IMPACT OF INCREASING DIALYSIS VOLUME ON ADEQUACY TARGETS - A PROSPECTIVE-STUDY

Failure to achieve target values for both urea (Kt/V) and creatinine c learance has been associated with increased morbidity and mortality in continuous ambulatory peritoneal dialysis patients. The conventional continuous ambulatory peritoneal dialysis regimen, which uses four 2-L exchanges per day, has resulted in up to 40% of such patients failing to achieve proposed targets for weekly Kt/V of 1.7 and weekly creatin ine clearance (WCC) of 50 L. In a prospective study, the impact of inc reasing prescribed volumes by 0.5 L per exchange was evaluated on atta ining urea and creatinine clearance targets over a l-yr period. At 1 y r, 17 patients remaining on the increased dialysis prescription were c ompared with 18 patients remaining on an unchanged regimen. The mean i ncrease in daily prescribed volume was 1.5 L (22%). This resulted in a significant increase in both peritoneal dialysis Kt/V (1.59 to 1.78 L = 12%) and peritoneal dialysis WCC (45.8 to 50.1 L = 10%) by 1 yr. Be cause of loss of renal function, there was no significant increase in total clearance at 1 yr, but this loss of renal clearance was offset b y the gain in peritoneal clearance. Residual renal function fell at a similar rate in both the increased dialysis and control groups. In the latter, although peritoneal clearance remained stable over the l-yr p eriod, loss of renal function resulted in reductions in both total Kt/ V and WCC. In conclusion, exchange volume can be increased to compensa te for loss of renal function over a l-yr period. Progressive loss of renal clearance resulted in only a modest gain in total solute clearan ce. It was the larger patients who tolerated the increase in exchange volumes. However, such patients (by virtue of their size) tended not t o achieve target values for solute clearance, and the modest gain in p eritoneal clearance was insufficient to increase the number of patient s in this group achieving such targets for dialysis adequacy.