What is peritoneal dialysis and how does it work?
Peritoneal dialysis is a treatment for kidney failure that uses the lining of your abdomen, or belly, to filter your blood inside your body. Doctors call this lining the peritoneum. A doctor will place a soft tube, called a catheter, in your belly a few weeks before you start treatment.
When you start peritoneal dialysis, dialysis solution—water with salt and other additives—flows from a bag through the catheter into your belly. When the bag is empty, you can disconnect your catheter from the bag and cap it so you can move around and do your normal activities. While the dialysis solution is inside your belly, it soaks up wastes and extra fluid from your body. After a few hours, you drain the used dialysis solution into a drain bag. You can then dispose of the used dialysis solution, which is now full of wastes and extra fluid, in a toilet or down the drain of a sink or bathtub. Then you start over with a fresh bag of dialysis solution.
The process of first draining the used dialysis solution and then replacing it with fresh solution is called an exchange. Most people do four to six exchanges every day, or during the night using a machine that moves the fluid in and out. The process goes on continuously, so you always have dialysis solution in your belly soaking up wastes and extra fluid from your body. For the best results from peritoneal dialysis, it is important that you perform all of your exchanges as your doctor instructs.
What are the types of peritoneal dialysis?
The two types of peritoneal dialysis are continuous ambulatory peritoneal dialysis—also called CAPD—and automated peritoneal dialysis—which doctors sometimes call APD or continuous cycler-assisted peritoneal dialysis. After learning about the types of peritoneal dialysis, you can choose the type that best fits your schedule and lifestyle. If one schedule or type of peritoneal dialysis does not suit you, you can talk with your doctor about trying another type.
- Continuous ambulatory peritoneal dialysis does not require a machine. You can do it in any clean, well-lit place. The time period that the dialysis solution is in your belly is called the dwell time. With continuous ambulatory peritoneal dialysis, the dialysis solution stays in your belly for a dwell time of 4 to 6 hours, or more. Each exchange takes about 30 to 40 minutes. During an exchange, you can read, talk, watch television, or sleep. Usually, you change the dialysis solution at least four times a day and sleep with solution in your belly at night. You do not have to wake up and perform exchanges during the night.
- Automated peritoneal dialysis uses a machine called a cycler to fill and empty your belly three to five times during the night while you sleep. In the morning, you begin one exchange with a daylong dwell time. You may do an additional exchange around the middle of the afternoon without the cycler to increase the amount of waste removed and reduce the amount of fluid left behind in your body.
If you weigh more than 175 pounds or if your peritoneum filters wastes slowly, you may need a combination of continuous ambulatory peritoneal dialysis and automated peritoneal dialysis. For example, some people use a cycler at night and perform one exchange during the day. Your health care team will help you determine the best schedule for you.
Who performs peritoneal dialysis?
After a short training period, most people can perform both types of peritoneal dialysis on their own. You will work with a dialysis nurse for 1 to 2 weeks to learn how to
- do manual exchanges for continuous ambulatory peritoneal dialysis without letting bacteria into your catheter
- perform automated peritoneal dialysis:
- prepare the cycler
- connect the bags of dialysis solution
- place the drain tube
People who do automated peritoneal dialysis need to learn how to do manual exchanges so they can get treatment in case of power failure or if they need an exchange during the day in addition to nighttime automated peritoneal dialysis.
Where is peritoneal dialysis done?
You can do both continuous ambulatory and automated peritoneal dialysis in any clean, private place, including at
- a hotel
- a friend’s home
- an office
Before you travel, you can have the manufacturer ship the supplies to your destination in advance.
What equipment and supplies will I use during peritoneal dialysis?
The equipment and supplies you need will depend on the type of peritoneal dialysis you will use. You could need the following equipment and supplies:
- catheter and transfer set
- dialysis solution
- supplies to keep your exit site clean
The health care team will provide you with the equipment you need to begin peritoneal dialysis and help you arrange to have supplies such as dialysis solution and surgical masks delivered to your home, usually on a monthly basis.
Catheter and Transfer Set
Before your first treatment, a surgeon places a catheter into your belly. You may need to stay overnight in the hospital; however, most people can go home after the procedure. You may receive general or local anesthesia. The catheter stays in permanently and will transfer the dialysis solution to and from your belly. You will learn to care for the skin around the catheter, called the exit site, as part of your dialysis training. The catheter tends to work better when you give the insertion site adequate time to heal. Healing usually takes 10 to 20 days. Planning your dialysis catheter insertion at least 3 weeks before your first exchange can improve treatment success.
