EP0240742A2
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EP
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Apparatus and method for measuring amount of oxygen in blood
Assignee: Terumo Corp
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Filing: 1987-03-06
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Granted: —
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Expires: 2007-03-06
Abstract
Abstract An apparatus for measuring the amount of oxygen in blood includes a light source for emitting light having at least two different wavelengths, a light intensity sensor for irradiating a blood with the light of each different wavelength from the light source, and for sensing the intensities of light, which correspond to the wavelengths, reflected from the blood, a calculating unit for calculating the average value of each reflected light intensity sensed by the light intensity sensor, a first arithmetic unit for selecting at least two of the average values and for determining the ratio thereof, a correcting unit for correcting the ratio on the basis of a correction value obtained from a relation between a reflected light intensity ratio of blood having a known degree of oxygen saturation and the known degree of oxygen saturation, and a second arithmetic unit for determining the degree of oxygen saturation of hemoglobin in the blood from the corrected ratio. The apparatus can also be used to calculate hemoglobin concentration from the intensity of light of a predetermined wavelength reflected from the blood, and to determine blood oxygen content from the degree of oxygen saturation of hemoglobin and the hemoglobin concentration. Methods of performing these operations are also disclosed.
Inventors
- 👤 Hiromasa Kohno
- 👤 Masahiro Nudeshima
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 22:35
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/314; G01N21/3151; G01N2021/3144; G01N2021/3148; G01N2021/3181
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
154 words
An apparatus for measuring the degree of saturation of oxygen in blood, comprising: a tight-emitting source for emitting light having at least two different wavelengths; light intensity sensing means for irradiating a blood with the light of each different wavelength from said tight-emitting source, and for sensing the intensities of light, which correspond to said wavelengths, reflected from the blood; calculating means for calculating an average value of each reflected light intensity sensed by said light intensity sensing means; first arithmetic means for selecting at least two of the average values and for determining the ratio thereof; correcting means for correcting said ratio on the basis of a correction value obtained from a relation between a reflected light intensity ratio of blood having a known degree of oxygen saturation and said degree of oxygen saturation; and second arithmetic means for determining a degree of saturation of oxygen in the blood from the corrected ratio.
Claim 2
Independent Claim
154 words
An apparatus for measuring the degree of saturation of oxygen in blood, comprising: a tight-emitting source for emitting light having at least two different wavelengths; light intensity sensing means for irradiating a blood with the light of each different wavelength from said tight-emitting source, and for sensing the intensities of light, which correspond to said wavelengths, reflected from the blood; calculating means for calculating an average value of each reflected light intensity sensed by said light intensity sensing means; first arithmetic means for selecting at least two of the average values and for determining the ratio thereof; correcting means for correcting said ratio on the basis of a correction value obtained from a relation between a reflected light intensity ratio of blood having a known degree of oxygen saturation and said degree of oxygen saturation; and second arithmetic means for determining a degree of saturation of oxygen in the blood from the corrected ratio.
Claim 3
Independent Claim
58 words
The apparatus according to claim I, wherein said correcting means corrects the ratio, in such a manner as to reduce the influence of a hematocrit value, by adding the correction value to at least one of any of the average values selected from among the average values of the reflected light intensities in order to obtain the ratio.
Claim 4
Dependent Claim
53 words
The apparatus according to claim 2, wherein the correction value added by said correcting means is a value which minimizes a standard deviation value between the degree of oxygen saturation calculated from the reflected light intensity ratio of blood having the known degree of oxygen saturation and said known degree of oxygen saturation.
Claim 5
Independent Claim
65 words
The apparatus according to claim I, wherein said second arithmetic means incorporates an arithmetic relation derived from a relationship between a reflected light intensity ratio, for different wavelengths, of blood having a known degree of oxygen saturation and said degree of oxygen saturation, and uses said arithmetic relation to determine the degree of saturation of oxygen from the reflected light intensity ratio of the blood.
Claim 6
Independent Claim
25 words
The apparatus according to claim I, wherein said tight-emitting source emits light having at least a wavelength absorbed equally by oxygenated hemoglobin and reduced hemoglobin.
Claim 7
Independent Claim
24 words
The apparatus according to claim I, wherein said tight-emitting source emits light at least having wavelengths of 665 nm, 795 nm and 910 nm.
