Patent ID: 8548546

Claim:
A pulse oximetry method comprising: irradiating living tissue with light beams of at least five wavelengths which are different from each other; receiving the light beams transmitted through or reflected from the living tissue and converting the received light beams to electric signals which correspond to the at least five wavelengths; time-segmenting time series data of the electric signals; calculating, with respect to each of the segmented time series data of the electric signals, a slope value of a regression line between each two of the electric signals; calculating an arterial oxygen saturation, SaO2, based on the slope values of each of the segmented time series data of the electric signals, by using an expression obtained in consideration of an effect related to tissue and venous blood; constructing a histogram of SaO2 for each predetermined number of time segments; and obtaining a mode value from the histogram as a measured value of SaO2 to be output of the pulse oximetry.