The catheter for peritoneal dialysis is made of soft tubing for comfort. The catheter has one or two cuffs made of a polyester material—called Dacron—that anchors the catheter in place. The end of the tubing inside your belly has many holes to let solution flow freely in and out.
A transfer set is tubing that connects the catheter to the bag of dialysis solution. When you first get your catheter, the section of tube that sticks out from your skin will have a secure cap on the end to prevent infection. A connector under the cap will attach to any type of transfer set.
When your dialysis training starts, your dialysis nurse will give you a transfer set and teach you how to
- keep bacteria from entering the catheter
- connect the transfer set to the disposable dialysis tubing at the beginning of an exchange and disconnect the transfer set at the end
Follow instructions carefully to prevent infection.
Between exchanges, you can keep your catheter and transfer set hidden inside your clothing. At the beginning of an exchange, you will remove the disposable cap from the transfer set and connect the set to a tube that branches like the letter Y. One branch of the Y-tube connects to the drain bag, while the other connects to the bag of fresh dialysis solution.
Dialysis solution comes in 1.5-, 2-, 2.5-, or 3-liter bags. Solutions contain a sugar called dextrose or a compound called icodextrin and minerals to pull the wastes and extra fluid from your blood into your abdominal cavity—the space in the body that holds organs such as the stomach, intestines, and liver. Different solutions have different concentrations of dextrose or icodextrin. Your doctor will prescribe a formula that fits your needs.
You will need a clean space to store your bags of solution and other supplies. You will also need to warm each bag of solution to body temperature before use. You can use an electric blanket or let the bag sit in a tub of warm water. Most solution bags come in a protective outer wrapper, and you can warm them in a microwave. Do not microwave a bag of solution after you have removed it from its wrapper.
In automated peritoneal dialysis, the cycler is the machine that automatically fills and drains your belly. You can program the cycler to give you different amounts of dialysis solution at different times. Most cyclers include the following:
- Solution supply. At the beginning of the session, you connect bags of dialysis solution to tubing that feeds the cycler. Most systems have a separate tube for the last bag because this solution may have a higher dextrose or icodextrin content so that it can work for a daylong dwell time.
- Pump. The pump sends the solution from the supply bags to a heater bag before it enters your body. The pump also sends the solution to the disposal container or drain line after use. However, the pump does not move the solution into and out of your belly; gravity performs that job.
- Heater bag. Before the solution enters your belly, the cycler warms a measured dose to body temperature. Once the solution is the right temperature and the previous exchange drains, the cycler releases a clamp to let the warmed solution flow into your belly.
- Fluid meter. The cycler’s timer releases a clamp to let the pump send the used dialysis solution into a disposal container or drain line. A fluid meter in the cycler measures and records how much solution the cycler removes. Some cyclers compare the amount that was put in with the amount that drains out. This comparison lets you and your doctor know if the treatment is removing enough fluid from your body.
- Disposal container or drain line. After measuring the used solution, the cycler pumps the used solution to a disposal container that you can throw away. With some systems, you can just string a long drain line from the cycler to a toilet or bathtub.
- Alarms. Sensors will trigger an alarm and shut off the cycler if a problem occurs.
How do I perform an exchange?
With continuous ambulatory peritoneal dialysis, you will perform the exchanges manually, following these steps:
- Always wash your hands before handling your catheter and transfer set, and wear a surgical mask when connecting the transfer set to the disposable tubing.
- Drain the used dialysis solution from your abdominal cavity into the drain bag. Near the end of the drain, you may feel a mild tugging sensation that tells you most of the fluid is gone.
- After you drain the used solution from your belly, you will close or clamp the transfer set so the fresh solution does not flow into your belly yet. Then you will let some of the fresh solution flow directly into the drain bag. This step removes air from the tubes.
- The final step is to clamp the line that goes to the drain bag, open the transfer set, and refill your belly with fresh dialysis solution from the hanging bag.
How will peritoneal dialysis affect my lifestyle?
You may not be able to do all the things you used to do. Adjusting to the effects of kidney failure can be difficult. You may have less energy. You may need to make changes in your work or home life, giving up some activities and responsibilities.
Following your schedule of exchanges will require some adjustment. If you do continuous ambulatory peritoneal dialysis during the day, you have some control over when you do the exchanges. A few times every day you must stop your normal activities and take about 30 minutes to perform an exchange. If you do automated peritoneal dialysis at night, you will have to set up your cycler every night. You may have to go to bed early to get all the hours of dialysis prescribed by your doctor.
