A comprehensive simulator of the human respiratory system: validation with experimental and simulated data

Area of Science:

• Physiology
• Computational Biology
• Respiratory System Modeling

Background:

• Understanding gas exchange and transport is crucial for respiratory physiology.
• Existing models often simplify complex interactions of oxygen and carbon dioxide regulation.
• Accurate modeling requires integrating multiple physiological factors.

Purpose of the Study:

• To develop and evaluate a comprehensive human model for oxygen (O2) and carbon dioxide (CO2) exchange, transport, and storage.
• To assess the model's ability to simulate realistic physiological responses under varying conditions.
• To provide a unified theoretical framework for respiratory control phenomena.

Main Methods:

• Developed a three-compartment model (lung, body tissue, brain tissue).
• Incorporated a controller for dynamic adjustment of alveolar ventilation and cardiac output based on chemoreceptor input.
• Included a novel CO2 dissociation curve, buffer base, nonlinear chemoreceptor interactions, pulmonary shunt, dead space, time delays, and Bohr/Haldane effects.

Main Results:

• Model simulations align with experimental dynamic and steady-state responses to hypercapnia and hypoxia.
• The model accurately predicts ventilation and gas partial pressures across a wide range of gas intake fractions.
• Blood CO2, HCO3-, and hydrogen ion concentrations match results from more complex simulators.

Conclusions:

• The proposed model offers a realistic and comprehensive framework for studying human respiratory gas exchange and control.
• It effectively integrates key physiological factors influencing O2 and CO2 homeostasis.
• The model's accuracy supports its utility in respiratory physiology research and simulation.