Apparatus for measuring the change in the concentration of a pigment in blood
First Claim
1. An apparatus for measuring a change in the concentration of a pigment injected into a blood vessel, an absorptivity coefficient of the blood being changed with respect to a first wavelength of light, the apparatus comprising:
- light quantity detecting means for continuously detecting quantities of radiation of light which have been transmitted/reflected by a living tissue containing pulsating blood, one of the detected radiations of light transmitted/reflected by the living tissue having the first wavelength of light;
first computing means for converting outputs from said light quantity detecting means to logarithmic values and for determining constant and pulsating components of the logarithmic values of each wavelength both before and after the change in the absorptivity coefficient of the blood, and for computing estimated transmitted/reflected light level of a supposed ischemic tissue, from the determined constant and pulsating components; and
second computing means for continuously computing the concentration of pigment injected into the blood vessel according to the estimated transmitted/reflected light level of the supposed ischemic tissue computed by said first computing means and according to the quantities of radiation of light detected by said light quantity detecting means.
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Accused Products
Abstract
An apparatus for measuring the change in the concentration of a pigment in blood is disclosed which comprises: light quantity detecting units for continuously detecting the quantities of radiations of light having different wavelengths that have been transmitted or reflected by living tissue containing pulsating blood; first computing unit which, when the concentration or absorptivity coefficient of a light-absorbing component in the blood changes with respect to light having either one of said wavelengths, computes the quantities of radiations of transmitted or reflected light having the wavelengths when the living tissue is in a state of ischemia on the basis of the constant and pulsating components of the quantity of each radiation of light that has been detected by the light quantity detectors both before and after the change occurred; and second computing unit which continuously determines the concentration of a pigment of interest in the blood by performing calculations based on the results of computation by the first computing means and on the quantities of radiations of light detected by the light quantity detecting units.
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Citations
12 Claims
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1. An apparatus for measuring a change in the concentration of a pigment injected into a blood vessel, an absorptivity coefficient of the blood being changed with respect to a first wavelength of light, the apparatus comprising:
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light quantity detecting means for continuously detecting quantities of radiation of light which have been transmitted/reflected by a living tissue containing pulsating blood, one of the detected radiations of light transmitted/reflected by the living tissue having the first wavelength of light; first computing means for converting outputs from said light quantity detecting means to logarithmic values and for determining constant and pulsating components of the logarithmic values of each wavelength both before and after the change in the absorptivity coefficient of the blood, and for computing estimated transmitted/reflected light level of a supposed ischemic tissue, from the determined constant and pulsating components; and second computing means for continuously computing the concentration of pigment injected into the blood vessel according to the estimated transmitted/reflected light level of the supposed ischemic tissue computed by said first computing means and according to the quantities of radiation of light detected by said light quantity detecting means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An apparatus for measuring a change in the oxygen saturation of blood, an absorptivity coefficient of the blood being changed with respect to a first wavelength of light, the apparatus comprising:
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light quantity detecting means for continuously detecting quantities of radiation of light which have been transmitted/reflected by a living tissue containing pulsating blood, one of the detected radiations of light transmitted/reflected by the living tissue having the first wavelength of light; first computing means for converting outputs from said light quantity detecting means to logarithmic values and for determining constant and pulsating components of the logarithmic values of each wavelength both before and after the change in the absorptivity coefficient of the blood, and for computing estimated transmitted/reflected light level of a supposed ischemic tissue, from the determined constant and pulsating components; and second computing means for continuously computing the oxygen concentration of the blood vessel according to the estimated transmitted/reflected light level of the supposed ischemic tissue computed by said first computing means and according to the quantities of radiation of light detected by said light quantity detecting means.
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Specification