[Effect of hyperoxia on the oxyhemoglobin dissociation curve in various periods of aging]

Gas composition of the arterial and venous blood and the oxyhemoglobin dissociation curve were determined before and after 20 minutes of oxygen inhalation in 9 apparently healthy subjects aged 60 to 74 years and in 9 young subjects aged 19 to 32 years. In hyperoxia of younger subjects, there was a shift to the left of both the oxyhemoglobin dissociation curve of the native blood and standard dissociation curve (pH 7.4). In old age, the shift to the left of the standard dissociation curve due to hypoxia was quite negligible and statistically insignificant, whereas in the native blood it was entirely absent because of the increased blood PCO2 and associated Bohr effect.