The relationship between peritoneal glucose absorption and body fluid loss by ultrafiltration during continuous ambulatory peritoneal dialysis.

Eight continuous ambulatory peritoneal dialysis (CAPD) patients were studied during six consecutive days using dialysate with a different glucose concentration on each day. For all dialysate glucose concentrations ranging from 70 to 198 mmol/l, an inverse linear relationship was found between the percentage of absorbed glucose and the ultrafiltration rate. In each patient a linear correlation was demonstrated between the dialysate glucose concentration and the quantity of body fluid removed by ultrafiltration. Therefore the dialysate glucose concentration without net removal of fluid could be calculated for each patient: DGCUF = 0. This DGCUF = 0 is a parameter of the relationship between the transport of water and glucose over the peritoneal membrane and can thus be considered a marker of the individual ultrafiltration. The calculated DGCUF = 0 was compared with DGCUF = 0 predicted from the glucose absorption using the equation as derived from our data: DGCUF = 0 (mmol/l) = 2.1 X glucose absorption (%) -67 (mmol/l). As marked day to day variations were found, the results of these predicted DGCUF = 0 should be interpreted cautiously when used for long-term follow-up of peritoneal permeability in CAPD patients.