JPH0629850B2 - Oxygen saturation measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention utilizes the absorption characteristics of hemoglobin in blood,
The present invention relates to an oxygen saturation measuring device for measuring oxygen saturation of hemoglobin.

[Prior Art] Conventionally, as an apparatus and method for measuring the oxygen saturation of hemoglobin in blood, the light of _two wavelengths λ ₁ and λ ₂ is irradiated into the blood, and the reflected light intensity is measured. The oxygen saturation is obtained from the relational expression such as.

SO ₂ = A + B × (I2 / I1) However, I1 and I2 are reflected light intensities of wavelengths λ ₁ and λ ₂ , respectively, and A and B are constants.

[Problems to be Solved by the Invention] However, in the above method, the physiological factors in blood, particularly the hematocrit value (ratio of red blood cells in blood) greatly influences the measurement result of oxygen saturation. There was a problem of coming. Specifically, the light absorption (reflection) characteristics of blood change depending on the absorption and scattering of pigments and particles in blood, but as shown in Fig. 13, light absorption (reflection) characteristics depend on the binding state of hemoglobin with oxygen and the irradiation wavelength. The coefficient changes greatly. Here, HbO ₂ is oxygenated hemoglobin, Hbr is reduced hemoglobin, and HbCO is carbon monoxide hemoglobin.

As can be seen from this figure, in the vicinity of the wavelength of 800 nm, HbO ₂ and Hbr cross each other, and it is understood that they have the same absorption coefficient. This wavelength is called an isosbestic point, which means that the absorption coefficient does not change depending on the oxygen saturation of hemoglobin.

Figures 14a and 14b show the relationship between the reflected light intensity at wavelengths of 660 nm and 800 nm and the oxygen saturation, and the hematocrit value (H
CT) and hemoglobin (Hb) concentrations are plotted and shown. Bovine blood was used as the blood sample.

In the case of the wavelength of 660 nm shown in FIG. 14a, the absorption coefficient of oxygenated hemoglobin is smaller than that of reduced hemoglobin, so that the reflected light intensity increases as the oxygen saturation increases. Further, in the case of the wavelength of 800 nm in FIG. 14b, since it is the wavelength at the isosbestic point, it can be seen that the change in oxygen saturation is not so affected.

Further, it can be seen from FIGS. 14a and 14b that the reflected light intensity decreases as the hematocrit value decreases for each wavelength.

It should be noted that the measurement of the reflected light intensities is a result obtained by previously calibrating the reflected light intensities with a white reflector to a predetermined value.

Here, from the measured values of the reflected light intensity at wavelengths 660 nm and 800 nm shown in FIGS. 14a and 14b, the oxygen saturation calculated using the above relational expression and the OSM2 hemoximeter (manufactured by Radiometer) were used. The relationship with the measured oxygen saturation is shown in FIG. From this result, the oxygen saturation calculated by the above relational expression was significantly affected by the hematocrit value in the region where the oxygen saturation was low, and the calculated oxygen saturation value had a large error.

Further, in the conventional method, the oxygen saturation in blood could not be continuously and accurately measured without being affected by the hematocrit value.

[Means for Solving Problems] An object of the present invention is to obtain an accurate oxygen saturation value without being affected by the hematocrit value even in a region where the oxygen saturation is low, and continuously. (EN) An oxygen saturation measuring device capable of accurately obtaining oxygen saturation in blood without being affected by a hematocrit value.

What achieves the above-mentioned object is that the first light irradiation function of irradiating blood with the first wavelength into the blood and the light with the first wavelength, and the absorption coefficient of oxygenated hemoglobin and reduced hemoglobin are different. Light irradiation having a second light irradiation function of irradiating blood with substantially equal second wavelength into blood and a third light irradiation function of irradiating blood with light of the same wavelength as the second wavelength. And a distance from the light irradiation unit having the second light irradiation function and a distance from the light irradiation unit having the third light irradiation function, and the light irradiation unit having each of the light irradiation functions. Detecting means for detecting the reflected light intensity from the blood of light radiated into the blood, and the third means based on the reflected light intensity of the light radiated by the third light radiating function detected by the detecting means. Hemoglobin concentration or hematocrit value using the reflected light intensity signal A correction value calculating means for calculating correction value (C ₁₎ to be used in order to reduce measurement errors caused by,
Using the correction value (C ₁ ) output from the correction value calculation means, the first reflection based on the reflected light intensity of the light emitted by the first light irradiation function that is continuously detected by the detection means. correction value of the light intensity signal _{(I1) (I1-C 1} ) and said detecting means by continuously detected by the second second reflected light intensity signal based on the reflected light intensity of the light emitted by the light irradiation function correction value (I2) and (I2-C ₁₎ is calculated,
Using these correction values (I1-C ₁₎ and a (I2-C _1), the correction reflected light intensity ratio calculating means for calculating a correction reflected light intensity ratio, output from the corrected reflected light intensity ratio calculation means An oxygen saturation calculator for calculating the oxygen saturation in blood using the corrected reflected light intensity ratio, and the correction value calculator further includes the second reflected light intensity signal and the third reflected light intensity signal. First correction value calculation means for calculating a first correction value based on a ratio with the light intensity signal, a first correction value output from the first correction value calculation means, and the detection means. The second correction value (C ₁ ) is calculated based on the third reflected light intensity signal (I3) based on the reflected light intensity of the light emitted by the third light irradiation function that is continuously detected. And an oxygen saturation measuring device having a second correction value calculating means.

Further, it is preferable that the light irradiating means comprises a light emitting source and a light irradiating section for irradiating light from the light emitting source into blood. Further, the light emitting means includes a light emitting source that emits light of the first wavelength, a light emitting unit that emits light from the light emitting source into blood, and a common light source that emits light of the second wavelength. And two light irradiation units for irradiating light from the light emitting source into blood from different positions. Further, the first light irradiation function and the second light irradiation function of the light irradiation means include a first light emission source that emits light of the first wavelength and a second light emission source that emits light of the second wavelength. And a common light irradiator that irradiates blood with light from the first and second light sources. Then, the light irradiating means includes the first
A first light emitting source that emits light of a wavelength, a second light emitting source that emits the light of the second wavelength, and a common that irradiates blood from the first light emitting source and the second light emitting source into blood. It is preferable that the first light irradiation unit and the second light irradiation unit that irradiates blood with light from a light emitting source that emits light of the second wavelength are used. Further, the detecting means is configured to reflect, from blood, the light emitted to the blood by the first light emitting function, the second light emitting function, and the third light emitting function of the light emitting means. It is preferably composed of one detection means for detecting the light intensity. Further, the detection means is a reflected light intensity from the blood of the light irradiated into the blood by the first light irradiation function, the second light irradiation function and the third light irradiation function of the light irradiation means. It is preferable that it comprises a plurality of detection means for detecting. Further, it is preferable that in the detection means, the distance from the light irradiation unit having the first light irradiation function is the same as the distance from the light irradiation unit having the second light irradiation function. Further, it is preferable that the light irradiating section is configured by an end face of an optical fiber that transmits the light from the light emitting source. Further, the detecting means includes a photodetector, a light transmitting section for transmitting light to the photodetector, and a photodetecting section, and the photodetecting section is constituted by an end face of an optical fiber forming the light transmitting section. It is preferable that they are Further, the first correction value calculation unit uses the reflected light intensity signal based on the reflected light intensity detected by the detection means to calculate the reflected light intensity ratio [I2 /
[I3], a calculation value input section for measuring the hemoglobin concentration by sampling the measurement blood, and a reflected light intensity signal ratio obtained from several kinds of blood of the same animal species as the measurement target blood measured in advance (I2 '/ I3')
And the hemoglobin concentration Hb, the reflected light intensity ratio [I2 / I corresponding to the hemoglobin concentration input by the above measurement value input means based on the correlation function h (x) calculated from the data.
3] s, the above [I2 / I3] s, and the above [I
2 / I3] to [I2 / I3] / [I2 / I3] s (=
[A]), a hemoglobin concentration reference value (Hb ′) input unit, and a reflected light intensity ratio g (Hb ′) at the hemoglobin concentration reference value (Hb ′) based on the above correlation function h (x). ′), And the first correction value ([I2) from the [A] and the reflected light intensity ratio g (Hb ′).
/ I3] _{Hb = Hb} ') is preferably comprised of a calculation unit for calculating the following formula [I2 / I3] _{Hb = Hb} ' = A * g (Hb '). Further, the first correction value calculation unit calculates the reflected light intensity ratio [I2 / I3] of the two from the reflected light intensity signal based on the reflected light intensity detected by the detection means, and samples the measured blood. Of the hemoglobin concentration and the reflected light intensity signal ratio (I2 '/ I3') and hemoglobin concentration Hb obtained from several bloods of the same animal species as the blood to be measured, which has been measured in advance. A calculation unit for the reflected light intensity ratio [I2 / I3] s corresponding to the hemoglobin concentration input by the measurement value input means based on the correlation function h (x) calculated from the data;
/ I3] s and the above [I2 / I3] to [I2 / I3]
A calculation unit that calculates / [I2 / I3] s (= [A]);
Reflected light intensity ratio g (H
b '), the first correction value ([I2 / I) from the storage unit for storing the value of [A] and the reflected light intensity ratio g (Hb').
3] _{Hb = Hb} ′) is preferably calculated by the formula [I2 / I3] _{Hb = Hb} ′ = A × g (Hb ′). Further, the oxygen saturation calculating means calculates the corrected reflected light intensity ratio (Rs ′) of a certain number of blood measured in advance from the corrected reflected light intensity ratio (Rs) calculated by the corrected reflected light intensity ratio calculating means. ) And the oxygen saturation, the oxygen saturation is preferably calculated based on the correlation function f (Rs) calculated based on the data. Further, the second correction value calculation means irradiates with the first correction value output from the first correction value calculation means and the third light irradiation function continuously detected by the detection means. Using the third reflected light intensity signal (I3) based on the reflected light intensity of the generated light, C ₁ = C ₀ × [I3] × first correction value (where C ₀ is It is a predetermined value stored in the second correction value calculation means.) It is preferable to calculate the second correction value (C ₁ ).

