Figure 1

Model overview: (A) the model structure to map the hemorrhage and fluid infusion inputs to the heart rate response. The model consists of three parts. The first part maps the transient change in the heart rate due to hemorrhage, the second part maps the transient change in the heart rate due to fluid infusion, and the last part maps the long-term changes due to hemorrhage. (B) This illustrates how the model maps the transient changes in the heart rate due to hemorrhage and fluid infusion. (C) This shows the time-varying long-term target for the heart rate rise due to hemorrhage. (D), (E) This illustrates the control-oriented approach to modeling the long-term changes in the heart rate due to hemorrhage.