LUNG RESPIRATION REACTION AND ENERGY METABOLISM INTENSITY IN NOT ADAPTED TO HYPOXIA PEOPLE EXPOSED TO INCREASED HYPOXIA

Abstract

In 13 healthy, not adapted to hypoxia people, parameters of pulmonary gas exchange, heart rate and oxyhemoglobin saturation level of the arterial blood (SpO₂) during 15-minute breathing of hypoxic air mixture with 17, 15 and 13 vol.% O₂ were studied. The group analysis showed that hypoxia of 17 vol.% O₂ did not cause changes in lung ventilation, the intensity of energy metabolism and heart rate. SpO₂ corresponds to the lower limit of normal, which means the absence of hypoxemia and the significant reaction to hypoxic exposure. At hypoxia of 15 vol.% O₂ there is a further SpO₂ drop, a slight increase of oxygen consumption (VO₂) and the intensity of energy metabolism. Hypoxia (13 vol.%) causes a ventilatory response in the first 5 minutes of exposure, a minute respiratory volume increases by 38%, VO₂ oxygen intake grows by 18-25%, and CO₂ emissions increase by 20-33% compared to normoxia. There is a further blood oxygenation level decrease till 86.5%, it is lower than the normal range for a healthy person. An individual analysis showed that changes in pulmonary gas exchange parameters were observed in 90% of patients at 17 vol.% O₂. It was found out that in people with respiratory system functional disabilities hypoxic hypometabolism response takes the first place for more economical use of small respiratory reserves. This response was observed two times more frequently than in healthy people. The increase of the pulmonary ventilation efficiency is the response to hypoxia as it has lower power inputs than the increase in ventilation.