Intraperitoneal fluid fluxes analyzed according to the 'three-pore' model in individual patients on CAPD

Individual CAPD patients have markedly different characteristics of their peritoneal membranes, making it desirable to measure the transport rates of each individual in order to ensure adequate dialysis. An analytical tool has been developed based on the three-pore concept of microvascular exchange, whereby it is possible to differentiate among possible causes for disturbances in PD. A so-called loss of ultrafiltration during PD can result from two different causes. First, an increased total pore cross-sectional area available for diffusion (or A0/delta x) can cause increased transport of glucose to blood and hence diminish the osmotic gradient such that a net filtration turns to net reabsorption of fluid from the abdominal cavity to the blood. Secondly, fluid loss can be due to a high lymph flow (>> 0.3 ml/min/1.73 m2).