Probes and Pulse Photometry Systems

Abstract

To suppress a decrease in calculation accuracy of photoabsorption substance in blood by pulse photometry.SOLUTION: A fourth light emitting part 214 and a seventh light emitting part 217 have a fourth light emitting surface and a seventh light emitting surface respectively where lights including wavelength to be used for calculation of carbonylhemoglobin concentration in blood of a subject are emitted. An eighth light emitting part 218 has an eighth light emitting surface to which light including wavelength that is not used for calculation of carbonylhemoglobin concentration in blood of the subject is emitted. Distance D47 between a fourth reference point 214b at the fourth light emitting part 214 seen from a normal line direction on the fourth light emitting surface and a seventh reference point 217b at the seventh light emitting part 217 seen from the normal line direction on the seventh light emitting surface is shorter than distance D48 between an eighth reference point 218b in the eighth light emitting part 218 seen from the normal line direction on the eighth light emitting surface and a fourth reference point 214b.SELECTED DRAWING: Figure 18

Description

[Technical Field]

[0001] The present invention relates to a probe connected to a pulse photometer for calculating the concentration of a light-absorbing substance in the blood of a subject. The present invention also relates to a pulse photometry system including the probe and the pulse photometer. [Background technology]

[0002] Patent Document 1 discloses this type of probe. The probe has at least three light-emitting elements. The wavelength of light emitted from each light-emitting element is different from the wavelength of light emitted from the other light-emitting elements. According to the principle of pulse photometry, the concentration of a specific light-absorbing substance in blood can be calculated using two wavelengths. The two wavelengths are selected so that a significant difference appears in the absorbance of the light-absorbing substance in blood. The probe described in Patent Document 1 uses three or more wavelengths to improve the accuracy of calculating the concentration of the specific light-absorbing substance in blood. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-192865 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to suppress a decrease in the accuracy of calculating the concentration of a light-absorbing substance in blood by pulse photometry. [Means for solving the problem]

[0005] One aspect of the present invention to achieve the above object is a probe connected to a pulse photometer, comprising: a first light-emitting unit having a first light-emitting surface from which first light having a first wavelength used to calculate a concentration of a light-absorbing substance in the first blood of the subject is emitted; a second light-emitting unit having a second light-emitting surface from which second light having a second wavelength different from the first wavelength and used to calculate the first blood light-absorbing substance concentration is emitted; a third light-emitting unit having a third light-emitting surface that emits third light having a third wavelength that is different from the first wavelength and the second wavelength and that is not used in calculating the first blood light-absorbing substance concentration; It is equipped with The distance between a first reference point in the first light-emitting portion when viewed from the normal direction of the first light-emitting surface and a second reference point in the second light-emitting portion when viewed from the normal direction of the second light-emitting surface is shorter than the distance between a third reference point in the third light-emitting portion when viewed from the normal direction of the third light-emitting surface and the first reference point.

[0006] One aspect of the present invention to achieve the above object is a pulse photometry system, comprising: a first light-emitting unit having a first light-emitting surface from which first light having a first wavelength is emitted; a second light-emitting unit having a second light-emitting surface from which second light having a second wavelength different from the first wavelength is emitted; a third light-emitting unit having a third light-emitting surface from which third light having a third wavelength different from the first wavelength and the second wavelength is emitted; a light receiving unit that outputs a first signal corresponding to the intensity of the first light that has passed through a tissue of a subject, a second signal corresponding to the intensity of the second light that has passed through the tissue, and a third signal corresponding to the intensity of the third light that has passed through the tissue; a processor that calculates a first blood light absorber concentration of the subject based on the first signal and the second signal, but not based on the third signal; It is equipped with The distance between a first reference point in the first light-emitting portion when viewed from the normal direction of the first light-emitting surface and a second reference point in the second light-emitting portion when viewed from the normal direction of the second light-emitting surface is shorter than the distance between a third reference point in the third light-emitting portion when viewed from the normal direction of the third light-emitting surface and the first reference point.

[0007] The configurations according to the above aspects can reduce the influence of light emitted from a light-emitting element not used in calculating the first blood concentration of the light absorber on a light-emitting element used in calculating the first blood concentration of the light absorber, thereby preventing a decrease in the accuracy of calculating the blood concentration of the light absorber by pulse photometry. [Brief explanation of the drawings]

[0008] [Figure 1] 1 illustrates the configuration of a pulse photometry system according to one embodiment. [Figure 2] 2 shows an example of the configuration of the light-emitting unit in the probe of FIG. 1. [Figure 3] 2 shows an example of the configuration of the light-emitting unit in the probe of FIG. 1. [Figure 4] 3 shows an example of the operation of the light emitting unit of FIG. 2. [Figure 5] 3 shows another example of the operation of the light emitting unit of FIG. 2. [Figure 6] 3 shows another example of the operation of the light emitting unit of FIG. 2. [Figure 7] 3 shows another example of the operation of the light emitting unit of FIG. 2. [Figure 8] 3 shows another example of the operation of the light emitting unit of FIG. 2. [Figure 9] 3 shows another example of the operation of the light emitting unit of FIG. 2. [Figure 10] 3 illustrates the structure of the light-emitting portion of FIG. 2; [Figure 11] 2 shows another example of the configuration of the light-emitting unit in the probe of FIG. 1. [Figure 12] 2 shows another example of the configuration of the light-emitting unit in the probe of FIG. 1. [Figure 13] 12 shows an example of the operation of the light emitting unit of FIG. [Figure 14] 12 shows another example of the operation of the light emitting unit of FIG. 11. [Figure 15] 12 shows another example of the operation of the light emitting unit of FIG. 11. [Figure 16] 12 shows another example of the operation of the light emitting unit of FIG. 11. [Figure 17] 12 shows another example of the operation of the light emitting unit of FIG. 11. [Figure 18] 12 shows another example of the operation of the light emitting unit of FIG. 11. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The following detailed description of exemplary embodiments will be given with reference to the accompanying drawings, in which the scale of each element has been appropriately changed so that it can be clearly seen.

[0010] 1 illustrates the configuration of a pulse photometry system 10 according to one embodiment. The pulse photometry system 10 includes a probe 20 and a pulse photometer 30.

[0011] The probe 20 includes a first light-emitting unit 211, a second light-emitting unit 212, a third light-emitting unit 213, a fourth light-emitting unit 214, a fifth light-emitting unit 215, a sixth light-emitting unit 216, a seventh light-emitting unit 217, and an eighth light-emitting unit 218. Each of the first light-emitting unit 211, the second light-emitting unit 212, the third light-emitting unit 213, the fourth light-emitting unit 214, the fifth light-emitting unit 215, the sixth light-emitting unit 216, the seventh light-emitting unit 217, and the eighth light-emitting unit 218 includes a light-emitting element. Examples of the light-emitting element include a light-emitting diode (LED), a laser diode (LD), and an EL element.

[0012] The first light emitting unit 211 is configured to emit a first light L1 having a first wavelength λ1. The first light emitting unit 211 may be configured to include a light emitting element that emits light having the first wavelength λ1, or may be configured to emit light of the first wavelength λ1 by passing light having a wavelength different from the first wavelength λ1 emitted from the light emitting element through an appropriate optical element.

[0013] The second light-emitting unit 212 is configured to emit second light L2 having a second wavelength λ2. The second light-emitting unit 212 may be configured to include a light-emitting element that emits light having the second wavelength λ2, or may be configured to emit light of the second wavelength λ2 by passing light having a wavelength different from the second wavelength λ2 emitted from the light-emitting element through an appropriate optical element.

[0014] The third light-emitting unit 213 is configured to emit third light L3 having a third wavelength λ3. The third light-emitting unit 213 may be configured to include a light-emitting element that emits light having the third wavelength λ3, or may be configured to emit light of the third wavelength λ3 by passing light having a wavelength different from the third wavelength λ3 emitted from the light-emitting element through an appropriate optical element.

[0015] The fourth light-emitting unit 214 is configured to emit fourth light L4 having a fourth wavelength λ4. The fourth light-emitting unit 214 may be configured to include a light-emitting element that emits light having the fourth wavelength λ4, or may be configured to emit light of the fourth wavelength λ4 by passing light having a wavelength different from the fourth wavelength λ4 emitted from the light-emitting element through an appropriate optical element.

