Tissue oxygen saturation is non-invasively measured using near-infrared spectroscopy, by two device, INVOS®(somanetics Corporation, USA ) and InSpectra™ (Hutchinson Technology, USA). InSpectra™ was introduced later than INVOS®.~With InSpectra™, clinicians have used a vascular occlusion test (VOT) to evaluate dynamic changes in tissue oxygen saturation during ischemia and reperfusion, and thus, microcirculatory function. There have been little data about VOT using INVOS®, although it is more popular device.~We hypothesized that there would be a difference between the values from INVOS® and InSpectra™. The aim of this study is to evaluate changes in tissue oxygen saturation in the thenar muscle during VOT using INVOS® and comapre it to InSpectra™ in a normal population.
Tissue oxygen saturation is non-invasively measured using near-infrared spectroscopy, by two device, INVOS®(somanetics Corporation, USA ) and InSpectra™ (Hutchinson Technology, USA). Each probes are attached to both thenar muscles and vascular occlusion test (VOT) is performed. The investigators will compare the Invos® data to InSpectra™ to investigate whether tissue oxygen saturation values by INVOS® can substitute for InSpectra™.