Keeping the same schedule you kept when your kidneys worked can be difficult now that your kidneys have failed. Accepting this new reality can be hard on you and your family. A counselor or renal social worker can answer your questions and help you cope. The word “renal” refers to the kidneys. Renal social workers specialize in helping people with chronic kidney disease (CKD) and kidney failure.
How will I know if my peritoneal dialysis treatments are working?
Your health care team will perform several tests to tell if your dialysis exchanges are removing enough wastes. These tests are especially important during the first weeks of treatment to determine whether your schedule is adequate.
Peritoneal Equilibration Test
For a peritoneal equilibration test, a dialysis nurse takes samples of your blood and dialysis solution during a 4-hour exchange. The peritoneal equilibration test measures how much dextrose your body absorbs from a bag of dialysis solution. The peritoneal equilibration test also measures how much urea and creatinine—waste products of normal muscle and protein breakdown—move from your blood into the dialysis solution.
For a clearance test, you will collect the used dialysis solution from a 24-hour period. A dialysis nurse takes a blood sample during the same 24-hour period. Your doctor or nurse compares the amount of urea in the used solution with the amount in your blood to see how much urea was removed. For the first months or even years of peritoneal dialysis treatment, you may still produce small amounts of urine. If you produce more than 100 milliliters (3 ounces) of urine per day, you will also collect your urine to measure its urea content.
From the measurements of used solution, blood, and, if available, urine, your health care team can determine your urea clearance—a measurement doctors call your Kt/V—and your creatinine clearance rate. These measurements will show whether you are using the right peritoneal dialysis schedule and doses. If your dialysis schedule is not removing enough wastes, your doctor will make adjustments. More information is provided in the NIDDK health topic, Peritoneal Dialysis Dose and Adequacy.
What problems could I have with peritoneal dialysis?
Peritoneal dialysis can lead to the following problems:
- fluid and dextrose absorption
The most common problem with peritoneal dialysis is peritonitis, a serious abdominal infection. This infection can occur if your exit site becomes infected or if the catheter becomes contaminated as you connect or disconnect it from the bags. Doctors treat peritonitis with antibiotics, which are added to the dialysis solution that you can usually take at home.
Your health care team will show you how to keep your catheter clean to prevent peritonitis. Newer catheters protect against the spread of bacteria; however, peritonitis is still a common problem that sometimes makes continuing peritoneal dialysis impossible. You should follow your health care team’s instructions carefully. Here are some general rules:
- Store your supplies in a cool, clean, dry place.
- Inspect each bag of solution for signs of contamination, such as cloudiness, before you use the solution.
- Find a clean, dry, well-lit space to perform your exchanges.
- Wash your hands every time you need to handle your catheter.
- Clean your skin where your catheter enters your body, as instructed by your health care team, every day.
- Wear a surgical mask when performing exchanges.
Report these signs of infection to your doctor immediately so he or she can treat peritonitis quickly to prevent additional problems:
- abdominal pain
- nausea or vomiting
- redness or pain around your catheter
- unusual color or cloudiness in used dialysis solution
- a catheter cuff that pushes out of your body
Fluid and Dextrose Absorption
When dialysis solution stays in the body too long, it becomes so full of wastes and extra fluid that it cannot absorb any more from the body. The process may even reverse, letting some wastes and extra fluid back into the body. The body also absorbs dextrose from the dialysis solution, which can cause weight gain because dextrose contains calories.
With continuous ambulatory peritoneal dialysis, you might have a problem with the long overnight dwell time. If your body absorbs too much fluid and dextrose overnight, you may be able to use a minicycler to exchange your solution once while you sleep. This extra exchange will shorten your dwell time, keep your body from absorbing too much fluid and dextrose, and filter more wastes and extra fluid from your body.
With automated peritoneal dialysis, you may absorb too much solution during the daytime exchange, which has a long dwell time. You may need an extra exchange in the midafternoon to keep your body from absorbing too much solution and remove more wastes and extra fluid from your body.
More information is provided in the NIDDK health topic, Kidney Failure: What to Expect.
What financial help is available to pay for peritoneal dialysis?
United States citizens who have kidney failure are eligible to receive Medicare. Treatment for kidney failure is expensive; however, Medicare pays much of the cost, usually up to 80 percent. Often, supplemental insurance pays the rest.
State Medicaid programs help people who are not eligible for Medicare or who still need help with the portion that Medicare does not cover. Medicaid programs provide funds for health care based on financial need. Your renal social worker can help you locate resources for financial assistance.
More information is provided in the NIDDK health topic, Financial Help for Treatment of Kidney Failure.
