Measurement process for blood gas analysis sensors

Claim 1

Process for measuring oxygen saturation of arterial blood in tissue by pulse oxymetry, comprising the steps of directing electromagnetic radiation of at least two different wavelengths at the tissue, determining radiation retained by the tissue for each said wavelength, producing an electric signal (I1, I2, . . . ) corresponding to radiation intensity retained for each said wavelength, producing at least one measured oxygen saturation variable (Ω1, Ω2 . . . ), and compensation for undesired dependency of each individual measured variable on haemoglobin content in the tissue, pigmentation and pilosity of the skin, wherein for at least one wavelength a level of the measured light attenuation (LA) in the tissue is allocated to pilosity, pigmentation in the skin and haemoglobin content (perfusion p) of the tissue and the level of light attenuation (LA) is used as a correcting factor for one or several measured variables Ωn, and wherein a value for the oxygen saturation of the arterial blood is obtained by selecting a calibration curve in dependence upon the LA from a number of possible calibration curves assigned by way of Ωn as an initial signal to one or several measured values for the measured variable Ωn.