Clearance, distribution volume, and dialyzer mass area transport coefficient of glucose in whole blood

The extracorporeal transport of glucose was studied to determine the dialyzer mass transfer coefficient K(0)A for glucose in whole blood under conditions of glucose delivery and glucose removal. Glucose was removed from blood or delivered to blood using glucose-free dialysate or dialysate with a glucose concentration of 200 mg/dl (11.1 mmol/L). FX8 dialyzers (Fresenius Medical Care, Bad Homburg, Germany) were studied at constant dialysate flow Q(d) (500 ml/min) and variable blood flows Q(b) (200, 300, and 400 ml/min) under countercurrent flow conditions in a series of laboratory bench studies. Glucose clearance K(d) and glucose distribution volume flow rate Q(e) were determined from glucose mass balance. In 32 studies done with bovine blood at different hematocrit levels glucose was calculated to distribute in plasma water and to be excluded from red cell water when passing the FX8 dialyzer. The dialyzer mass transfer area coefficient K(0)A for glucose computed from Q(e), Q(d), and K(d) was 301.6 ± 45.2 ml/min and not different between modes of glucose delivery or glucose removal but lower than expected from the diffusivity of glucose estimated for aqueous solutions.