Signal processing apparatus
First Claim
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1. A method of determining whether a signal is reliable enough for use in a determination of a physiological characteristic of pulsing blood, the m 2. The method of claim 1, further comprising indicating when the indication of correlation is below a threshold.
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Abstract
The present invention involves a method and an apparatus for analyzing measured signals, including the determination of a measurement of correlation in the measured signals during a calculation of a physiological parameter of a monitored patient. Use of this invention is described in particular detail with respect to blood oximetry measurements.
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Citations
41 Claims
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1. A method of determining whether a signal is reliable enough for use in a determination of a physiological characteristic of pulsing blood, the m 2. The method of claim 1, further comprising indicating when the indication of correlation is below a threshold.
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3. The method of claim 2, wherein the threshold comprises about 0.75.
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4. The method of claim 2, wherein the indicating comprises disqualifying the at least two intensity signals.
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5. The method of claim 2, wherein the indicating comprises generating an indication that the light-sensitive detector is defective.
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6. The method of claim 2, wherein the indicating comprises generating an indication that the light-sensitive detector is malfunctioning.
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7. The method of claim 2, wherein the indicating comprises generating an indication that the at least two intensity signals do not satisfy an expected signal model.
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8. The method of claim 2, wherein the indicating comprises generating an audio warning.
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9. The method of claim 2, wherein the indicating comprises generating a visual warning.
- 10. The method of claim 2, wherein at least some of the plurality of intensity signals include motion induced noise.
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16. In a system that calculates a physiological characteristic, a method of determining a measure of confidence that one or more intensity signals will result in an accurate determination of a physiological characteristic of pulsing blood, the method comprising:
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receiving a plurality of intensity signals from light-sensitive detector which detects light of a plurality of wavelengths attenuated by body tissue carrying pulsing blood;
determining an indication of correlation between at least two of the plurality of intensity signals; and
based on the indication of correlation, conducting an evaluation of whether one or more intensity signals will result in an accurate determination of a physiological characteristic. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of determining oxygen saturation of pulsing blood, the method comprising:
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receiving a plurality of signals from a light-sensitive detector which detects light of at least first and second wavelengths attenuated by body tissue carrying pulsing blood;
determining representative values of oxygen saturation based on the plurality of intensity signals; and
averaging the representative values over time to determine a resulting value of the oxygen saturation of the pulsing blood, wherein the averaging is varied depending upon a level of motion noise in at least one of the plurality of intensity signals.
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27. A patient monitor capable of determining one or more physiological characteristics of pulsing blood using intensity signals from an optical probe, the patient monitor comprising:
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at least one conductive element which receives a plurality of intensity signals from light-sensitive detector which detects light of a plurality of wavelengths attenuated by body tissue carrying pulsing blood; and
a processor which determines an indication of correlation between at least two of the plurality of intensity signals and, based on the indication of correlation, determines whether to include one or more of the plurality of intensity signals in a determination of a physiological characteristic of pulsing blood. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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Specification