Direct Measurement of In-Vitro Transport of Water and Peritoneal Dialysis Solution

Icodextrin is clinically employed as an osmotic agent in continuous ambulatory peritoneal dialysis (CAPD). However, the mechanism of water transport induced by this glucose polymer solution is yet to be completely elucidated. In this study, we performed a simple experiment to shade light on properties of high molecular weight icodextrin and low molecular weight dextrose as osmotic agents. The materials and methods used includes 10 ml cellophane bags containing a peritoneal dialysis solution were placed in a 200 ml container full of either water or blood plasma. The experiments are performed using cellophane bags with 3.5 kDa and 10kDa molecular weight cut-off.24-hour monitoring of water transport induced by 7.5 % icodextrin solution, and that induced by 1.5 % and 4.25 % dextrose solutions are compared. It is observed in the study that in a beaker containing water, mass of the cellophane bags containing 1.5 % and 4.5 % dextrose solutions increase up to 6.6 % and 10.7 % respectively within 24 hours. In blood plasma containers, the cellophane bags containing 1.5 % and 4.25 % dextrose solution exhibited mass loss, indicating an overall fluid flux flowing from the cellophane bag. In contrast, masses of cellophane bags containing 7.5 % icodextrin solution increase up to 30 %. Moreover, the constant slope of the averaged mass changes after the dwell time of 8 hours also indicated a constant incoming fluid flux. We may conclude that in plasma beaker, cellophane bags containing dextrose solution exhibit mass decrease and volume reduction. On the other hand, cellophane bags containing icodextrin solution exhibits mass increases regardless of whether the cellophane bags were suspended in water or blood plasma despite the similar osmolarity of blood plasma and icodextrin solution.