Provision of optimal dialysis for peritoneal dialysis patients

Prescription of optimal dialysis is of major importance in determining the overall prognosis and nutritional status of patients receiving chronic peritoneal dialysis (PD). A mathematical model of peritoneal dialysis kinetics was used to examine typical dialysis prescriptions for patients receiving continuous ambulatory peritoneal dialysis (CAPD) or automated peritoneal dialysis (APD), and using a new automatic night‐time dialysis machine. Based on the recommendations of the CANUSA and other studies, a creatinine clearance delivery target of 70 L per week (the equivalent of 6.9 mL/min) was selected. At the start of dialysis, creatinine clearances of greater than 70 L/week are achieved in most patients on PD, but by 2 years deterioration of residual renal function (RRF) results in standard dialysis prescriptions of 4×2 L exchanges per day providing adequate solute clearance to only a minority of patients. Prescriptions of 4×2.5 or 4×3.0 L exchanges per day may be required to provide optimal solute clearance to most patients without RRF. Automated peritoneal dialysis, especially when prescribed without day‐time fluid, often delivers inadequate solute clearance. In order to achieve optimal solute clearance with APD it is essential that patients have dialysate in the abdomen by day, and most need to perform a mid‐day exchange. Five exchanges per day can be easily achieved, using the new technology that performs a night‐time exchange, and this often results in optimal solute clearance. Optimization of dialysis prescriptions may be expected to result in improvement in objective measures of morbidity and mortality. For the individual patient, it is essential to take into account the creatinine clearances achieved with the dialysis prescribed, the body surface area, peritoneal transport rates and the contribution of measured residual renal function.