[0016] The fifth light-emitting unit 215 is configured to emit fifth light L5 having a fifth wavelength λ5. The fifth light-emitting unit 215 may be configured to include a light-emitting element that emits light having the fifth wavelength λ5, or may be configured to emit light of the fifth wavelength λ5 by passing light having a wavelength different from the fifth wavelength λ5 emitted from the light-emitting element through an appropriate optical element.

[0017] The sixth light-emitting unit 216 is configured to emit sixth light L6 having a sixth wavelength λ6. The sixth light-emitting unit 216 may be configured to include a light-emitting element that emits light having the sixth wavelength λ6, or may be configured to emit light of the sixth wavelength λ6 by passing light having a wavelength different from the sixth wavelength λ6 emitted from the light-emitting element through an appropriate optical element.

[0018] The seventh light-emitting unit 217 is configured to emit seventh light L7 having a seventh wavelength λ7. The seventh light-emitting unit 217 may be configured to include a light-emitting element that emits light having the seventh wavelength λ7, or may be configured to emit light of the seventh wavelength λ7 by passing light having a wavelength different from the seventh wavelength λ7 emitted from the light-emitting element through an appropriate optical element.

[0019] The eighth light-emitting unit 218 is configured to emit eighth light L8 having an eighth wavelength λ8. The eighth light-emitting unit 218 may be configured to include a light-emitting element that emits light having the eighth wavelength λ8, or may be configured to emit light of the eighth wavelength λ8 by passing light having a wavelength different from the eighth wavelength λ8 emitted from the light-emitting element through an appropriate optical element.

[0020] The first wavelength λ1, the second wavelength λ2, the third wavelength λ3, the fourth wavelength λ4, the fifth wavelength λ5, the sixth wavelength λ6, the seventh wavelength λ7, and the eighth wavelength λ8 are different.

[0021] The probe 20 includes a light receiving unit 22. The light receiving unit 22 is configured to include a light receiving element that outputs a detection signal corresponding to the intensity of incident light. The detection signal may be an analog signal or a digital signal. Examples of the light receiving element include a photodiode, phototransistor, photoresistor, etc. that are sensitive to at least a first wavelength λ1, a second wavelength λ2, a third wavelength λ3, a fourth wavelength λ4, a fifth wavelength λ5, a sixth wavelength λ6, a seventh wavelength λ7, and an eighth wavelength λ8.

[0022] The probe 20 is configured to be attachable to the subject's body 40. In this example, the first light-emitting unit 211, the second light-emitting unit 212, the third light-emitting unit 213, the fourth light-emitting unit 214, the fifth light-emitting unit 215, the sixth light-emitting unit 216, the seventh light-emitting unit 217, the eighth light-emitting unit 218, and the light-receiving unit 22 are arranged so that the first light L1, the second light L2, the third light L3, the fourth light L4, the fifth light L5, the sixth light L6, the seventh light L7, and the eighth light L8 pass through the body 40 and enter the light-receiving unit 22.

[0023] The first light-emitting unit 211, the second light-emitting unit 212, the third light-emitting unit 213, the fourth light-emitting unit 214, the fifth light-emitting unit 215, the sixth light-emitting unit 216, the seventh light-emitting unit 217, the eighth light-emitting unit 218, and the light-receiving unit 22 may be arranged so that the first light L1, the second light L2, the third light L3, the fourth light L4, the fifth light L5, the sixth light L6, the seventh light L7, and the eighth light L8 are reflected by the body 40 and enter the light-receiving unit 22.

[0024] The pulse photometer 30 includes a processor 31 , an output interface 32 , and an input interface 33 .

[0025] The processor 31 is configured to be able to control the turning on and off operations of each of the first light-emitting unit 211, the second light-emitting unit 212, the third light-emitting unit 213, the fourth light-emitting unit 214, the fifth light-emitting unit 215, the sixth light-emitting unit 216, the seventh light-emitting unit 217, and the eighth light-emitting unit 218.

[0026] Specifically, the processor 31 allows each of the first control signal CS1, the second control signal CS2, the third control signal CS3, the fourth control signal CS4, the fifth control signal CS5, the sixth control signal CS6, the seventh control signal CS7, and the eighth control signal CS8 to be output from the output interface 32.

[0027] The first control signal CS1 causes the first light-emitting unit 211 to emit the first light L1. The second control signal CS2 causes the second light-emitting unit 212 to emit the second light L2. The third control signal CS3 causes the third light-emitting unit 213 to emit the third light L3. The fourth control signal CS4 causes the fourth light-emitting unit 214 to emit the fourth light L4. The fifth control signal CS5 causes the fifth light-emitting unit 215 to emit the fifth light L5. The sixth control signal CS6 causes the sixth light-emitting unit 216 to emit the sixth light L6. The seventh control signal CS7 causes the seventh light-emitting unit 217 to emit the seventh light L7. The eighth control signal CS8 causes the eighth light-emitting unit 218 to emit the eighth light L8.

[0028] Each of the first control signal CS1, the second control signal CS2, the third control signal CS3, the fourth control signal CS4, the fifth control signal CS5, the sixth control signal CS6, the seventh control signal CS7, and the eighth control signal CS8 may be an analog signal or a digital signal. If each of the first control signal CS1, the second control signal CS2, the third control signal CS3, the fourth control signal CS4, the fifth control signal CS5, the sixth control signal CS6, the seventh control signal CS7, and the eighth control signal CS8 is an analog signal, the output interface 32 may include an appropriate conversion circuit including a D / A converter.

[0029] When first light L1 that has passed through the body 40 enters the light-receiving unit 22, the light-receiving unit 22 outputs a first detection signal DS1. When second light L2 that has passed through the body 40 enters the light-receiving unit 22, the light-receiving unit 22 outputs a second detection signal DS2. When third light L3 that has passed through the body 40 enters the light-receiving unit 22, the light-receiving unit 22 outputs a third detection signal DS3. When fourth light L4 that has passed through the body 40 enters the light-receiving unit 22, the light-receiving unit 22 outputs a fourth detection signal DS4. When fifth light L5 that has passed through the body 40 enters the light-receiving unit 22, the light-receiving unit 22 outputs a fifth detection signal DS5. When sixth light L6 that has passed through the body 40 enters the light-receiving unit 22, the light-receiving unit 22 outputs a sixth detection signal DS6. When seventh light L7 that has passed through the body 40 enters the light-receiving unit 22, the light-receiving unit 22 outputs a seventh detection signal DS7. When the eighth light L8 that has passed through the body 40 is incident on the light receiving unit 22, the light receiving unit 22 outputs an eighth detection signal DS8.

[0030] The input interface 33 is configured to be able to accept each of the first detection signal DS1, second detection signal DS2, third detection signal DS3, fourth detection signal DS4, fifth detection signal DS5, sixth detection signal DS6, seventh detection signal DS7, and eighth detection signal DS8 output from the light receiving unit 22. When each of the first detection signal DS1, second detection signal DS2, third detection signal DS3, fourth detection signal DS4, fifth detection signal DS5, sixth detection signal DS6, seventh detection signal DS7, and eighth detection signal DS8 is an analog signal, the input interface 33 includes an appropriate conversion circuit including an A / D converter.

[0031] FIG. 2 shows an example of the arrangement of the first light-emitting unit 211, the second light-emitting unit 212, the third light-emitting unit 213, the fourth light-emitting unit 214, the fifth light-emitting unit 215, the sixth light-emitting unit 216, the seventh light-emitting unit 217, and the eighth light-emitting unit 218 in the probe 20.

[0032] The first light-emitting unit 211 has a first light-emitting surface 211a. The first light-emitting surface 211a is a surface from which light emitted from a light-emitting element included in the first light-emitting unit 211 is emitted, and forms a part of the outer surface of the probe 20.

[0033] The second light-emitting unit 212 has a second light-emitting surface 212a. The second light-emitting surface 212a is a surface from which light emitted from a light-emitting element included in the second light-emitting unit 212 is emitted, and forms a part of the outer surface of the probe 20.

[0034] The third light-emitting unit 213 has a third light-emitting surface 213a. The third light-emitting surface 213a is a surface from which light emitted from a light-emitting element included in the third light-emitting unit 213 is emitted, and forms a part of the outer surface of the probe 20.

