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Measurement of cardiac output and blood volume by non-invasive detection of indicator dilution

  • US 8,082,016 B2
  • Filed: 01/19/2007
  • Issued: 12/20/2011
  • Est. Priority Date: 05/22/2001
  • Status: Expired due to Fees
First Claim
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1. A method of determining concentration of a fluorescent indicator that is indocyanine green (ICG) having a concentration CICG within the cardiovascular system of a subject comprising:

  • a. administering to the cardiovascular system a detectable amount of the indicator that fluoresces when illuminated;

    b. illuminating a portion of the cardiovascular system with an excitation light of a first wavelength and causing the administered indicator to emit an emergent fluorescence light of a second wave length;

    c. detecting the intensity (x) of the excitation light that is reflected by or transmitted through a portion of the cardiovascular system;

    d. detecting the intensity (y) of the emergent fluorescence light;

    e. determining the ratio (y)/(x);

    f. determining the concentration (CICG) of the fluorescence indicator in the cardiovascular system based on the determined ratio (y)/(x), wherein the concentration of the fluorescence indicator is proportional to the ratio; and

    g. determining a ratio CICG/CHb of indocyanine green concentration (CICG) to the blood hemoglobin concentration (CHb) wherein the ratio CICG/CHb is proportional to the change of the ratio (y)/(x).

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