[Effect of hyperoxia on indices of external respiration, cardiovascular system and blood gas composition]

In eight healthy male test subjects, aged 19-32, pulmonary ventilation, oxygen consumption, partial pressure of oxygen and carbon dioxide in the alveolar air, arterial and venous blood, ECG, arterial pressure and skin microcirculation were measured during 20 min inhalation of 70% oxygen. In hyperoxic subjects cardiac output remained unaltered, respiration rate decreased, respiration volume increased, alveolar-arterial and arterio-venous difference of PO2 increased, the difference between the actual and expected Q-T slightly decreased, capillary cirulation changed indicating a spactic reaction of peripheral vessels. At the same time oxygen consumption, ventilation equivalent, coefficient of oxygen utilization, partial pressure of carbon dioxide in the alveolar air, arterial and venous blood, heart rate, maximum arterial pressure remained essentially unchanged.