Peritoneal Dialysis

The patient performs their own dialysis at home using their own peritoneum as the filter — but cloudy effluent means infection is brewing and you need to act fast.

Peritoneal dialysis (PD) uses the peritoneal membrane as a semipermeable filter. A permanent Tenckhoff catheter is surgically placed in the abdomen. Dialysate containing dextrose is instilled, dwells for a prescribed time (typically 4–8 hours for CAPD, shorter cycles overnight for APD/CCPD), and then drains by gravity. Solutes cross the membrane by diffusion; fluid removal (ultrafiltration) depends on the osmotic gradient created by dextrose concentration — higher dextrose pulls more fluid. The biggest threat is peritonitis. Cloudy effluent is the hallmark sign and must be reported immediately; a WBC count >100/mm³ with >50% neutrophils in effluent confirms it. Strict aseptic technique during exchanges is the primary prevention. Outflow should be clear and straw-colored. If outflow is slow or absent, reposition the patient — turning side to side or elevating the head of bed often resolves it. The nurse monitors daily weight, strict I&O (compare instilled versus drained volumes), and abdominal girth. Protein loss through the peritoneum is significant, so the patient needs a high-protein diet (1.2–1.5 g/kg/day) — more than hemodialysis patients. Fluid and potassium restrictions are generally less strict than with hemodialysis.

Key Distinctions

Don't confuse cloudy effluent (peritonitis) with bloody effluent (common and benign after initial catheter placement or menses in women). Students mix up PD's high-protein diet requirement with hemodialysis dietary restrictions — PD patients lose more albumin across the peritoneum. Slow outflow is repositioned first, not treated as an emergency — it's usually catheter tip migration or constipation, not infection.

Clinical Pearl

Cloudy out = call it out. Clear and straw-colored effluent is your green light; anything cloudy means peritonitis until proven otherwise.