OVERVIEW

What is peritoneal dialysis?

Peritoneal dialysis (PD) utilizes the peritoneum as a semipermeable membrane, creating a solute concentration gradient between its two sides. Solutes move from the higher concentration side to the lower concentration side (diffusion), while water moves from the hypotonic side to the hypertonic side (osmosis). By continuously replacing the peritoneal dialysis fluid, it achieves the removal of metabolic waste, toxins, and corrects water and electrolyte imbalances. It is commonly used as a replacement therapy for kidney failure.

What are the basic types of peritoneal dialysis?

• Continuous ambulatory peritoneal dialysis (CAPD);

• Automated peritoneal dialysis (APD);

• Different dialysis methods are selected based on the patient's peritoneal permeability and lifestyle, including intermittent peritoneal dialysis (IPD), continuous cycling peritoneal dialysis (CCPD), nocturnal intermittent peritoneal dialysis (NIPD), daytime automated peritoneal dialysis (DADP), and tidal peritoneal dialysis (TPD).

What is the principle of peritoneal dialysis?

The fundamental principle of peritoneal dialysis is based on the semipermeable nature of the peritoneum. A specific amount of dialysis fluid is introduced into the abdominal cavity and retained for a period. Solute and water exchange occurs between the blood in the peritoneal capillaries and the dialysis fluid in the cavity, driven by solute concentration and osmotic gradients. This process removes accumulated metabolic waste and corrects water, electrolyte, and acid-base imbalances. In peritoneal dialysis, solute exchange primarily occurs through diffusion and convection, while water removal is achieved via ultrafiltration by increasing osmotic pressure.

SYMPTOMS

None

CAUSES

Which patients are suitable for peritoneal dialysis?

• Acute renal failure: For hemodynamically unstable acute renal failure and patients with severe bleeding tendency, peritoneal dialysis is the preferred treatment.

• Chronic renal failure.

• Acute drug or toxin poisoning: Peritoneal dialysis can remove drugs and toxins with the following characteristics:

• Dialyzable, with a molecular weight less than 5000 Daltons;

• Exist in the blood in an unbound form. Compared to hemodialysis and hemoperfusion, peritoneal dialysis is less effective in treating poisoning but can be attempted when the above equipment is unavailable.

• Other conditions: Acute drug or toxin poisoning when blood purification equipment is unavailable; severe water-electrolyte imbalance, acid-base imbalance, acute liver failure, severe acute pancreatitis, widespread purulent peritonitis, refractory heart failure, and multiple myeloma, among others.

Which patients are not suitable for peritoneal dialysis?

• Absolute contraindications: Include severe reduction in effective peritoneal surface area and loss of abdominal integrity. The former is mainly caused by extensive adhesions, fibrosis, or loss of the peritoneum due to various diseases, trauma, or surgery. The latter primarily includes irreparable abdominal defects, especially diaphragmatic defects. Peritoneal dialysis is also not possible when there is a continuous drainage tube in the abdominal cavity.

• Relative contraindications: Mainly include chronic obstructive pulmonary disease and respiratory dysfunction, recent abdominal surgery, systemic vascular diseases, protein-calorie malnutrition, late-stage pregnancy or large intra-abdominal tumors, and localized peritonitis, among others.

DIAGNOSIS

Are the treatment effects of peritoneal dialysis and hemodialysis similar? Which type of dialysis should patients generally choose?

The effects of the two are similar. Peritoneal dialysis offers better protection for residual kidney function compared to hemodialysis and is more suitable for patients with hemodynamic instability. Since peritoneal dialysis is simple to perform and can be done at home, it is more convenient for those who need to attend school or work. Hemodialysis provides better control of fluid ultrafiltration, with long-term outcomes similar to peritoneal dialysis, but requires visiting the hospital 3–4 times a week for treatment.
Hemodialysis is suitable for patients who cannot undergo peritoneal dialysis due to peritoneal damage or loss of integrity caused by disease, or those who are unable to learn the procedure for various reasons.

Is the effect of peritoneal dialysis the same as that of human kidneys?

