Muscle oxygenation by fast near infrared spectrophotometry (NIRS) in ischemic forearm

Fast scanning near infrared spectroscopy (680-1050nm) was utilized to evaluate human forearm muscle oxygenation in 15 adults volunteers. Spectra were recorded in hypoxic hypoxia, ischemia and venous outflow restriction. Derivative spectra were performed with the aim to obtain a quantitative information of Hb/Mb oxygen saturation free from volume and scattering changes. The absorption spectra O.D. demonstrate an increase of deoxy-Hb/Mb in hypoxic condition with a moderate volume changes. In ischemia a rapid Hb/Mb desaturation occurred until a plateau was reached at 4th min. The cuff release was followed by hyperemia with Hb volume raise and oxy-Hb/Mb increase above the control. Spectral data support the hypothesis that derivative NIRS can be used to identify muscle oxygenation changes.