How Peritoneal Dialysis Works, What Treatment Involves, and What Patients Should Know
Peritoneal dialysis, often called PD, is a treatment for kidney failure that cleans the blood inside the body. Instead of sending blood through an external dialysis machine, PD uses the peritoneum, the natural lining of the abdomen, as a filter.
A soft tube called a peritoneal dialysis catheter is placed permanently into the abdomen. A specially prepared cleansing fluid, called dialysis solution or dialysate, flows through the catheter into the abdominal cavity. While the solution remains inside, waste and extra fluid move from the blood vessels in the peritoneal lining into the dialysis fluid. After several hours, the used fluid is drained and replaced with fresh solution. This process is called an exchange.
Peritoneal dialysis can remove waste, extra sodium, and excess fluid when the kidneys can no longer do so adequately. It can help control blood pressure and improve symptoms of kidney failure, but it does not cure kidney disease or replace all the functions of healthy kidneys.
Understanding the Peritoneum
The peritoneum is a thin membrane that lines the inside of the abdominal wall and covers many of the organs in the abdomen. It contains a large network of small blood vessels.
During peritoneal dialysis, this membrane acts as a natural filter. Waste products and extra fluid move from the blood across the peritoneal membrane and into the dialysis solution. The used solution is later drained out of the body, carrying those wastes and fluids with it.
The blood itself does not leave the body during PD. There are also no needles placed into a fistula or graft for each treatment.
How an Exchange Works
A peritoneal dialysis exchange has three basic stages:
1. Drain
Used dialysis solution is drained from the abdomen through the catheter and into a drainage bag or drain line.
2. Fill
Fresh dialysis solution flows from a sterile bag through the catheter and into the abdomen.
3. Dwell
The fresh solution remains inside the abdomen for a prescribed amount of time. This is called the dwell time. During the dwell, waste and extra fluid move into the solution.
After the dwell period is finished, the fluid is drained, and the process begins again. Exchanges must be completed according to the dialysis prescription because skipping or shortening treatments can allow waste and fluid to build up.
What Is in the Dialysis Solution?
Peritoneal dialysis solution contains sterile water, minerals, and an ingredient that helps pull excess fluid from the bloodstream.
Many solutions contain a form of sugar called dextrose. Different bags contain different strengths of dextrose. A higher-strength solution usually removes more fluid, but a stronger solution is not automatically better. Frequent use may increase glucose absorption, weight gain, and blood sugar problems.
Some patients may use a solution containing icodextrin for a longer dwell. The nephrologist and PD team choose the solution type, strength, volume, and schedule based on fluid status, blood pressure, remaining kidney function, laboratory results, and the peritoneal membrane’s ability to transport waste.
Patients should never choose a stronger bag or alter the treatment prescription without instructions from the PD team.
The Two Main Types of Peritoneal Dialysis
There are two primary ways to perform PD:
Continuous Ambulatory Peritoneal Dialysis
Continuous ambulatory peritoneal dialysis is commonly called CAPD.
CAPD is performed manually without a machine. The patient drains the used solution and fills the abdomen with fresh solution several times during the day. Each exchange generally takes approximately 30 to 40 minutes, followed by a dwell lasting several hours.
During the dwell, the patient is disconnected from the bags and can usually walk around, work, read, eat, rest, or perform normal daily activities. Many CAPD schedules include multiple daytime exchanges and a longer overnight dwell. The exact schedule is individualized.
Automated Peritoneal Dialysis
Automated peritoneal dialysis, often called APD, uses a machine known as a cycler.
The patient connects to the cycler at night. While the patient sleeps, the machine repeatedly drains used fluid, fills the abdomen with fresh solution, and allows the solution to dwell for prescribed periods.
Depending on the prescription, fluid may remain in the abdomen during the day, or an additional daytime exchange may be required. Automated treatment may provide more daytime freedom, but the patient must prepare the machine, connect it correctly, respond to alarms, and follow the full nighttime schedule.
Where Peritoneal Dialysis Can Be Performed
PD is generally considered a home-based treatment, but it may also be performed in another clean and private location, such as:
→ At home
→ At work
→ At school
→ While traveling
→ In some assisted-living environments
Supplies require adequate clean and dry storage space. Patients using a cycler also need reliable electricity and a safe setup near the sleeping area.