[0035] The fourth light-emitting unit 214 has a fourth light-emitting surface 214a. The fourth light-emitting surface 214a is a surface from which light emitted from the light-emitting element included in the fourth light-emitting unit 214 is emitted, and forms a part of the outer surface of the probe 20.

[0036] The fifth light-emitting unit 215 has a fifth light-emitting surface 215a. The fifth light-emitting surface 215a is a surface from which light emitted from the light-emitting element included in the fifth light-emitting unit 215 is emitted, and forms a part of the outer surface of the probe 20.

[0037] The sixth light-emitting unit 216 has a sixth light-emitting surface 216a. The sixth light-emitting surface 216a is a surface from which light is emitted from the light-emitting element included in the sixth light-emitting unit 216, and forms part of the outer surface of the probe 20.

[0038] The seventh light-emitting unit 217 has a seventh light-emitting surface 217a. The seventh light-emitting surface 217a is a surface from which light emitted from the light-emitting element included in the seventh light-emitting unit 217 is emitted, and forms a part of the outer surface of the probe 20.

[0039] The eighth light-emitting unit 218 has an eighth light-emitting surface 218a. The eighth light-emitting surface 218a is a surface from which light emitted from the light-emitting element included in the eighth light-emitting unit 218 is emitted, and forms part of the outer surface of the probe 20.

[0040] Fig. 3 illustrates an external view of a portion of the probe 20 as viewed from the direction of arrow III in Fig. 2. A first normal N1, a fifth normal N5, a seventh normal N7, and an eighth normal N8 may be defined for the first light-emitting surface 211a, the fifth light-emitting surface 215a, the seventh light-emitting surface 217a, and the eighth light-emitting surface 218a, respectively. Although not shown, a second normal N2, a third normal N3, a fourth normal N4, and a sixth normal N6 may be defined for the second light-emitting surface 212a, the third light-emitting surface 213a, the fourth light-emitting surface 214a, and the sixth light-emitting surface 216a, respectively.

[0041] 2 illustrates the appearance of each of first light-emitting section 211, second light-emitting section 212, third light-emitting section 213, fourth light-emitting section 214, fifth light-emitting section 215, sixth light-emitting section 216, seventh light-emitting section 217, and eighth light-emitting section 218 viewed from the directions along first normal N1, second normal N2, third normal N3, fourth normal N4, fifth normal N5, sixth normal N6, seventh normal N7, and eighth normal N8, respectively. When viewed from the same directions, first light-emitting surface 211a, second light-emitting surface 212a, third light-emitting surface 213a, fourth light-emitting surface 214a, fifth light-emitting surface 215a, sixth light-emitting surface 216a, seventh light-emitting surface 217a, and eighth light-emitting surface 218a have the same shape.

[0042] The first light-emitting portion 211 has a first reference point 211b, which is defined as the center of the first light-emitting surface 211a when viewed in the direction in which the first normal line N1 extends.

[0043] The second light-emitting portion 212 has a second reference point 212b, which is defined as the center of the second light-emitting surface 212a when viewed in the direction in which the second normal line N2 extends.

[0044] The third light-emitting portion 213 has a third reference point 213b. The third reference point 213b is defined as the center of the third light-emitting surface 213a when viewed from the direction in which the third normal N3 extends.

[0045] The fourth light-emitting portion 214 has a fourth reference point 214b. The fourth reference point 214b is defined as the center of the fourth light-emitting surface 214a when viewed in the direction in which the fourth normal N4 extends.

[0046] The fifth light-emitting portion 215 has a fifth reference point 215b, which is defined as the center of the fifth light-emitting surface 215a when viewed in the direction in which the fifth normal N5 extends.

[0047] The sixth light-emitting portion 216 has a sixth reference point 216b, which is defined as the center of the sixth light-emitting surface 216a when viewed in the direction in which the sixth normal N6 extends.

[0048] The seventh light-emitting portion 217 has a seventh reference point 217b, which is defined as the center of the seventh light-emitting surface 217a when viewed in the direction in which the seventh normal N7 extends.

[0049] The eighth light-emitting portion 218 has an eighth reference point 218b, which is defined as the center of the eighth light-emitting surface 218a when viewed in the direction in which the eighth normal N8 extends.

[0050] However, the first reference point 211b, the second reference point 212b, the third reference point 213b, the fourth reference point 214b, the fifth reference point 215b, the sixth reference point 216b, the seventh reference point 217b, and the eighth reference point 218b may be set at any suitable position as long as the same conditions are satisfied for each light-emitting surface. For example, the upper right corner of each light-emitting surface may be set as the reference point.

[0051] An example of the operation of pulse photometry system 10 configured as described above will be described with reference to Figure 4. In this example, pulse photometer 30 calculates the concentration Φo of oxygenated hemoglobin (OHb) and the concentration Φc of carboxyhemoglobin (COHb). Oxyhemoglobin is an example of a first light-absorbing substance in blood. Carbonmonoxide hemoglobin is an example of a second light-absorbing substance in blood.

[0052] In this example, a first light-emitting element 211 and a second light-emitting element 212 are used to calculate the concentration Φo of oxygenated hemoglobin. The absorbance of oxygenated hemoglobin is wavelength-dependent. The first wavelength λ1 and the second wavelength λ2 are selected as two wavelengths at which a significant difference appears in the absorbance of oxygenated hemoglobin. The first wavelength λ1 is an example of a first wavelength used to calculate the concentration of a first light-absorbing substance. The second wavelength λ2 is an example of a second wavelength used to calculate the concentration of a first light-absorbing substance.

[0053] The first light L1 emitted from the first light emitter 211 is absorbed by arterial blood, venous blood, tissue, etc. as it passes through the subject's body 40. Therefore, the intensity of the first light L1 incident on the light receiver 22 is reduced compared to the intensity at the time of emission from the first light emitter 211. In other words, the absorbance A1 of the first light L1 can be defined as the ratio of the emission intensity from the first light emitter 211 to the incidence intensity on the light receiver 22.

[0054] Similarly, the second light L2 emitted from the second light emitter 212 is absorbed by arterial blood, venous blood, tissue, etc. as it passes through the subject's body 40. Therefore, the intensity of the second light L2 incident on the light receiving unit 22 is reduced compared to the intensity at the time of emission from the first light emitter 211. In other words, the absorbance A2 of the second light L2 can be defined as the ratio of the emission intensity from the second light emitter 212 to the incidence intensity on the light receiving unit 22.

[0055] As the subject's heart beats, the arterial blood vessels pulsate, changing the thickness of the arterial blood vessels through which the first light L1 and the second light L2 pass. In other words, the amount of arterial blood that absorbs the first light L1 and the second light L2 changes. Therefore, as the subject's blood pulsates, the intensities of the first light L1 and the second light L2 incident on the light receiving unit 22 change, changing the absorbance A1 of the first light L1 and the absorbance A2 of the second light L2. The amounts of change in each absorbance are defined as a first change ΔA1 and a second change ΔA2.

[0056] The oxygenated hemoglobin concentration Φo is calculated based on the ratio (ΔA1 / ΔA2) of the first change amount ΔA1 to the second change amount ΔA2. That is, the processor 31 of the pulse photometer 30 calculates the oxygenated hemoglobin concentration Φo based on the first detection signal DS1 and the second detection signal DS2 output from the light receiving unit 22.

[0057] The processor 31 can output a signal OS corresponding to the oxygenated hemoglobin concentration Φo from the output interface 32. The signal is subjected to appropriate processing. Examples of such processing include calculating a value that can be obtained based on the concentration Φo, displaying at least one of the value of the concentration Φo and a value obtained based on the concentration Φo, and performing an alarm based on at least one of the value of the concentration Φo and a value obtained based on the concentration Φo. An example of a value that can be obtained based on the concentration Φo is percutaneous arterial oxygen saturation (SpO2).

