Pulse and active pulse spectraphotometry
First Claim
1. A pulse spectraphotometry system comprising:
- a light source adapted to illuminate a tissue site with optical radiation having a plurality of wavelengths selected from at least one of a primary band and a secondary band, said tissue site having a modulated blood volume;
a detector configured to receive said optical radiation attenuated by said tissue site and to generate a detector output responsive to absorption of said optical radiation within said tissue site;
a normalizer operating on said detector output to generate a plurality of normalized plethysmographs corresponding to said plurality of wavelengths; and
a processor configured to calculate a ratio of fractional volumes of analytes in said blood volume based upon said normalized plethysmographs.
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Accused Products
Abstract
A pulse and active pulse spectraphotometry system comprises a light source adapted to illuminate a tissue site with optical radiation having a plurality of wavelengths selected from at least one of a primary band and a secondary band. The tissue site has a modulated blood volume resulting from the pulsatile nature of arterial blood or from an induced pulse. A detector is configured to receive the optical radiation attenuated by the tissue site and to generate a detector output responsive to absorption of the optical radiation within the tissue site. A normalizer operating on the detector output generates a plurality of normalized plethysmographs corresponding to the plurality of wavelengths. Further, a processor is configured to calculate a ratio of fractional volumes of analytes in the blood volume based upon the normalized plethysmographs.
201 Citations
24 Claims
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1. A pulse spectraphotometry system comprising:
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a light source adapted to illuminate a tissue site with optical radiation having a plurality of wavelengths selected from at least one of a primary band and a secondary band, said tissue site having a modulated blood volume;
a detector configured to receive said optical radiation attenuated by said tissue site and to generate a detector output responsive to absorption of said optical radiation within said tissue site;
a normalizer operating on said detector output to generate a plurality of normalized plethysmographs corresponding to said plurality of wavelengths; and
a processor configured to calculate a ratio of fractional volumes of analytes in said blood volume based upon said normalized plethysmographs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A pulse spectraphotometry method comprising the steps of:
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illuminating a tissue site having a pulsatile blood flow with a narrowband optical radiation;
time division multiplexing said optical radiation over a plurality of wavelengths;
selecting at least a portion of said wavelengths within a range of about 1620 nm to about 1730 nm;
detecting an attenuated optical radiation from said tissue site as the result of said illuminating step; and
calculating a ratio of analytes in said blood flow based upon said attenuated optical radiation. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A pulse spectraphotometry system comprising:
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an optical radiation means for illuminating a tissue site;
a filter means for determining a nominal wavelength of said optical radiation, said nominal wavelength selected from a range of about 1620 nm to about 1730 nm. a detector means for receiving said optical radiation after transmission through or reflection from said tissue site and generating a corresponding plethysmograph signal; and
a processor means for calculating a ratio of analyte portions of pulsatile blood flow within said tissue site based upon said plethysmograph signal. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification