JPH03136637A - Non-observing type blood component concentration measuring device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Industrial Application Field) The present invention is useful in the field of medicine and medical care, for measuring the oxygen saturation level of arterial blood and for measuring light-absorbing pigments such as indocyanine phosphorus in blood. Regarding a non-invasive two-plate component concentration measuring device for measuring the relative concentration of substances, we have developed a non-invasive device that can measure the concentration of components in blood with high precision without being affected by pulsation of pure tissues other than blood. The present invention relates to an invasive blood component concentration measuring device.

(Prior art) Conventional non-invasive blood component concentration measurement devices detect pulsating fluctuations in the degree of attenuation of the incident light in the living tissue when light of a plurality of different wavelengths is incident on the living tissue. The ratio or difference between the two is determined, and the concentration of the blood component is measured non-invasively from this result.

Various devices of this kind have been known in the past, such as those shown in Japanese Patent Publication No. 53-26437 and Japanese Patent Application No. 61-257668, both of which were proposed by the present inventors.

A device of this type applied to the measurement of blood oxygen saturation is widely known as a pulse oximeter. Here, oxygen saturation is the concentration ratio of oxyhemoglobin to the sum of oxyhemoglobin and deoxyhemoglobin.

Although the principle of the non-invasive blood component concentration measuring device is described in detail in the above-mentioned publication, it will be briefly explained below using the case of measuring oxygen saturation as an example.

As shown in FIG. 5, the living tissue R is schematically divided into two layers: a blood layer R1 and a layer R2 of tissue excluding blood (hereinafter referred to as pure tissue), and the thickness of the blood layer R1 is pulsating. Pure tissue layer R2
Assume that the thickness of is constant.

When this living tissue R is irradiated with light, the amount of incident light IO is
The light is attenuated by the living tissue R, and the amount of transmitted light that passes through the living tissue R is 1. Further, when the thickness of the blood layer R1 increases by ΔDb due to pulsation, the amount of transmitted light decreases to (■-ΔI). At this time, the degree of light attenuation ΔA in the thickness change ΔDb of the blood layer R1 can be written as follows.

ΔA=lOQ [I/(I-ΔI)] Furthermore, if the pulsation of the logarithm of the amount of transmitted light is Δlog I, the degree of attenuation ΔA can be written as follows.

ΔA=Δlog I Also, two different wavelengths λ1. 1 t of biological assembly with λ2 light
When incident on the IR, each wavelength λ1. Attenuation of pulsation component at λ2 ΔA1. It has been confirmed by theory and experiment that the ratio Φ of ΔA2 is approximately expressed by the following formula.

To Φ=8 /AA = 2 E2+F2 /1 alTl descending entrance... (1> Here, E is the extinction coefficient of hemoglobin, F is the scattering coefficient in blood, and i=1.2 is the light wavelength λ1 .λ2 shall be indicated.

Furthermore, assuming that the only light absorption components in blood are oxyhemoglobin and deoxyhemoglobin in blood cells, the extinction coefficient of hemoglobin is expressed by the following equation.

E・=SE・+(1-3)E・・・・・・・(2)
+ 01 1' However, S is oxygen saturation, and Eoi and Eri are oxyhemoglobin and deoxyhemoglobin extinction coefficients, respectively.

Here, the wavelength λ1 is chosen to be 805 nm, and the wavelength λ2 is chosen to be 605 nm.
If 60 nm is chosen, Eo1=E, 1=E1. It is also known that F1=F2=F. Therefore, equation (1) can be written as follows.

Φ=ΔA2/ΔA1 ......(3) In this equation (3), El, Eo2, Er2, and F are known values, so Φ=ΔA2/ΔA1 is actually measured and used in equation (3). By substituting and solving this for S, the oxygen saturation S can be determined.

Next, the configuration of a conventional blood component concentration measuring device will be explained based on FIG. 6.

In this figure, a light emitting diode 31 that emits light of wavelength λ1 and a light emitting diode 32 that emits light of wavelength λ2 are turned on alternately in response to the output of an oscillator (O8C) 33, and the light of these light emitting diodes 31 and 32 ( The amounts of incident light are IOl and IO2>, respectively, which are incident on the living tissue R such as the earlobe.

The light incident on the living tissue R is absorbed and scattered by the pure tissues and blood components in the living tissue R and is attenuated, and the transmitted light that has passed through the living tissue R is received by the photodiode 34. The light receiving output of the photodiode 34 is amplified by an amplifier 35 and supplied to a logarithmic converter 36.

