Predictive oximetry model and method
First Claim
4-1. The method of claim 1, wherein said mathematical relationship comprises a ratio of logarithms (R), said ratio of logarithms (R) being determined according to the following equation
R=(log (Tp@W1/log Tn,p@W1))/log (Tp@W2/log Tn,p @W2))wherein, Tp represents said total pulsatile transmittance equivalent value, Tn,p represents said total non-pulsatile transmittance equivalent value, W1 represents a first wavelength and W2 represents a second wavelength.
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Abstract
The invention comprises a method for determining oxygen saturation in a subject, comprising the steps of compiling a data base of measured spectral data that includes pulsatile AC and non-pulsatile DC components, and spectral values of oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb); determining absorbed pulsatile components and non-pulsatile components as a function of the oxyHb and deoxyHb values; determining total pulsatile and non-pulsatile optical density as a function of the absorbed pulsatile and non-pulsatile components; determining a mathematical relationship between at least one pulsatile AC parameter and at least one non-pulsatile DC parameter; and estimating oxygen saturation based on the mathematical relationship.
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Citations
60 Claims
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4-1. The method of claim 1, wherein said mathematical relationship comprises a ratio of logarithms (R), said ratio of logarithms (R) being determined according to the following equation
R=(log (Tp@W1/log Tn,p@W1))/log (Tp@W2/log Tn,p @W2))wherein, Tp represents said total pulsatile transmittance equivalent value, Tn,p represents said total non-pulsatile transmittance equivalent value, W1 represents a first wavelength and W2 represents a second wavelength.
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6-7. -7. (canceled)
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7. A method of determining oxygen saturation in a subject, comprising the steps of:
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compiling a data base of measured spectral data characterizing the transmission of light through a tissue of interest in the subject, said spectral data including pulsatile AC and non-pulsatile DC components of said transmitted light, and spectral values of oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb); determining light scattering intensity (I) of said AC and DC components; determining absorbed pulsatile components and non-pulsatile components as a function of said oxyHb and deoxyHb values; determining total pulsatile optical density as a function of said absorbed pulsatile components and said AC component scattered light intensity; determining total non-pulsatile optical density as a function of said absorbed non-pulsatile components and said DC component scattered light intensity; determining at least one total pulsatile transmittance equivalent value as a function of said total pulsatile optical density; determining at least one total non-pulsatile transmittance equivalent value as a function of said total non-pulsatile optical density; determining a ratio of logarithms as a function of said pulsatile and non-pulsatile transmittance equivalent values; and estimating oxygen saturation based on said ratio of logarithms. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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9-12. -12. (canceled)
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14-22. -22. (canceled)
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15. A method of determining oxygen saturation in a subject, comprising the steps of:
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providing a pulse oximetry system, said pulse oximetry system including a tissue probe having a radiation emitter that is adapted to transmit light having a first wavelength through a tissue of interest and a radiation detector that is adapted to receive said transmitted light after transmission through said tissue; measuring said transmission of light through said tissue of interest in the subject with said pulse oximetry system; compiling a data base of measured spectral data characterizing said transmission of light through said tissue of interest, said spectral data including pulsatile AC and non-pulsatile DC components of said transmitted light, and spectral values of oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb); determining light scattering intensity of said AC and DC components; determining absorbed pulsatile components and non-pulsatile components as a function of said oxyHb and deoxyHb values; determining total pulsatile optical density as a function of said absorbed pulsatile components and said AC component scattered light intensity; determining total non-pulsatile optical density as a function of said absorbed non-pulsatile components and said DC component scattered light intensity; determining at least one total pulsatile transmittance equivalent value as a function of said total pulsatile optical density; determining at least one total non-pulsatile transmittance equivalent value as a function of said total non-pulsatile optical density; determining a ratio of logarithms as a function of said pulsatile and non-pulsatile transmittance equivalent values; and estimating oxygen saturation based on said ratio of logarithms. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. A method of calibrating a pulse oximetery system, comprising the steps of:
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providing a pulse oximetry system, said pulse oximetry system including a tissue probe having a radiation emitter that is adapted to transmit light having a first wavelength through a tissue of interest and a radiation detector that is adapted to receive said transmitted light after transmission through said tissue; measuring said transmission of light through said tissue of interest in the subject with said pulse oximetry system; compiling a data base of measured spectral data characterizing the transmission of light through a tissue of interest in the subject, said spectral data including pulsatile AC and non-pulsatile DC components of said transmitted light, and spectral values of oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb); determining light scattering intensity of said AC and DC components; determining absorbed pulsatile components and non-pulsatile components as a function of said oxyHb and deoxyHb values; determining a corrected ratio of logarithms based on said absorbed pulsatile and non-pulsatile components, and said AC and DC component scattered light intensities, said corrected ratio of logarithms representing oxygen saturation in a subject.
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27-30. -30. (canceled)
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32-36. -36. (canceled)
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40-41. -41. (canceled)
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44-45. -45. (canceled)
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47-50. -50. (canceled)
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52-55. -55. (canceled)
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60-61. -61. (canceled)
Specification