[0058] In this example, the third light-emitting element 213 and the fourth light-emitting element 214 are used to calculate the concentration Φc of carboxyhemoglobin. The absorbance of carboxyhemoglobin is wavelength-dependent. The third wavelength λ3 and the fourth wavelength λ4 are selected as two wavelengths at which a significant difference appears in the absorbance of carboxyhemoglobin. The fourth wavelength λ4 is an example of a third wavelength that is not used in calculating the first blood light-absorbing substance concentration. The fourth wavelength λ4 is also an example of a third wavelength that is used in calculating the second blood light-absorbing substance concentration. The third wavelength λ3 is an example of a fourth wavelength that is not used in calculating the first blood light-absorbing substance concentration. The third wavelength λ3 is also an example of a fourth wavelength that is used in calculating the second blood light-absorbing substance concentration.

[0059] For the third light L3 and the fourth light L4, absorbances A3 and A4 are obtained as they pass through the subject's body 40, and third and fourth change amounts ΔA3 and ΔA4 associated with pulsation can be defined. The carboxyhemoglobin concentration Φc is calculated based on the ratio (ΔA3 / ΔA4) of the third change amount ΔA3 to the fourth change amount ΔA4. That is, the processor 31 of the pulse photometer 30 calculates the carboxyhemoglobin concentration Φc based on the third detection signal DS3 and the fourth detection signal DS4 output from the light receiving unit 22.

[0060] The processor 31 can output a signal OS corresponding to the carboxyhemoglobin concentration Φc from the output interface 32. The signal OS is subjected to appropriate processing. Examples of such processing include calculating a value that can be obtained based on the concentration Φc, displaying at least one of the value of the concentration Φc and a value obtained based on the concentration Φc, and performing a reporting operation based on at least one of the value of the concentration Φc and a value obtained based on the concentration Φc.

[0061] In this example, the first light-emitting section 211, the second light-emitting section 212, the third light-emitting section 213, and the fourth light-emitting section 214 are arranged so as to satisfy the following conditions. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b. The distance D43 between the fourth reference point 214b and the third reference point 213b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D43 between the fourth reference point 214b and the third reference point 213b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b.

[0062] According to the above configuration, the first light-emitting element 211 and the second light-emitting element 212 used to calculate the oxygenated hemoglobin concentration Φo can be arranged closer to each other, and the third light-emitting element 213 and the fourth light-emitting element 214 used to calculate the carboxyhemoglobin concentration Φc can be arranged closer to each other.

[0063] This reduces the influence of the optical path length difference from the multiple light-emitting elements used in the calculation of the oxygenated hemoglobin concentration Φo and the carbon monoxide hemoglobin concentration Φc on the change in absorbance due to pulsation from the light-receiving element 22. Therefore, it is possible to suppress a decrease in the accuracy of calculating the concentration of light-absorbing substances in blood by pulse photometry.

[0064] As illustrated in FIG. 5, the seventh light-emitting unit 217 can be used to calculate the carboxyhemoglobin concentration Φc. The seventh wavelength λ7 is selected as a wavelength at which a significant difference in the absorbance of carboxyhemoglobin appears relative to at least one of the third wavelength λ3 and the fourth wavelength λ4. The seventh wavelength λ7 is an example of a fourth wavelength not used in calculating the first blood light absorber concentration. The seventh wavelength λ7 is also an example of a fourth wavelength used in calculating the second blood light absorber concentration. The seventh light L7 also provides an absorbance A7 as it passes through the subject's body 40, and a seventh change ΔA7 associated with pulsation can be defined.

[0065] The seventh light-emitting element 217 may be used in addition to the third light-emitting element 213 and the fourth light-emitting element 214, or may be used in place of either the third light-emitting element 213 or the fourth light-emitting element 214. In the former case, by using the seventh change amount ΔA7 as a correction term for the calculation result of the ratio between the third change amount ΔA3 and the fourth change amount ΔA4, the influence of other light-absorbing substances in blood can be suppressed and the calculation accuracy of the carboxyhemoglobin concentration Φc can be improved. In the latter case, when the carboxyhemoglobin concentration Φc cannot be calculated satisfactorily using the third light-emitting element 213 and the fourth light-emitting element 214 for various reasons, the seventh light-emitting element 217 can be used as an alternative light source to attempt to calculate the carboxyhemoglobin concentration Φc.

[0066] In this example, the first light-emitting section 211, the second light-emitting section 212, the fourth light-emitting section 214, and the seventh light-emitting section 217 are arranged so as to satisfy the following conditions. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b. The distance D47 between the fourth reference point 214b and the seventh reference point 217b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D47 between the fourth reference point 214b and the seventh reference point 217b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b.

[0067] According to the above configuration, the first light-emitting element 211 and the second light-emitting element 212 used to calculate the oxygenated hemoglobin concentration Φo can be arranged closer to each other, and the fourth light-emitting element 214 and the seventh light-emitting element 217 used to calculate the carboxyhemoglobin concentration Φc can be arranged closer to each other.

[0068] This reduces the influence of the optical path length difference from the multiple light-emitting elements used in the calculation of the oxygenated hemoglobin concentration Φo and the carbon monoxide hemoglobin concentration Φc on the change in absorbance due to pulsation from the light-receiving element 22. Therefore, it is possible to suppress a decrease in the accuracy of calculating the concentration of light-absorbing substances in blood by pulse photometry.

[0069] 6 shows another example of the operation of pulse photometry system 10. In this example, pulse photometer 30 calculates the concentration Φr of deoxygenated hemoglobin (RHb). Deoxygenated hemoglobin is an example of a first light-absorbing substance in blood.

[0070] In this example, the third light-emitting element 213 and the eighth light-emitting element 218 are used to calculate the concentration Φr of deoxygenated hemoglobin. Deoxygenated hemoglobin has wavelength-dependent absorbance. The eighth wavelength λ8 is selected as a wavelength at which a significant difference appears in the absorbance of deoxygenated hemoglobin compared to the third wavelength λ3. The third wavelength λ3 is an example of a first wavelength used to calculate the concentration of the first absorbent. The eighth wavelength λ8 is an example of a second wavelength used to calculate the concentration of the first absorbent.

[0071] For the eighth light L8, absorbance A8 is obtained as it passes through the subject's body 40, and an eighth change amount ΔA8 associated with pulsation can be defined. The concentration Φr of deoxyhemoglobin is calculated based on the ratio (ΔA3 / ΔA8) of the third change amount ΔA3 to the eighth change amount ΔA8. That is, processor 31 of pulse photometer 30 calculates the concentration Φr of deoxyhemoglobin based on the third detection signal DS3 and the eighth detection signal DS8 output from light receiving unit 22.

[0072] The processor 31 can output a signal OS corresponding to the concentration Φr of deoxygenated hemoglobin from the output interface 32. The signal OS is subjected to appropriate processing. Examples of such processing include calculating a value that can be obtained based on the concentration Φr, displaying at least one of the value of the concentration Φr and a value obtained based on the concentration Φr, and performing an alarm based on at least one of the value of the concentration Φr and a value obtained based on the concentration Φr. Assuming that abnormal hemoglobin, such as carboxyhemoglobin or methemoglobin, is not present in the hemoglobin in arterial blood, the concentration of oxygenated hemoglobin can be determined by determining the concentration of deoxygenated hemoglobin. In this case, an example of a value that can be obtained based on the concentration Φr is percutaneous arterial oxygen saturation (SpO2).

[0073] Another example of a relationship in which the concentration of one substance can be determined by determining the concentration of the other substance when two types of light-absorbing substances are assumed to exist in the blood system is the relationship between the concentration of total hemoglobin and the concentration of water in blood.

[0074] In this example, at least one of the fifth light-emitting element 215 and the sixth light-emitting element 216 is used to determine the attachment state of the probe 20 to the subject's body 40. For example, if at least one of the intensity of the fifth light L5 and the intensity of the sixth light L6 incident on the light-receiving element 22 is below a threshold, the processor 31 of the pulse photometer 30 determines that the attachment state of the probe 20 to the subject's body 40 is inappropriate. Each of the fifth wavelength λ5 and the sixth wavelength λ6 is an example of a third wavelength that is not used in calculating the first blood light-absorber concentration.

[0075] In this example, the fifth light-emitting section 215, the sixth light-emitting section 216, the third light-emitting section 213, and the eighth light-emitting section 218 are arranged so as to satisfy the following conditions. The distance D38 between the third reference point 213b and the eighth reference point 218b is shorter than the distance D35 between the third reference point 213b and the fifth reference point 215b. The distance D38 between the third reference point 213b and the eighth reference point 218b is shorter than the distance D36 between the third reference point 213b and the sixth reference point 216b.

