Patent ID: 7248909

Claim:
A method of monitoring methemoglobinemia in a subject comprising the steps of: providing a broadband diffuse optical spectroscopy device, the device having a first light source emitting light at a plurality of wavelengths and second light source comprising a broadband light source, first and second source optical fibers optically coupled, respectively, to the first and second light sources, first and second detector optical fibers optically coupled, respectively, to a detector and a spectrometer, the broadband diffuse optical spectroscopy device including a probe that is configured for placement adjacent to the subject's skin; radiating the subject with light from the first light source; detecting intensity-modulated diffuse reflectance signals using the detector; determining absorption and reduced scattering coefficients at each wavelength of the first light source; radiating the subject with radiation from the second light source; acquiring broadband reflectance measurements using the spectrometer; determining absolute reflectance spectra based on the broadband reflectance measurements and the absorption and reduced scattering coefficients; calculating μ a spectra from the absolute reflectance spectra; and determining the concentration of methemoglobin, deoxyhemoglobin, and oxyhemoglobin, based on wavelength-dependent extinction coefficient spectra; calculating a percentage of methemoglobin based on the formula [MetHb]/([Hb-O 2 ]+[Hb-R]+[MetHb]); and displaying the percentage of methemoglobin on a computer display connected to the broadband diffuse optical spectroscopy device.