Cyanotic infant sensor
First Claim
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1. A method for determining a physiological parameter, the method comprising:
- receiving, from one or more detectors, one or more intensity signals responsive to light of a plurality of wavelengths attenuated by body tissue of a patient, said light emitted from a plurality of emitters, wherein said plurality of emitters and said one or more detectors are matched to reduce variations in a response of said one or more detectors that are not attributable to variations in a mean pathlength ratio of said light traveling through said body tissue between said plurality of emitters and said one or more detectors;
electronically retrieving mapping data including a relationship between DC response ratio data, ratio-of-ratios data, and oxygen saturation data;
electronically calculating a DC response ratio value responsive to said one or more intensity signals;
electronically calculating a ratio-of-ratios value responsive to said one or more intensity signals; and
electronically deriving an oxygen saturation measurement responsive to said mapping data.
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Abstract
A pulse oximetry sensor comprises emitters configured to transmit light having a plurality of wavelengths into a fleshy medium. A detector is responsive to the emitted light after absorption by constituents of pulsatile blood flowing within the medium so as to generate intensity signals. A sensor head has a light absorbing surface adapted to be disposed proximate the medium. The emitters and the detector are disposed proximate the sensor head. A detector window is defined by the sensor head and configured so as to limit the field-of-view of the detector.
617 Citations
20 Claims
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1. A method for determining a physiological parameter, the method comprising:
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receiving, from one or more detectors, one or more intensity signals responsive to light of a plurality of wavelengths attenuated by body tissue of a patient, said light emitted from a plurality of emitters, wherein said plurality of emitters and said one or more detectors are matched to reduce variations in a response of said one or more detectors that are not attributable to variations in a mean pathlength ratio of said light traveling through said body tissue between said plurality of emitters and said one or more detectors; electronically retrieving mapping data including a relationship between DC response ratio data, ratio-of-ratios data, and oxygen saturation data; electronically calculating a DC response ratio value responsive to said one or more intensity signals; electronically calculating a ratio-of-ratios value responsive to said one or more intensity signals; and electronically deriving an oxygen saturation measurement responsive to said mapping data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A pulse oximeter comprising:
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a sensor configured to output one or more intensity signals responsive to light attenuated by body tissue of a patient wearing said sensor, said sensor comprising plurality of emitters and one or more detectors, wherein said plurality of emitters and said one or more detectors are matched to reduce variations in a response of said one or more detectors that are not attributable to variations in a mean pathlength ratio of said light traveling through said body tissue between said plurality of emitters and said one or more detectors; a memory storing mapping data representing relationships between DC response data, ratio-of-ratios data, and oxygen saturation data; and a processor responsive to said output signals to determine a DC response and a ratio;
said processor configured to determine a measurement value responsive to said relationships stored in said memory. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A physiological sensor for outputting one or more intensity signals responsive to light attenuated by body tissue of a patient wearing, said sensor comprising:
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a plurality of emitters having predetermined emitter operating characteristics, wherein a first subset of the plurality of emitters are matched to transmit light at a first wavelength and a second subset of the plurality of emitters are matched to transmit light at a second wavelength, and wherein an emitted DC intensity ratio of said plurality of emitters for at least one predetermined DC drive current is matched to a first predetermined constant; and one or more detectors having predetermined detector operating characteristics, wherein a DC response ratio of said one or more detectors having a first wavelength response over a second wavelength response for at least one predetermined DC incident intensity has been matched to a second predetermined constant; wherein matching of said emitters to said first and second wavelengths, said matching of said emitted DC intensity ratio to said first predetermined constant, and said matching of said DC response ratio to said second predetermined constant collectively reduce variations in a response of said one or more detectors that are not attributable to variations in a mean pathlength ratio of said light traveling through said body tissue between said one or more emitters and said one or more detectors.
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Specification