In this modality of renal replacement therapy, the peritoneum acts as a semipermable membrane similar to a hemodialysis filter.
This technique has several advantages because it allows independence from the long time spent in dialysis units, it does not require stringent dietary restrictions, as in hemodialysis, and rehabilitation rates are better than those observed in with more patients returning to full-time employment.
Residual renal function is maintained for a longer period, for instance 1 to 2 years, while the patient is undergoing peritoneal dialysis, thus improving and mortality. In continuous ambulatory peritoneal dialysis, dialysate of 2.0- to 3.0-L volumes is left in the peritoneal cavity for varying amounts of time to be exchanged four to six times daily. In continuous cyclic peritoneal dialysis, the patient is connected to a machine referred to as a cycler that allows inflow of smaller volumes of dialysate with shorter dwell time through the night, so the patient is free of dialysis during the day. Several modifications in this regimen can be made to fit the specific patient to achieve adequate clearance. The rate of removal of various solutes depends on the concentration gradient, surface area, and permeability of the peritoneal membrane to the solute. Smaller molecules move across the peritoneal membrane with ease and are influenced by dialysate flow rates or ultrafiltration rates. Ultrafiltration is achieved through increasing dextrose concentration in the dialysate. In spite of lower weekly creatinine clearance values in patients undergoing peritoneal dialysis, residual renal function is preserved longer, and the survival of these patients matches that of patients undergoing hemodialysis.
The two major drawbacks of peritoneal dialysis are infection of the percutaneous catheter placed into the peritoneal cavity and difficulty in achieving adequate clearance in patients with large body mass. Peritonitis in patients undergoing peritoneal dialysis can be treated with intraperitoneal antibiotics.
Catheter removal is indicated in some cases of peritonitis, for instance, bacterial peritonitis not responding to antibiotics and fungal peritonitis.