Mathematical Model for the Study of Hemorrhagic Shock and Fluid Resuscitation:Transcapillary Exchange

摘要

Mathematical models used to predict plasma volume responses to hemorrhage andfluid resuscitation must consider both fluid and solute exchange across the capillary wall. In this paper, we review four models of transcapillary exchange that might be incorporated into a compartmental model for plasma volume prediction. The simplest of the four transcapillary flux models, attributed to Kedem and Katchalsky (1958), assumes a discrete capillary wall structure, ideal solutions, and capillary wall homogeneity. The remaining models become progressively more complex by successive elimination of these three assumptions. To assess their effects on whole-body plasma volume predictions, the four models of transcapillary exchange were incorporated into a simple two-compartment (blood and interstitial space) model. Next, plasma volume predictions were generated for the following simulation conditions: instantaneous 25% loss of blood volume, instantaneous 50% increase in plasma NaCl concentration, instantaneous 50% increase in plasma albumin concentration, and instantaneous 25% loss of blood volume with a 50% increase in plasma NaCl concentration. Plasma volume predictions, generated by the four models, were indistinguishable over these simulation conditions. From these results, we conclude that the simplest of the transcapillary flux models may be used for predicting plasma volume responses to hemorrhage and resuscitative fluid administration.... Model, Hemorrhage, Fluid resuscitation, Transcapillary exchange.