Further, what achieves the above-mentioned object is a first light irradiation function of irradiating blood with a first wavelength of light and the absorption of oxygenated hemoglobin and reduced hemoglobin, which is different from the light of the first wavelength. A second light irradiation function for irradiating blood with a second wavelength having substantially the same coefficient into blood and a third light irradiation function for irradiating blood with a light with the same wavelength as the second wavelength are provided. The light irradiation means is provided so that the distance from the light irradiation unit having the second light irradiation function and the distance from the light irradiation unit having the third light irradiation function are different, and the light having each of the light irradiation functions is provided. Detecting means for detecting the intensity of reflected light from the blood of the light radiated into the blood by the irradiating section, and a first means based on the reflected light intensity of the light radiated by the third light irradiation function Using the reflected light intensity signal of No. 3, the hemoglobin concentration or hematocrit Correction value used to reduce the measurement error caused by the preparative value (C ₁₎ and the correction value calculating means for calculating a correction value outputted from the correction value calculating means (C ₁₎
First detected continuously by the detection means using
The first correction value of the reflected light intensity signal based on the reflected light intensity of the light emitted by the light irradiation function _{(I1) (I1-C 1} )
And a second one based on the reflected light intensity of the light emitted by the second light irradiation function that is continuously detected by the detection means.
Correction value of the reflected light intensity signal (I2) and (I2-C ₁₎ is calculated by using these correction values (I1-C ₁₎ and a (I2-C _1), calculates the corrected reflected light intensity ratio A correction reflected light intensity ratio calculating means; and an oxygen saturation calculating means for calculating oxygen saturation in blood using the corrected reflected light intensity ratio output from the corrected reflected light intensity ratio calculating means. The value calculation means includes a first correction value output means having a first correction value calculation means based on the hemoglobin concentration reference value or a first correction value storage means at a predetermined hemoglobin concentration, and the first correction value. A third reflected light intensity signal (I3) based on the first correction value output from the output unit and the reflected light intensity of the light emitted by the third light irradiation function that is continuously detected by the detection unit. ) And the second correction value (C ₁ )
And an oxygen saturation measuring device having a second correction value calculating means.

Then, the first correction value output means is a hemoglobin concentration reference value (Hb ') input section and a reflected light intensity signal ratio (I2) obtained from several bloods of the same animal species as the blood to be measured which is measured in advance. '/ I3') and the hemoglobin concentration Hb, the reflected light intensity ratio g (Hb ') at the reference value (Hb') of the hemoglobin concentration is calculated based on the reference correlation function h (x). Light intensity ratio g
It is preferable to use (Hb ') as the first correction value. The first correction value output means stores the value of the reflected light intensity ratio g (Hb ') at a predetermined hemoglobin concentration, and outputs the reflected light intensity ratio as the first correction value. Preferably there is.

The first invention of the present application will be described with reference to the embodiment shown in FIG.

The oxygen saturation measuring device of the present invention corrects the influence of the light irradiation means 1, the detection means 2 for detecting the reflected light intensity from the blood of the light irradiated into the blood by the light irradiation means 1, and the hematocrit value. It is formed by the correcting means 3, the oxygen saturation calculating means 4 for calculating the oxygen saturation using the output from the correcting means 3, and the display 5 for displaying the output from the oxygen saturation calculating means 3.

The light irradiating means 1 has a first light irradiating function of irradiating blood with a first wavelength into the blood and a first light irradiating function which is different from the light with the first wavelength and has an almost equal extinction coefficient between oxygenated hemoglobin and reduced hemoglobin. It has a second light irradiation function of irradiating light with two wavelengths into blood and a third light irradiation function of irradiating blood with light of the same wavelength as the second wavelength.

And in what is shown in FIG. 1, the light irradiation means 1 is
And a second light emitting source that emits light of a first wavelength, a second light emitting source that emits light of a second wavelength, and a first light emitting source and A common first light irradiator that irradiates blood with light from the second light emission source and a third light irradiator that emits light of a second wavelength that constitutes a third light irradiation function.
And a second light irradiator that irradiates blood with light from this light source.

More specifically, the light irradiating means 1 comprises a light emitting source and a light irradiating section for irradiating light from the light emitting source into the blood. The light emitting source is composed of three light emitting diodes 11, 12, 13 and the light emitting diode 11 is The light emitting diodes 12 and 13 emit light of a wavelength of about 660 nm (λ ₁ ), and the light emitting diodes 12 and 13 emit light of about 800 nm (λ ₂ ). Generate a pulse with an interval and a predetermined time width,
The light emitting diodes 11, 12 and 13 are configured to alternately emit light through the drive circuit 15. And light emitting diode
The light emitted from 11 and the light emitted from the light emitting diode 12 are transmitted through the optical coupler 17 to the optical fiber 18a for emitting light.
The light is irradiated into the blood from the light irradiation section 20 formed by the end face of the optical fiber 18a. By doing so, the light irradiation unit can be one, the device can be downsized, and the light irradiation unit of the light having the wavelength λ ₁ from the light emitting diode 11 and the wavelength from the light emitting diode 12 can be The light irradiation part of the light of λ ₂ can be set at the same distance with respect to the detecting means described later.

Further, the light emitted from the light emitting diode 13 passes through the optical fiber 18b for light emission and is irradiated into the blood by the light irradiation section 19 formed by the end face of the optical fiber 18b.

The light irradiation means 1 is not limited to the one shown in FIG.
May be three light-emitting sources and three light-irradiating units for irradiating blood from the respective light-emitting sources into blood.
Light source that emits light of a wavelength of, a light irradiation unit that irradiates light from the light source into blood, a common light source that emits light of a second wavelength, and light from this light source from different positions. It may be configured with two light irradiation units that irradiate the inside.

The detection means 2 is for detecting the reflected light intensity from the blood of the light emitted from the light irradiation means 1. In the structure shown in FIG. 1, the light detecting section 21 of the detecting means 1 is formed by the end face of the optical fiber 18c for receiving light, and the distance from the light irradiating section 19 and the distance from the light irradiating section 20 are the same. It is provided differently.

