Muscle tissue oxygen pressures in healthy volunteers during acute exposure to hypoxia

Abstract

Tissue pO₂ values (tibial anterior muscle), oxygen saturation, transcutaneous pO₂, arterial p0₂, and rheological parameters were measured in 10 young (mean age 26,9 ± 0,9 years) as well as in 10 older (mean age 59,3 ± 5,9 years) apparently healthy volunteers during acute exposure to hypoxia according to a pressure altitude of approximately 8500 feet for 20 minutes. Hypoxia exposure was achieved by inspiration of an oxygen reduced gas mixture (116 mm Hg pO₂). Average arterial pO₂ and oxygen saturation decreased significantly in the young but not in the older volunteers. Tissue pO₂ values showed a marked and significant decrease in both groups (23.9 mm Hg to 12.8 mm Hg in the young and 20.8 mm Hg to 12.2 mm Hg in the older volunteers (medians)). Transcutaneous pO₂ values also decreased significantly in both groups. The studied hemorheological parameters did not change significantly. The data show, that even a short exposure to moderately elevated pressure altitudes leads to a marked decrease in tissue oxygen tensions in young as well as in older healthy persons.