MEASUREMENTS OF PLASMA COLLOID OSMOTIC-PRESSURE, TOTAL PROTEIN AND SODIUM CONCENTRATION DURING HEMODIALYSIS - CAN SINGLE-POOL SODIUM MODELING EXPLAIN THE RESULTS

Considering the plasma colloid osmotic pressure (COP) as a possible parameter for the monitoring of dialysis treatment compatibility, a characteristic time course was found. The COP and thetotal protein concentration very often do not increase significantly during the first treatment hour in spite of ultrafiltration. An increase in the plasma sodium concentration, which was higher than expected, was found to be the reason for a plasma dilution effect. This can be explained by a transcapillary sodium transfer coefficient which is not infinitely high as assumed in single-pool sodium modelling. From a 2-pool model considering the plasma volume as a separate pool and including capillary filtration time courses for plasma sodium, total protein concentration and COP could be calculated, which was very similar to the measured curves. © 1990 S. Karger AG, Basel.