Claim 8
Dependent Claim
12 words
The apparatus according to claim 3, wherein the correction value is 0.55.
Claim 9
Independent Claim
125 words
A method of measuring the degree of saturation of oxygen in blood, comprising the steps of: (a) irradiating a blood with light from a light-emitting source having at least two different wavelengths; (b) sensing the intensities of light, which correspond to said wavelengths, reflected from the irradiated blood; (c) calculating an average value of each reflected light intensity sensed; (d) selecting at least two of the average values and determining the ratio thereof; (e) correcting said ratio on the basis of a correction value obtained from a relation between a reflected light intensity ratio of blood having a known degree of oxygen saturation and said degree of oxygen saturation; and (f) determining a degree of saturation of oxygen in the blood from the corrected ratio.
Claim 10
Independent Claim
125 words
A method of measuring the degree of saturation of oxygen in blood, comprising the steps of: (a) irradiating a blood with light from a light-emitting source having at least two different wavelengths; (b) sensing the intensities of light, which correspond to said wavelengths, reflected from the irradiated blood; (c) calculating an average value of each reflected light intensity sensed; (d) selecting at least two of the average values and determining the ratio thereof; (e) correcting said ratio on the basis of a correction value obtained from a relation between a reflected light intensity ratio of blood having a known degree of oxygen saturation and said degree of oxygen saturation; and (f) determining a degree of saturation of oxygen in the blood from the corrected ratio.
Claim 11
Dependent Claim
100 words
The method according to claim 8, wherein said step (e) comprises making the correction, in such a manner as to reduce the influence of a hematocrit value, by adding the correction value to at least one of any of the average values selected from among the average values of the reflected light intensities in order to obtain the ratio, said.correction value being predetermined so as to minimize a standard deviation value between the degree of oxygen saturation calculated from the reflected light intensity ratio of blood having the known degree of oxygen saturation and said known degree of oxygen saturation.
Claim 12
Dependent Claim
60 words
The method according to claim 8, wherein said step (f) comprises determining the degree of saturation of oxygen from the reflected light intensity ratio of the blood by using an arithmetic relation derived from a relationship between a reflected light intensity ratio, for different wavelengths, of blood having a known degree of oxygen saturation and said degree of oxygen saturation.
Claim 13
Dependent Claim
24 words
The method according to claim 8, wherein said light-emitting source emits light at least having wavelengths absorbed equally by oxygenated hemoglobin and reduced hemoglobin.
Claim 14
Dependent Claim
28 words
The method according to claim 8, wherein said light-emitting source emits light at least having wavelengths of 665 nm and 795 nm or 665 nm and 910 nm.
Claim 15
Dependent Claim
12 words
The method according to claim 9, wherein the correction value is 0.55.
Claim 16
Independent Claim
57 words
An apparatus for measuring hemoglobin concentration, comprising a light-emitting source for emitting light having a predetermined wavelength; light intensity sensing means for irradiating a blood with the light of the predetermined wavelength and for sensing the intensity of light reflected from the blood; and concentration calculating means for calculating hemoglobin concentration from said intensity of reflected light.
Claim 17
Independent Claim
57 words
An apparatus for measuring hemoglobin concentration, comprising a light-emitting source for emitting light having a predetermined wavelength; light intensity sensing means for irradiating a blood with the light of the predetermined wavelength and for sensing the intensity of light reflected from the blood; and concentration calculating means for calculating hemoglobin concentration from said intensity of reflected light.
Claim 18
Dependent Claim
55 words
The apparatus according to claim 14, wherein said concentration calculating means incorporates an arithmetic relation derived from a relationship between intensity of light reflected from blood having a predetermined hemoglobin concentration and said predetermined hemoglobin concentration, and uses said arithmetic relation to determine the hemoglobin concentration from the intensity of light reflected from the blood.
Claim 19
Dependent Claim
65 words
The apparatus according to claim 15, wherein said concentration calculating means includes means for comparing an intensity of light reflected from blood having a known hemoglobin concentration and an intensity of reflected light calculated from said known hemoglobin concentration, and for producing a signal indicative of the difference between these two intensities, and means for correcting the arithmetic relation so as to minimizine said difference.
