Gas Composition of Alveolar Air and Tolerability of Personal Respiratory Protection Equipment

Abstract

Introduction. When using personal protective equipment for respiratory organs of an insulating type in case of depletion of a regenerative cartridge, hypoxic-hypercapnic changes in the gas composition of the body occur, which have a negative effect on the tolerance of personal protective equipment for respiratory organs. The combination of additional respiratory resistance with hypoxia and hypercapnia further worsens the tolerance of respiratory protective equipment. The purpose of this study was to study the tolerance of personal respiratory protection when changing the gas composition of the alveolar air. Material and methods. The study was conducted on healthy subjects of both sexes (78 people), aged 20 to 36 years. To simulate the conditions for the use of personal respiratory protective equipment, inspiratory resistive respiratory loads of 20% of the maximum intraoral pressure were used during the Mueller test. The tolerance of respiratory protective equipment was evaluated using the Borg visual analog scale of dyspnea, which reflected the level of subjective discomfort occurring due to additional respiratory resistance is turned on. The methodology for changing the gas composition of the alveolar air in the subjects consisted of using a system that allowed adding oxygen from the line to the closed spirograph circuit and turning the carbon dioxide adsorber on and off. Results. The tolerance of personal respiratory protection is associated with the nature of the gas composition of the alveolar air. A minimum of subjective discomfort was observed in the presence of hyperoxic-hypocapnic composition of the pulmonary air; on the contrary, an increase in subjective discomfort on the Borg scale was observed with a reduced oxygen content and an increased concentration of carbon dioxide. The use of personal respiratory protective equipment against the background of hypoxia-hypercapnia negatively changes the functional state of the body: there was observed an increase in physiological expenditures by leading effectors. Normalization of the gas composition of the body under the use of personal respiratory protection did not lead to complete optimization of the functional state of the subjects. Conclusion. Hypoxia and hypercapnia arising from the depletion of regenerative cartridges of the respiratory protective equipment of an insulating type leads to a significant deterioration in the tolerance to additional respiratory resistance. The alleged mechanism of this phenomenon should be considered as an increase in fatigue of the respiratory muscles.