CAPD (Peritoneal Dialysis) — How It Works, Benefits & Recovery — Procedure Guide, Recovery & Risks | MyMedicPlus

Continuous Ambulatory Peritoneal Dialysis (CAPD) is a home-based renal replacement therapy for end-stage renal disease (ESRD) that uses the patient's own peritoneal membrane — the thin lining of the abdominal cavity — as a natural semi-permeable filter. Dialysate fluid (typically 2 litres of a glucose-based solution) is infused through a permanent silicone Tenckhoff catheter into the peritoneal cavity, where it dwells for 4–8 hours. During the dwell, uraemic waste products (urea, creatinine, potassium, phosphate), excess fluid, and small toxins diffuse passively from the peritoneal capillaries into the dialysate along concentration and osmotic gradients. The spent dialysate is then drained by gravity into a collection bag, and fresh dialysate is infused. This cycle is repeated 3–5 times per day by the patient at home, with no machinery required — the exchanges are powered entirely by gravity and manual technique. An automated variant, automated peritoneal dialysis (APD or CCPD), uses a cycler machine to perform multiple shorter exchanges overnight while the patient sleeps. CAPD requires consistent aseptic technique to prevent peritonitis, the most serious complication. It is particularly suited to patients who live far from dialysis centres, have difficult vascular access, have residual renal function worth preserving, or who prioritise lifestyle flexibility.

CAPD is indicated for patients with end-stage renal disease — defined as a glomerular filtration rate (GFR) persistently below 10–15 ml/min/1.73m² — who require renal replacement therapy. Patient selection criteria include adequate manual dexterity and cognitive ability to perform aseptic exchanges, a satisfactory home environment with clean space and running water, motivation for self-care, and the absence of significant peritoneal membrane dysfunction or prior extensive abdominal surgery that would impair dialysis adequacy. CAPD is particularly advantageous for patients with residual urine output, as peritoneal dialysis preserves residual renal function better than haemodialysis for an average of 2–3 years longer, reducing cardiovascular morbidity. Patients with severe cardiovascular instability who do not tolerate the haemodynamic shifts of intermittent haemodialysis benefit from the gentle continuous nature of CAPD. Children with ESRD frequently use peritoneal dialysis. Absolute contraindications include a non-functioning peritoneum (obliterated by adhesions or prior surgery), active abdominal inflammatory or oncological disease, and inability to perform or supervise exchanges safely.

Catheter insertion is the first step and is performed as a minor surgical procedure under local anaesthesia with sedation or general anaesthesia. The surgeon places a soft silicone Tenckhoff catheter (a thin tube with Dacron cuffs that promote tissue ingrowth and prevent pericatheter infection) through the anterior abdominal wall, with its tip positioned in the true pelvis under laparoscopic or open guidance. The catheter exit site is positioned in the lateral lower quadrant, and the catheter allowed to heal for 2 weeks before use. Patients then attend a 5–10 day training programme delivered by a specialist peritoneal dialysis nurse, learning strict aseptic technique, fluid management, and troubleshooting. Each exchange takes 30–40 minutes and follows a standardised sequence: (1) wash hands thoroughly; (2) connect the spent dialysate bag to the drain port and drain by gravity over 15–20 minutes; (3) connect the fresh dialysate bag; (4) infuse 2 litres over 10 minutes; (5) clamp and disconnect using ultraviolet spike or disconnect system; (6) record vital signs, fluid balance, and dialysate appearance. The dialysate glucose concentration (1.36%, 2.27%, or 3.86%) is selected based on fluid removal needs, guided by weight and blood pressure. Dialysis adequacy is monitored monthly through urine and dialysate collections measuring weekly creatinine clearance and Kt/V.

The central benefit of CAPD is that it returns dialysis to the patient's home and schedule, eliminating the 3-times-weekly travel to a hospital unit and 4-hour machine sessions required by conventional haemodialysis. This lifestyle freedom allows patients to maintain employment, travel, and participate in family life without the rigid haemodialysis timetable. Studies consistently show that peritoneal dialysis patients report higher health-related quality of life scores and greater treatment satisfaction than in-centre haemodialysis patients, particularly in the first 2–3 years of therapy. CAPD preserves residual renal function significantly longer than haemodialysis — a meaningful advantage because even small amounts of urine output (>100 ml/day) reduce cardiovascular events, anaemia, phosphate load, and hospitalisation rates. The continuous nature of CAPD maintains more stable blood pressure, fluid balance, and biochemistry without the peaks and troughs of intermittent haemodialysis, reducing intradialytic hypotension episodes. CAPD is also relatively inexpensive compared with in-centre haemodialysis when home infrastructure costs are offset against facility costs. For diabetic patients, glucose in the dialysate is slowly absorbed and provides approximately 300–600 kcal/day, reducing insulin requirements.

Peritonitis is the most serious complication of CAPD, occurring at a rate of approximately one episode per 24–36 patient-months. It presents with cloudy dialysate, abdominal pain, and fever. Diagnosis requires dialysate white cell count above 100 cells/mm³ with more than 50% neutrophils and dialysate culture. Treatment with intraperitoneal antibiotics is effective in 80–85% of episodes; refractory or recurrent peritonitis requires catheter removal and temporary haemodialysis. Catheter exit-site infections and tunnel infections are prevented by daily exit-site care and mupirocin antibiotic ointment prophylaxis. Hernia formation (inguinal, umbilical, incisional) occurs in 10–25% of CAPD patients due to chronically raised intraperitoneal pressure and requires surgical repair. Ultrafiltration failure — progressive inability of the peritoneal membrane to remove fluid — develops in approximately 10% of patients after 5–8 years. Encapsulating peritoneal sclerosis is a rare but life-threatening late complication characterised by progressive peritoneal fibrosis with bowel obstruction, occurring predominantly after more than 8 years of PD. Metabolic complications include hypertriglyceridaemia from glucose absorption and obesity.

After Tenckhoff catheter insertion, patients are typically discharged within 24–48 hours with wound care instructions and the catheter clamped for a healing period of 2 weeks. During this period, exit-site daily cleaning with chlorhexidine or povidone-iodine is taught by the PD nurse. Training commences at 2 weeks and takes 5–10 days for most patients to become competent and confident with exchange technique. Monthly clinic visits thereafter monitor dialysis adequacy (Kt/V above 1.7), residual renal function (24-hour urine collection), blood pressure, anaemia, nutritional status (serum albumin), and peritoneal membrane function (peritoneal equilibration test annually). Patients are supported by a 24-hour on-call PD nurse service for troubleshooting. Dietary advice includes a high-protein diet (1.2–1.4 g/kg/day) to offset protein losses into the dialysate, phosphate restriction, and fluid balance management tailored to residual urine output and ultrafiltration volume. Travel is fully compatible with CAPD with advance planning to arrange dialysate supply delivery to the destination.