[0076] According to the above configuration, it is possible to reduce the influence of light emitted from the light-emitting unit not used in calculating the deoxygenated hemoglobin concentration Φr on the light-emitting unit used in calculating the deoxygenated hemoglobin concentration Φr, thereby suppressing a decrease in the accuracy of calculating the blood light-absorbing substance concentration by pulse photometry.

[0077] 7, the seventh light-emitting unit 217 can be used to calculate the concentration Φr of deoxygenated hemoglobin. The seventh wavelength λ7 is selected as a wavelength at which a significant difference in absorbance of deoxygenated hemoglobin appears relative to at least one of the third wavelength λ3 and the eighth wavelength λ8. The seventh wavelength λ7 is an example of the second wavelength used to calculate the concentration of the first absorbent.

[0078] The seventh light-emitting element 217 may be used in addition to the third light-emitting element 213 and the eighth light-emitting element 218, or may be used in place of either the third light-emitting element 213 or the eighth light-emitting element 218. In the former case, by using the seventh change amount ΔA7 as a correction term for the calculation result of the ratio between the third change amount ΔA3 and the eighth change amount ΔA8, the influence of other light-absorbing substances in blood can be suppressed and the calculation accuracy of the deoxygenated hemoglobin concentration Φr can be improved. In the latter case, when the deoxygenated hemoglobin concentration Φr cannot be calculated satisfactorily using the third light-emitting element 213 and the eighth light-emitting element 218 for various reasons, the seventh light-emitting element 217 can be used as an alternative light source to attempt to calculate the deoxygenated hemoglobin concentration Φr.

[0079] In this example, the fifth light-emitting section 215, the sixth light-emitting section 216, the third light-emitting section 213, and the seventh light-emitting section 217 are arranged so as to satisfy the following conditions. The distance D37 between the third reference point 213b and the seventh reference point 217b is shorter than the distance D35 between the third reference point 213b and the fifth reference point 215b. The distance D37 between the third reference point 213b and the seventh reference point 217b is shorter than the distance D36 between the third reference point 213b and the sixth reference point 216b.

[0080] The above configuration also reduces the influence of light emitted from light-emitting units not used in calculating the deoxyhemoglobin concentration Φr on the light-emitting units used in calculating the deoxyhemoglobin concentration Φr, thereby preventing a decrease in the accuracy of calculating the blood light-absorbing substance concentration by pulse photometry.

[0081] 8 shows another example of the operation of pulse photometry system 10. In this example, pulse photometer 30 calculates the concentration Φ of oxygenated hemoglobin (OHb) and the concentration Φ of methemoglobin (MetHb). Oxygenated hemoglobin is an example of a first light-absorbing substance in blood. Methemoglobin is an example of a second light-absorbing substance in blood.

[0082] In this example, in order to calculate the concentration Φo of oxygenated hemoglobin, the first light-emitting element 211 and the second light-emitting element 212 are used. The calculation method is the same as the example described with reference to Figures 4 and 5, so repeated description will be omitted.

[0083] In this example, the fourth light-emitting element 214 and the eighth light-emitting element 218 are used to calculate the concentration Φm of methemoglobin. Methemoglobin has wavelength-dependent absorbance. The fourth wavelength λ4 and the eighth wavelength λ8 are selected as two wavelengths that result in a significant difference in the absorbance of methemoglobin. The fourth wavelength λ4 is an example of a third wavelength that is not used in calculating the concentration of the first blood light-absorbing substance. The fourth wavelength λ4 is also an example of a third wavelength that is used in calculating the concentration of the second blood light-absorbing substance. The eighth wavelength λ8 is an example of a fourth wavelength that is not used in calculating the concentration of the first blood light-absorbing substance. The eighth wavelength λ8 is also an example of a fourth wavelength that is used in calculating the concentration of the second blood light-absorbing substance.

[0084] The concentration Φm of methemoglobin is calculated based on the ratio (ΔA4 / ΔA8) of the fourth change amount ΔA4 to the eighth change amount ΔA8. That is, the processor 31 of the pulse photometer 30 calculates the concentration Φm of methemoglobin based on the fourth detection signal DS4 and the eighth detection signal DS8 output from the light receiving unit 22.

[0085] The processor 31 can output a signal OS corresponding to the methemoglobin concentration Φm from the output interface 32. The signal OS is subjected to appropriate processing. Examples of such processing include calculating a value that can be obtained based on the concentration Φm, displaying at least one of the value of the concentration Φm and a value obtained based on the concentration Φm, and performing a reporting operation based on at least one of the value of the concentration Φm and a value obtained based on the concentration Φm.

[0086] In this example, the first light-emitting section 211, the second light-emitting section 212, the fourth light-emitting section 214, and the eighth light-emitting section 218 are arranged so as to satisfy the following conditions. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b. The distance D48 between the fourth reference point 214b and the eighth reference point 218b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D48 between the fourth reference point 214b and the eighth reference point 218b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b.

[0087] According to the above configuration, the first light-emitting element 211 and the second light-emitting element 212 used to calculate the oxygenated hemoglobin concentration Φo can be arranged closer to each other, and the fourth light-emitting element 214 and the eighth light-emitting element 218 used to calculate the methemoglobin concentration Φm can be arranged closer to each other.

[0088] This reduces the influence of the optical path length difference from the multiple light-emitting elements used in the calculation of the oxygenated hemoglobin concentration Φo and the methemoglobin concentration Φm on the change in absorbance due to pulsation from the light-receiving element 22. Therefore, it is possible to suppress a decrease in the accuracy of calculating the concentration of light-absorbing substances in blood by pulse photometry.

[0089] As illustrated in FIG. 9, the seventh light-emitting unit 217 can be used to calculate the concentration Φm of methemoglobin. The seventh wavelength λ7 is selected as a wavelength at which a significant difference in the absorbance of methemoglobin appears relative to at least one of the fourth wavelength λ4 and the eighth wavelength λ8. The seventh wavelength λ7 is an example of a fourth wavelength that is not used to calculate the concentration of the first blood light-absorbing substance. The seventh wavelength λ7 is also an example of a fourth wavelength that is used to calculate the concentration of the second blood light-absorbing substance.

[0090] The seventh light-emitting element 217 may be used in addition to the fourth light-emitting element 214 and the eighth light-emitting element 218, or may be used in place of either the fourth light-emitting element 214 or the eighth light-emitting element 218. In the former case, by using the seventh change amount ΔA7 as a correction term for the calculation result of the ratio between the fourth change amount ΔA4 and the eighth change amount ΔA8, the influence of other light-absorbing substances in blood can be suppressed and the calculation accuracy of the methemoglobin concentration Φm can be improved. In the latter case, when the methemoglobin concentration Φm cannot be calculated satisfactorily using the fourth light-emitting element 214 and the eighth light-emitting element 218 for various reasons, the seventh light-emitting element 217 can be used as an alternative light source to attempt to calculate the methemoglobin concentration Φm.

[0091] In this example, the first light-emitting section 211, the second light-emitting section 212, the fourth light-emitting section 214, and the seventh light-emitting section 217 are arranged so as to satisfy the following conditions. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b. The distance D47 between the fourth reference point 214b and the seventh reference point 217b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D47 between the fourth reference point 214b and the seventh reference point 217b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b.

[0092] According to the above configuration, the first light-emitting element 211 and the second light-emitting element 212 used to calculate the oxygenated hemoglobin concentration Φo can be arranged closer to each other, and the fourth light-emitting element 214 and the seventh light-emitting element 217 used to calculate the methemoglobin concentration Φm can be arranged closer to each other.

[0093] This reduces the influence of the optical path length difference from the multiple light-emitting elements used in the calculation of the oxygenated hemoglobin concentration Φo and the methemoglobin concentration Φm on the change in absorbance due to pulsation from the light-receiving element 22. Therefore, it is possible to suppress a decrease in the accuracy of calculating the concentration of light-absorbing substances in blood by pulse photometry.

[0094] Figure 10 illustrates an example of the configuration of semiconductor light-emitting element 210 that may be included in each of first light-emitting section 211, second light-emitting section 212, third light-emitting section 213, fourth light-emitting section 214, fifth light-emitting section 215, sixth light-emitting section 216, seventh light-emitting section 217, and eighth light-emitting section 218.

