Optimization of Oxygen Delivery in Fluid Resuscitation for Hemorrhagic Shock: A Computer Simulation Study

The main objective of fluid resuscitation in hemorrhage induced hypovolemia is to increase oxygen delivery to vital organs and to restore other hemodynamic variables to acceptable physiological range. Since replacement of blood with fluid causes both increase in cardiac output and decrease in the plasma oxygen carrying unit concentration, there is an overall opposing effect on total oxygen delivery rate to tissue. Thus, optimal fluid infusion rate and volume may be expected. The purpose of this study was to study the temporal dynamics of oxygen delivery rate during fluid replacement in a controlled hemorrhage scenario and seek these optimal values. A hemodynamic model of the human adult cardiovascular system was developed to simulate and evaluate arterial oxygen delivery at normal and at hemorrhagic conditions in different fluid resuscitation regimes. The results demonstrated the existence of a unique optimal fluid replacement regimen for maximal oxygen delivery rate at different controlled bleeding scenarios. The maintenance of high oxygen delivery rate was better with lower fluid infusion rates. The model results indicate that hematocrit and mean arterial pressure can be used to determine the optimal infusion rate and fluid infusion endpoint in fluid resuscitation.