[Standard values and normal limits for arterial blood gases in healthy elderly Japanese subjects].
We studied the standard values and normal limits for arterial blood gases in healthy elderly Japanese subjects. The criteria for inclusion were; 1) older than 60 years and able to walk independently, 2) non-smoker, 3) no respiratory symptoms, 4) no thoracic deformity, 5) no clinical signs of chest disease, 6) no abnormal findings in chest X ray, and 7) no cardiac disease or obesity. The number of subjects was 78. The oldest subject was a 96-year-old female. Arterial punctures were performed with the subjects in a recumbent position. PaO2 ranged from 79 to 106 Torr, with a mean value of 89.8 Torr. PaCO2 ranged from 32 to 48 Torr with a mean value of 39.6 Torr. Maximum values of alveolar-arterial O2 tension difference and arterial-alveolar N2 tension difference were 20.2 Torr and 11.6 Torr, respectively. The regression equation for PaO2 with respect to age was; PaO2 = 99.32-0.126 x (age), and its residual standard deviation was 6.06 Torr. These values were not different from those obtained in healthy young Japanese subjects.