METHOD AND APPARATUS FOR PROCESSING SIGNALS REFLECTING PHYSIOLOGICAL CHARACTERISTICS
First Claim
1. A device for the monitoring of a physiological characteristic of a patient'"'"'s blood, comprising:
- a first radiation emitter that emits light at a first wavelength;
a second radiation emitter that emits light at a second wavelength;
a radiation detector configured to receive light at said first and second wavelengths after absorbance through the patient'"'"'s blood and provide a first intensity signal and a second intensity signal corresponding to said first and second received wavelengths; and
a controller for computing said physiological characteristic of said patient'"'"'s blood from a corrected first intensity signal and a corrected second intensity signal determined by applying a residual derived from a combination of said first and second intensity signals as multiplied by a residual factor and subtracted from a difference between said first and second intensity signals to said first and second intensity signals.
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Accused Products
Abstract
The invention comprises a method and apparatus for processing signals reflecting a physiological characteristic by detecting the intensity of light following tissue absorption at two wavelengths and subtracting the best estimate of the desired signal from the difference between the signals. Corrected first and second intensity signals are determined by applying a residual derived from a combination of the first and second intensity signals as multiplied by a residual factor and subtracted from a difference between the first and second intensity signals to the first and second intensity signals. In one embodiment, the method and apparatus are used to determine arterial oxygen saturation.
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Citations
25 Claims
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1. A device for the monitoring of a physiological characteristic of a patient'"'"'s blood, comprising:
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a first radiation emitter that emits light at a first wavelength;
a second radiation emitter that emits light at a second wavelength;
a radiation detector configured to receive light at said first and second wavelengths after absorbance through the patient'"'"'s blood and provide a first intensity signal and a second intensity signal corresponding to said first and second received wavelengths; and
a controller for computing said physiological characteristic of said patient'"'"'s blood from a corrected first intensity signal and a corrected second intensity signal determined by applying a residual derived from a combination of said first and second intensity signals as multiplied by a residual factor and subtracted from a difference between said first and second intensity signals to said first and second intensity signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for processing signals reflecting a physiological characteristic of a patient'"'"'s blood, comprising the steps of:
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coupling an oximeter sensor arrangement to a tissue region of said patient;
passing first and second lights through said patient'"'"'s tissue region, wherein said first light is substantially in a red light range and said second light is substantially in an infrared light range;
detecting said first and second lights absorbed by said tissue region and providing a first intensity signal and a second intensity signal corresponding to said absorbed first and second lights; and
computing said physiological characteristic of said patient'"'"'s blood from a corrected first intensity signal and a corrected second intensity signal determined by applying a residual derived from a combination of said first and second intensity signals as multiplied by a residual factor and subtracted from a difference between said first and second intensity signals to said first and second intensity signals. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for determining a patient'"'"'s arterial oxygen saturation comprising the steps of:
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coupling an oximeter sensor arrangement to a tissue region of said patient;
passing first and second lights through said patient'"'"'s tissue region, wherein said first light is substantially in a red light range and said second light is substantially in an infrared light range;
detecting said first and second lights absorbed by said tissue region and providing a first intensity signal and a second intensity signal corresponding to said absorbed first and second lights; and
computing said arterial oxygen saturation of said patient'"'"'s blood from a corrected first intensity signal and a corrected second intensity signal determined by applying a residual derived from a combination of said first and second intensity signals as multiplied by a residual factor and subtracted from a difference between said first and second intensity signals to said first and second intensity signals, wherein said residual factor is determined by minimizing the absolute value of the difference between said residual at a first timepoint of a pulse corresponding to a time midpoint and an average of said residual at a second timepoint of said pulse corresponding to a first data minimum and at a third timepoint of said pulse corresponding to a first data maximum.
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Specification