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Exchange_O2_CO2_HCO3_and_H

Four region, distributed model for the O2-CO2 transport, exchange and metabolism.

Model number: 0134

Description

  A detailed nonlinear four-region (red blood cell, plasma, interstitial fluid, and 
  parenchymal cell) axially distributed convection-diffusion-permeation-reaction-binding 
  computational model is developed to study the simultaneous transport and exchange of 
  oxygen (O2) and carbon dioxide (CO2) in the blood-tissue exchange system of an organ. 
  Since the pH variation in blood and tissue influences the transport and exchange of O2 
  and CO2 (Bohr and Haldane effects), and since most CO2 is transported as HCO3- (bicarbonate) 
  via the CO2 hydration (buffering) reaction, the transport and exchange of HCO3- and H+ are 
  also simulated along with that of O2 and CO2. Furthermore, the model accounts for the 
  competitive nonlinear binding of O2 and CO2 with the hemoglobin inside the red blood cells 
  (nonlinear O2-CO2 interactions, Bohr and Haldane effects), and myoglobin-facilitated transport 
  of O2 inside the parenchymal cells. The consumption of O2 through cytochrome-C oxidase reaction 
  inside the parenchymal cells is based on Michaelis-Menten kinetics. The corresponding 
  production of CO2 is determined by respiratory quotient (RQ), depending on the relative 
  consumption of carbohydrate, protein, and fat. The model gives a physiologically realistic 
  description of O2 transport and metabolism in the microcirculation of the organ. Furthermore, 
  because model solutions for tracer transients and steady states can be computed highly efficiently,
  this model may be the preferred vehicle for routine data analysis where repetitive solutions and 
  parameter optimization are required, as is the case in PET imaging for estimating myocardial O2 
  consumption.

Equations

    Dash, R.K. and Bassingwaighte, J.B., Simultaneous Blood-Tissue Exchange of Oxygen, Carbon Dioxide,
    Bicarbonate, and Hydrogen Ion, Ann Biomed Eng 34(7): 1129-1148 2006.