CLINICAL PATHOPHYSIOLOGICAL STUDIES ON AGE DIFFERENCE OF RESPIRATORY REGULATION IN LOW OXYGEN INHALATION

Abstract

A. Age Difference in Arterial Blood Oxygen Saturation During a Period of Low Oxygen Air Respiration Attention has been called upon the fact that the degree of arterial blood oxygen saturation which serves as a criteria in the estimation of low oxygen air respiration may vary depending upon a number of conditions regardless of the same low oxygen air inspired. Considering this fact, the author has attempted to investigate this by statistically studying the data of arterial blood oxygen saturation during low oxygen air breathing. Method ; Estimation of arterial blood oxygen saturation (SaO2) during a period of 10% oxygen inhalation in various age groups composed of 46 healthy individuals were tabulated. SaO2 values were also, studied on another group of 20 healthy young adults during 10 ± 0.5% oxygen inhalation by venous catheterization. Results : (1) Without Venous Catheterization In the study of age relationship with the SaO2 values of 46 cases during 10 ± 0.5% low oxygen air inhalation without resorting to venous catheterization, a significant negative correlation, r=-0.66 (p <0.01), was obtained. The values of arterial oxygen saturation of respective age group were as follows : Young adult group (ages 20-39, 16 cases, average age 27.4) 74.0-5.4 per cent. Middle age group (ages 40-59, 11 cases, average age 50.4) 65.4 ± 7.1 per cent. Old age group (ages 60-78, 19 cases, average age 68.8) 63.6 ± 5.1 per cent showing a low value. (2) With Venous Catheterization The healthy young adults (ages 21-38, 20 cases, average 30.8) were studied under the same low oxygen inhalation with venous catheterization. The SaO2 value was found to be 62.6 ± 7.9 per cent, a definitely lower value when compared with that (74.0 ± 5.4 per cent ) of the none catheterized young adults. From the foregoing results, it was found that in the old age persons without venous catheterization, the SaO2 reduction was more marked than that of the young adults without catheterization and just comparable to that of the latter with catheterization.