Continuous spectroscopic measurement of total hemoglobin
First Claim
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1. A method of measuring total hemoglobin of whole blood, comprising:
- activating a light source to emit light toward whole blood;
receiving a reference signal containing a spectra of the light source;
deactivating the light source;
receiving a dark signal;
activating the light source to emit light toward the whole blood;
receiving a total hemoglobin remitted spectra signal from the whole blood; and
calculating a difference in light absorbance between the total hemoglobin remitted spectra signal of at least two wavelengths to measure the total hemoglobin of the whole blood.
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Abstract
Methods for measuring the total hemoglobin of whole blood include measuring reflective light at multiple wavelengths within the visible spectrum, calculating light absorbance at each of the multiple wavelengths, performing a comparison in a change in like absorbance between the multiple wavelengths, and/or relating the comparison to total hemoglobin. A system for measuring total hemoglobin of whole blood may include at least one light source, a catheter, optical fibers, at least one photodetector, data processing circuitry, and/or a display unit.
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Citations
36 Claims
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1. A method of measuring total hemoglobin of whole blood, comprising:
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activating a light source to emit light toward whole blood; receiving a reference signal containing a spectra of the light source; deactivating the light source; receiving a dark signal; activating the light source to emit light toward the whole blood; receiving a total hemoglobin remitted spectra signal from the whole blood; and calculating a difference in light absorbance between the total hemoglobin remitted spectra signal of at least two wavelengths to measure the total hemoglobin of the whole blood. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An apparatus for measuring total hemoglobin of blood comprising:
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a light source configured to transmit light of an isobestic wavelength; a transmit optical fiber for propagating the light into blood; a first receive optical fiber positioned a first distance from the transmit optical fiber, for receiving the light from the blood; a second receive optical fiber positioned a second distance from the transmit optical fiber, for receiving the light from the blood, the second distance being different from the first distance; a detector configured to measure a change in light absorbance of the light between the first receive optical fiber and the light from the second receive optical fiber; and a processing unit configured to measure total hemoglobin of the blood using the change in the light absorbance between the light from the first receive optical fiber and the light from the second receive optical fiber. - View Dependent Claims (21, 22, 23, 24)
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25. A method of determining total hemoglobin of whole blood, comprising:
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directing light toward whole blood; measuring a reference signal containing a spectra of the light; receiving a remitted spectra signal from the whole blood; determining an absorbance using the reference signal and the remitted spectra signal; and calculating a difference in absorbance between the remitted spectra signal of at least two wavelengths to measure the total hemoglobin of the whole blood. - View Dependent Claims (26, 27, 28, 29, 30, 31)
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32. An apparatus for determining total hemoglobin of whole blood, comprising:
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an oximetry catheter; an optical module positioned within the oximetry catheter; a system console to emit light through the optical module into whole blood and to receive reflected light through the oximetry catheter from the whole blood; and a processing unit to convert the reflected light to spectral data, to calculate a difference in absorbance between the spectral data of at least two wavelengths, and to calculate total hemoglobin of the whole blood using the difference in absorbance. - View Dependent Claims (33, 34, 35, 36)
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Specification