FIG. 2 shows an end face of a specific example of the sensor probe 50 having the light irradiation parts 19 and 20 of the light irradiation means and the light detection part 21 of the light detection means.

Between the center of the light emitting part 20 formed by the end face of the light emitting optical fiber in which two light emitting optical fibers and one light receiving optical fiber are linearly arranged and the light detecting part 21 formed by the end face of the light receiving fiber. Is 0.25 mm, the distance between the centers of the light emitting portion 19 formed by the end face of the optical fiber for light emission and the light detecting portion 21 formed by the end face of the light receiving fiber is 0.50 mm, and between them They are provided at different distances and are fixed with an epoxy resin adhesive 52. Then, with the distance between the two light-emitting optical fibers and one light-receiving optical fiber set in this way, the hemoglobin concentration was changed using bovine blood collected from three different individuals, and the light with a wavelength of 800 nm was changed. Using the reflected light intensities I2 (0.25 mm) and I3 with different light emission-light reception intervals,
(0.5 mm) was measured. The relationship between I2 and hemoglobin concentration was as shown in FIG. 16, and the relationship between I3 and hemoglobin concentration was as shown in FIG. It was found that I2 and I3 did not change in the same tendency due to the difference in hemoglobin concentration. By using the ratio of I2 and I3, a signal resulting from the hemoglobin concentration can be obtained. Therefore, in the present invention, I3 is used in addition to I2 in order to reduce the measurement error due to the hemoglobin concentration. As an optical fiber, multi-component glass, core diameter 200
The thing with a micrometer was used. The peripheral portion of the end surface of the sensor probe 50 is polished to have a smooth surface so as not to impair the light transmittance and to prevent thrombus. In the sensor probe described above, the number of the photodetection section 21 is one in order to make the sensor probe smaller, but the number is not limited to this, and the photodetection section may be composed of a plurality of pieces.

Then, FIG. 3 shows a state in which the sensor probe 50 is attached to a connector 56 that can be attached to an extracorporeal circulation circuit (not shown) such as an artificial heart-lung machine. Connector 56
Has an attachment port 58 for the sensor probe 50 protruding outward in the middle of its axial direction. The end surface of the sensor probe 50 is such that the inner wall surface of the connector 56 and the end surface of the sensor probe 50 are substantially flush when attached to the connector 56 so as not to disturb the blood flow flowing in the connector 56. It is processed.

The detection means 2 has a photodiode 16 and a detection amplifier 23 that receive the light detected by the light detection unit 21 and transmitted through the light receiving optical fiber 18c.
16 generates a current according to the intensity of the optical signal, and the detection amplifier 23
Is converted into a voltage signal. Further, the detection means 2 has a signal separation circuit for separating the voltage signal of the detection amplifier 23 into a signal corresponding to the emission wavelengths of the light emitting diodes 11, 12, 13 and the signal separation circuit is an analog switch 24. , 25, 26, 27 and buffer amplifiers 28, 29, 30.

The analog switch 24 has three switches SW1, SW2 and SW3, and each switch is turned “ON” or “OFF” by a signal from the pulse generator 14. For example, when the light emitting diode 11 emits light, the signal from the pulse generator 14 is applied to the analog switch 24, and only SW1 is “ON”.
Then, the voltage signal of the detection amplifier 23 is applied to the capacitor 25 to generate an average signal voltage across the capacitor 25. This indicates the reflected light intensity of the wavelength λ ₁ which is emitted from the light emitting diode 11 into the blood from the light emitting unit 20, is reflected in the blood, and is received by the photodiode 16 via the light detecting unit 21. is there. This average signal voltage is continuously output through the buffer amplifier 28 and is reflected light intensity signal I1.
Becomes Similarly, the same operation is performed by the combination of the light emitting diode 12, the SW2 of the analog switch 24, the capacitor 26, and the buffer amplifier 29, and the wavelength λ _{2 of the} light emitting diode 12 is performed.
And outputs the reflected light intensity signal I2. Furthermore, the light emitting diode 13, the SW3 of the analog switch 24, the capacitor 27,
The same operation is performed by the combination of the buffer amplifiers 30, and the reflected light intensity signal I3 of the wavelength λ ₂ of the light emitting diode 13 is output.

Further, the detection means 2 has a processing means for the signals of the reflected light intensities I1, I2, I3 output from the signal separation circuit, and the signal processing means has the reflected light intensity signals I1, I2, I3.
Analog-to-digital converter that converts digital to digital signals
31 and an average value calculator 32 that stores the digitized reflected light intensity signals I1, I2, I3 output from the analog-digital converter 31 a predetermined number of times (n times) or within a predetermined time and calculates an average value. have.

Then, the correction means 3 for correcting the influence of the hematocrit value
Is a first correction value calculation unit 40 and a second correction value calculation unit 42
And a corrected reflected light intensity ratio calculation unit 44.

The first correction value calculation unit 40 includes one digitized reflected light intensity signal I2, I3 output from the average value calculation unit 32.
(For example, the reflected light intensity signals I2, I at the start of measurement
3 digitized signal) and the reflected light intensity ratio (I2 /
I3) is included. I2 and I3
As shown in FIG. 16 and FIG. 17, the changes are different due to the difference in the hemoglobin concentration, and particularly, the difference is large in the region where the hemoglobin concentration is low. Then, by calculating the ratio of I2 and I3, a signal due to the hemoglobin concentration can be obtained. And
The output from the calculation unit of the reflected light intensity ratio (I2 / I3) is output as the first correction value. Therefore, in this case, the first correction value calculation unit 40 becomes a calculation unit that calculates the reflected light intensity ratio (I2 / I3) from the digitized reflected light intensity signals I2 and I3, and newly adds the first correction value. Until the value is calculated, the first correction value becomes a fixed correction value.

Further, preferably, as shown in FIG. 4, the first correction value calculation unit 40 calculates the reflected light intensity ratio (I2 / I3) calculation unit 60.
A measurement value input means 62 for sampling the measurement blood and measuring the hemoglobin concentration thereof, and I2 / I3 and hemoglobin concentration Hb obtained from several kinds of blood of the same animal species as the measurement target blood which has been measured in advance. From the data,
Reference correlation function h (x) h (x) = b ₂ · x ² + b ₁ · x + b ₀ that is a calculated higher-order correlation curve (for example, quadratic regression curve) [where x = I2 / I3, hereinafter, h (X) is referred to as an Hb calibration curve], and an inverse function g (H) of the above h (x)
b) the inverse function g (Hb) storage unit 64 and the inverse function g
From (Hb), the reflected light reference ratio [I2 / I3] corresponding to the hemoglobin concentration input by the above measurement value input means
s calculation unit 65 and [I2 / I output from this calculation unit
3] s and one digitized reflected light intensity signal I2, I3 output from the average value calculation unit 32, the reflected light intensity ratio (I2 / I3) is output from the operation unit (I2 / I3) From the calculation unit 66 for calculating (I2 / I3) / [I2 / I3] s (= A), and the hemoglobin concentration reference value (H
b ') From the input section 67 and the Hb calibration curve of the Hb calibration curve storage section 63, the reflected light intensity ratio g (Hb') is calculated from the reference value (Hb ') of the hemoglobin concentration (for example, hemoglobin concentration of 15%).
And the reflected light intensity ratio g output from the calculation unit 68 that calculates (I2 / I3) / [I2 / I3] s (= A)
G (H
b ′), a first correction value [I2 / I3] _{Hb = Hb} ′ [I2 / I3] _{Hb = Hb} ′ = A × g (Hb ′). preferable. Even in this case, the first correction value is a fixed correction value until the first correction value is newly calculated.

