Patent ID: 7738935
Filing Date: 2010-06-15
Classification: A61B,A61N

Abstract:
1. A method for reducing effects of motion when measuring blood oxygen saturation, comprising the following steps of: (a) transmitting light having a first wavelength, light having a second wavelength and light having a third wavelength through body tissue; (b) receiving a portion of the light having the first wavelength, a portion of the light having the second wavelength and a portion of the light having the third wavelength; (c) producing a first signal based on the received portion of light having the first wavelength, a second signal based on the received portion of light having the second wavelength, and a third signal based on the received portion of light having the third wavelength; (d) determining a difference between the second signal and the first signal to produce a first plethysmography signal, and a difference between the third signal and the first signal to produce a second plethysmography signal; (e) estimating blood oxygen saturation using the first and second plethysmography signals, wherein the estimating is performed using a processor.