×

Modified Pulse Oximetry Technique For Measurement Of Oxygen Saturation In Arterial And Venous Blood

  • US 20080208019A1
  • Filed: 02/22/2007
  • Published: 08/28/2008
  • Est. Priority Date: 02/22/2007
  • Status: Abandoned Application
First Claim
Patent Images

1. A method for the measurement of oxygen saturation in arterial blood, the method comprising:

  • (a) applying to the skin an apparatus including;

    (i) light-sources for generating light of three peak wavelengths λ

    1, λ

    2 and λ

    3;

    (ii) a detector arrangement; and

    (iii) an electronics unit, the apparatus configured to detect, for each light-source, the transmitted light through the tissue;

    (b) for each light source, deriving a PPG curve;

    (c) deriving from the three PPG curves a parameter related to the relative change in light transmission for each of the three wavelengths, and the ratio R12 and R13 of that parameter for the two wavelengths λ

    1 and λ

    2 and for the two wavelengths λ

    1, and λ

    3, respectively; and

    (d) determining the oxygen saturation in arterial blood, SaO2, from the solution of three equations including;

    a. relationship between SaO2 and R12, which includes the optical path-lengths l1 and l2;

    b. relationship between SaO2 and R13, which includes the optical path-lengths l1 and l3;

    c. relationship between small changes in the path-length l and small changes in the wavelength λ

    ,where the first two equations include the values of the extinction coefficient for the three peak wavelength for oxygenated blood ε

    o and for deoxygenated blood ε

    d.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×