This logarithmic converter (LOG>36) logarithmically converts the input light reception signal, so that the pulsation amplitude of the logarithmically converted output corresponds to the change in the degree of attenuation due to the pulsation of the thickness of the blood layer R1. Become.

The converted output signal of the logarithmic converter 36 is sent to a multiplexer (M
PX>37, each wavelength λ1. After being distributed into signals for each λ2, a low pass filter (LPF) 38
．． 39, the signals from which noise components have been removed are passed through a bypass filter (HPF) 40.
．． 41, and a pulsation signal corresponding to the degree of attenuation of the pulsation is extracted.

The output signal of each HPF40.41 is sent to the next stage detection circuit (D
ET>42.43 and are detected, the pulsating fluctuation of the degree of attenuation (amplitude value) ΔA1. ΔA2
A signal corresponding to is detected.

Here, the pulsation variation ΔA1 is as follows: ΔAl =log II log(Ii-Δ11)=
Δ1Oc111, and the pulsation fluctuation ΔA2 is Δ, A2=IO(] II I(XI (I2−Δ
I2)=Δ100I2.

Detection output signal from each detection circuit 42.43 (ΔA1゜A
2> are respectively supplied to the light attenuation ratio calculation circuit 44, and the pulsation fluctuations ΔA1. ΔA
Calculation to find the ratio Φ of 2, Φ=ΔA2/ΔA1=Δl0CII2/Δ10(Ill
will be carried out.

The output signal of this variation ratio calculation circuit 44 is supplied to the oxygen saturation calculation circuit 45 which performs calculation according to the formula S=f (Φ) obtained by solving the formula (3) for S, and is inputted from the coefficient circuit 46. Based on the data of the extinction coefficients E1'E02'Er2 of hemoglobin and the scattering coefficient F of blood, an operation is performed to obtain the oxygen saturation S from the fluctuation ratio Φ.

(Problems to be Solved by the Invention) By the way, in the above-mentioned conventional blood component concentration measuring device,
For example, when measuring the oxygen saturation S, there is a problem that a certain degree of measurement error occurs and sufficient accuracy cannot be obtained especially in a region where high oxygen saturation is required and high accuracy is required. This problem also poses a hindrance to the widespread application of the pulse oximeter principle to other areas. As a result of theorizing a non-invasive blood component concentration measuring device and researching simulations of biological tissue, the inventors found that the pure tissue layer R2 pulsates in the opposite phase to the pulsation of blood. I discovered that. We have come to believe that the main cause of the measurement error is that the pulsation of the pure tissue layer R2 has not been considered in the past.

The present invention was proposed to solve these problems, and it is possible to measure the concentration of blood components with high precision without being affected by pure tissue whose thickness changes due to blood pulsation. The purpose of the present invention is to provide a non-invasive blood component concentration measuring device.

[Structure of the Invention] (Means for Solving the Problems) As schematically shown in FIG. 2, when the thickness of the blood layer R1 in the biological tissue R increases by ΔDb due to blood pulsation,
Pure tissue layer R2 is compressed by blood and escapes, and has a thickness of ΔDt.
only decreases.

This ΔDt is equal to or smaller than ΔDb.

Taking into consideration the pulsation of the opposite phase in the pure tissue layer R2, an equation for determining the ratio of the variation in the degree of light attenuation based on the pulsation in the living tissue is written as follows.

Φ21 mi ΔA2 / ΔA1 = (F - "η Takumi - Tori 1) (G
2/H)・(△Dt/△Db))/(aRyoT] Ear-first (Gi/H) (△Dt/△Db)) ・・・・・・(4)
Here, G1. G2 is the optical wavelength λ1. It is a constant including the extinction coefficient of pure tissue at λ2, and H is the volume ratio of red blood cells in the blood (hematocrit). As shown here, by taking the ratio of ΔA, three new unknowns H1ΔDt, ΔDb are calculated when considering the pulsation of pure tissue.
are combined into one unknown quantity, so this corresponds to an increase in the number of unknown quantities by one.

As shown in equation (4), the variation Δ in the thickness of blood layer R1
The larger the variation ΔDt in the thickness of the pure tissue layer R2 compared to Db, and the smaller the hemadcrit H, the greater the contribution rate of the variation in the pure tissue, and the conventional measurement based on equation (1) It can be seen that the error becomes larger. Therefore, (Gi /H) ・(ΔD, /ΔD
If the influence of b) can be eliminated using appropriate means, measurement accuracy can be improved.