Travel is possible, but it requires advance planning. Supplies may sometimes be delivered to the destination, while the patient may need to transport the cycler or arrange for manual exchanges.
The Peritoneal Dialysis Catheter
Before starting PD, a surgeon places a soft, flexible catheter into the abdomen. Part of the catheter remains inside the peritoneal cavity, while a short section exits through the skin.
The place where the catheter leaves the body is called the exit site.
Whenever possible, the catheter is placed before dialysis is urgently needed so that the area has time to heal. NIDDK notes that planning placement at least several weeks before full treatment can improve the chance of successful use.
The catheter usually remains in place as long as the patient continues PD. It must be protected from pulling, twisting, contamination, and infection.
Training Before Beginning Treatment
Patients and caregivers receive training from a peritoneal dialysis nurse before performing treatment independently.
Training may include:
→ How to wash and dry the hands correctly
→ How to wear a mask during connections
→ How to inspect dialysis-solution bags
→ How to connect and disconnect without contamination
→ How to perform manual exchanges
→ How to operate and troubleshoot a cycler
→ How to care for the catheter exit site
→ How to measure and record drained fluid
→ How to recognize infection
→ What to do during a power outage
→ Who to call when a treatment problem occurs
Training may take 1 to 2 weeks or longer, depending on the patient’s needs. A family member or caregiver may also learn the procedure so help is available during illness or recovery.
Preventing Infection
Preventing infection is one of the most important responsibilities in peritoneal dialysis.
Every connection creates a possible pathway for germs to enter the catheter and abdominal cavity. Patients must use the exact technique taught by the dialysis team rather than creating their own shortcuts.
Important precautions include:
→ Wash and dry hands thoroughly before touching supplies
→ Wear the recommended mask during connections
→ Perform exchanges in a clean, dry, well-lit area
→ Keep pets away from the exchange area and supplies
→ Inspect each bag for damage, leaks, contamination, or cloudiness
→ Keep the catheter capped and secured
→ Clean and examine the exit site as instructed
→ Store supplies in a clean, dry location
→ Never use expired or damaged solution
→ Contact the PD team immediately after accidental contamination
Careful hand hygiene, proper masking, clean connections, and daily exit-site care can reduce infection risk.
What Is Peritonitis?
Peritonitis is an infection or inflammation inside the abdominal cavity. It is one of the most serious complications of peritoneal dialysis.
Signs may include:
→ Cloudy drained dialysis fluid
→ Abdominal pain or tenderness
→ Fever or chills
→ Nausea or vomiting
→ Feeling weak or unusually ill
→ Diarrhea in some cases
→ Difficulty draining the fluid
→ Redness or pain around the catheter
Cloudy drainage should never be ignored, even if the patient does not yet have severe pain or fever. The PD team may need to test the fluid and begin antibiotics quickly.
Peritonitis is often treated with antibiotics placed directly into the dialysis solution. Prompt treatment may protect the peritoneal membrane and reduce the risk of hospitalization, catheter removal, or a change in dialysis methods.
Exit-Site and Tunnel Infections
An infection may also develop where the catheter leaves the skin or along the catheter pathway under the skin.
Possible warning signs include:
→ Redness
→ Swelling
→ Warmth
→ Tenderness
→ Drainage or pus
→ Crusting that is new or worsening
→ Pain along the catheter path
→ Fever
Patients should not apply unapproved creams, powders, alcohol, peroxide, or home remedies to the exit site. The dialysis team should evaluate suspected infection and decide which cleaning method or antibiotic is appropriate.
Other Possible Complications
In addition to infection, PD may be associated with several other concerns.
Hernias
Dialysis fluid increases pressure inside the abdomen. This may contribute to a hernia near the belly button, the catheter area, the abdomen, or the groin.
Report a new lump, bulge, discomfort, or swelling to the PD team.
Weight Gain
Dextrose from the dialysis solution can be absorbed into the body. This may add calories, increase appetite, raise blood sugar, and contribute to weight gain over time.
High Blood Sugar
People with diabetes may notice higher or less predictable glucose levels because dialysis solution can contain dextrose. Diabetes medicines or insulin may need adjustment.
Drain Pain
Some patients experience discomfort near the end of the draining or filling process. Persistent or severe pain should be reported because it may indicate catheter-position problems, constipation, infection, or another complication.
