Method for measuring venous oxygen saturation

A method for measuring a venous oxygen saturation comprising the steps of:

• illuminating an area of tissue of a subject with intensity modulated light in the visible and near infrared spectral range at at least two wavelengths on a common side of said area of tissue;
• sensing diffusely reflected light caused by said illumination to acquire time resolved measurement data for each of said at least two wavelengths;
• and
• processing said time resolved measurement data at each of said at least two wavelengths to determine the absolute saturation of the venous compartment, said processing comprising determining a reduced scattering coefficient and an oscillation absorption coefficient, quantifying an amplitude of respiration induced absorption oscillations using said reduced scattering coefficient and said oscillation absorption coefficient and using one of either a Fourier transformation or a band pass filter, and fitting said amplitude of respiration induced absorption oscillations with a linear combination of extinction spectra of oxygenated and deoxygenated hemoglobin.

A method for measuring the venous oxygen saturation comprising the steps of:

• illuminating an area of tissue with a probe generating intensity modulated light at a plurality of wavelengths;
• sensing diffusely reflected light caused by said illumination to acquire time resolved measurement data;
• processing said time resolved measurement data to determine the absolute saturation of the venous compartment, said processing comprising at least determining an amplitude of respiration induced absorption oscillations;
• and
• verifying that said measurement data is accurate.

A computer program product for causing a computer to measure the venous oxygen saturation, the program product comprising computer executable instructions stored on a computer readable medium, the program instructions when executed causing the computer to:

• illuminate an area of tissue using a probe generating intensity modulated light at a plurality of wavelengths;
• sense diffusely reflected light caused by said illumination to acquire time resolved measurement data;
• process said time resolved measurement data to determine the absolute saturation of the venous compartment, said processing comprising at least determining an amplitude of respiration induced absorption oscillations;
• and
• verify that said time resolved measurement data represents venous compartment data.