Therefore, a new third optical wavelength λ of approximately 880 nm was selected.
3 is incident on living tissue, the transmitted light 1 part 3 is measured, and the pulsating variation ΔA3 of the degree of light attenuation in the living tissue is determined.
The ratio Φ31 to the pulsating variation ΔA1 of the degree of attenuation at the light wavelength λ1 is taken. In this wavelength range of λ3, as shown in FIG. 3, the dependence of the hemoglobin extinction coefficient on oxygen saturation is sufficiently small.

Therefore, the ratio Φ31 of this pulsation variation can be approximately given by the following equation.

O=△A /△A = (33+F3 1-31 - (G3/H)・(△Dt/△Db>)/(a〒"row+
F, go (a1/H) value ΔDt/ΔDb)) (5) Here, F3, F3, and G3 are the above-mentioned E, , Fi, and G regarding the optical wavelength λ3.

In these equations (4) and (5), Fi ``F2 ''F3 =F, and the pure structure term is (1/H) ・(ΔDt/ΔDb) 2T,
Rewriting the formula, it becomes as follows.

Φ=ΔA/ΔA=<Jπ ``αDingsanmon 1-21-G T)/(α〒]1T day-G1T)・・・・・・(
6) O=ΔA/ΔA=(3E3+F) 1-31 -G T)/I E +F)-GlT)3
1 1 ......(7) Here, as mentioned above, the extinction coefficient E2 of hemoglobin at wavelength ^ is E2=SEo2+(1-8) Er2 -----・=
(8), and the extinction coefficient of hemoglobin is E1. It is assumed that E3 does not depend on the oxygen saturation S. (8) to (6)
By substituting equations into the equations, equations (6) and (7) of the simultaneous equations are converted to S2.
(Eo2 E, 2>”...(9>) In this equation (9), each extinction coefficient E1 of hemoglobin.
Eo2. E, 2. E3, scattering coefficient F of red blood cells, extinction coefficient Gi of pure tissue (however, i = 1.2.3> is a value that can be determined in advance without individual differences, so Φ2
1. By actually measuring Φ31 and substituting it into equation (9)', the oxygen saturation degree S can be determined.

By using three different appropriate optical wavelengths λ1 to λ3 in this way, the pure tissue term Gi
It is possible to eliminate the influence of T and measure the relative concentrations of two blood components, oxyhemoglobin and deoxyhemoglobin. Therefore, this method is hereinafter referred to as the tissue elimination method.

By the way, the relative concentration of bilirubin, which is a naturally occurring pigment in plasma, and the relative concentration of hemoglobin, such as indocyanine phosphorus (ICG) and methylene blue, which are artificially injected pigments for biological measurements, can also be determined based on the principle of a pulse oximeter. It can be measured using Note that these dyes that are artificially injected into a living body are used to obtain biological information such as cardiac output, circulating blood flow, and the liver's foreign body excretion function.

In order to simultaneously measure the oxygen saturation S and the relative concentration of the dye in plasma, it is necessary to newly make light of the fourth wavelength λ4 incident on the living tissue. In this case, the pulsating variation ΔA4 in the degree of attenuation at the light wavelength λ4 is measured, and the ratio Φ41 to the pulsating variation ΔA1 at the wavelength λ1 is determined.

When measuring the oxygen saturation S and the relative concentration of one dye, the ratio of pulsation fluctuations Φ21. Φ31. Φ41 is given by the following equation.

Φ21mi△A2/△A1=(ETK "Wang'r7匡"), /
Ch))E2+Ed2 (cd/ch) 10F)
a 'rl / [E1+Edi (cd /ch))
(E10Edi (cd/ch) +F) -01
'rl...(10) Φ31=ΔA3/ΔA1 =t r7 correctable - CE3
+Ed3 (Cd /Ch) 10F)-G3T]/
[1+d1CC) (E1+Ed1 (Cd /Ch) 10F) Gi
'rl・・・・・・(11) Φ41=ΔA4/△Ai=tr 7 possible 11 go/C
1l) HE4 +Ed4 (Cd /C1l)
10F)...(12) Here, E is the extinction coefficient of hemoglobin at wavelength λ4, Ed1 to Ed4 are the extinction coefficients of dyes at each wavelength,
ch is blood hemoglobin concentration, Cd is blood pigment concentration, G
is a constant containing the attenuation coefficient of pure tissue at wavelength λ4.

