Non-invasive optical measurement of blood hematocrit
First Claim
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1. A device for determining blood hematocrit, the device comprising:
- an array of light sources for delivering radiation to a sample;
a power supply;
a modulation system in electrical contact with each of the light sources and the power supply, the modulation system configured to modulate electrical power delivered from the power supply to each of the light sources at a unique modulation frequency;
a detection system comprising a first optical detector and a plurality of second optical detectors, the first optical detector being configured to receive radiation from the sample, and, in response generating a first set of radiation-induced electrical signals, each corresponding to radiation delivered from a separate light source to the sample, and the plurality of second optical detectors each being configured to detect radiation directly from one of the light sources, and, in response generating a second set of radiation-induced electrical signals, each corresponding to radiation delivered from a separate light source, a signal processor for receiving the first set of electrical signals and, in response, generating a first set of digital electrical signals;
a microprocessor configured to receive the first set of digital electrical signals to calculate blood hematocrit, the microprocessor being programmed to first process the first set of digital electrical signals to determine a first spectrum and then processing the first spectrum or a spectrum determined from the first spectrum with a mathematical model to determine blood hematocrit.
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Abstract
The invention provides an optical method and apparatus for non-invasively determining blood hematocrit. The method includes the step of first irradiating blood with optical radiation. Radiation reflected or transmitted from the blood is then collected to determine an optical spectrum. Hematocrit is then determined by comparing this spectrum to a mathmatical model relating optical properties to blood Hematocrit.
223 Citations
21 Claims
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1. A device for determining blood hematocrit, the device comprising:
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an array of light sources for delivering radiation to a sample;
a power supply;
a modulation system in electrical contact with each of the light sources and the power supply, the modulation system configured to modulate electrical power delivered from the power supply to each of the light sources at a unique modulation frequency;
a detection system comprising a first optical detector and a plurality of second optical detectors, the first optical detector being configured to receive radiation from the sample, and, in response generating a first set of radiation-induced electrical signals, each corresponding to radiation delivered from a separate light source to the sample, and the plurality of second optical detectors each being configured to detect radiation directly from one of the light sources, and, in response generating a second set of radiation-induced electrical signals, each corresponding to radiation delivered from a separate light source, a signal processor for receiving the first set of electrical signals and, in response, generating a first set of digital electrical signals;
a microprocessor configured to receive the first set of digital electrical signals to calculate blood hematocrit, the microprocessor being programmed to first process the first set of digital electrical signals to determine a first spectrum and then processing the first spectrum or a spectrum determined from the first spectrum with a mathematical model to determine blood hematocrit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A device for determining blood hematocrit, the device comprising:
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a mount;
an array of light sources attached to the mount;
a fiber optic cable attached to each light source, the fiber optic cable including a delivery fiber for delivering radiation to the sample, a reference fiber for delivering radiation to a detection system, a beam splitter for splitting light into the delivery fiber and the reference fiber, and a signal fiber for delivering radiation reflected by the sample to a detection system;
a power supply electrically coupled to the mount;
a modulation system electrically coupled to the mount and arranged to modulate electrical power delivered from the power supply to each of the light sources;
a detection system comprising a first optical detector attached to the mount and coupled to the signal fiber for receiving radiation delivered from the sample, and, in response generating a first set of electrical signals, each corresponding to sample radiation delivered from a separate light source to the sample, and a second optical detector attached to the mount and coupled to each reference fiber for receiving radiation from each of the light sources, and, in response generating a second set of radiation-induced electrical signals, each corresponding to radiation delivered from a separate light source;
a signal processor electrically coupled to the mount for receiving the first set of electrical signals, and, in response to the radiation, generating a first set of digital signals, and for receiving the second set of electrical signals, and, in response to the radiation, generating a second set of digital electrical signals; and
a microprocessor configured to receive the first set and the second set of digital signals and to calculate blood hematocrit, said microprocessor being programmed to process the first set of digital signals to determine a first spectrum and then processing the first spectrum or a spectrum determined from the first spectrum with a mathematical model to determine blood hematocrit of the sample. - View Dependent Claims (20, 21)
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Specification