The effect of oxygen administration on gas exchange and cardiopulmonary function in normal subjects

Abstract

The effects of six different inspired oxygen concentrations on arterial (14 subjects) and mixed venous (8 subjects) pH, P CO 2 and P O 2 were measured. In all 14 subjects, o, CO 2 , minute ventilation, mean arterial blood pressure and heart rate were measured at each inspired concentration. Inspired O 2 concentrations between 21 and 40% produced a linear increase in arterial oxygen pressure and content and a progressive small rise in mixed venous oxygen content, with only minimal increase in mixed venous O 2 pressure and without change in O 2 , pH, P CO 2 , ventilation or cardiac output. With 100% O 2 the further rise in arterial P O 2 was accompanied by a significant increase in mixed venous oxygen pressure. The ventilation increased slightly; there was no change in cardiac output or acid-base balance.