Monitoring led wavelength shift in photoplethysmography
First Claim
1. A method for use in photoplethysmographic measurement of blood analyte levels comprising the steps of:
- measuring a voltage drop across a light signal emitter as the light signal emitter emits a light signal for use in determining a blood analyte level;
establishing a spectral characteristic of the emitted light signal based on the measured voltage drop across the light signal emitter; and
using the established spectral characteristic of the emitted light signal in determining a blood analyte level.
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Abstract
The present invention is directed to a method and system for the determination of a spectral characteristic of light signals emitted by light signal emitters of a photoplethysmographic probe to achieve improved accuracy in photoplethysmographic blood analyte level determinations. In one embodiment, a system for use in photoplethysmography includes a plurality of light signal emitters (20A-D) within a photoplethysmographic probe (12) and a voltage sensor (60) and data processor (70) within a photoplethysmographic monitor unit (14) to which the probe (12) is connectable. The voltage sensor (60) is operable to sense a voltage drop across each light signal emitter (20A-D) as each emits a corresponding light signal (22A-D) for transmission through a tissue under test. The data processor (70) is operable to establish at least one spectral characteristic, such as the center wavelength, of each emitted light signal (22A-D) based on the sensed voltage drops.
107 Citations
34 Claims
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1. A method for use in photoplethysmographic measurement of blood analyte levels comprising the steps of:
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measuring a voltage drop across a light signal emitter as the light signal emitter emits a light signal for use in determining a blood analyte level;
establishing a spectral characteristic of the emitted light signal based on the measured voltage drop across the light signal emitter; and
using the established spectral characteristic of the emitted light signal in determining a blood analyte level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of providing a spectral characteristic of a light signal emittable from a light signal emitter of a photoplethysmographic probe to a photoplethysmographic measurement unit wherein the spectral characteristic is usable in the determination of a blood analyte level by the photoplethysmographic measurement unit, said method comprising the steps of:
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obtaining data correlating a voltage drop across the light signal emitter with the spectral characteristic of the light signal;
storing the data wherein the data is usable to establish the spectral characteristic of the emitted light signal when the photoplethysmographic probe is used in determining a blood analyte level;
measuring the voltage drop across the light signal emitter as the light signal emitter emits the light signal; and
using the stored data to establish the spectral characteristic of the emitted light signal based on the measured voltage drop across the light signal emitter. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A system for use in photoplethysmographic measurement of at least one blood analyte level in a tissue under test comprising:
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a plurality of light signal emitters operable to emit a corresponding plurality of light signals for transmission through the tissue under test;
a voltage sensor operable to sense a voltage drop across each said light signal emitter as each said light signal emitter emits a corresponding light signal; and
a data processor operable to establish at least one spectral characteristic of each said emitted light signal based on the sensed voltage drop across said light signal emitter corresponding therewith, wherein said at least one spectral characteristic is usable in determining at least one blood analyte level. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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29. A photoplethysmographic probe connectable with a photoplethysmographic monitor unit for use in photoplethysmographic measurement of at least one blood analyte level in a tissue under test comprising:
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a plurality of light signal emitters operable to emit a corresponding plurality of light signals for transmission through the tissue under test; and
a data storage device for storing data correlating a sensed voltage drop across each said light signal emitter when operated to emit a light signal with at least one spectral characteristic of each said emitted light signal, wherein said data is accessible to said monitor unit for use in establishing said at least one spectral characteristic of each said emitted light signal based on the sensed voltage drop across each said light signal emitter. - View Dependent Claims (30, 31, 32, 33, 34)
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Specification