Further, in the above description, the Hb calibration curve storage unit 63, the hemoglobin concentration reference value (Hb ′) input unit 67, and the Hb
a calculation unit 68 for calculating a reflected light intensity ratio g (Hb ') from a reference value (Hb') of hemoglobin concentration (for example, hemoglobin concentration 15%) from the inverse function g (Hb) calculated based on the b calibration curve. The case where the reference value (Hb ') of the hemoglobin concentration is fixed to the hemoglobin concentration of 15% in advance and the reflected light intensity ratio calculated from the Hb calibration curve at that time (when the hemoglobin concentration is 15%) has been described. By using a storage unit that stores the value of g (Hb ′), the Hb calibration curve storage unit, the hemoglobin concentration reference value input unit 67, and the Hb calibration curve storage unit Hb calibration curve are used to determine the hemoglobin concentration reference value (Hb ′) Reflected light intensity ratio g (Hb ′)
It is also possible not to provide a calculation unit for calculating

The first correction value signal X (= [I2 / I3] _{Hb = Hb} ') output from the first correction value calculation unit 40 is continuously output from the average value calculation unit 32 and digitized. The reflected light intensity signal [I3] is input to the second correction value calculation unit 42. In the second correction value calculation unit, the second correction value C ₁ C ₁ = C ₀ × [I3] × [I2 / I3] _{Hb = Hb} ′ is calculated using the constant C ₀ stored in advance. In this way, the sequentially detected I3 is added to the calculation of the correction value (C1). Regarding the correction value used for accurate calculation of oxygen saturation, I3
Since a suitable correction value is obtained by using, I3 is integrated in the calculation of C1. I
The reason why a suitable correction value is obtained by using 3 is not clear, but it is considered that I3 is a reflected light intensity signal of 80 nm wavelength light and does not depend on oxygen saturation. A constant value is detected. However, in a situation where such an oxygen saturation measuring device is used, for example, in heart surgery, blood transfusion for supplementing bleeding during surgery, and infusion administration for fluid replacement are performed. This is expected to change the hemoglobin concentration. When I2 changes due to some factor (for example, a rapid partial change in blood flow, a temporary defect of the light receiving element, a temporary voltage drop of the light emitting element, etc.), the same wavelength light is emitted. The reflected light intensity signal I3 of I3 is likely to change for the same reason. It is expected that such a change can be dealt with by using I3 for the calculation of the second correction value.

The second correction value signal C ₁ output from the second correction value calculation unit 44 is continuously output together with the digitized reflected light intensity signals [I1] [I2] output from the average value calculation unit 32. It is input to the corrected reflected light intensity ratio calculation unit 44. Then, the calculating unit 44 uses the above signals to correct the corrected reflected light intensity ratio R
s, Rs = ([I2] -C 1) / ([I1] -C 1) computed.

Then, the oxygen saturation calculation means 4 calculates Rs = ([I
2] −C ₁ ) / ([I1] −C ₁ ) and the oxygen saturation were subjected to cubic regression to obtain a standard correlation function f (x), x = Rs f (x) = a ₃ · Rs ³ + A ₂ · Rs ² + a ₁ · Rs + a
_It has a storage unit for ₀ (= SO ₂ ), and the corrected reflected light intensity ratio calculation unit 44
The oxygen saturation degree SO ₂ is calculated from the corrected reflected light intensity ratio signal Rs output from the above. The constant C _{0 of} the second correction value C ₁
Indicates the variation of data with respect to the standard correlation function f (x) by the standard deviation, and the value was determined so as to be the minimum.

The signal output from the oxygen saturation calculation means 4 is displayed on the display 35. As the display device 35, a known device such as a cathode ray tube, a printer, a liquid crystal display device or a recorder may be used as long as it can notify the measured value to the outside.

Next, the second invention of the present application will be described with reference to the embodiment shown in FIG.

The oxygen saturation measuring device of the present invention comprises a light irradiation unit 1, a detection unit 2 for detecting the intensity of light reflected from blood by the light irradiated into the blood by the light irradiation unit 1, a correction unit 3, and a correction unit. It is formed by an oxygen saturation calculation means 4 for calculating the oxygen saturation using the output from 3 and a display 5 for displaying the output from the oxygen saturation calculation means 4.

The light irradiation means 1, the detection means 2, the oxygen saturation calculation means 4 and the display 5 are the same as those shown in FIGS. 1 to 3. Therefore, different correcting means will be described.

The correction unit 3 includes a first correction value calculation unit 40, a second correction value calculation unit 42, and a corrected reflected light intensity ratio calculation unit 44.

As shown in FIG. 6, the first correction value calculation unit 40 calculates I2 / I3 and hemoglobin concentration Hb obtained from several kinds of blood of the same animal species as the blood to be measured which is measured in advance.
And the reference correlation function h (x) h (x) = b ₂ · x ² + b ₁ · x + b _0, which is a calculated higher-order correlation curve (for example, a quadratic regression curve), where x = I2 / I3, hereinafter h (x) is referred to as Hb calibration curve], and its inverse function g calculated based on the above Hb calibration curve
(Hb) storage unit 64 and hemoglobin concentration reference value (H
b ′) The input light source 67 and the reflected light intensity ratio g which becomes the first correction value from the reference value (Hb ′) of the hemoglobin concentration (eg, hemoglobin concentration 15%) from the Hb calibration curve of the Hb calibration curve storage unit 63. And (Hb ').

Also, in the above description, the Hb calibration curve storage unit 63, the hemoglobin concentration reference value (Hb ′) input unit 67, and the inverse function g (Hb) calculated based on the above Hb calibration curve are used to determine the hemoglobin concentration reference value. From the value (Hb ') (for example, hemoglobin concentration of 15%), the reflected light intensity ratio g (H
The case where the calculation unit 68 for calculating b ′) is provided has been described, but the reference value (H
b ') is fixed to, for example, a hemoglobin concentration of 15%, and the storage unit stores the value of the reflected light intensity ratio g (Hb') calculated from the Hb calibration curve at that time (when the hemoglobin concentration is 15%). Thus, the reflected light intensity ratio g (Hb ') of the hemoglobin concentration reference value (Hb') is calculated from the Hb calibration curve storage unit, the hemoglobin concentration reference value input unit 67, and the Hb calibration curve of the Hb calibration curve storage unit. The calculation unit may not be provided. The first correction value calculator 40 outputs the first output from the calculator 68 that calculates the reflected light intensity ratio g (Hb ').
Correction value signal X (= [I2 / I3] _{Hb = Hb} ') of the second correction value calculation unit together with the digitized reflected light intensity signal [I3] continuously output from the average value calculation unit 32. Entered in 42. The second correction value calculation unit calculates a second correction value C ₁ C ₁ = C ₀ × [I3] × [I2 / I3] _{Hb = Hb} ′ using the constant C ₀ stored in advance. .

The second correction value signal C ₁ output from the second correction value calculation unit 44 is continuously output together with the digitized reflected light intensity signals [I1] [I2] output from the average value calculation unit 32. It is input to the corrected reflected light intensity ratio calculation unit 44. Then, the calculating unit 44 uses the above signals to correct the corrected reflected light intensity ratio R
s, Rs = ([I2] −C ₁ ) / ([I1] −C ₁ ) is calculated.

Then, the oxygen saturation calculation means 4 calculates Rs = ([I
2] −C ₁ ) / ([I1] −C ₁ ) and the oxygen saturation are subjected to cubic regression to obtain a standard correlation function f (x), x = Rs f (x) = a ₃ · _RS. ³ + a ₂ · _RS ² + a ₁ · _RS + a ₀ (= S
O ₂ ) is stored in the corrected reflected light intensity ratio calculation unit 44.
The oxygen saturation degree SO ₂ is calculated from the corrected reflected light intensity ratio signal Rs output from the above. The constant C _{0 of} the second correction value C ₁
Indicates the variation of data with respect to the standard correlation function f (x) by the standard deviation, and the value was determined so as to be the minimum.

The signal output from the oxygen saturation calculation means 4 is displayed on the display 35.

Next, an oxygen saturation measuring method by the oxygen saturation measuring device of the present invention will be described with reference to the flowcharts of FIGS. 7 to 9 using an embodiment.

(Embodiment 1) In the embodiment shown in FIG. 7, as step S1, the connector having the shape shown in FIG. 3 to which the sensor probe shown in FIG. 2 is attached is attached to the blood circuit.