Eating, Diet, and Nutrition
Eating the right foods can help you feel better while on peritoneal dialysis. Talk with your dialysis center’s dietitian to find a meal plan that works for you. Your dietary needs will depend on your treatment and other factors such as your weight and activity level. Staying healthy with CKD requires watching what is in your diet:
- Protein is in foods from animals and plants. Protein provides the building blocks that maintain and repair muscles, organs, and other parts of your body. Peritoneal dialysis can remove proteins from your body, so eat high-quality, protein-rich foods such as meat, fish, and eggs. However, many high-protein foods also contain phosphorous, which can weaken your bones. Talk with your dietitian about ways to get the protein you need without getting too much phosphorous.
- Phosphorus is a mineral that helps your bones stay healthy and your blood vessels and muscles work. Phosphorus is a natural part of foods rich in protein, and food producers often add it to many processed foods. Phosphorus can weaken your bones and make your skin itch if you consume too much. Peritoneal dialysis may not remove enough phosphorus from your body, so you will probably need to limit or avoid high-phosphorus foods such as milk and cheese, dried beans, peas, colas, nuts, and peanut butter. You may also need to take a pill called a phosphate binder that keeps phosphorus in your food from entering your bloodstream.
- Fluid includes water and drinks such as fruit juice and milk and water in foods such as fruits, vegetables, ice cream, gelatin, soup, and ice pops. You need water for your body to function properly; however, too much can cause swelling and make your heart work harder. Over time, having too much fluid in your body can cause high blood pressure and congestive heart failure. Peritoneal dialysis might cause you to have either too much or too little fluid, depending on the strength of the solution you use. Your diet can also influence whether you have too much or too little fluid. Your dietitian will help you determine how much liquid you need to consume each day.
- Sodium is a part of salt. Many canned, packaged, frozen, and fast foods contain sodium. Sodium is also a part of many condiments, seasonings, and meats. Too much sodium makes you thirsty, which makes you drink more liquid. Try to eat fresh foods that are naturally low in sodium, and look for products that say “low sodium” on the label, especially in canned and frozen foods.
- Potassium is a mineral that helps your nerves and muscles work the right way. Peritoneal dialysis can pull too much potassium from your blood, so you may need to eat more high-potassium foods such as bananas, oranges, potatoes, and tomatoes. However, be careful not to eat too much potassium. Your dietitian will help you choose the right amount.
- Calories are units for measuring the energy provided by foods and drinks. Eating foods with too many calories, such as oily and sugary foods, can make you gain weight. Your body can absorb the dextrose from your dialysis solution, which can increase your calorie intake. You may find you need to take in fewer calories to prevent weight gain. Your dietitian can help you create and follow a diet to stay at a healthy weight.
- Supplements help provide some of the vitamins and minerals that may be missing from your diet. Peritoneal dialysis also removes some vitamins from your body. Your doctor may prescribe a vitamin and mineral supplement that scientists have designed specifically for people with CKD and kidney failure. Never take vitamin and mineral supplements that you can buy over the counter. They may be harmful to you. Talk with your doctor before taking any medicine, including vitamin and mineral supplements, that he or she has not prescribed for you.
You may have a difficult time changing your diet at first. Eating the right foods will help you feel better. You will have more strength and energy. More information is provided in the NIDDK health topic, Make the Kidney Connection: Food Tips and Healthy Eating Ideas.
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.
What are clinical trials, and are they right for you?
Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.
What clinical trials are open?
Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.
About the Kidney Failure Series
You and your doctor will work together to choose a treatment that's best for you. The publications of the NIDDK Kidney Failure Series can help you learn about the specific issues you will face.
- What I need to know about Kidney Failure and How it’s Treated
- Treatment Methods for Kidney Failure: Hemodialysis
- Treatment Methods for Kidney Failure: Peritoneal Dialysis
- Treatment Methods for Kidney Failure: Kidney Transplantation
- Kidney Failure: Eat Right to Feel Right on Hemodialysis
- Kidney Failure: What to Expect
- Vascular Access for Hemodialysis
- Hemodialysis Dose and Adequacy
- Peritoneal Dialysis Dose and Adequacy
- Amyloidosis and Kidney Disease
- Anemia in Chronic Kidney Disease
- Chronic Kidney Disease-Mineral and Bone Disorder
- Financial Help for Treatment of Kidney Failure
Learning as much as you can about your treatment will help make you an important member of your health care team.
This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings through its clearinghouses and education programs to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.
The NIDDK would like to thank:
Karl D. Nolph, M.D., University of Missouri School of Medicine for reviewing this publication.