Synchronized External Pulsation for Improved Tolerance to Acceleration Stress: Model Studies and Preliminary Experiments

Moore, Thomas W.; Jaron, Dov; Chu, Chia-Lin; Dinnar, Uri; Hrebien, Leonid; White, Michael; Hendler, Edwin; Dubin, Stephen

doi:10.1109/tbme.1985.325437

Cited by 4 publications

(1 citation statement)

References 21 publications

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“…The resulting model of resistance ( R n ) and compliance ( C n ) of the n th segment can be expressed as: where l n , r n , h n , and Y n are the length, radius, wall thickness, and Young ' s modulus of the nth segment, respectively. Blood viscosity is represented by m ( 27 ).…”

Section: Cardiovascular Model Descriptionmentioning

confidence: 99%

Role of Carotid Baroreflex and Sympathetic Responses in the Push-Pull Effect: A Simulation Study

Liu

Zhang²,

Zhang³

et al. 2012

Aviation, Space, and Environmental Medicine

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The simulation results support that the carotid baroreflex and sympathetic responses might have little specific influences on the PPE. It also suggests that the limited range of G alteration and transition rate should be considered when using tilting experiments to investigate sympathetic response to PPE. The limitation of the present model due to the lack of sufficient data on the contribution of different peripheral vascular beds and their myogenic response is discussed.

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Section: Cardiovascular Model Descriptionmentioning

confidence: 99%

Role of Carotid Baroreflex and Sympathetic Responses in the Push-Pull Effect: A Simulation Study

Liu

Zhang²,

Zhang³

et al. 2012

Aviation, Space, and Environmental Medicine

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Incorporating vessel taper and compliance properties in Navier-Stokes based blood flow models

Moore

Jaron

1993

Ann Biomed Eng

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A popular and useful technique used to model blood flow in cardiovascular simulations is to divide each blood vessel into a series of segments, each with its own lumped resistance, inertance, and compliance parameters. The values of these parameters are usually obtained through a simplification of the Navier-Stokes equations for fluid flow. However, the simplification often ignores the nonlinear and convective terms of the equations, resulting in errors in the parameter values, especially in the value found for resistance per unit length. We report a new method for the calculation of vessel resistance per unit length which takes into account the effects of vessel taper and wall compliance. It is shown that these effects can be addressed by the addition of two time-varying terms to the calculation of resistance per unit length. One term, due to vessel taper, is proportional to volumetric flow rate Q. The other term, due to vessel compliance, is proportional to delta p/delta t. These variables are readily available in computer simulations of blood flow in lumped parameter systems. Using data for the descending aorta, the new parameter values, when averaged over a cardiac cycle, compare favorably with results in the literature.

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Modeling the circulation with three-terminal electrical networks containing special nonlinear capacitors

et al. 1992

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Development, first of analog and later of digital computers, as well as algorithms for analysis of electrical circuits, stimulated the use of electrical circuits for modeling the circulation. The networks used as building blocks for electrical models can provide accurate representation of the hydrodynamic equations relating the inflow and outflow of individual segments of the circulation. These networks, however, can contain connections in which voltages and currents have no analogues in the circulation. Problems arise because (a) electrical current must flow in closed loops, whereas no such constraints exist for hydraulic models; and (b) electrical capacitors have a number of characteristics that are not analogous to those of hydraulic compliant chambers. Disregarding these differences can lead to erroneous results and misinterpretation of phenomena. To ensure against these errors, we introduce an imaginary electrical element, the nonlinear residual-charge capacitor (NRCC), with characteristics equivalent to those of a compliant chamber. If one uses appropriate circuit connections and incorporates the residual-charge capacitor, then all voltages and currents in the model are proper analogues of pressures and flows in the circulation. It is shown that the capacitive current represents the rate of change of volume of blood inside the vessel, as well as the rate of the corresponding displacement of volume of the surrounding tissue.

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Synchronized External Pulsation for Improved Tolerance to Acceleration Stress: Model Studies and Preliminary Experiments

Cited by 4 publications

References 21 publications

Role of Carotid Baroreflex and Sympathetic Responses in the Push-Pull Effect: A Simulation Study

Role of Carotid Baroreflex and Sympathetic Responses in the Push-Pull Effect: A Simulation Study

Incorporating vessel taper and compliance properties in Navier-Stokes based blood flow models

Modeling the circulation with three-terminal electrical networks containing special nonlinear capacitors

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