At step S2, about 660n from the light irradiation section 20 formed by the end face of the optical fiber of the light irradiation means shown in FIG.
Light of m (λ ₁ ) and light of approximately 800 nm (λ ₂ ) is sequentially irradiated into the blood from the light irradiation section 19 formed by the end face of the optical fiber, and the detection means 2 causes the light irradiation means 1 to emit the light. The intensity of the reflected light from the blood of each of the obtained lights is detected n times.

In step S3, the average value of the reflected light intensities detected n times is calculated, and the reflected light intensity signals I1 and I are digitized.
2 and I3 are output.

In step S4, it is determined whether or not the first correction value is calculated as the correction for preventing the influence of the hematocrit value. If yes, the process proceeds to step 5.

In step S5, the reflected light intensity ratio (I2 / I3) is calculated from the one (first output) digitized reflected light intensity signal I2, I3 output in step 3, and a first correction value is calculated. [I2 / I3] Store as _{Hb = Hb} '.

In step S6, the first correction value stored in step S5, the digital reflected light intensity signal [I3] continuously output in step S3, and C ₀ stored in advance (in this embodiment, The second correction value C ₁ C ₁ = C ₀ × [I3] × [I2 / I3] _{Hb = Hb} ′ is calculated from 0.23).

In step S7, the corrected reflected light intensity ratio is calculated using the second correction value C ₁ output in step S6 and the digitized reflected light intensity signals [I1] [I2] continuously output in step S3. Rs and Rs = ([I2] −C ₁ ) / ([I1] −C ₁ ) are calculated.

In step S8, Rs = ([I2] −C ₁ ) for data from a certain number of blood measured in advance from the corrected reflected light intensity ratio Rs output in step S7.
/ ([I1] -C ₁₎ and a correlation curve between the oxygen saturation 3 ascribed next reference correlation function f (x), x = Rs f (x) = a 3 · Rs 3 + a 2 · Rs 2 + a ₁・ Rs + a
₀ (= SO ₂ ) (In this example, f (x) = − 4.165 Rs ³ +38.08 Rs ² −136.0 Rs + 180.
Oxygen saturation is calculated from 0.

In step S9, the oxygen saturation calculated in step S8 is displayed.

In step S10, it is determined whether the measurement is to be ended. If not, the process returns to step S2 to repeat the measurement.

FIG. 10 shows the relationship between the number of data (oxygen saturation measured for n = 79) and the oxygen saturation measured with an OSM2 hemoximeter (manufactured by Radiometer) used as a control by using the method of Example 1. From the results, the oxygen saturation value (x) obtained by the method of the present invention is correlated with the oxygen saturation value (y) by the OSM2 hemoximeter, and the correlation coefficient is 1 (y = x ), The error (SD) was sufficiently small, and it was confirmed that accurate measurement could be performed.

(Example 2) In Example 2 shown in FIG.
The connector having the shape shown in FIG. 3 to which the sensor probe shown in the figure is attached is attached to the blood circuit.

At step S2, about 660n from the light irradiation section 20 formed by the end face of the optical fiber of the light irradiation means shown in FIG.
Light of m (λ ₁ ) and light of approximately 800 nm (λ ₂ ) is sequentially irradiated into the blood from the light irradiation section 19 formed by the end face of the optical fiber, and the detection means 2 causes the light irradiation means 1 to emit the light. The intensity of the reflected light from the blood of each of the obtained lights is detected n times.

In step S3, the average value of the reflected light intensities detected n times is calculated, and the reflected light intensity signals I1 and I are digitized.
2 and I3 are output.

In step S4, as a correction for preventing the influence of the hematocrit value, it is determined whether or not to calculate the first correction value used for the correction of the hemoglobin concentration, and if so, the process proceeds to steps 5a and 5b1.
In step 5a, the reflected light intensity ratio (I2 / I3) is calculated from the one (first output) digitized reflected light intensity signal I2, I3 output in step 3, and [I2] / [ I3] is calculated.

In step 5b1, the measurement blood is sampled and the hemoglobin concentration thereof is measured.

As step 5b2, I2 / I3 and hemoglobin concentration H obtained from several types of blood that have been measured and stored in advance.
A higher-order correlation curve (for example, 2
Next-order regression curve) h (x) h (x) = b ₂ · x ² + b ₁ · x + b ₀ h (x) = − 21.51x ² + 53.02x−7.912 [where x = I2 / I3 , H (x) will be referred to as an Hb calibration curve below.] Inverse function g of the Hb calibration curve h (x) stored in the same manner as
(Hb) The reflected light intensity ratio [I2 / I3] s corresponding to the hemoglobin concentration measured by the above is calculated.

In step S6, [I2] / [I3] output in step 5a and [I2] / [I3] output in step 5b2 are output.
The ratio [I2] / [I3] / [I2 / I3] s (= A) of the two is calculated from 2 / I3] s.

In step S7, the reflected light intensity ratio g (Hb ') of the reference value (Hb') of hemoglobin concentration (hemoglobin concentration 15% in this embodiment) is calculated from the stored Hb calibration curve, and output from step S6. [I2] / [I3] / [I2 / I3] s (= A), the first correction value [I2 / I3] _{Hb = Hb} ′ [I2 / I3] _{Hb = Hb} ′ = A × g Calculate (Hb ').

In step S8, the first correction value stored in step S7, the digital reflected light intensity signal [I3] continuously output in step S3, and C ₀ stored in advance (in this embodiment, The second correction value C ₁ C ₁ = C ₀ × [I3] × [I2 / I3] _{Hb = Hb} ′ is calculated from 0.26).

In step S9, the corrected reflected light intensity is calculated by the second correction value C ₁ output in step 8 and the digitized reflected light intensity signals [I1] and [I2] continuously output in step S3. the ratio Rs, Rs = ([I2] -C 1) / calculates the ([I1] -C _1).

In step S10, Rs = ([I2] −C ₁ ) for data from some blood measured in advance from the corrected reflected light intensity ratio Rs output in step S9.
/ ([I1] -C ₁₎ and a correlation curve between the oxygen saturation 3 ascribed next reference correlation function h (x), x = Rs h (x) = a 3 · Rs 3 + a 2 · Rs 2 + a ₁・ Rs + a
₀ (= SO ₂ ) (In this example, h (x) = − 4.165Rs ³ + 38.08Rs ² −136.0Rs + 18
Calculate oxygen saturation from 0.0.

In step S11, the oxygen saturation calculated in step S10 is displayed.

In step S12, it is determined whether the measurement is to be ended. If not, the process returns to step S2 to repeat the measurement.

The oxygen saturation obtained according to this Example 2 and the OSM2 hemoximeter used as a control (manufactured by Radiometer)
Fig. 11 shows the relationship with the oxygen saturation measured in. From this result, the oxygen saturation value (x) obtained by the method of the present invention is extremely high in correlation coefficient = 1 (y = x) with respect to the oxygen saturation value (y) measured by the OSM2 hemoximeter. It was confirmed that the error (SD) was close enough and accurate measurement was possible.

(Example 3) In Example 3 shown in FIG.
The connector having the shape shown in FIG. 3 to which the sensor probe shown in the figure is attached is attached to the blood circuit.

At step S2, about 660n from the light irradiation section 20 formed by the end face of the optical fiber of the light irradiation means shown in FIG.
Light of m (λ ₁ ) and light of approximately 800 nm (λ ₂ ) is sequentially irradiated into the blood from the light irradiation section 19 formed by the end face of the optical fiber, and the detection means 2 causes the light irradiation means 1 to emit the light. The intensity of the reflected light from the blood of each of the obtained lights is detected n times.

In step S3, the average value of the reflected light intensities detected n times is calculated, and the reflected light intensity signals I1 and I are digitized.
2 and I3 are output.

In step S4, it is determined whether or not to calculate the first correction value, and if so, the process proceeds to step 5.

