Peritoneal dialysis is achieved by repeated cycles of instillation and drainage of dialysis fluid within the peritoneal cavity, with the two main functions of dialysis—solute and fluid removal—occurring due to the contact between dialysis fluid and the capillary circulation of the parietal and visceral peritoneum across the peritoneal membrane. It can be used to provide renal replacement therapy in acute kidney injury or chronic kidney disease. Practical aspects—choice of peritoneal dialysis as an effective modality for renal replacement in the short to medium term (i.e. several years) is, for most patients, a lifestyle issue. Typically, a patient on continuous ambulatory peritoneal dialysis will require three to four exchanges of 1.5 to 2.5 litres of dialysate per day. Automated peritoneal dialysis and use of the glucose polymer dialysis solution icodextrin enables flexibility of prescription that can mitigate the effects of membrane function (high solute transport). Peritonitis—this remains the most common complication of peritoneal dialysis, presenting with cloudy dialysis effluent, with or without abdominal pain and/or fever, and confirmed by a leucocyte count greater than 100 cells/µl in the peritoneal fluid. Empirical antibiotic treatment, either intraperitoneal or systemic, with cover for both Gram-positive and Gram-negative organisms, should be commenced immediately while awaiting specific cultures and sensitivities. Long-term changes in peritoneal membrane function influence survival on peritoneal dialysis if fluid removal is less efficient (ultrafiltration failure), especially in the absence of residual kidney function. This is the main limitation of treatment, along with avoiding the risk of encapsulating peritoneal sclerosis—a life-threatening complication of peritoneal dialysis, particularly if of long duration (15–20% incidence after 10 years), that is characterized by severe inflammatory thickening, especially of the mesenteric peritoneum, resulting in an encapsulation and progressive obstruction of the bowel.
