Process and apparatus for non-invasive, continuous in vivo measurement of hematocrit
First Claim
1. A method of obtaining a hematocrit from a sample of in vivo tissue comprising:
- (a) irradiating the sample with a single incident wavelength on a sample of tissue;
(b) simultaneously measuring wavelength shifted (IE) and unshifted (EE) light emitted from the tissue; and
(c) determining a relative volume of light emitted from two phases, wherein the two phases comprise a first Rayleigh and Mie scattering and fluorescent phase associated with red blood cells, and a second, non-scattering phase associated with plasma, wherein the hematocrit is calculated from the volume of light emitted by the first phase (φ
r) relative to the total volume of light emitted from the first and second phases (φ
r+φ
p),wherein the determining comprises calculating;
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Abstract
The invention provides a method and apparatus obtaining a hematocrit from a sample of in vivo tissue. The method comprises irradiating the sample with a single incident wavelength on a sample of tissue, simultaneously measuring wavelength shifted (IE) and unshifted (EE) light emitted from the tissue, and determining a relative volume of light emitted from two phases, wherein the two phases comprise a first Rayleigh and Mie scattering and fluorescent phase associated with red blood cells, and a second, non-scattering phase associated with plasma. The hematocrit is calculated from the volume of light emitted by the first phase relative to the total volume of light emitted from the first and second phases.
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Citations
27 Claims
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1. A method of obtaining a hematocrit from a sample of in vivo tissue comprising:
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(a) irradiating the sample with a single incident wavelength on a sample of tissue; (b) simultaneously measuring wavelength shifted (IE) and unshifted (EE) light emitted from the tissue; and (c) determining a relative volume of light emitted from two phases, wherein the two phases comprise a first Rayleigh and Mie scattering and fluorescent phase associated with red blood cells, and a second, non-scattering phase associated with plasma, wherein the hematocrit is calculated from the volume of light emitted by the first phase (φ
r) relative to the total volume of light emitted from the first and second phases (φ
r+φ
p),wherein the determining comprises calculating; - View Dependent Claims (2, 3, 4, 5, 8, 9, 10, 11, 12, 13, 14, 15)
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6. A method of obtaining a hematocrit from a sample of in vivo tissue comprising:
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(a) irradiating the sample with a single incident wavelength on a sample of tissue; (b) simultaneously measuring wavelength shifted (IE) and unshifted (EE) light emitted from the tissue; and (c) determining a relative volume of light emitted from two phases, wherein the two phases comprise a first Rayleigh and Mie scattering and fluorescent phase associated with red blood cells, and a second, non-scattering phase associated with plasma, wherein the hematocrit is calculated from the volume of light emitted by the first phase (φ
r) relative to the total volume of light emitted from the first and second phases (φ
r+φ
p),wherein the determining comprises calculating; - View Dependent Claims (7, 21, 22, 23, 24, 25, 26, 27)
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16. An apparatus for obtaining a hematocrit from a sample of tissue comprising:
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(a) means for irradiating the sample with a single incident wavelength on a sample of tissue; (b) means for simultaneously measuring wavelength shifted and unshifted light emitted from the tissue; (c) means for determining a relative volume of light emitted from two phases, wherein the two phases comprise a first predominantly Rayleigh and Mie scattering and fluorescent phase associated with red blood cells, and a second, non-scattering phase associated with plasma; and (d) means for calculating a volume fraction of red blood cells (φ
r) relative to the total volume of red blood cells and plasma (φ
r+φ
p),wherein the determining comprises calculating; - View Dependent Claims (17, 18, 19)
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20. An apparatus for obtaining a hematocrit from a sample of tissue comprising:
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(a) means for irradiating the sample with a single incident wavelength on a sample of tissue; (b) means for simultaneously measuring wavelength shifted and unshifted light emitted from the tissue; (c) means for determining a relative volume of light emitted from two phases, wherein the two phases comprise a first predominantly Rayleigh and Mie scattering and fluorescent phase associated with red blood cells, and a second, non-scattering phase associated with plasma; and (d) means for calculating a volume fraction of red blood cells (φ
r) relative to the total volume of red blood cells and plasma (φ
r+φ
p),wherein the determining comprises calculating;
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Specification