Effects of Breath-Holding Tests on PetCO2 and Arterial Blood Oxygenation in Men

To evaluate the state of external respiration system, breath-holding tests are usually used. However, there are few studies of the peculiarities of the gas exchange in breath-holding with previous hyperventilation. The purpose of the study was to analyze the dynamics of changes in the PetCO2 level and arterial blood oxygenation during breath-holding tests with and without previous hyperventilation in healthy young men. Materials and methods. The СО2 level was recorded in the side stream on the Datex Normocap capnograph (Datex, Finland). This value was recorded for 5 minutes at rest, 5 minutes after half-breath hold, for 5 minutes of regulated breathing with a frequency of 30 cycles per minute, 5 minutes after half-breath hold. The capnogram, atmospheric pressure level and humidity were used to assess the level of СО2 at the end of exhalation (PetCO2), respiratory rate, the ratio of inspiratory duration to expiratory duration (Rie). Statistical processing of the results was performed by parametric methods. According to the method of sigmoid deviation, three groups of individuals were distinguished by the PetCO2 level: I – PetCO2 < 32.7 mmHg, II – PetCO2 – 32.7-36.2 mmHg, III – PetCO2 > 36.2 mmHg. Results and discussion. Breath-holding during the test after hyperventilation was significantly greater than in the first attempt (62.99±3.31 s and 33.78±2.24 s, p