Skeletal muscle oxygenation monitoring by near infrared spectroscopy.

The oxygenation of human forearm muscle tissue was studied using an optic fiber fast scanning spectrophotometer. We investigated near infrared (700-1100 nm) hemoglobin (Hb) and myoglobin (Mb) spectral changes in flow and/or oxygen-limited conditions. The superimposition of deoxy Hb and deoxy Mb spectra was confirmed "in vivo" on perfluorocarbon-blood exchanged transfused rats. Oxygenation changes were evaluated in 15 volunteers during 10 min forearm arterial occlusion. Rapid desaturation occurred until a plateau was reached after about 4 min, suggesting rapid anaerobic glycolytic activation.