Mathematical modeling of the respiratory system in swine with acute respiratory distress syndrome.

Abstract- Objective: The objective of this study is to develop a low-order mathematical model of respiratory gas exchange for design and evaluation of physiological closed-loop controlled (PCLC) mechanical ventilation and oxygenation systems, particularly under acute respiratory distress syndrome (ARDS) conditions. APPROACH: Experimental data from 11 swine subjects undergoing ARDS followed by hemorrhage were used to derive the mathematical model. The animals were ventilated using a PCLC system that regulated inspired oxygen fraction (FiO2), positive end-expiratory pressure (PEEP), and other ventilation parameters. The mathematical model takes metabolic carbon dioxide production rate (V ̇CO2), FiO2, and PEEP as inputs and outputs end-tidal CO2 pressure (PetCO2), arterial oxygen pressure (PaO2), and oxygen saturation (SaO2). MAIN RESULTS: The mathematical model accurately reproduced observed gas exchange dynamics in ARDS conditions, effectively capturing O2 and CO2 behavior in response to the controlled ventilation parameters. SIGNIFICANCE: The present study focuses on mathematical model development and calibration using experimental data. The current results support its utility in simulating respiratory gas exchange under lung injury conditions. SIGNIFICANCE: This low-order mathematical model may offer a promising tool for evaluating and designing PCLC mechanical ventilation and oxygenation, with potential applications in controller development and its preclinical testing.