In step 5, a reference correlation function h which is a higher-order correlation curve (for example, a quadratic regression curve) calculated from the data of I2 / I3 and hemoglobin concentration Hb obtained from several kinds of blood which are measured and stored in advance. (X) h (x) = b ₂ · x ² + b ₁ · x + b ₀ h (x) = − 69.60x ² + 100.1x−15.18 [where x = I2 / I3, hereinafter, h (x) is Hb calibration Is called a line], and the reflected light intensity ratio g (H) of the reference value (Hb ′) of hemoglobin concentration (hemoglobin concentration 15% in this embodiment)
b ′) is calculated and becomes the first correction value [I2 / I3]
Calculate _{Hb = Hb} ′.

In step S6, the first correction value calculated and stored in step S5, the digital reflected light intensity signal [I3] continuously output in step S3, and C ₀ stored in advance (in this embodiment) Then, the second correction value C ₁ C ₁ = C ₀ × [I3] × [I2 / I3] is calculated from 0.26).

In step S7, the corrected reflected light intensity is calculated by the second correction value C ₁ output in step 6 and the digitized reflected light intensity signals [I1] and [I2] continuously output in step S3. the ratio Rs, Rs = ([I2] -C 1) / calculates the ([I1] -C _1).

In step S8, Rs = ([I2] −C ₁ ) for data from a certain number of blood measured in advance from the corrected reflected light intensity ratio Rs output in step S7.
/ ([I1] -C ₁₎ and a correlation curve between the oxygen saturation 3 ascribed next reference correlation function h (x), x = Rs f (x) = a 3 · Rs 3 + a 2 · Rs 2 + a ₁・ Rs + a
₀ (= SO ₂ ) (In this example, f (x) = − 4.165Rs ³ + 38.08Rs ² −136.0Rs + 18
Calculate oxygen saturation from 0.0.

In step S9, the oxygen saturation calculated in step S8 is displayed.

In step S10, it is determined whether the measurement is to be ended. If not, the process returns to step S2 to repeat the measurement.

The oxygen saturation obtained in this Example 3 and the OSM2 hemoximeter used as a control (manufactured by Radiometer)
Fig. 12 shows the relationship with the oxygen saturation measured in. From this result, the oxygen saturation value (x) obtained by the method of the present invention is extremely high in correlation coefficient = 1 (y = x) with respect to the oxygen saturation value (y) measured by the OSM2 hemoximeter. It was confirmed that the error (SD) was close enough and accurate measurement was possible.

EFFECTS OF THE INVENTION The oxygen saturation measuring device of the first invention of the present application is different from the first light irradiation function of irradiating blood with the light of the first wavelength into the blood and the oxygen of the first wavelength. A second light irradiation function of irradiating blood with a second wavelength having substantially the same absorption coefficient of deoxyhemoglobin and deoxyhemoglobin, and a third function of irradiating blood with a light of the same wavelength as the second wavelength. A light irradiating means having a light irradiating function, and a distance from the light irradiating section having the second light irradiating function and a distance from the light irradiating section having the third light irradiating function are different from each other, And detecting means for detecting the intensity of light reflected from blood by the light radiated into the blood by the light irradiating portion of each of the light irradiating functions, and detecting the light irradiating by the third light irradiating function by the detecting means. A third reflected light intensity signal based on the reflected light intensity is used to generate hemoglobin. By using the correction value calculating means for calculating a correction value (C ₁₎ to be used in order to reduce measurement errors due to concentration or hematocrit, the correction value outputted from the correction value calculating means (C _1), wherein The correction value (I1) of the first reflected light intensity signal (I1) based on the reflected light intensity of the light emitted by the first light irradiation function that is continuously detected by the detection means.
-C ₁ ) and the correction value (I2-C) of the second reflected light intensity signal (I2) based on the reflected light intensity of the light emitted by the second light irradiation function that is continuously detected by the detection means.
₁₎ is calculated, and these correction values (I1-C ₁₎ and (I2-C
₁ ) is used to calculate the corrected reflected light intensity ratio calculating means, and the corrected reflected light intensity ratio output from the corrected reflected light intensity ratio calculating means is used to determine the oxygen saturation in blood. Oxygen saturation calculation means for calculating, and further, the correction value calculation means, based on the ratio of the second reflected light intensity signal and the third reflected light intensity signal, the first correction A first correction value calculation means for calculating a value, a first correction value output from the first correction value calculation means, and the third light irradiation function continuously detected by the detection means. A second correction value calculating means for calculating a second correction value (C ₁ ) based on a third reflected light intensity signal (I3) based on the reflected light intensity of the emitted light. Therefore, even in the low oxygen saturation region, it is not affected by the hematocrit value. You can obtain the value of the exact oxygen saturation, and continuously can be obtained that rather accurately affected by the hematocrit value oxygen saturation in the blood.

Further, the oxygen saturation measuring apparatus of the second invention of the present application has a first light irradiation function of irradiating blood with light of the first wavelength into the blood, and oxygenated hemoglobin different from the light of the first wavelength. A second light irradiation function of irradiating blood with a second wavelength of light having an absorption coefficient substantially equal to that of reduced hemoglobin, and a third light irradiation of irradiating blood with a light of the same wavelength as the second wavelength. A light irradiation unit having a function, and a distance from the light irradiation unit having the second light irradiation function and a distance from the light irradiation unit having the third light irradiation function are different from each other, and Detection means for detecting the intensity of light reflected from blood by the light radiated into the blood by the light irradiating portion having the light irradiating function, and reflection of the light irradiating by the third light irradiating function detected by the detecting means. Using the third reflected light intensity signal based on the light intensity, the hemoglobin concentration or A correction value calculating means for calculating correction value (C ₁₎ to be used to reduce the measurement error caused by the hematocrit value, using the correction value output from the correction value calculating means (C _1), said detecting means continuous by the first correction value of the first reflected light intensity signal based on the reflected light intensity of the irradiated light by the light irradiation function _{(I1) (I1-C 1} ) and said detection means is continuously detected by The correction value (I2) of the second reflected light intensity signal (I2) based on the reflected light intensity of the light emitted by the second light irradiation function detected by
2-C ₁ ) is calculated, and these correction values (I 1-C ₁ ) and (I
2-C ₁ ) and the corrected reflected light intensity ratio calculating means for calculating the corrected reflected light intensity ratio and the corrected reflected light intensity ratio output from the corrected reflected light intensity ratio calculating means. Oxygen saturation calculation means for calculating the oxygen saturation, wherein the correction value calculation means stores the first correction value at a predetermined hemoglobin concentration or the first correction value calculation means based on the hemoglobin concentration reference value. First correction value output means having means, and first output from the first correction value calculation means
Of the second reflected light intensity signal (I3) based on the reflected light intensity of the light emitted by the third light emitting function that is continuously detected by the detection means. Since it has a second correction value calculating means for calculating the correction value (C ₁ ), it is possible to obtain an accurate oxygen saturation value without being affected by the hematocrit value even in a low oxygen saturation region. In addition, the oxygen saturation in blood can be continuously and accurately obtained without being affected by the hematocrit value.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the oxygen saturation measuring apparatus of the first invention of the present application, and FIG. 2 is an end view showing an example of a sensor probe used in the oxygen saturation measuring apparatus of the present invention. 3 is a cross-sectional view of the connector to which the sensor probe shown in FIG. 2 is attached, and FIG. 4 is a block diagram showing a specific example of the first correction value calculation unit in the block diagram of FIG. 1, and FIG. FIG. 7 is a block diagram of an embodiment of the oxygen saturation measuring apparatus of the second invention of the present application, FIG. 6 is a block diagram showing a specific example of the first correction value calculation unit in the block diagram of FIG. 4, and FIG. FIG. 8 is a flow chart showing an oxygen saturation measuring method by an oxygen saturation measuring apparatus according to an embodiment of the first invention of the present application, and FIG. 8 shows an oxygen saturation measuring apparatus of another embodiment of the first invention of the present application. FIG. 9 is a flow chart showing the oxygen saturation measuring method. FIG. 10 is a flow chart showing an oxygen saturation measuring method by the oxygen saturation measuring apparatus according to one embodiment of the second invention of the present application, and FIG. 10 is oxygen obtained by the oxygen saturation measuring apparatus according to one embodiment of the first invention of the present application. FIG. 11 is a diagram showing the relationship between the saturation and the oxygen saturation measured by the OSM2 hemoximeter used as a control, and FIG. 11 is the oxygen obtained by the oxygen saturation measuring device of another embodiment of the first invention of the present application. FIG. 12 is a graph showing the relationship between the saturation and the oxygen saturation measured by the OSM2 hemoximeter used as a control, and FIG. 12 is the oxygen saturation obtained by the oxygen saturation measuring device of one embodiment of the second invention of the present application. And the oxygen saturation measured by the OSM2 hemoximeter used as a control. Fig. 13 shows the absorption characteristics of blood. Figs. 14a and 14b show a wavelength of about 660n.
Fig. 15 shows the relationship between m and the reflected light intensity of about 800 nm, plotted by changing the hematocrit value (HCT).
The figure is a diagram showing the relationship between the oxygen saturation obtained by the conventional oxygen saturation measuring method and the oxygen saturation measured by the OSM2 hemoximeter used as a control. FIG. 16 is a diagram showing the relationship between the hemoglobin concentration and the reflected light intensity (I2) measured using the OSM2 hemoximeter. FIG. 17 is a diagram showing the relationship between the hemoglobin concentration measured using the OSM2 hemoximeter and the reflected light intensity (I3). DESCRIPTION OF SYMBOLS 1 ... Light irradiation means, 2 ... Detection means, 3 ... Correction means, 4 ... Oxygen saturation calculation means, 5 ... Indicator, 11-13 ... Light emitting diode, 14 ... Pulse generator, 15 ...... Drive circuit, 18a, 18b, 18c …… Optical fiber 19,20 …… Light irradiation part, 21 …… Photo detection part, 16 …… photodiode, 23 …… Detection amplifier 24 …… Analog switch, 28 to 30… ... buffer amplifier, 40 ... first correction value calculation unit, 42 ... second correction value calculation unit, 44 ... correction reflected light intensity ratio calculation unit, 50 ... sensor probe, 56 ... connector 58 ... port