[0095] The semiconductor light emitting element 210 includes a substrate 210a, an N-type semiconductor layer 210b, a light emitting layer 210c, a P-type semiconductor layer 210d, a P-type transparent electrode 210e, a P-side electrode 210f, an N-side electrode 210g, and a protective film 210h.

[0096] 10 corresponds to the side closer to the light-emitting surface of each light-emitting unit. In this example, in all of the light-emitting units provided in the probe 20, the P-type semiconductor layer is disposed closer to the light-emitting surface. With this configuration, all of the light-emitting units can be efficiently manufactured using a common semiconductor process.

[0097] In all the light-emitting portions provided in the probe 20, the N-type semiconductor layer may be disposed closer to the light-emitting surface.

[0098] 10, both the P-side electrode 210f and the N-side electrode 210g are disposed on the side facing the light-emitting surface. However, a configuration in which at least one of the P-side electrode 210f and the N-side electrode 210g is disposed on the side facing the substrate 210a may also be employed.

[0099] Figure 11 shows another example of the arrangement of the first light-emitting unit 211, the second light-emitting unit 212, the third light-emitting unit 213, the fourth light-emitting unit 214, the fifth light-emitting unit 215, the sixth light-emitting unit 216, the seventh light-emitting unit 217, and the eighth light-emitting unit 218 in the probe 20. Figure 12 shows an example of the appearance of a part of the probe 20 as seen from the direction of arrow XII in Figure 11. Elements that are substantially the same as those in the example shown in Figures 2 and 3 are given the same reference numerals, and repeated explanations will be omitted.

[0100] 13 shows an example of the operation of pulse photometry system 10 including probe 20 configured as illustrated in FIGS. 11 and 12. In this example, pulse photometer 30 calculates the concentration of oxygenated hemoglobin, Φ, and the concentration of carboxyhemoglobin, Φ. Oxyhemoglobin is an example of a first light-absorbing substance in blood. Carbonmonoxide hemoglobin is an example of a second light-absorbing substance in blood.

[0101] In this example, a first light-emitting unit 211 and a second light-emitting unit 212 are used to calculate the concentration Φo of oxygenated hemoglobin. The configuration for calculating the concentration Φo of oxygenated hemoglobin is the same as the example described with reference to Fig. 4, so repeated description will be omitted. The first wavelength λ1 is an example of a first wavelength used to calculate the concentration of the first light-absorbing substance. The second wavelength λ2 is an example of a second wavelength used to calculate the concentration of the first light-absorbing substance.

[0102] In this example, the third light-emitting unit 213 and the fourth light-emitting unit 214 are used to calculate the carboxyhemoglobin concentration Φc. The configuration for calculating the carboxyhemoglobin concentration Φc is the same as the example described with reference to FIG. 4, so repeated description will be omitted. The fourth wavelength λ4 is an example of a third wavelength not used in calculating the first blood light-absorbing substance concentration. The fourth wavelength λ4 is also an example of a third wavelength used in calculating the second blood light-absorbing substance concentration. The third wavelength λ3 is an example of a fourth wavelength not used in calculating the first blood light-absorbing substance concentration. The third wavelength λ3 is also an example of a fourth wavelength used in calculating the second blood light-absorbing substance concentration.

[0103] In this example, the first light-emitting section 211, the second light-emitting section 212, the third light-emitting section 213, and the fourth light-emitting section 214 are arranged so as to satisfy the following conditions. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b. The distance D43 between the fourth reference point 214b and the third reference point 213b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D43 between the fourth reference point 214b and the third reference point 213b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b.

[0104] According to the above configuration, the first light-emitting element 211 and the second light-emitting element 212 used to calculate the oxygenated hemoglobin concentration Φo can be arranged closer to each other, and the third light-emitting element 213 and the fourth light-emitting element 214 used to calculate the carboxyhemoglobin concentration Φc can be arranged closer to each other.

[0105] This reduces the influence of the optical path length difference from the multiple light-emitting elements used in the calculation of the oxygenated hemoglobin concentration Φo and the carbon monoxide hemoglobin concentration Φc on the change in absorbance due to pulsation from the light-receiving element 22. Therefore, it is possible to suppress a decrease in the accuracy of calculating the concentration of light-absorbing substances in blood by pulse photometry.

[0106] As illustrated in Fig. 14, the seventh light-emitting unit 217 can be used to calculate the carboxyhemoglobin concentration Φc. The configuration for calculating the carboxyhemoglobin concentration Φc is the same as the example described with reference to Fig. 5, so repeated description will be omitted. The seventh wavelength λ7 is an example of a fourth wavelength that is not used to calculate the first blood light-absorbing substance concentration. The seventh wavelength λ7 is also an example of a fourth wavelength that is used to calculate the second blood light-absorbing substance concentration.

[0107] In this example, the first light-emitting section 211, the second light-emitting section 212, the fourth light-emitting section 214, and the seventh light-emitting section 217 are arranged so as to satisfy the following conditions. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b. The distance D47 between the fourth reference point 214b and the seventh reference point 217b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D47 between the fourth reference point 214b and the seventh reference point 217b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b.

[0108] According to the above configuration, the first light-emitting element 211 and the second light-emitting element 212 used to calculate the oxygenated hemoglobin concentration Φo can be arranged closer to each other, and the fourth light-emitting element 214 and the seventh light-emitting element 217 used to calculate the carboxyhemoglobin concentration Φc can be arranged closer to each other.

[0109] This reduces the influence of the optical path length difference from the multiple light-emitting elements used in the calculation of the oxygenated hemoglobin concentration Φo and the carbon monoxide hemoglobin concentration Φc on the change in absorbance due to pulsation from the light-receiving element 22. Therefore, it is possible to suppress a decrease in the accuracy of calculating the concentration of light-absorbing substances in blood by pulse photometry.

[0110] Figure 15 shows another example of the operation of pulse photometry system 10 including probe 20 configured as illustrated in Figures 11 and 12. In this example, pulse photometer 30 calculates the concentration Φr of deoxygenated hemoglobin. Deoxygenated hemoglobin is an example of a first light-absorbing substance in blood.

[0111] In this example, the third light-emitting element 213 and the eighth light-emitting element 218 are used to calculate the concentration Φr of deoxygenated hemoglobin. Deoxygenated hemoglobin has wavelength-dependent absorbance. The configuration for calculating the concentration Φr of deoxygenated hemoglobin is the same as the example described with reference to FIG. 6, so repeated description will be omitted. The third wavelength λ3 is an example of a first wavelength used to calculate the concentration of the first light-absorbing substance. The eighth wavelength λ8 is an example of a second wavelength used to calculate the concentration of the first light-absorbing substance.

[0112] In this example, at least one of the fifth light-emitting unit 215 and the sixth light-emitting unit 216 is used to determine the attachment state of the probe 20 to the subject's body 40. The configuration related to the attachment state determination is the same as the example described with reference to Fig. 6, so repeated description will be omitted. Each of the fifth wavelength λ5 and the sixth wavelength λ6 is an example of a third wavelength that is not used in calculating the first blood light-absorbing substance concentration.

[0113] In this example, the fifth light-emitting section 215, the sixth light-emitting section 216, the third light-emitting section 213, and the eighth light-emitting section 218 are arranged so as to satisfy the following conditions. The distance D38 between the third reference point 213b and the eighth reference point 218b is shorter than the distance D35 between the third reference point 213b and the fifth reference point 215b. The distance D38 between the third reference point 213b and the eighth reference point 218b is shorter than the distance D36 between the third reference point 213b and the sixth reference point 216b.

[0114] According to the above configuration, it is possible to reduce the influence of light emitted from the light-emitting unit not used in calculating the deoxygenated hemoglobin concentration Φr on the light-emitting unit used in calculating the deoxygenated hemoglobin concentration Φr, thereby suppressing a decrease in the accuracy of calculating the blood light-absorbing substance concentration by pulse photometry.

[0115] 16, the seventh light-emitting unit 217 can be used to calculate the concentration Φr of deoxyhemoglobin. The configuration for calculating the concentration Φr of deoxyhemoglobin is the same as the example described with reference to FIG. 7, so repeated description will be omitted. The seventh wavelength λ7 is an example of the second wavelength used to calculate the concentration of the first light-absorbing substance.