Claim 20
Dependent Claim
25 words
The apparatus according to claim 14, wherein said light intensity sensing means calculates an average value of the intensity of light reflected from the blood.
Claim 21
Dependent Claim
19 words
The apparatus according to claim 14, wherein said predetermined wavelength is absorbed equally by oxygenated hemoglobin and reduced hemoglobin.
Claim 22
Independent Claim
80 words
A method of measuring hemoglobin.concentration, comprising the steps of: (a) irradiating a blood with light from a light-emitting source for emitting light having a predetermined wavelength, and sensing the intensity of light reflected from the irradiated blood, and (b) calculating hemoglobin concentration based on the intensity of light reflected from the blood on the basis of an arithmetic relation derived from a relationship between intensity of light reflected from blood having a predetermined hemoglobin concentration and said predetermined hemoglobin concentration.
Claim 23
Independent Claim
80 words
A method of measuring hemoglobin.concentration, comprising the steps of: (a) irradiating a blood with light from a light-emitting source for emitting light having a predetermined wavelength, and sensing the intensity of light reflected from the irradiated blood, and (b) calculating hemoglobin concentration based on the intensity of light reflected from the blood on the basis of an arithmetic relation derived from a relationship between intensity of light reflected from blood having a predetermined hemoglobin concentration and said predetermined hemoglobin concentration.
Claim 24
Dependent Claim
54 words
The method according to claim 19, wherein said step (b) comprises steps of comparing an intensity of light reflected from a blood having a known hemoglobin concentration and an intensity of reflected light calculated from said known hemoglobin concentration, and correcting the arithmetic relation so as to minimize a difference between the two intensities.
Claim 25
Dependent Claim
19 words
The method according to claim 19, wherein said predetermined wavelength is absorbed equally by oxygenated hemoglobin and reduced hemoglobin.
Claim 26
Independent Claim
186 words
An apparatus for measuring blood oxygen content, comprising: a light-emitting source for emitting light having at least two different wavelengths; light intensity sensing means for irradiating a blood with the light of each different wavelength from said light-emitting source, and for sensing the intensities of light, which correspond to said wavelengths, reflected from the blood; calculating means for calculating an average value of each reflected light intensity sensed by said light intensity sensing means; first arithmetic means for selecting at least two of the average values and for determining the ratio thereof; correcting means for correcting said ratio on the basis of a correction value obtained from a relation between a reflected light intensity ratio of blood having a known degree of oxygen saturation and said degree of oxygen saturation; means for determining a degree of oxygen saturation of hemoglobin in the blood on the basis of the corrected ratio; concentration calculating means for calculating hemoglobin concentration from one of said average values or reflected light intensities; and means for determining blood oxygen content from said degree of blood saturation of hemoglobin and said hemoglobin concentration.
Claim 27
Independent Claim
186 words
An apparatus for measuring blood oxygen content, comprising: a light-emitting source for emitting light having at least two different wavelengths; light intensity sensing means for irradiating a blood with the light of each different wavelength from said light-emitting source, and for sensing the intensities of light, which correspond to said wavelengths, reflected from the blood; calculating means for calculating an average value of each reflected light intensity sensed by said light intensity sensing means; first arithmetic means for selecting at least two of the average values and for determining the ratio thereof; correcting means for correcting said ratio on the basis of a correction value obtained from a relation between a reflected light intensity ratio of blood having a known degree of oxygen saturation and said degree of oxygen saturation; means for determining a degree of oxygen saturation of hemoglobin in the blood on the basis of the corrected ratio; concentration calculating means for calculating hemoglobin concentration from one of said average values or reflected light intensities; and means for determining blood oxygen content from said degree of blood saturation of hemoglobin and said hemoglobin concentration.
Claim 28
Dependent Claim
58 words
The apparatus according to claim 22, wherein said correcting means corrects the ratio, in such a manner as to reduce the influence of a hematocrit value, by adding the correction value to at least one of any of the average values selected from among the average values of the reflected light intensities in order to obtain the ratio.
Claim 29
Dependent Claim
53 words
The apparatus according to claim 23, wherein the correction value added by said correcting means is a value which minimizes a standard deviation value between the degree of oxygen saturation calculated from the reflected light intensity ratio of blood having the known degree of oxygen saturation and said known degree of oxygen saturation.
