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Digital Computer Simulation of Cardiovascular System in Bleeding Patient for Clinical Management

  • Yasuhiro Fukui
  • Toru Masuzawa
  • Makoto Ozaki
  • N. Ty. Smith
Conference paper

Abstract

A cardiovascular system model that simulates interactive responses to drugs has been developed on a small digital computer to realize virtual reality. The overall model basically consists of three models. The first is a momentum transport model that represents relations between blood pressure and flow in the cardiovascular system. In this model, the cardiovascular system is divided into Twelve components and modeled by using equivalent electrical circuits. The second is a mass transport model comprising twelve compartments corresponding to the respective components of the cardiovascular system. This model represents the distribution of the administered drug in the various cardiovascular components. The third is an interaction model that represents the relations between the momentum and mass transport models. This model causes variations in the resistance and capacitance parameters of the momentum transport model as a function of the current drug concentrations in the appropriate compartments of the mass transport model. The capacitances representing the ventricles are varied in a time- dependent fashion to simulate the beat of the heart. Simulation is performed by using the Euler method to solve a system of 24 ordinary differential equations governing the momentum and mass transport models on a 32-bit micro computer, a Macintosh IIfx.

The model was assessed by performing a demonstration of the cardiovascular response to the dopamine during hemorrhage. The effect of hemorrhage upon to the cardiovascular system is added to the models as hemorrhagic model. The hemorrhagic model affects the momentum transport model by reducing total blood volume and changing the peripheral resistance, compliance, heart contractility and rate. Hemorrhage model reduces total blood volume, cardiac output, mean arterial pressure, central venous pressure, coronary flow, cerebral flow, renal flow and other ogans’ flow by 28 %, 49%, 43%, 58%, 15%, 16%, 65% and 53% respectively and increases heart rate and systemic vascular resistance by 53 % and 14% of each value in normal cardiovascular condition.

The effect of dopamine upon the cardiovascular system is incorporated into the interaction model. Administration of dopamine as a constant infusion (10 μg/kg/min.) during hemorrhagic hypotension results in the increase of cardiac output, mean arterial pressure, central venous pressure, coronary flow, cerebral flow, renal flow, and other ogans’ flow by 11 %, 16%, 6%, 6%, 7%, 24% and 8% of each value in normal cardiovascular condition from hemorrhagic level respectively.

Simulated hemodynamics during hemorrhage and dopamine infusion was similar to real hemodynamics. We believe that it will become possible to estimate the hemodynamics of dopamine administered to the bleeding patient before actual administration of the drug by adding parameter estimation to match the model to a real patient. Also, The simulation is very useful to educate medical students for hemodynamics.

Keywords

Equivalent Electrical Circuit Total Blood Volume Mass Transport Model Heart Contractility Cerebral Flow 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Tokyo 1992

Authors and Affiliations

  • Yasuhiro Fukui
    • 1
  • Toru Masuzawa
    • 2
  • Makoto Ozaki
    • 3
  • N. Ty. Smith
    • 4
  1. 1.Dept. of Applied Elect. Eng., Faculty of Sci. and EngTokyo Denki UnivHiki-gun, SaitamaJapan
  2. 2.Dept. of Artifical Organ, Research InstituteNational Cardiovascular CenterSuita, OsakaJapan
  3. 3.Dept. of AnesthesiologyTokyo Woman’s Medical CollegeShinjuku-ku, TokyoJapan
  4. 4.Dept. of AnesthesiaUniversity of California San Diego and U.S.V.A. Medical CenterUSA

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