Catheter Flow Problems
Fluid may drain slowly or stop because of:
→ Constipation
→ Catheter movement
→ Kinking or clamping of the tubing
→ Fibrin or other blockage
→ Body position
→ A mechanical catheter problem
Constipation is a particularly common cause of poor drainage. Patients should follow the bowel plan provided by the PD team.
Fluid Overload
If PD is not removing enough fluid, the patient may develop:
→ Swelling
→ Rapid weight gain
→ High blood pressure
→ Shortness of breath
→ Difficulty lying flat
These symptoms require prompt contact with the dialysis team.
Dehydration or Excessive Fluid Removal
Removing too much fluid may cause:
→ Dizziness
→ Weakness
→ Low blood pressure
→ Muscle cramps
→ Fainting
→ Excessive thirst
Patients should not independently alter solution strength to correct swelling or low blood pressure.
How Will Patients Know Whether PD Is Working?
The dialysis team monitors symptoms, laboratory results, fluid removal, blood pressure, weight, and overall health.
Patients may be asked to record:
→ Daily weight
→ Blood pressure
→ Amount of solution placed into the abdomen
→ Amount drained
→ Appearance of drained fluid
→ Blood sugar when applicable
→ Bowel movements
→ Swelling or breathing changes
→ Any alarms or treatment problems
Blood, used dialysis solution, and sometimes urine are collected periodically to determine whether enough waste and fluid are being removed. If the treatment is inadequate, the nephrologist may change the number of exchanges, dwell time, solution volume, solution type, or cycler program.
Remaining Kidney Function Still Matters
Some patients continue to make urine after beginning PD. Even a small amount of remaining kidney function can assist with fluid and waste removal.
Patients should not assume that making urine means dialysis is unnecessary. Urine volume does not always show how effectively the kidneys are removing toxins.
The healthcare team may monitor urine output and adjust the PD prescription as remaining kidney function changes.
Eating and Drinking on Peritoneal Dialysis
PD removes wastes and fluid continuously or daily, so dietary instructions may differ from those used in traditional in-center hemodialysis. However, patients still need an individualized renal meal plan.
Important areas include:
Protein
Peritoneal dialysis removes some protein and amino acids. Many patients, therefore, need more dietary protein than they needed before starting dialysis.
Sodium
Too much sodium may increase thirst, swelling, blood pressure, and difficulty removing fluid.
Fluid
Some patients may have more flexible fluid limits than people receiving in-center hemodialysis, especially when they still make urine. Others require restriction because of swelling, heart disease, or inadequate fluid removal.
Potassium
PD often removes potassium more continuously, so some patients may not need the same potassium restriction as patients on hemodialysis. Others may still develop high or low potassium levels. Laboratory results determine the plan.
Phosphorus
Phosphorus may still accumulate. Patients may need dietary limits and phosphate binders with meals.
Calories and Blood Sugar
Dextrose absorbed from the dialysis solution contributes calories and may increase glucose levels. Patients with diabetes should work closely with the PD team and renal dietitian.
Medications During Peritoneal Dialysis
PD patients may take medications for:
→ Blood pressure
→ Anemia
→ Phosphorus control
→ Vitamin D and parathyroid hormone management
→ Diabetes
→ Constipation
→ Infection prevention or treatment
→ Other health conditions
Some medicines may require kidney-specific dosing. Patients should tell every prescriber and pharmacist that they use peritoneal dialysis.
Certain antibiotics may be placed directly into the PD solution when treating peritonitis. Patients should never add medicine to a dialysis bag unless specifically trained and instructed by the PD team.
Peritoneal Dialysis and Daily Life
PD may offer greater scheduling flexibility and independence than center-based dialysis. It may also allow treatment to happen more gradually, which some patients tolerate better.
Possible advantages include:
→ Treatment at home
→ Greater control over the schedule
→ Fewer trips to a dialysis center
→ No needles for routine treatment
→ More continuous fluid and waste removal
→ Greater ability to work, attend school, or travel
→ Possible preservation of remaining kidney function
However, PD also requires daily responsibility.
