanges. Infections of the peritoneum (peritonitis), and infections of the exit site of the catheter are potential problems. Patients are taught how to do exchanges in a way that prevents bacterial contamination that could result in infection.
Some patients prefer the CAPD treatment option because the diet is less restrictive than the hemodialysis diet; that’s because dialysis is happening continuously with CAPD. Also, CAPD patients don’t rely on a machine or partner to dialyze, so they can be more independent.
Continuous Cycling Peritoneal Dialysis
CCPD can be done alone or with a partner. Like CAPD, it uses the peritoneum as a filter. Unlike CAPD, it involves the use of a machine, called a cycler.
A cycler circulates dialysate solution in and out of the peritoneal cavity at evenly spaced intervals during the night for eight to 10 hours. In the morning, dialysate flows into the abdomen and the patient or partner detaches the cycler machine tubing from the peritoneal catheter.
Dialysate is carried in the peritoneal cavity during the day, for about 15 hours. During that time, patients are free to go about their daily activities. Before the patient goes to sleep, the catheter is reattached to the cycler, the fluid is drained out and the night exchanges are started. This cycle is repeated daily. CCPD training takes from one to five days.
Another type of peritoneal dialysis similar to CCPD is called PD Plus( therapy. This is mainly used by patients who have no remaining kidney function or by larger patients, both of whom need more efficient dialysis than do other patients.
PD Plus (requires a cycler that provides automated exchanges during the night while the patient sleeps. After the last exchange in the morning, the patient is disconnected from the cycler and goes about daily activities for most of the day. At that time, an exchange is preformed either using the cycler as source of dialysate if the patient is at home or using the CAPD method. This daily exchange is important in removing excessive fluid and toxins and is the main difference between CCPD and PD Plus).
A person may prefer CCPD over CAPD because it is done while sleeping. As in CAPD, they have fewer dietary restrictions to follow than do hemodialysis patients.
Peritoneal dialysis is done every day or every night at home. Peritoneal dialysis training is done in a dialysis center and takes about one week. You will need storage space for supplies in your home. The cycler is the size of a nightstand and requires a standard 3-prong electrical outlet. Peritoneal dialysis does not require any alterations to your home.
“Using the Kidney You Never Thought You Had”
There is a free patient education booklet-“Using the Kidney You Never Thought You Had” that will give you more information about peritoneal dialysis. Call toll free 1-866-kidney1 or 1-866-543-6391.
Care of the Peritoneal Dialysis Catheter
After your peritoneal dialysis catheter access is placed you will have a surgical dressing applied to the area of the incision. This dressing should stay in place for 3-4 days unless drainage is noted. Your doctor or nurse will do the first dressing change. He/she will apply a smaller dressing. Dressing changes are usually done once a week for 2-4 weeks unless drainage is noted coming through the dressing. Once the exit site (where the catheter comes out of the skin) has matured and healed, dressing changes will be done daily. You will be taught how to do this, and how to evaluate the exit site for any problems. You may have some discomfort and bruising of your abdomen after surgery that will get better in approx. 1-2 weeks.
Once your catheter is mature and ready to use you will be doing your own care of the exit site. Follow these helpful hints to keep your access healthy:
- Clean & monitor your access daily. Finding changes early can prevent serious problems.
- Pay attention to the skin around the exit site. It should not be red or swollen. This may be a sign of inflammation or infection.
- Drainage at the exit site may mean an infection and needs to be reported to the doctor or nurse immediately.
- Sometimes small scabs can form at the exit site. NEVER pick or remove these scabs. Your nurse will teach you how to take care of these areas.
- Feel the catheter tunnel (where the catheter is under the skin). There should be no swelling or tenderness.
- our exit site should not hurt. If you are experiencing pain, report this to your doctor or nurse.
- Inspect the catheter and adapter regularly for cracks. (Bacteria can get in and cause infection)
- Always secure the catheter end to your skin or dressing to prevent tension and tugging.
- Shower daily following your nurse’s instructions and wear clean clothes.
- Never put anything on your exit site such as lotion, powder or creams without checking with your doctor or nurse first.
- If you must go swimming, remember these points:
- Your exit site must be completely healed before swimming
- As soon as you are finished swimming, change into dry clothes and redo your exit site care.
- Never swim in a lake, pond, river or non-chlorinated pool. DO NOT use hot tubs. These bodies of warm water contain germs that can cause infections.
- A healthy exit site is dry, clean and has no redness or pain.
Because peritoneal dialysis patients are not seen at the dialysis clinic frequently, you play an important part in caring for your exit site. Monitoring your access daily and reporting any changes or problems as soon as you notice them are important ways to maintain the health of your catheter and ultimately a smooth course of dialysis treatment.
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