JPH0591991A - Apparatus for measuring coloring agent concentration in blood - Google Patents

Abstract

PURPOSE:To provide an apparatus for measuring coloring agent concn. in blood by means of which the coloring agent concn. in blood can be more accurately measured. CONSTITUTION:A living body 17 is irradiated with const. amt. of light having a wave length being absorbed in a specified coloring agent and a light having a wave length being not abosrbed in the specified coloring agent by means of emission diodes 15 and 16, and a sensor is mounted on the living body in such a way that a light obtd. from the living body 17 can be received by a photodiode. When a calibration key 8 is operated, a physiological saline is fed into the living body 17 by means of an injector 11 and the data on the amt. of light at that time is stored in a RAM 4 and calibration is performed. When a start key 9 is operated, the specified coloring agent is fed into the living body by means of an injector 12 and the coloring agent concn. is measured by using the data of the amt. of light obtd. at that time, the data on the amt. of light stored in the RAM 4 and a specified operational equation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blood pigment concentration measuring apparatus, and more particularly, to a blood pigment concentration measuring apparatus for injecting a specific pigment selectively ingested and excreted only in the liver into blood. The present invention relates to a blood dye concentration measuring device.

[0002]

2. Description of the Related Art
In No. 6, we proposed a liver function testing device that can reduce the mental and physical burden on the subject and can automatically carry out test diagnosis of liver function. That is, this proposed liver function test apparatus irradiates a living tissue with a first light pulse and a second light pulse, calculates a calculated value of a difference between transmitted light or reflected light of each light pulse, and calculates a minimum value. The function of the simulation curve in the change of the calculation result is calculated by using the square method, and the plasma elimination rate k and the retention rate R% of the specific dye are calculated based on the function.

[0003]

However, the above-mentioned proposed liver function testing apparatus sets the data when there is no blood under a certain assumption in order to eliminate fluctuations in blood volume. The dye concentration inside was calculated. However, it was found that this method lacked accuracy.

Therefore, a main object of the present invention is to provide a blood dye concentration measuring device which can accurately measure blood dye concentration.

[0005]

SUMMARY OF THE INVENTION The present invention is a blood dye concentration measuring apparatus for measuring the dye concentration in blood of living tissue, which is a first device for injecting a transparent liquid into blood of living tissue.
Injection means, second injection means for injecting a specific dye into the blood of the biological tissue, first light having a wavelength absorbed by the specific dye and second light having a wavelength not absorbed by the biological tissue. Light source means for irradiating the living tissue, photoelectric conversion means for outputting first and second photoelectric conversion signals corresponding to the first and second light emitted from the living tissue by the light source means, and photoelectric conversion Sampling means for sampling the first and second photoelectric conversion outputs from the means, the sampling means output at each wavelength when the transparent liquid is injected into the blood of the living tissue by the first injection means, and the second sampling means output And a calculation means for calculating the blood dye concentration by substituting the output of the sampling means at each wavelength when the specific dye is injected into the blood of the biological tissue by the injection means into a predetermined calculation expression. It is.

[0006]

The blood dye concentration measuring apparatus according to the present invention has a first light of a wavelength that is absorbed by a specific dye and a second light of a wavelength that is not absorbed when a transparent liquid is injected into the blood of a living tissue.
When irradiating the living tissue with the above-mentioned light, sampling the first and second photoelectric conversion signals corresponding to the first and second light obtained from the living tissue, and injecting the specific dye into the blood of the living tissue. Irradiating the living tissue with the first and second light,
The first and second photoelectric conversion signals obtained from the biological tissue are sampled, and the respective sampling outputs are substituted into a predetermined arithmetic expression to calculate the blood dye concentration.

[0007]

1 is a diagram for explaining the principle of the present invention. Referring to FIG. 1, it is assumed that a transparent liquid (for example, physiological saline) is injected into blood at time t = t ₂ and a dye is injected into blood at time t = t ₀ . The total absorption A (t ₁ ) at t = t ₁ is expressed by the following equation (1).