Possible challenges include:
→ Performing treatment every day
→ Strict infection-prevention procedures
→ Storing many boxes of supplies
→ Having a permanent abdominal catheter
→ Managing cycler alarms or manual exchanges
→ Changes in body image
→ Sleep interruptions
→ Weight gain or blood-sugar changes
→ Risk of peritonitis
→ Limited ability to lift heavy objects in some circumstances
PD is not easier in every way; it is a different type of dialysis with different benefits and responsibilities.
Who May Be a Candidate for PD?
Peritoneal dialysis may be considered for many people with kidney failure, including those who value home treatment and can safely manage the procedure.
The healthcare team will consider:
→ Medical condition
→ Previous abdominal surgeries
→ Ability to perform sterile connections
→ Vision, hand strength, and mobility
→ Home environment
→ Storage space
→ Availability of caregiver support
→ Personal lifestyle and treatment preferences
→ History of hernias or abdominal disease
→ Ability to follow a daily treatment schedule
Having a physical limitation does not automatically rule out PD. Assistance from PD, adaptive equipment, or a caregiver may make treatment possible.
Some abdominal conditions, severe membrane problems, repeated infections, or certain surgical complications may make PD more difficult or unsuitable. The nephrologist and PD surgeon must evaluate each person individually.
Peritoneal Dialysis and Kidney Transplantation
Patients using PD can still be evaluated and listed for kidney transplantation.
When a transplant becomes available, the transplant center will give instructions about the last PD treatment, bringing medications, and reporting any infection symptoms. Active peritonitis or another serious infection may temporarily delay transplantation because anti-rejection medicines would weaken the immune system.
After successful transplant surgery, PD is usually stopped. The catheter may be removed during the transplant operation or later, depending on the center’s practice and whether temporary dialysis might still be needed.
When to Contact the Peritoneal Dialysis Team Immediately
Call the PD team promptly for:
→ Cloudy drainage
→ Abdominal pain
→ Fever or chills
→ Redness, swelling, pus, or pain at the exit site
→ A tear, leak, or disconnection in the tubing
→ Accidental contamination
→ Failure of fluid to drain
→ Much less fluid removed than expected
→ Blood in the drained fluid that is persistent or significant
→ Rapid weight gain
→ Worsening swelling
→ New shortness of breath
→ Severe constipation
→ Repeated vomiting or diarrhea
→ Dizziness or very low blood pressure
→ Cycler alarms that cannot be corrected using the approved instructions
Call 911 for severe breathing difficulty, chest pain, fainting, extreme confusion, inability to awaken, or another medical emergency.
Questions to Ask Before Choosing Peritoneal Dialysis
Ask the kidney team:
→ Is peritoneal dialysis medically appropriate for me?
→ Would CAPD or automated PD fit my needs better?
→ How many exchanges will I need?
→ Will I need dialysis fluid in my abdomen during the day?
→ How much storage space is required?
→ Can someone help me if I am ill or unable to perform treatment?
→ How will travel and supply delivery work?
→ How should I protect the catheter during bathing and activity?
→ Which symptoms suggest peritonitis?
→ What should I do after accidental contamination?
→ How will PD affect my blood sugar, weight, and diet?
→ What happens during a power failure?
→ Can I continue working or attending school?
→ Can I still pursue kidney transplantation?
→ What circumstances might require switching to hemodialysis?
The Most Important Message
Peritoneal dialysis is a home-based treatment that uses the lining of the abdomen to remove waste and extra fluid from the blood. It can provide flexibility, independence, and gradual daily dialysis, but it requires consistency, careful hygiene, proper catheter care, and prompt action when problems arise.
Successful PD depends on completing every prescribed exchange, protecting the catheter from contamination, monitoring the drained solution, and communicating with the dialysis team.
Patients should not be expected to learn everything at once. Training, repetition, written instructions, caregiver support, and access to the PD nurse are important parts of safe treatment.
Important Medical Disclaimer
This information is for general education and does not replace an individualized dialysis prescription or medical advice. Peritoneal dialysis schedules, solution strengths, fluid limits, medications, and catheter-care instructions vary according to each patient’s health, laboratory results, remaining kidney function, and treatment response.
Never skip exchanges, change solution strength, add medicine to a dialysis bag, alter the cycler settings, or make any other changes to your peritoneal dialysis prescription without first consulting your nephrologist or PD nurse.
Learn more from a trusted medical source: NIDDK – Peritoneal Dialysis