Claim 30
Dependent Claim
59 words
The apparatus according to claim 22, wherein said concentration calculating means incorporates an arithmetic relation derived from a relationship between intensity of light reflected from blood having a known hemoglobin concentration and said known hemoglobin concentration, and uses said arithmetic relation to determine the hemoglobin concentration from the average values of the intensity of light reflected from the blood.
Claim 31
Dependent Claim
65 words
The apparatus according to claim 25, wherein said concentration calculating means includes means for comparing an intensity of light reflected from blood having a known hemoglobin concentration and an intensity of reflected light calculated from said known hemoglobin concentration, and for producing a signal indicative of the difference between these two intensities, and means for correcting the arithmetic relation so as to minimizine said difference.
Claim 32
Dependent Claim
25 words
The apparatus according to claim 22, wherein said light-emitting source emits light having at least a wavelength absorbed equally by oxygenated hemoglobin and reduced hemoglobin.
Claim 33
Independent Claim
161 words
A method of measuring blood oxygen content, comprising the steps of: (a) irradiating a blood with light from a light-emitting source having at least two different wavelengths; (b) sensing the intensities of light, which correspond to said wavelengths, reflected from the irradiated blood; (c) calculating an average value of each reflected light intensity sensed; (d) selecting at least two of the average values and determining the ratio thereof; (e) correcting said ratio on the basis of a correction value obtained from a relation between a reflected light intensity ratio of blood having a known degree of oxygen saturation and said degree of oxygen saturation; (e) determining a degree of oxygen saturation of hemoglobin in the blood on the basis of the corrected ratio; (f) selecting one of said average values or reflected light intensities and calculating hemoglobin concentration based thereon; and (g) determining the oxygen content of the blood from said degree of blood saturation of hemoglobin and said hemoglobin concentration.
Claim 34
Independent Claim
161 words
A method of measuring blood oxygen content, comprising the steps of: (a) irradiating a blood with light from a light-emitting source having at least two different wavelengths; (b) sensing the intensities of light, which correspond to said wavelengths, reflected from the irradiated blood; (c) calculating an average value of each reflected light intensity sensed; (d) selecting at least two of the average values and determining the ratio thereof; (e) correcting said ratio on the basis of a correction value obtained from a relation between a reflected light intensity ratio of blood having a known degree of oxygen saturation and said degree of oxygen saturation; (e) determining a degree of oxygen saturation of hemoglobin in the blood on the basis of the corrected ratio; (f) selecting one of said average values or reflected light intensities and calculating hemoglobin concentration based thereon; and (g) determining the oxygen content of the blood from said degree of blood saturation of hemoglobin and said hemoglobin concentration.
Claim 35
Dependent Claim
101 words
The method according to claim 28, wherein said step (e) comprises making the correction, in such a manner as to reduce the influence of a hematocrit value, by adding the correction value to at least one of any of the average values selected from among the average values of the reflected light intensities in order to obtain the ratio, said correction value being predetermined so as to minimize a standard deviation value between the degree of oxygen saturation calculated from the reflected light intensity ratio of blood having the known degree of oxygen saturation and said known degree of oxygen saturation.
Claim 36
Dependent Claim
49 words
The method according to claim 28, wherein said step (f) comprises determining hemoglobin concentration from the intensity of light reflected from the blood by using an arithmetic relation derived from a relationship between intensity of light reflected from blood having a known hemoglobin concentration and said known hemoglobin concentration.
Claim 37
Dependent Claim
54 words
The method according to claim 30, wherein said step (f) comprises steps of comparing an intensity of light reflected from a blood having a predetermined hemoglobin concentration and an intensity of reflected light calculated from said predetermined hemoglobin concentration, and correcting the arithmetic relation so as to minimize a difference between the two intensities.
Claim 38
Dependent Claim
25 words
The method according to claim 28, wherein said light-emitting source emits light having at least a wavelength absorbed equally by oxygenated hemoglobin and reduced hemoglobin.
Claim 39
Dependent Claim
12 words
The method according to claim 29, wherein the correction value is 0.55.
References Cited (Backward Citations)
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