Patent ID: 8515514
Filing Date: 2013-08-20
Classification: A61B

Abstract:
1. A method for compensating for subject-specific variability in a pulse oximeter intended for non-invasively determining in in-vivo measurement the amount of at least two light-absorbing substances in the blood of a subject and provided with emitters for emitting radiation at a minimum of two different wavelengths and with a detector for transforming the radiation received into an electrical output signal, the method comprising the steps of measuring a detector output signal when living tissue of the subject is present between the emitters and the detector in a sensor, wherein the detector output signal depends on the tissue, reading from a memory a nominal calibration comprising nominal extinction matrix E reading from the memory nominal characteristics describing conditions under which the nominal calibration has been done, the nominal characteristics comprising: establishing values for both calculations for the sensor on the living tissue of the subject using the detector output signal, forming a subject-specific calibration by correcting the nominal extinction matrix E solving hemoglobin fractions using the corrected nominal extinction matrix in a Lambert-Beer model.