New instrument to measure oxygen saturation and total hemoglobin volume in local skin by near-infrared spectroscopy

Most conventional instruments to measure oxygen saturation and total hemoglobin volume were solely based on analysis of relative changes in oxygenated hemoglobin, deoxygenated hemoglobin and their total. To test the validity of the data obtained with this instrument, the authors analyzed the relationship of oxygen saturation in blood flowing through small vessels in skin (StO₂) to arterial blood oxygen saturation (SaO₂), oxygen saturation in venous blood (SvO₂) in the hypobaric chamber. The analyses revealed that StO₂ has a significant positive correlation with SaO₂ (r=0.846, P<0.001) and SvO₂ (r=0.983, P<0.001). These results suggest that StO₂ measured with this instrument reflects oxygen saturation in blood flowing through small vessels of skin