Whole body transvascular filtration coefficient and interstitial space capacitance

Infusion experiments with Ringer's solution were performed on 5 splenectomized dogs with continuous monitoring of blood volume and hematocrit. The plasma volume was calculated from these data and followed during the infusion and also during the recovery period. Applying electrical equivalent simulation analysis to the result of the plasma volume, the capacitance of the interstitial fluid space and the transvascular filtration coefficient of water in the whole body were determined simultaneously. The mean values of the capacitance and the coefficient were 5.91 ml/kg-mmHg and 0.314 ml/min-kg-mmHg, respectively. From this simulation study, a transfer function which predicts the fluid shift between the vascular system and the interstitial fluid space was also derived. Using the transfer function, predictions of the changes in plasma volume are possible from any given rate of infusion.