Regarding these simultaneous equations (10), (11), and (12), the oxygen saturation S and the relative concentration of the dye Cd/
By solving for each of Ch, the ratio of the actually measured pulsation fluctuation component Φ21. Φ31. By substituting the value of Φ41 and each coefficient value, the oxygen saturation S and the relative concentration of the dye C
d/Ch can be calculated.

In this way, by using four different light wavelengths λ1 to λ4, it is possible to measure the relative concentrations of three blood components, oxyhemoglobin, deoxyhemoglobin, and one other pigment, by the tissue elimination method. can.

When measuring the relative concentration of four blood components including carboxyhemoglobin in addition to these blood components, five different light wavelengths λ1 to λ5 may be used.

Based on the above-mentioned premise, if the non-invasive blood component concentration measuring device according to the present invention is configured to achieve the above object, it will include: a light generating means that emits light of N different wavelengths to irradiate living tissue; A light receiving means for receiving the transmitted light or reflected light in the living tissue of the light emitted from the light generating means, and a light receiving means for receiving the transmitted light or the reflected light in the living tissue of the light emitted from the light generating means, and a change in the degree of light attenuation in the living tissue based on the received light output signal from the light receiving means. Based on the detection output signals for N different wavelengths output from the attenuation change detection circuit, the ratio of the change in attenuation is determined between N different wavelengths. -1 An attenuation ratio calculation circuit that narrows down the attenuation ratio calculation circuit and an N that is calculated between different wavelengths by assuming that the change in the attenuation in living tissue is due to the change in the thickness of blood and the change in the thickness of pure tissue that does not contain blood.
- The change in light attenuation outputted from the light attenuation ratio calculation circuit for the arithmetic expression obtained by solving the N-1 simultaneous equations of the ratio of the changes in the light attenuation for the concentration of the blood component. Calculation is performed based on the ratio value and the respective extinction coefficient values of N-1 blood components and pure tissue for N different wavelengths, and the relative concentration of N-1 blood components is calculated. The blood component concentration calculation circuit calculates the blood component concentration.

(Function) According to the above-described configuration, it is possible to extract a light reception output signal corresponding to the amount of tissue transmitted light or reflected light of each wavelength in the light receiving means. Since the amount of transmitted light or reflected light varies depending on the pulsation of blood and pure tissue, this received light output signal fluctuates due to the pulsation.

The logarithmically converted signal obtained by taking the logarithm of this light reception output signal fluctuates due to pulsations, and by detecting the pulsations of the logarithmically converted signal with a light attenuation change detection circuit, it is possible to detect the light attenuation in living tissue for each wavelength. A signal corresponding to the pulsation change is obtained.

The attenuation ratio calculation circuit receives the output signal from the detection circuit and can calculate the ratio of N-1 pulsation changes between different wavelengths.

The blood component concentration calculation circuit calculates the relative concentrations of N-1 blood components obtained by solving simultaneous equations of the ratios of N-1 pulsation changes, taking into account the influence of pure tissue pulsation. Calculations are performed by substituting the measured value of the ratio of pulsation changes and each coefficient value into the equation, and the concentration (relative Concentration) can be measured with high accuracy.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

The block diagram in FIG. 1 shows an embodiment of the non-invasive blood component concentration measuring device according to the present invention, and shows an embodiment of the non-invasive blood component concentration measuring device according to the present invention. 3 of λ3
An example will be shown in which oxygen saturation S is measured using two light wavelengths without being affected by pulsation of pure tissue.

In the second diagram, the wavelength λ1. λ2. Light emitting diodes 1, 2, 3 . . . each emit light of λ3. are lit alternately in response to the output of the oscillator 4, and these light emitting diodes 1, 2 .
3 light (incident light amount is respectively ■01.■02.l03)
is incident on a living tissue R such as an earlobe, and this living tissue R
The transmitted light is received by the photodiodes 5 which are arranged opposite to each other with the two sides in between. Here, the wavelength λ1. λ2. As mentioned above, λ3 is, for example, 805 nm or 660 nm.
, 880 nm, respectively.

f) - The light receiving output at each wavelength of the diode 5 is the amount of transmitted light after being attenuated by the living tissue R. I2
,1. Corresponding to
is supplied to

In the multiplexer 8, the logarithmically converted output signal is λ1. λ2
．． Distributed to each wavelength of λ3, LPF9.10.11
are supplied respectively. The LPFs 9°10 and 11 remove high frequency noise components contained in each signal, and their output signals are supplied to the HPFs 12 and 1314, respectively. In HPF12.13.14, each wavelength λ1. λ2. Amplitude signals corresponding to pulsating fluctuations in the degree of attenuation with respect to λ3 are respectively taken out, and their output signals are supplied to amplitude detection circuits 15, 16, and 17. Incidentally, the LPFs 9°10 and 11 and the HPFs 12, 13, and 14 may each be configured simply by a bandpass filter (BPF).