No, peritoneal dialysis can only partially replace the functions of normal human kidneys, such as removing toxins, excess fluid, and electrolytes. Healthy kidneys also perform endocrine functions and regulate blood pressure, among other roles.

Does peritoneal catheter placement require general anesthesia? Is the postoperative recovery time long?

If the peritoneal catheter placement is performed laparoscopically, general anesthesia is required. For conventional open surgery, local anesthesia is typically used. The procedure usually takes about 1–2 hours. Postoperatively, it is important to keep the incision site disinfected, clean, and dry. Patients can generally be discharged the day after surgery.

TREATMENT

Is peritoneal dialysis complicated to perform?

Generally, patient education on peritoneal dialysis procedures and precautions can begin before the peritoneal dialysis catheter placement surgery is completed. After repeated training sessions, patients must pass an assessment before they can independently perform peritoneal dialysis. Through nurse-led instruction, most patients can master the basic steps of peritoneal dialysis. For elderly patients or those with limited mobility, family members or caregivers living with the patient can also be trained to assist with the procedure.

Is peritoneal dialysis expensive? How are so many dialysis solutions delivered home?

Peritoneal dialysis is a convenient and relatively more economical dialysis treatment compared to hemodialysis that can be performed at home. The cost of dialysis solutions is partially reimbursed based on the patient's medical insurance, and patients can also apply for critical illness insurance to increase outpatient reimbursement rates. Regarding the delivery of peritoneal dialysis solutions, patients typically need to visit the nephrology outpatient department of a local hospital, where doctors will develop a peritoneal dialysis plan based on the patient's condition. The manufacturer will then deliver the dialysis solutions directly to the patient's home.

What other diseases can peritoneal dialysis cause?

• Infectious complications: Peritonitis is the most common complication of peritoneal dialysis, often caused by improper aseptic techniques, infections at the incision or catheter tunnel, weakened immunity, contaminated dialysis solution, advanced age, and other factors. Microorganisms causing peritonitis primarily enter the abdominal cavity through the dialysis catheter, but may also infiltrate from the skin around the catheter exit or spread directly from intestinal or pelvic infections. Rarely, infections may originate from the bloodstream. Types include bacterial, fungal, and chemical peritonitis.

• Metabolic complications:

• Fluid and electrolyte imbalances, such as pulmonary or cerebral edema due to water and sodium retention. Since peritoneal dialysis solutions lack potassium, hypokalemia may occur.

• Poor blood sugar control and unstable glucose levels.

• Protein-losing syndrome, caused by the loss of proteins, amino acids, and water-soluble vitamins. Approximately 5 grams of protein are lost daily, leading to symptoms like fatigue, poor appetite, and drowsiness. Severe cases may result in coma, so peritoneal dialysis patients should maintain balanced nutrition.

• Lung infections: Occurring in about 25% of cases, possibly due to elevated diaphragm or prolonged bed rest.

• Mechanical complications: These include poor drainage, catheter blockage, abdominal pain or bloating, dialysis solution leakage, bleeding, and organ damage. These issues are often related to local irritation from the dialysis solution or catheter, improper placement, or inadequate suturing.

DIET & LIFESTYLE

What special considerations should be taken for the home environment of peritoneal dialysis patients?

• Master the method of peritoneal dialysis and pay attention to aseptic techniques.

• It is best to set up a relatively independent peritoneal dialysis operation room at home, equipped with a dedicated ultraviolet disinfection lamp, and ensure ventilation to maintain dryness.

• Do not keep pets at home.

PREVENTION

How to Reduce the Occurrence of Complications in Peritoneal Dialysis?

• Pay attention to the cleanliness of the peritoneal dialysis environment and follow standardized procedures.

• If abdominal pain or abnormal reduction in ultrafiltration volume occurs, seek medical attention promptly and retain cloudy peritoneal dialysis fluid for culture testing.

• Monitor daily body weight, blood pressure, urine output, and fluid intake. Accurately record the time and volume of each peritoneal dialysis exchange, and regularly submit peritoneal dialysis fluid for testing.