Claims (28)

[Claims] 1. A first light irradiation function for irradiating blood with light of a first wavelength into light, and a first light irradiation function which is different from the light of the first wavelength and in which oxygenated hemoglobin and reduced hemoglobin have substantially equal absorption coefficients. A light irradiating means having a second light irradiating function of irradiating the blood with the light of the second wavelength into the blood, and a third light irradiating function of irradiating the blood with the light of the same wavelength as the second wavelength. The distance from the light irradiation unit of the second light irradiation function and the third
And a detection means for detecting the reflected light intensity from the blood of the light radiated into the blood from the light irradiating portion of each light irradiating function, which is provided so as to have a different distance from the light irradiating portion of the light irradiating function Reducing a measurement error caused by a hemoglobin concentration or a hematocrit value by using a third reflected light intensity signal based on the reflected light intensity of the light emitted by the third light emitting function detected by the detecting means. a correction value calculating means for calculating correction value (C ₁₎ to be used for, using the correction value output from the correction value calculating means (C _1), a first that is continuously detected by said detecting means the second light irradiation function is continuously detected by the first correction value of the reflected light intensity signal (I1) of (I1-C ₁₎ and the detection means based on the reflected light intensity of the irradiated light by the light irradiation function Light emitted by Correction value of the second reflected light intensity signal based on the reflected light intensity (I2) of (I2-C ₁₎ is calculated,
Using these correction values (I1-C ₁₎ and a (I2-C _1), the correction reflected light intensity ratio calculating means for calculating a correction reflected light intensity ratio, output from the corrected reflected light intensity ratio calculation means An oxygen saturation calculating means for calculating the oxygen saturation in blood using the corrected reflected light intensity ratio, and the correction value calculating means further comprises the second reflected light intensity signal and the third reflected light intensity signal. First correction value calculation means for calculating a first correction value based on a ratio with the light intensity signal, a first correction value output from the first correction value calculation means, and the detection means. The second correction value (C ₁ ) is calculated based on the third reflected light intensity signal (I3) based on the reflected light intensity of the light emitted by the third light emitting function that is continuously detected. An oxygen saturation measuring device comprising: a second correction value calculating means. 2. The oxygen saturation measuring device according to claim 1, wherein the light irradiating means comprises a light emitting source and a light irradiating section for irradiating blood from the light emitting source into the blood. . 3. The light irradiating means includes a light emitting source for emitting light of the first wavelength, a light irradiating section for irradiating light from the light emitting source into blood, and a light emitting unit for emitting light of the second wavelength. 2. The oxygen saturation measuring device according to claim 1, further comprising: the light emitting source and the two light irradiating units for irradiating light from the light emitting source into the blood from different positions. 4. The first light irradiating function and the second light irradiating function of the light irradiating means include a first light emitting source that emits light of the first wavelength and a light of the second wavelength. The second light emitting source for emitting light, and a common light irradiating unit for irradiating blood with light from the first light emitting source and the second light emitting source, according to claim 1. Oxygen saturation measuring device. 5. The light irradiating means emits light of the first wavelength and emits light of the first wavelength and second light source of the second wavelength.
And a common first light irradiator that irradiates blood from the first and second light sources into the blood.
2. The oxygen saturation measuring device according to claim 1, further comprising: a second light irradiating section that irradiates blood with light from a light emitting source that emits light of the wavelength. 6. The detection means includes the first light irradiation function, the second light irradiation function and the third light irradiation function of the light irradiation means.
6. The detection means according to any one of claims 1 to 5, which comprises one detection means for detecting the respective reflected light intensities from the blood of the light irradiated into the blood by the light irradiation function of Oxygen saturation measuring device. 7. The detection means includes the first light irradiation function, the second light irradiation function and the third light irradiation function of the light irradiation means.
Oxygen saturation according to any one of claims 1 to 5, which comprises a plurality of detection means for detecting the intensity of light reflected from blood by the light irradiation function of blood. Degree measuring device. 8. The detector according to claim 1, wherein the distance from the light irradiation unit having the first light irradiation function is the same as the distance from the light irradiation unit having the second light irradiation function. The oxygen saturation measuring device according to the item. 9. The oxygen saturation degree according to any one of claims 1 to 8, wherein the light irradiating section is constituted by an end face of an optical fiber for transmitting light from a light emitting source. measuring device. 10. The detecting means includes a photodetector, a light transmitting section for transmitting light to the photodetector, and a photodetecting section, and the photodetecting section is an optical fiber constituting the light transmitting section. The oxygen saturation measuring device according to any one of claims 1 to 9, which is constituted by an end face. 11. A first correction value computing unit, a computing unit for computing a reflected light intensity ratio [I2 / I3] of the two from a reflected light intensity signal based on the reflected light intensity detected by the detecting means, and A measurement value input section for sampling the blood and measuring the hemoglobin concentration thereof, and a reflected light intensity signal ratio (I2 '/ I) obtained from several types of blood of the same animal species as the measurement target blood which was measured in advance.
3 ') and the hemoglobin concentration Hb, the reflected light intensity ratio [I corresponding to the hemoglobin concentration input by the above measurement value input means based on the correlation function h (x) calculated from the data.
2 / I3] s operation unit, [I2 / I3] s, and [I2 / I3] to [I
2 / I3] / [I2 / I3] s (= [A]), a hemoglobin concentration reference value (Hb ') input unit, and a hemoglobin concentration reference based on the above correlation function h (x). Value (H
b ′), a calculation unit that calculates the reflected light intensity ratio g (Hb ′), and the first unit from the [A] and the reflected light intensity ratio g (Hb ′).
A correction unit ([I2 / I3] _{Hb = Hb} ') is calculated by the following formula [I2 / I3] _{Hb = Hb} ' = A * g (Hb '). The oxygen saturation measuring device according to any one of items 1 to 10. 12. A first correction value calculating unit calculates a reflected light intensity ratio [I2 / I3] from a reflected light intensity signal based on the reflected light intensity detected by the detecting means, and a blood measuring unit. A measurement value input unit for sampling and measuring the hemoglobin concentration, and a reflected light intensity signal ratio (I2 ′ / I) obtained from several types of blood of the same animal species as the measurement target blood, which was measured in advance.
3 ') and the hemoglobin concentration Hb, the reflected light intensity ratio [I corresponding to the hemoglobin concentration input by the above measurement value input means based on the correlation function h (x) calculated from the data.
2 / I3] s operation unit, [I2 / I3] s, and [I2 / I3] to [I
2 / I3] / [I2 / I3] s (= [A]), and a reflected light intensity ratio g (H) at a predetermined hemoglobin concentration.
b ′), a first correction value ([I2 / I3] _{Hb = Hb} ′) is obtained from the following formula [I2] from the storage unit for storing the value of [A] and the reflected light intensity ratio g (Hb ′). / I3] The oxygen saturation measuring device according to any one of claims 1 to 10, further comprising a calculation unit that calculates _{Hb = Hb} '= A * g (Hb'). 13. The oxygen saturation calculator calculates the corrected reflected light intensity ratio of a certain number of blood measured in advance from the corrected reflected light intensity ratio (Rs) calculated by the corrected reflected light intensity ratio calculating device. The oxygen according to any one of claims 1 to 12, wherein the oxygen saturation is calculated based on a correlation function f (Rs) calculated based on the data of (Rs') and oxygen saturation. Saturation measuring device. 14. The second correction value calculating means is the first correction value calculating means.
