Analysis of the body gas exchange indicators in high-altitude flight on the basis of the static model of the respiratory system

• Main Authors: Matyushev, T. V., Dvornikov, M. V., Ryzhenkov, S. P., Petrov, M. A.
• Format: Conference Proceeding
• Language: English
• Subjects: Algorithms; Alkalosis; Altitude; Atmospheric pressure; Blood; Carbon dioxide; Gas exchange; Gas mixtures; Gases; High altitude; Mathematical models; Oxygen consumption; Oxygenation; Parameters; Passenger aircraft; Pressure drop; Respiratory system; Static models
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0036005

The article presents an analysis of the dynamics of a person’s gas exchange in high-altitude flight based on a static model of the body’s respiratory system. The structure of the static model of the respiratory system and the algorithm for calculating the gas exchange of the body, based on the calculation formulas of high-altitude physiology, pathophysiology, are developed. The quantitative parameters that determine the nature of the relationship between the components of gas exchange are clarified. A computational experiment was conducted to simulate the rise to a height. Four sections were identified in the model: inhaled, exhaled, alveolar gas mixture and arterial blood. The stresses, concentrations, masses of gases, the degree of oxygenation and arterial blood pH were calculated. The calculation algorithm can be represented as follows. The volumes of minute and alveolar ventilation, O2 consumption, and CO2 emissions were determined, respectively, by formulas approximating experimental data. The results of the analysis of the calculations showed that when a person rises to a height with a drop in pressure, a change in tidal volumes occurs, the volume of the alveolar space decreases and the dead space increases in the ratio from 4.7 to 0.7. Analysis of the CO2 and pH values in arterial blood at the selected flight mode of the passenger plane and model parameters showed that compensated alkalosis is maintained up to a barometric pressure of 550 mm Hg, subcompensated alkalosis up to 450 mm Hg and with 450 mm Hg uncompensated alkalosis develops, leading to a violation of the acid-base reactions of the body. Therefore, despite the fact that the level of O2 saturation in the alveolar mixture maintains the value of O2 in the arterial blood at a high level, the resulting disturbances lead to uncompensated respiratory alkalosis, which causes a shift of the oxymyoglobin dissociation curve to the left.