The impact of peritoneal permeability and residual renal function on PD prescription

Our objective was to evaluate the impact of peritoneal transport characteristics and residual renal function on peritoneal clearance and to determine the dialysis volume required to achieve targets for KT/V and weekly creatinine clearance (WCC) in patients with differing weights, renal function, and transport status. Retrospective analysis and mathematical model simulation of urea and creatinine clearance were used. This review demonstrates the important contribution of both residual renal function and peritoneal transport in attaining target values for KT/V and WCC. The limitations of a standard 4 x 2 L dialysis prescription are highlighted in anuric patients and those with low peritoneal transport. In addition, the limitations of short dwell, rapid exchange dialysis modalities are emphasized, especially in patients with low and low average peritoneal transport where daily clearance is demonstrated to be considerably less than conventional continuous ambulatory peritoneal dialysis (CAPD). Attainment of proposed targets for KT/V (1.7) and WCC (50 L) is greatly dependent on residual renal function. In CAPD, peritoneal transport characteristics determine urea clearance through an effect on ultrafiltrate. Thus low transporters of identical weight will have greater values for peritoneal dialysis KT/V. Creatinine clearance is considerably influenced by transport status. The majority of low and low average groups will need some degree of renal function to achieve currently proposed targets. In these patients, conversion to high volume, short dwell modalities will further compromise small solute clearance unless daytime long dwells or tidal dialysis is instigated.