Maintaining Peritoneal Dialysis Adequacy: The Process of Incremental Prescription.

Abstract

Urea kinetics (weekly Kt/V) greater than 1.7 generally define adequate peritoneal dialysis (PD). Adequacy of PD depends on residual renal function and PD clearance. Preserving residual renal function and peritoneal membrane characteristics helps to maintain PD adequacy.The dose of PD can be augmented by increasing the total dialysate volume. Greater volume can be achieved by increasing either the fill volume per exchange or the number of exchanges. Increased time on dialysis can be achieved by keeping PD fluid in the peritoneal cavity at all times. Increasing the convective force enhances solute removal with ultrafiltration.Incremental PD is used during urgent starts and in patients who are newly starting or who have been on PD. Urgent starts require use of frequent low-volume exchanges to avoid leaks at surgical sites. The dialysate volume can be gradually increased provided that no leakage occurs, up to approximately 2 L per exchange on day 14 for an average-size adult. New-start patients require only 1 - 2 exchanges daily if they still have residual renal function. Incremental PD retains patients on PD as residual renal function wanes and peritoneal membrane characteristics change because of dextrose exposure, infection, and inflammation.Use of a cycler permits patients to achieve adequacy by increasing the volume per cycle and the number of cycles per treatment. Using a non-dextrose-based solution, such as icodextrin, allows patients to achieve adequate ultrafiltration with less dextrose exposure.Adequate dialysis can be achieved by manipulating the dialysate dwell volume and the frequency of exchanges, and by optimizing ultrafiltration.