[0116] In this example, the fifth light-emitting section 215, the sixth light-emitting section 216, the third light-emitting section 213, and the seventh light-emitting section 217 are arranged so as to satisfy the following conditions. The distance D37 between the third reference point 213b and the seventh reference point 217b is shorter than the distance D35 between the third reference point 213b and the fifth reference point 215b. The distance D37 between the third reference point 213b and the seventh reference point 217b is shorter than the distance D36 between the third reference point 213b and the sixth reference point 216b.

[0117] The above configuration also reduces the influence of light emitted from light-emitting units not used in calculating the deoxyhemoglobin concentration Φr on the light-emitting units used in calculating the deoxyhemoglobin concentration Φr, thereby preventing a decrease in the accuracy of calculating the blood light-absorbing substance concentration by pulse photometry.

[0118] 17 shows another example of the operation of pulse photometry system 10 including probe 20 configured as illustrated in FIGS. 11 and 12. In this example, pulse photometer 30 calculates the concentration of oxygenated hemoglobin, Φ, and the concentration of methemoglobin, Φ. Oxygenated hemoglobin is an example of a first light-absorbing substance in blood. Methemoglobin is an example of a second light-absorbing substance in blood.

[0119] In this example, in order to calculate the concentration Φo of oxygenated hemoglobin, the first light-emitting unit 211 and the second light-emitting unit 212 are used. The configuration for calculating the concentration Φo of oxygenated hemoglobin is the same as that of the example described with reference to Figs. 4 and 5, and therefore, repeated description will be omitted.

[0120] In this example, the fourth light-emitting unit 214 and the seventh light-emitting unit 217 are used to calculate the methemoglobin concentration Φm. The configuration for calculating the methemoglobin concentration Φm is the same as the example described with reference to FIG. 9, so repeated explanation will be omitted. The fourth wavelength λ4 is an example of a third wavelength not used in calculating the first blood light-absorbing substance concentration. The fourth wavelength λ4 is also an example of a third wavelength used in calculating the second blood light-absorbing substance concentration. The seventh wavelength λ7 is an example of a fourth wavelength not used in calculating the first blood light-absorbing substance concentration. The seventh wavelength λ7 is also an example of a fourth wavelength used in calculating the second blood light-absorbing substance concentration.

[0121] In this example, the first light-emitting section 211, the second light-emitting section 212, the fourth light-emitting section 214, and the seventh light-emitting section 217 are arranged so as to satisfy the following conditions. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D12 between the first reference point 211b and the second reference point 212b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b. The distance D47 between the fourth reference point 214b and the seventh reference point 217b is shorter than the distance D41 between the fourth reference point 214b and the first reference point 211b. The distance D47 between the fourth reference point 214b and the seventh reference point 217b is shorter than the distance D42 between the fourth reference point 214b and the second reference point 212b.

[0122] According to the above configuration, the first light-emitting element 211 and the second light-emitting element 212 used to calculate the oxygenated hemoglobin concentration Φo can be arranged closer to each other, and the fourth light-emitting element 214 and the seventh light-emitting element 217 used to calculate the methemoglobin concentration Φm can be arranged closer to each other.

[0123] This reduces the influence of the optical path length difference from the multiple light-emitting elements used in the calculation of the oxygenated hemoglobin concentration Φo and the methemoglobin concentration Φm on the change in absorbance due to pulsation from the light-receiving element 22. Therefore, it is possible to suppress a decrease in the accuracy of calculating the concentration of light-absorbing substances in blood by pulse photometry.

[0124] 18 shows another example of the operation of pulse photometry system 10 including probe 20 configured as illustrated in FIGS. 11 and 12. In this example, pulse photometer 30 calculates a carboxyhemoglobin concentration Φc and a methemoglobin concentration Φm. Carboxyhemoglobin is an example of a first light-absorbing substance in blood. Methemoglobin is an example of a second light-absorbing substance in blood.

[0125] In this example, the fourth light-emitting element 214 and the seventh light-emitting element 217 are used to calculate the carboxyhemoglobin concentration Φc. The configuration for calculating the carboxyhemoglobin concentration Φc is the same as the example described with reference to FIG. 5, so repeated explanation will be omitted. The fourth wavelength λ4 is an example of a first wavelength used to calculate the first blood light-absorbing substance concentration. The seventh wavelength λ7 is an example of a second wavelength used to calculate the first blood light-absorbing substance concentration.

[0126] In this example, the fourth light-emitting element 214 and the eighth light-emitting element 218 are used to calculate the methemoglobin concentration Φm. The configuration for calculating the methemoglobin concentration Φm is the same as the example described with reference to Fig. 8, so repeated description will be omitted. The eighth wavelength λ8 is an example of a third wavelength that is not used to calculate the first blood light-absorbing substance concentration.

[0127] In this example, the fourth light-emitting section 214, the seventh light-emitting section 217, and the eighth light-emitting section 218 are arranged so as to satisfy the following conditions. The distance D47 between the fourth reference point 214b and the seventh reference point 217b is shorter than the distance D48 between the fourth reference point 214b and the eighth reference point 218b.

[0128] It should be noted that the third light-emitting unit 213 may be used instead of the eighth light-emitting unit 218. In this case, the third light-emitting unit 213, the fourth light-emitting unit 214, and the seventh light-emitting unit 217 are arranged so as to satisfy the following conditions. The distance D47 between the fourth reference point 214b and the seventh reference point 217b is shorter than the distance D37 between the third reference point 213b and the seventh reference point 217b.

[0129] For example, consider a case where the importance of calculating the carboxyhemoglobin concentration Φc is higher than the importance of calculating the methemoglobin concentration Φm. With the above configuration, it is possible to reduce the influence of the optical path length difference from the multiple light-emitting elements used in the calculation to the light-receiving element 22 on the change in absorbance due to pulsation for the carboxyhemoglobin concentration Φc. In other words, when some of the multiple light-emitting elements are used in combination to calculate the concentrations of multiple light-absorbing substances, it is possible to suppress a decrease in the calculation accuracy of the light-absorbing substance concentrations, which are relatively more important.

[0130] The above-described embodiments are merely examples for facilitating understanding of the present invention, and the configurations according to the above-described embodiments may be appropriately modified or improved without departing from the spirit and scope of the present invention.

[0131] Depending on the number and types of light-absorbing substances in blood whose concentrations need to be calculated, pulse photometry system 10 may be configured to include any number of light-emitting units, three or more. Examples of other light-absorbing substances in blood include bilirubin and glucose.

[0132] The light-absorbing substances in blood whose concentrations are to be calculated may include not only substances produced in the subject's body, but also dyes injected into blood vessels for purposes such as cardiac output measurement using indocyanine green (ICG), liver function measurement, and contrast examinations.

[0133] In the above embodiment, the plurality of light-emitting elements are arranged at equal intervals. However, the interval between adjacent light-emitting elements can be determined appropriately depending on the number and types of light-absorbing substances in blood whose concentrations need to be calculated.