And a third reflected light intensity signal based on the reflected light intensity of the light emitted by the third light emitting function continuously detected by the detecting means and the first correction value output from the correction value calculating means The oxygen saturation measuring device according to any one of claims 1 to 13, wherein the second correction value (C ₁ ) is calculated from the following equation using (I3). C ₁ = C ₀ × [I3] × first correction value (where C ₀ is a predetermined value stored in the second correction value calculation means). 15. A first device for irradiating blood with a first wavelength light
And a second light irradiation function of irradiating blood with light of a second wavelength, which is different from the light of the first wavelength and has substantially the same absorption coefficient of oxygenated hemoglobin and reduced hemoglobin, A light irradiating means having a third light irradiating function for irradiating blood with the same wavelength as the second wavelength, a distance from the light irradiating section having the second light irradiating function, and the third
And a detection means for detecting the reflected light intensity from the blood of the light radiated into the blood from the light irradiating portion of each light irradiating function, which is provided so as to have a different distance from the light irradiating portion of the light irradiating function A measurement error caused by a hemoglobin concentration or a hematocrit value by using a third reflected light intensity signal (I3) based on the reflected light intensity of the light emitted by the third light irradiation function, which is detected by the detection means. by using the correction value calculating means for calculating correction value (C ₁₎ to be used to reduce the correction value outputted from the correction value calculating means (C ₁₎ and is continuously detected by said detecting means the first correction value of the reflected light intensity signal based on the reflected light intensity of the light emitted by the first light irradiation function _{(I1) (I1-C 1} ) and continuously detected second is by the detection unit Illuminated by the light irradiation function Calculating correction values of the second reflected light intensity signal based on the reflected light intensity of the light (I2) and (I2-C _1),
Using these correction values (I1-C ₁₎ and a (I2-C _1), the correction reflected light intensity ratio calculating means for calculating a correction reflected light intensity ratio, output from the corrected reflected light intensity ratio calculation means An oxygen saturation calculating means for calculating the oxygen saturation in blood using the corrected reflected light intensity ratio, wherein the correction value calculating means is a first correction value calculating means or a predetermined value based on the hemoglobin concentration reference value. First correction value output means having a storage means for storing the first correction value at the hemoglobin concentration, the first correction value output from the first correction value calculation means, and the detection means continuously detecting the first correction value. A second correction value for calculating the second correction value (C ₁ ) using the third reflected light intensity signal (I3) based on the reflected light intensity of the light emitted by the third light irradiation function Oxygen saturation measurement characterized by having a calculation means Apparatus. 16. The oxygen saturation measuring device according to claim 15, wherein the light irradiating means comprises a light emitting source and a light irradiating unit for irradiating blood from the light emitting source into the blood. . 17. The light irradiating means includes a light emitting source that emits light of the first wavelength, a light irradiating unit that irradiates blood from the light emitting source into blood, and a light emitting unit that emits light of the second wavelength. 16. The oxygen saturation measuring device according to claim 15, which comprises: the light emitting source of 1) and two light emitting portions that emit light from the light emitting source into blood from different positions. 18. The first light irradiating function and the second light irradiating function of the light irradiating means include a first light emitting source that emits light of the first wavelength and a light of the second wavelength. 16. The method according to claim 15, comprising a second light emitting source for emitting light, and a common light irradiating unit for irradiating blood with light from the first light emitting source and the second light emitting source. Oxygen saturation measuring device. 19. The light emitting means includes a first light emitting source that emits light of the first wavelength, a second light emitting source that emits light of the second wavelength, the first light emitting source and the first light emitting source. A common first light irradiator that irradiates blood with light from two light sources and a second light irradiator that irradiates blood with light from a light source that emits light of the second wavelength. 16. The oxygen saturation measuring device according to claim 15, which has. 20. The detecting means detects the amount of light emitted from the blood irradiated into the blood by the first light irradiation function, the second light irradiation function and the third light irradiation function of the light irradiation means. The oxygen saturation measuring device according to any one of claims 15 to 19, which comprises one detecting means for detecting the intensity of each reflected light. 21. The detection means detects the amount of light emitted from the blood irradiated into the blood by the first light irradiation function, the second light irradiation function and the third light irradiation function of the light irradiation means. 20. The oxygen saturation measuring device according to any one of claims 15 to 19, which comprises a plurality of detecting means for detecting the intensity of reflected light. 22. The detector according to claim 15, wherein the distance from the first light irradiation means is the same as the distance from the second light irradiation means. The oxygen saturation measuring device according to. 23. The oxygen saturation degree according to any one of claims 15 to 22, wherein the light irradiating section is constituted by an end face of an optical fiber for transmitting light from a light emitting source. measuring device. 24. The detecting means includes a photodetector, a light transmitting section for transmitting light to the photodetector, and a photodetecting section, wherein the photodetecting section is an optical fiber constituting the light transmitting section. 24. The oxygen saturation measuring device according to any one of claims 15 to 23, which is constituted by an end face. 25. The first correction value output means comprises a hemoglobin concentration reference value (Hb ') input section, and a reflected light intensity signal obtained from several kinds of blood of the same animal species as the blood to be measured which is measured in advance. Ratio (I2 '/ I
3 ') and the hemoglobin concentration Hb, the reflected light intensity ratio g (Hb') at the reference value (Hb ') of the hemoglobin concentration is calculated based on the reference correlation function h (x). The oxygen saturation measuring device according to any one of claims 15 to 24, wherein the ratio g (Hb ') is used as the first correction value. 26. The first correction value output means stores a value of a reflected light intensity ratio g (Hb ') at a predetermined hemoglobin concentration, and outputs the reflected light intensity ratio as a first correction value. What is claimed is: Claims 15 to 15
25. The oxygen saturation measuring device according to any one of 24. 27. The oxygen saturation calculating means calculates a corrected reflected light intensity ratio for a certain number of blood measured in advance from the corrected reflected light intensity ratio (Rs) calculated by the corrected reflected light intensity ratio calculating means. The oxygen according to any one of claims 15 to 26, wherein the oxygen saturation is calculated based on a correlation function f (Rs) calculated based on the data of (Rs') and oxygen saturation. Saturation measuring device. 28. The second correction value calculation means is the first correction value calculation means.
And a third reflected light intensity signal based on the reflected light intensity of the light emitted by the third light emitting function continuously detected by the detecting means and the first correction value output from the correction value calculating means The oxygen saturation measuring device according to any one of claims 15 to 27, wherein the second correction value (C ₁ ) is calculated from the following equation using (I3). C ₁ = C ₀ × [I3] × first correction value (where C ₀ is a predetermined value stored in the second correction value calculation means).