Pulse oximeter and sensor optimized for low saturation
First Claim
1. A method for measuring blood oxygen saturation, comprising the steps of:
- providing a sensor and a pulse oximeter;
selecting a light source and a light detector as a part of said sensor;
optimizing a wavelength spectrum of light received by said light detector from said light source for an oxygen saturation reading less than 80 percent, said optimizing comprising receiving at said detector only red and infrared portions of said spectrum, including a portion between 700 and 790 nanometers;
placing said sensor on a patient; and
determining said blood oxygen saturation said sensor and said pulse oximeter.
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Accused Products
Abstract
A pulse oximeter sensor with a light source optimized for low oxygen saturation ranges and for maximizing the immunity to perturbation induced artifact. Preferably, a red and an infrared light source are used, with the red light source having a mean wavelength between 700-790 nm. The infrared light source can have a mean wavelength as in prior art devices used on patients with high saturation. The sensor of the present invention is further optimized by arranging the spacing between the light emitter and light detectors to minimize the sensitivity to perturbation induced artifact. The present invention optimizes the chosen wavelengths to achieve a closer matching of the absorption and scattering coefficient products for the red and IR light sources. This optimization gives robust readings in the presence of perturbation artifacts including force variations, tissue variations and variations in the oxygen saturation itself.
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Citations
47 Claims
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1. A method for measuring blood oxygen saturation, comprising the steps of:
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providing a sensor and a pulse oximeter; selecting a light source and a light detector as a part of said sensor; optimizing a wavelength spectrum of light received by said light detector from said light source for an oxygen saturation reading less than 80 percent, said optimizing comprising receiving at said detector only red and infrared portions of said spectrum, including a portion between 700 and 790 nanometers; placing said sensor on a patient; and
determining said blood oxygen saturation said sensor and said pulse oximeter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 21, 22, 23)
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16. A method for measuring blood oxygen saturation, comprising the steps of:
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providing a sensor and a pulse oximeter; selecting a light source and a light detector as a part of said sensor; optimizing a wavelength spectrum of light received by said light detector from said light source for an oxygen saturation reading less than 80 percent, said optimizing comprising receiving only red and infrared spectrums at said light detector including a first infrared spectrum in a range of 800-1000 nanometers and a red spectrum with a mean wavelength between 700 and 790 nanometers; placing said sensor on a patient; and determining said blood oxygen saturation using said sensor and said pulse oximeter.
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17. A method for measuring blood oxygen saturation in a fetus, comprising the steps of:
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providing a sensor, having a light source and a light detector, and a pulse oximeter; detecting light at said detector comprising only red and infrared spectrums; selecting the infrared spectrum so as to have a wavelength spectrum useful for measuring oxygen saturation in a patient with high saturation; optimizing a wavelength spectrum of said red spectrum to a mean wavelength between 700 and 790 nanometers for an oxygen saturation reading between 15 and 65 percent, said optimizing increasing an immunity of a measurement of blood oxygen saturation to perturbation artifact; placing said sensor on said fetus; measuring an intensity of at least two light signals from said light source at said light detector after being scattered through a portion of said fetus; and determining said blood oxygen saturation using said intensity and said pulse oximeter. - View Dependent Claims (18)
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19. A method for using a pulse oximeter to measure blood oxygen saturation in a patient, comprising the steps of:
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selecting a light source and a light detector for a sensor; detecting light at said detector comprising first and second light spectrums, each of the light spectrums having an extinction and a scattering coefficient associated with blood perfused tissue; optimizing said light spectrums by choosing wavelength spectrums whose product of their respective extinction and scattering coefficients form first and second values, a ratio between said first and second values being between 0.5 and 2 for a majority of the oxygen saturation reading range of 0 to 65 percent; placing said sensor on said patient; and determining said blood oxygen saturation using said sensor and said pulse oximeter. - View Dependent Claims (20)
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24. A sensor for a pulse oximeter for measuring blood oxygen saturation, comprising:
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a light source; a light detector; one of said light source and light detector including means for providing light comprising first and second spectrums, each of the spectrums being optimized for the products of their respective extinction and scattering coefficients in blood perfused tissue, the products forming first and second values, a ratio between said first and second values being between 0.5 and 2 for a majority of the oxygen saturations less than 80 percent. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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31. A sensor for a pulse oximeter for measuring blood oxygen saturation in a fetus, comprising:
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a radiation source; a radiation detector; at least one of said source and detector being optimized for reducing the sensitivity of a blood oxygen saturation measurement to pertubation induced artifact for saturations less than 65%, by using only spectrums in the red and infrared range, including 700-790 nanometers. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38)
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39. A method of using a pulse oximeter, comprising the steps of:
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receiving at least first and second signals from a sensor obtained by scattering light through tissue, the light having at least first and second wavelength spectrums, the first and second spectrums being optimized for an oxygen saturation reading less than 80%; and calculating the oxygen saturation using coefficients suitable for only red and infrared spectrums including the first and second optimized spectrums.
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40. A processing system for use with a pulse oximeter comprising:
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an input connector for receiving at least first and second signals from a sensor obtained by scattering light through tissue, the light having at least first and second wavelength spectrums; a memory storing coefficients suitable for only red and infrared spectrums including said first and second spectrums, the spectrums being optimized for an oxygen saturation reading less than 80%; and a processor, coupled to said memory and said input;
connector, for calculating the oxygen saturation using said. coefficients. - View Dependent Claims (41, 42, 43, 44)
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45. A processing system for use with a pulse oximeter, comprising:
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an input connector for receiving at least first and second signals from a sensor obtained by scattering light through tissue, the light having at least red and infrared spectrums; a memory storing coefficients suitable for said spectrums, each of the spectrums being optimized for the products of their respective extinction and scattering coefficients in blood perfused tissue, the products forming first and second values, a ratio between said first and second values being between 0.5 and 2 for a majority of oxygen saturations less than 80 percent; and a processor, coupled to said memory, for calculating the oxygen saturation using said coefficients.
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46. A processing system for use with a pulse oximeter for measuring blood oxygen saturation in a fetus, comprising:
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an input connector for receiving at least first and second signals from a sensor obtained by detecting light;
having at least only red and infrared spectrums, the light being scattered from tissue;a memory storing coefficients suitable for said spectrums being optimized for reducing the sensitivity of a blood oxygen saturation measurement to perturbation induced artifact for saturations less than 65 percent; and a processor, coupled to said memory, for calculating the oxygen saturation using said coefficients.
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47. A processing system for use with a pulse oximeter, comprising:
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an input connector for receiving at least first and second signals from a sensor obtained by scattering light through tissue, the light having at least first and second wavelength values; a memory storing coefficients suitable for said first and second spectrums, the spectrums being optimized for an oxygen saturation reading less than 80% by choosing a only spectrums in the red and infrared range including a first infrared spectrum with a mean wavelength in a range of 800-1000 nanometers and a red spectrum with a mean wavelength between 700 and 790 nanometers; a processor, coupled to said memory and said input connector, for calculating the oxygen saturation using said coefficients.
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Specification