Evaluation and Management of Ultrafiltration Problems in Peritoneal Dialysis

Abstract

luid balance management is one of the primaryfunctions of renal replacement therapy. Peritonealdialysis (PD), because of its continuous nature, hasbeen considered an optimal approach to this thera-peutic goal, avoiding fluctuant volume status and af-fording better homeostatic stability (1). This superiorpotential of PD has been illustrated in several studiesshowing, in discreet patient groups, better blood pres-sure control in PD compared to hemodialysis (HD) (2).This therapeutic advantage, however, has not been uni-versally utilized and population surveys still show ashigh a prevalence of hypertension and cardiovascularmortality in PD as in HD populations (3–5). While thelatter may be ascribed in both populations to an in-herited disease burden from the pre end-stage renaldisease (ESRD) phase of renal disease, it is clear thatthe full potential of PD for optimal volume homeosta-sis has remained underutilized (6). Several factors maybe responsible for this underutilization and for the as-sumption prevalent among physicians that HD affordsa more effective means of volume control. By its verynature as a continuous therapy, PD lacks the dramaticillustration of rapid volume removal observed with HD.Similarly, by its very nature as a home therapy, PDlacks the recurrent frequent examination by physi-cians/nurses of volume status afforded by three-timesweekly HD, so the opportunities for triggered inter-ventions are more temporally spaced than in HD. Thesetwo contrasting phenomena (dramatic volume removaland frequent examination) may also explain why theconcept of “dry weight,” a cornerstone clinical operat-ing indicator in HD, is not widely used in the approachto volume management in PD. Patients on PD are rou-tinely instructed to measure their weight on a dailybasis. Guidelines on therapy modifications based onchanges in weight can be safely taught to mostpatients.