A (t ₁ ) = A _d + A _HB + A _T where A _{d is the} light absorption by the dye A _{HB is the} light absorption by the hemoglobin (HB) A _{T is the} light absorption by the tissue, and the light absorption at t = t _4. The quantity A (t ₄ ) is A (t ₄ ) = A _HB + A _t (2) Further, at t = t ₅ , blood is eliminated by the transparent liquid, and only the light absorption amount _AT by the tissue is obtained. Therefore, A (t ₅ ) = A _T (3) Since A _T = A (t ₅ ) is considered to be constant now, A (t ₄ ) −A (t ₅ ) = A _HB , and according to Beer-Lambert's law, A (t ₄ ) −A (t ₅ ). ) = K _Hb · C _Hb (t ₄ ) · d where C _Hb (t ₄ ): hemoglobin concentration at time t ₄ d: optical path length K _Hb : distribution absorption coefficient of hemoglobin Is represented by λ ₁ , the wavelength not absorbed is represented by λ _2, and suffixes 1 and 2 are added to the respective wavelengths, and the expressions (1) and (4) are as follows.

A¹(T₁) = A¹ _d+ A¹ _HB+ A¹ _T… (5) A²(T₁) = A² _HB+ A² _T… (6) A¹(T_Four) -A¹(T_Five) = K¹ _Hb・ C_Hb(T_Four) ・ D… (7) A²(T_Four) -A²(T_Five) = K² _Hb・ C_Hb(T_Four) ・ D ... (8) Apply Beer-Lambert's law to dyes
And the equations (5) and (6) are¹(T₁) = K¹ _d・ C_d(T₁) ・ D + K¹ _Hb・ C_Hb(T₁) ・ D + A¹ _T … (9) A²(T₁) = K² _Hb・ C_Hb(T₁) ・ D + A² _T… (10) Therefore, the desired blood pigment concentration C_d(T₁) Is
It looks like this:

C_d(T₁) ・ D = 1 / K¹ _d(A¹(T₁) -K¹ _HbC_Hb(T₁) ・ D-A ¹ _T ) = 1 / K¹ _d(A¹(T₁) -K¹ _Hb/ K² _Hb(A²(T₁) -A² _T) -A ¹ _T ) ... (11) In the above equation (11), A¹(T₁), A²(T₂) Is a measurement
Determined according to the rule, A¹ _T, A² _TIs t = t_FiveBy absorption at
There is one, so I need it first. Also, K¹ _Hb, K² _HbIs constant
So C_d(T₁) ・ D will be obtained.

Here, the amount of light incident on the living body is I¹ ₀, I²
₀And the amount of transmitted light is T¹(T), T²Let (t)
And equation (11) gives Cd (t₁) ・ D ＝ / K¹ _d(LogT¹(T₁) / I¹ ₀-Logt¹(T _Five ) / I¹ ₀-K¹ _Hb/ K² _Hb(LogT²(T₁) / I² ₀-LogT²(T _Five ) / I² ₀) = 1 / K¹ _d(LogT¹(T₁) / T¹(T_Five) -K¹ _Hb/ K² _Hb(Log T²(T₁) / T²(T_Five)) ... (12) Further, from the expressions (10) and (8),₂of
Since there is no absorption by the dye at the wavelength,²(T₁) -A²(T_Five) = K² _Hb・ C_Hb(T₁) ・ D ... (13) Therefore, equation (12) and equation (13)
R, C_d(T₁) = {LogT²(T₁) / T²(T_Five)} / {K¹ _d・ K² _Hb・ C_Hb(T₁)} {LogT¹(T₁) / T¹(T_Five) -K¹ _Hb/ K² _HblogT ² (T₁) / T²(T_Five)} Becomes C_HbIf (t) is constant, blood pigment concentration C_d
(T₁) Is T¹(T₁), T²(T₁), T
¹(T_Five), T²(T_Five) Is calculated by measuring
Wear.

