Patent ID: 6842635

Claim:
A method for monitoring oxygenation of blood comprising the steps of: determining a first reference spectrum over a plurality of wavelengths; determining a second reference spectrum over the plurality of wavelengths; transmitting light containing the plurality of wavelengths into blood; measuring a remitted spectrum over the plurality of wavelengths; calculating a measured blood absorption spectrum as a function of the remitted spectrum, the first reference spectrum and the second reference spectrum; and, removing effects of light scattering from the measured blood absorption spectrum by a removing effects method comprising the steps of: calculating a correction function that is a function of a plurality of isobestic points of the measured blood absorption spectrum; correcting the measured blood absorption spectrum by the correction function; normalizing the measured blood absorption spectrum following the correcting step; calculating an optimal spectrum as a function of a substantially oxygenated reference absorption spectrum and a substantially deoxygenated reference absorption spectrum, so that the optimal spectrum best matches the measured blood absorption spectrum in a determined sense; and, calculating an estimate of SO 2 as a function of the optimal spectrum.