In amplitude detection circuit 15.16.17, HPF12.13
By detecting each output signal from 14, a signal corresponding to the amplitude value of the pulsation of the degree of attenuation is detected. These detection signals have wavelengths λ1.
λ2. The pulsating variation in the degree of attenuation at λ3 ΔA1. ΔA2
．． This corresponds to ΔA3. Here, the pulsation variation Δ
A, ΔA2゜ΔA3 are respectively ΔAl = log Ii -10(] (11-Δ1
1) = Δ10 (111 ΔA2 = loc + I2 !O'l (I2 - Δ
■2)=Δ10(II2 ΔA3 =log l31Q(] (]I3−ΔWork3=
Δl0gl3. Note that the Ii component corresponds to the maximum value of the amount of transmitted light, and the (I·-ΔIi) component corresponds to the minimum value of the amount of transmitted light.

The output signals of the amplitude detection circuits 15, 16, and 17 are respectively supplied to the attenuation ratio calculation circuits 18 and 19, and the ratio Φ of the pulsation variation ΔA1ΔA2 corresponding to equations (6) and (7) is
21, and ΔA1. Calculations for determining the ratio Φ31 of ΔA3 are performed as follows: 21=Δ100I2/ΔIQg11 Φ31=ΔIQ (JI3/Δ10g11).

The output signals of the attenuation ratio calculation circuits 18 and 19 are as described above (
9) El input from the coefficient circuit 21 is supplied to the blood component concentration calculation circuit #120 for calculating the equation.
' EO2, Er2' E3 ' ” G1 ” 2
'Each coefficient value of G3 and actual measured value Φ21. A calculation is performed to determine the oxygen saturation level S from Φ31.

By the way, as another example, when measuring the relative concentration of a dye such as indocyanine phosphorus (ICG>) in addition to the oxygen saturation S, a light emitting diode that emits a fourth light wavelength λ4 is separately provided, and this light emitting diode The amount of transmitted light is detected by the photodiode 5. Here, the wavelength of λ4 is set to, for example, about 730 nm (see FIG. 4).

In addition, an LPF and an HPF for processing the logarithmically converted output signal for the optical wavelength λ4 distributed by the multiplexer 8, and a detection circuit for detecting the pulsating variation ΔA4 in the degree of attenuation are separately provided.

Then, in the attenuation ratio calculation circuit, the above-mentioned equation (10),
Ratio of fluctuations Φ2 corresponding to equations (11) and (12)
1. Φ31. It is sufficient to perform an operation to obtain Φ41. .

In addition, the blood component concentration calculation circuit calculates the measured Φ21. Φ
31. Based on the value of Φ41 and each coefficient value, formula (10), (1
It is only necessary to perform calculations to solve the simultaneous equations of equations (1) and (12) with respect to the oxygen saturation S and the relative concentration of the dye Cd/Ch.

Note that, without being limited to the above-mentioned example, by using three different light wavelengths λ1 to λ3 and assuming that all hemoglobin in the blood is oxyhemoglobin, the relative concentration of pigments (indocyanine, etc.) in plasma to oxyhemoglobin can be calculated. It can also be measured.

Furthermore, the relative concentrations of three blood components, oxyhemoglobin, deoxyhemoglobin, and plasma pigment (indocyanine), can also be measured using four different light wavelengths λ1 to λ4. Furthermore, using five different light wavelengths λ1 to λ5, the relative concentrations of each of the four blood components oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and plasma pigments (indocyanine, etc.) are measured. You can also do it.

In addition, in the embodiment described above, the blood layer R1 and the pure tissue layer R2
We have explained the case where the maximum and minimum values of the pulsations in the amount of transmitted light are found when the thickness of This method can be applied to the case of determining the change in attenuation degree ΔA with respect to a change in , and can also be applied to irregular changes.

In addition, the amount of transmitted light varies due to pulsation.

