Table 2.
Model parameters.
| Parameter | Units | Meaning |
|---|---|---|
| t 0 | min | Starting time for numerical integration |
| t end | min | Final time for numerical integration |
| t delta | min | Time integration step |
| t bleedstart | min | Starting time of hemorrhage |
| t bleedend | min | End time of hemorrhage |
| k VED0 | L | Ventricular volume end-diastolic at zero filling pressure |
| P 0LV | mmHg | Passive empirical ventricular pressure |
| k ELV | /L | Constant characterizing the passive empirical pressure/volume relationship |
| R valve | mmHg · min · L−1 | Hydraulic resistance opposing ventricular filling |
| C A | L · mmHg−1 | Compliance of arterial compartment |
| C V | L · mmHg−1 | Compliance of venous compartment |
| V Aun | L | Arterial unstressed volume at which the pressure induced by wall tension is 0 mmHg |
| ν cut | /min | First-order low-pass cut-off frequency (determining the time constant of the baroreflex response) |
| S sat | mmHg | Deviation from set point in mmHg where SNA reaches 99% saturation either way (determining the shape and maximal slope of the logistic baroreflex nonlinearity) |
| P Aset | mmHg | Set point for baroreflex regulation of mean arterial pressure |
| V total | L | Total blood volume |
| F withdrawal | L | External blood withdrawal from the venous compartment |
| ν HRmin | /min | Heart rate minimum value |
| ν HRmax | /min | Heart rate maximum value |
| C PRSWmin | mmHg | Preload recruitable stroke work minimum value |
| C PRSWmax | mmHg | Preload recruitable stroke work maximum value |
| R TPRmin | mmHg · min · L−1 | Total peripheral/systemic vascular hydraulic resistance minimum value |
| R TPRmax | mmHg · min · L−1 | Total peripheral/systemic vascular hydraulic resistance maximum value |
| V VunMin | L | Venous unstressed volume at which the pressure induced by wall tension is 0 mmHg minimum value |
| V VunMax | L | Venous unstressed volume at which the pressure induced by wall tension is 0 mmHg maximum value |
| S F | # | Flag: -1 for closed loop; open reflex otherwise |
| k Vcap | L/min/mmHg | Rate of transcapillary refill per mmHg of difference between venous and interstitial pressure |
| V Vun0min | L | Venous unstressed volume at which the pressure induced by wall tension is 0 mmHg minimum initial value |
| V Vun0max | L | Venous unstressed volume at which the pressure induced by wall tension is 0 mmHg maximum initial value |
| P A0 | mmHg | Arterial pressure initial value |
| S 0 | # | Sympathetic nervous activity initial value |
| S E0 | # | Stimulating output from baroreflex central processing initial value |
| V A0 | L | Arterial volume at Tzero |
| V V0 | L | Venous volume at Tzero |
| V Vun0 | L | Venous unstressed volume at which the pressure induced by wall tension is 0 mmHg initial value |
| P CVP0 | mmHg | Pressure in the central vein initial value |
| ν HR0max | /min | Maximum initial value for heart rate |
| t Syst | min | Duration of systole (ventricular contraction period of the cardiac cycle) |
| ν HR0 | /min | Initial value for heart rate |
| t Diast0 | min | Duration of diastole, endpoint of filling initial value |
| C PRSW0 | mmHg | Preload recruitable stroke work initial value |
| R TPR0 | mmHg · min · L−1 | Total peripheral/systemic vascular hydraulic resistance initial value |
| I C0 | L · min−1 | Arterio-venous capillary blood flow initial value |
| I CO0 | L · min−1 | Veno-arterial flow (cardiac output) initial value |
| V ES0 | L | End-systolic ventricular volume initial value |
| V ED0 | L | End-diastolic ventricular volume initial value |
| L | End-systolic ventricular volume tilde initial value | |
| L | End-diastolic ventricular volume tilde initial value | |
| P ED0 | mmHg | End-diastolic ventricular pressure initial value |
| P ES0 | mmHg | End-systolic ventricular pressure initial |
| I bleed0 | L · min−1 | External blood withdrawal from the venous compartment initial value |
| I refill0 | L/min | Transcapillary refilling rate initial |