[0134] The pulse photometer 30 may be provided as an independent device, or may be implemented as a device that provides a function for calculating the concentration of light-absorbing substances in blood in a biological information monitor that acquires multiple types of biological parameters. [Explanation of symbols]

[0135] 10: pulse photometry system, 20: probe, 210: semiconductor light emitting element, 210b: N-type semiconductor layer, 210d: P-type semiconductor layer, 211: first light emitting portion, 211a: first light emitting surface, 211b: first reference point, 212: second light emitting portion, 212a: second light emitting surface, 212b: second reference point, 213: third light emitting portion, 213a: third light emitting surface, 213b: third reference point, 214: fourth light emitting portion, 214a: fourth light emitting surface, 214b: fourth reference point, 215: fifth light-emitting unit, 215a: fifth light-emitting surface, 215b: fifth reference point, 216: sixth light-emitting unit, 216a: sixth light-emitting surface, 216b: sixth reference point, 217: seventh light-emitting unit, 217a: seventh light-emitting surface, 217b: seventh reference point, 218: eighth light-emitting unit, 218a: eighth light-emitting surface, 218b: eighth reference point, 22: light-receiving unit, 30: pulse photometer, 31: processor, 33: input interface 40: subject's body, DS1: first detection signal, DS2: second detection signal, DS3: third detection signal, DS4: fourth detection signal, DS5: fifth detection signal, DS6: sixth detection signal, DS7: seventh detection signal, DS8: eighth detection signal, L1: first light, L2: second light, L3: third light, L4: fourth light, L5: fifth light, L6: sixth light, L7: seventh light, L8: eighth light, N1: first normal, N2: second normal line, N3: third normal, N4: fourth normal, N5: fifth normal, N6: sixth normal, N7: seventh normal, N8: eighth normal, λ1: first wavelength, λ2: second wavelength, λ3: third wavelength, λ4: fourth wavelength, λ5: fifth wavelength, λ6: sixth wavelength, λ7: seventh wavelength, λ8: eighth wavelength, Φc: concentration of carboxyhemoglobin, Φm: concentration of methemoglobin, Φo: concentration of oxygenated hemoglobin, Φr: concentration of deoxyhemoglobin

Claims

1. A probe connected to a pulse photometer, a first light-emitting unit having a first light-emitting surface from which first light having a first wavelength used to calculate a concentration of a light-absorbing substance in the first blood of the subject is emitted; a second light-emitting unit having a second light-emitting surface from which second light having a second wavelength different from the first wavelength and used to calculate the first blood light-absorbing substance concentration is emitted; a third light-emitting unit having a third light-emitting surface that emits third light having a third wavelength that is different from the first wavelength and the second wavelength and that is not used in calculating the first blood light-absorbing substance concentration; a light receiving unit that outputs a first signal corresponding to the intensity of the first light that has passed through a tissue of the subject, a second signal corresponding to the intensity of the second light that has passed through the tissue, and a third signal corresponding to the intensity of the third light that has passed through the tissue; It is equipped with the first light-emitting surface, the second light-emitting surface, and the third light-emitting surface are normal to each other; a first reference point on the first light-emitting surface, a second reference point on the second light-emitting surface, and a third reference point on the third light-emitting surface are located at the center of each light-emitting surface; the first light-emitting surface and the second light-emitting surface are arranged to be aligned in a first direction intersecting the normal direction without sandwiching the light-receiving unit therebetween, the first light-emitting surface and the third light-emitting surface are arranged to be aligned in the normal direction and a second direction intersecting the first direction without sandwiching the light-receiving unit therebetween, a distance between the first reference point and the second reference point as viewed from the normal direction is shorter than a distance between the third reference point and the first reference point as viewed from the normal direction; probe.

2. A probe connected to a pulse photometer, a first light-emitting unit having a first light-emitting surface from which first light having a first wavelength used to calculate a concentration of a light-absorbing substance in the first blood of the subject is emitted; a second light-emitting unit having a second light-emitting surface from which second light having a second wavelength different from the first wavelength and used to calculate the first blood light-absorbing substance concentration is emitted; a third light-emitting unit having a third light-emitting surface that emits third light having a third wavelength that is different from the first wavelength and the second wavelength and that is not used in calculating the first blood light-absorbing substance concentration; It is equipped with the first light-emitting surface, the second light-emitting surface, and the third light-emitting surface are normal to each other; a first reference point on the first light-emitting surface, a second reference point on the second light-emitting surface, and a third reference point on the third light-emitting surface are located at the center of each light-emitting surface; the first light-emitting surface and the second light-emitting surface are arranged to be aligned in a first direction intersecting the normal direction, the first light-emitting surface and the third light-emitting surface are arranged to be aligned in the normal direction and a second direction intersecting the first direction, a distance between the first reference point and the second reference point as viewed from the normal direction is shorter than a distance between the third reference point and the first reference point as viewed from the normal direction; The third light is used to calculate a second blood light absorber concentration of the subject, which is different from the first blood light absorber concentration. probe.

3. the first light-emitting unit, the second light-emitting unit, and the third light-emitting unit each include a semiconductor light-emitting unit in which the same type of semiconductor layer is arranged closer to the first light-emitting surface, the second light-emitting surface, and the third light-emitting surface, respectively; The probe according to claim 1 or 2.

4. a fourth light-emitting unit having a fourth light-emitting surface that emits fourth light having a fourth wavelength that is different from the first wavelength, the second wavelength, and the third wavelength and that is not used in calculating the first blood light-absorbing substance concentration, a normal direction of the fourth light-emitting surface coincides with the normal direction, a fourth reference point of the fourth light-emitting surface is a center of the fourth light-emitting surface; a distance between the fourth reference point and the third reference point as viewed from the normal direction is shorter than a distance between the first reference point or the second reference point and the third reference point; A probe according to any one of claims 1 to 3.

5. the third light and the fourth light are used to calculate a second blood light absorber concentration of the subject, which is different from the first blood light absorber concentration; The probe of claim 4.

6. the first light-emitting unit, the second light-emitting unit, the third light-emitting unit, and the fourth light-emitting unit each include a semiconductor light-emitting unit in which the same type of semiconductor layer is arranged closer to the first light-emitting surface, the second light-emitting surface, the third light-emitting surface, and the fourth light-emitting surface, respectively; The probe according to claim 4 or 5.

7. the first blood light-absorbing substance concentration and the second blood light-absorbing substance concentration are two selected from an oxygenated hemoglobin concentration, a deoxygenated hemoglobin concentration, a carboxyhemoglobin concentration, and a methemoglobin concentration; The probe according to claim 2 or 5.

8. a first light-emitting unit having a first light-emitting surface from which first light having a first wavelength is emitted; a second light-emitting unit having a second light-emitting surface from which second light having a second wavelength different from the first wavelength is emitted; a third light-emitting unit having a third light-emitting surface from which third light having a third wavelength different from the first wavelength and the second wavelength is emitted; a light receiving unit that outputs a first signal corresponding to the intensity of the first light that has passed through a tissue of a subject, a second signal corresponding to the intensity of the second light that has passed through the tissue, and a third signal corresponding to the intensity of the third light that has passed through the tissue; a processor that calculates a first blood light absorber concentration of the subject based on the first signal and the second signal, but not based on the third signal; the first light-emitting surface, the second light-emitting surface, and the third light-emitting surface are normal to each other; a first reference point on the first light-emitting surface, a second reference point on the second light-emitting surface, and a third reference point on the third light-emitting surface are located at the center of each light-emitting surface; the first light-emitting surface and the second light-emitting surface are arranged to be aligned in a first direction intersecting the normal direction without sandwiching the light-receiving unit therebetween, the first light-emitting surface and the third light-emitting surface are arranged to be aligned in the normal direction and a second direction intersecting the first direction without sandwiching the light-receiving unit therebetween, a distance between the first reference point and the second reference point as viewed from the normal direction is shorter than a distance between the third reference point and the first reference point as viewed from the normal direction; Pulse photometry system.

9. A first light-emitting unit having a first light-emitting surface from which first light having a first wavelength is emitted; a second light-emitting unit having a second light-emitting surface from which second light having a second wavelength different from the first wavelength is emitted; a third light-emitting unit having a third light-emitting surface from which third light having a third wavelength different from the first wavelength and the second wavelength is emitted; a light receiving unit that outputs a first signal corresponding to the intensity of the first light that has passed through a tissue of a subject, a second signal corresponding to the intensity of the second light that has passed through the tissue, and a third signal corresponding to the intensity of the third light that has passed through the tissue; a processor that calculates a first blood light absorber concentration of the subject based on the first signal and the second signal, but not based on the third signal; the first light-emitting surface, the second light-emitting surface, and the third light-emitting surface are normal to each other; a first reference point on the first light-emitting surface, a second reference point on the second light-emitting surface, and a third reference point on the third light-emitting surface are located at the center of each light-emitting surface; the first light-emitting surface and the second light-emitting surface are arranged to be aligned in a first direction intersecting the normal direction, the first light-emitting surface and the third light-emitting surface are arranged to be aligned in the normal direction and a second direction intersecting the first direction, a distance between the first reference point and the second reference point as viewed from the normal direction is shorter than a distance between the third reference point and the first reference point as viewed from the normal direction; The third light is used to calculate a second blood light absorber concentration of the subject, which is different from the first blood light absorber concentration. Pulse photometry system.

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