It can also be applied to the case where the concentration of blood components is measured by measuring the amount of reflected light after the light is attenuated by the living tissue R instead of receiving (I·-ΔIi).

In addition, the attenuation ratio calculation circuit and the blood component concentration calculation circuit are configured by a microprocessor, and the output signal of the detection circuit is amplified and A/D converted, and then supplied to the microprocessor to calculate the concentration of each blood component. It is clear that it is also possible to configure it to calculate.

[Effects of the Invention] As explained above, according to the present invention, when measuring the concentration of N-1 blood components in biological tissue using N different light wavelengths, the Since the influence of tissue pulsation can be removed, the concentration of blood components can be measured with high accuracy.

Therefore, according to the present invention, in addition to the concentration of oxyhemoglobin and deoxyhemoglobin, it is also possible to accurately measure the concentration of abnormal hemoglobin and artificially injected pigments such as indocyanine, which can be used in medical and medical settings. It is very effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the non-invasive blood component concentration measuring device according to the present invention, and FIG. 2 is an explanatory diagram schematically showing the state of pulsation of a pure tissue layer that pulsates together with a blood layer. Figure 3 is a characteristic diagram showing the extinction coefficient of oxidized hemoglobin (02Hb) and deoxyhemoglobin (RHb) against wavelength, Figure 4 is a characteristic diagram showing the extinction coefficient of dye indocyanine phosphorus (ICG) against wavelength, and Figure 5 is FIG. 6 is an explanatory diagram showing a pulsation model of a blood layer, which is a premise for conventional measurement. FIG. 6 is a block diagram showing a conventional non-invasive blood component concentration measuring device. 1.2.3... Light emitting diode 4... Oscillator 5... Photodiode 6... Amplifier 7... Logarithmic converter 8... Multiplexer 9, 10.11... Low pass filter 12, 13.1
4... Bypass filter 15, 16.17... Amplitude detection circuit ia, 19... Attenuation ratio calculation circuit 20... Blood component concentration calculation circuit 21... Coefficient circuit

Claims (3)

[Claims] (1) A light generating means that emits light of N different wavelengths to be irradiated onto living tissue, a light receiving means that receives transmitted light or reflected light in the living tissue of the light emitted from the light generating means, and this light receiving means. a light attenuation change detection circuit that detects a change in light attenuation in living tissue for N different wavelengths based on a received light output signal from the means; and N different light attenuation change detection circuits that are output from the light attenuation change detection circuit. an attenuation ratio calculation circuit that calculates N-1 ratios of changes in attenuation between different wavelengths based on detection output signals for wavelengths; An N-1 simultaneous equation of the ratio of the N-1 changes in attenuation, which was established between different wavelengths and changes in the thickness of pure tissues not including For the calculation formula, the value of the ratio of the change in attenuation output from the attenuation ratio calculation circuit and the attenuation of each of N-1 blood components and pure tissue for N different wavelengths. A non-invasive blood component concentration measuring device comprising a blood component concentration calculation circuit that calculates relative concentrations of N-1 blood components by performing calculations based on coefficient values. . (2) A light generating means that emits light of N different wavelengths to be irradiated onto living tissue; a light receiving means that receives transmitted light or reflected light in the living tissue of the light emitted from the light generating means; and this light receiving means. a light attenuation change detection circuit that detects a change in light attenuation in living tissue for N different wavelengths based on a received light output signal from the means; and N different light attenuation change detection circuits that are output from the light attenuation change detection circuit. an attenuation ratio calculation circuit that calculates N-1 ratios of changes in attenuation between different wavelengths based on detection output signals for wavelengths; and N-1 blood components for N different wavelengths; a coefficient storage circuit that stores the respective light attenuation coefficient values of pure tissues; Assuming that it is due to the sum of the changes in the attenuation, the N-1 simultaneous equations of the ratios of the N-1 changes in the attenuation between different wavelengths can be converted into the equation solved for the concentration of the blood component. On the other hand, a calculation is performed based on the value of the ratio of the change in the degree of attenuation outputted from the attenuation degree ratio calculation circuit and the attenuation coefficient value outputted from the coefficient storage circuit, and N-1
1. A non-invasive blood component concentration measuring device comprising: a blood component concentration calculation circuit that calculates relative concentrations of individual blood components. (3) The non-invasive blood method according to claims (1) and (2), wherein the attenuation ratio calculation circuit and the blood component concentration calculation circuit are configured by a circuit including a microprocessor. Medium component concentration measuring device.