State Analysis of Total Stressed Blood Volume and Arterial Elastance During Induced Sepsis

Sepsis can cause major complications in the cardiovascular system. Accurate monitoring of model-based bio-markers, such as total stressed blood volume, SBV_T , have been shown to be important parameters in determining the effectiveness of fluid therapy in sepsis patients. Another such parameter is arterial elastance, E_a, which is a measure of the relative stiffness of arteries. This work investigates the effect of fluid therapy and induced sepsis on these parameters through a state average analysis and comparison to previously defined clinical references. A three chambered lumped cardiovascular system model was implemented to develop model based analogues of the two parameters in six porcine subjects. A mean state average increase of 20.9% in SBV_T was found in response to fluid therapy, while a mean state average decrease of 32.7% occurred, in surviving subjects, after sepsis was induced. E_a showed a mean state average drop of 12.2% during fluid therapy and an increase of 45% after sepsis is induced. Both results match hypothesised expectations.