FIG. 2 is a schematic block diagram of an embodiment of the present invention. Referring to FIG. 2, CPU 1 is I / O port 2
, I / O port 2, ROM3 and RAM4
The display 5, the printer 6, the operation unit 7, the injector drive circuit 10, the LED drive circuit 14, and the A / D converter 21 are connected. A program based on the flow charts shown in FIGS. 3 and 4 described later is stored in the ROM 3 in advance.
The RAM 4 stores light amount data, which will be described later, data calculated by the CPU 1, and the like. The display 5 displays the calculation result,
The printer 6 prints them.

The operation unit 7 includes a calibration key 8 and a measurement key 9. The injector drive circuit 10 is an I / O
The injectors 11 and 12 are driven according to a control signal given from the CPU 1 via the port 2. The injector 11 injects physiological saline as a transparent liquid into the living body 17 via the catheter 13 held by the living body 17, and the injector 12 injects a specific dye into the living body 17 via the catheter 13.

The LED drive circuit 14 drives the light emitting diodes 15 and 16 in response to a control signal supplied from the CPU 1 via the I / O port 2. The light emitting diode 15 irradiates the living body 17 with light of wavelength λ ₁ which is absorbed by the specific dye, and the light emitting diode 16 irradiates the living body 17 with light of wavelength λ ₂ which is not absorbed by the specific dye. The light of wavelengths λ ₁ and λ ₂ that has passed through the living body 17 is received by the photodiode 18. The received light output of the photodiode 18 is amplified by the preamplifier 19 and the amplifier 20 and given to the A / D converter 21. The A / D converter 21 converts the received light output into light amount data of a digital signal and gives it to the CPU 1 via the I / O port 2. The CPU 1 sends the light amount data to RA
Store in M4.

3 and 4 are flow charts for explaining the operation of the embodiment of the present invention.

Next, the specific operation of the embodiment of the present invention will be described with reference to FIGS. When the power is turned on, the CPU 1 executes I / O in step SP11.
A control signal is given to the LED drive circuit 14 through the O port 2, and the light emitting diode 1 of the sensor attached to the living body 17
The living body 17 is irradiated with light having wavelengths λ ₁ and λ ₂ from 5 and 16. The photodiode 18 receives the light that has passed through the living body 17, the received light output is amplified by the preamplifier 19 and the amplifier 20, and is converted by the A / D converter 21 into light amount data T ¹ and T ² of digital signals. This light quantity data T ¹ ,
T ² is given to the CPU 1 via the I / O port 2.
The CPU 1 controls the LED drive circuit 14 so that the light quantity data T ¹ and T ² have predetermined values.

In step SP12, the CPU 1 determines whether or not the calibration key 8 has been operated,
If not operated, it is determined in step SP14 whether the start key 9 has been operated. Step SP
When it is determined in 12 that the calibration key 8 is operated, the process proceeds to step SP13 and calibration is performed.

That is, in step SP21 shown in FIG. 4, the CPU 1 controls the injector drive circuit 10 to inject the physiological saline from the injector 11 into the living body 17 via the catheter 13. The light having the wavelengths λ ₁ and λ ₂ that has passed through the living body 17 at this time is detected by the photodiode 18, amplified by the preamplifier 19 and the amplifier 20, and then the light amount data T ¹ , T ² by the A / D converter 21.
Is converted to the I / O port 2 and given to the CPU 1 through the I / O port 2. The CPU 1 detects the light amount data T ¹ and T ² , and determines in step SP23 whether or not the trailing edge of the light amount data is detected. If no fall is detected, step S
Returning to P22, T ¹ and T ² are detected again. When falling in step SP23 is detected, it determines whether it has detected the time constant value corresponding to t ₅ shown in FIG. 1 in step SP24. When a constant value is detected, step SP25
At that time, the light quantity data T ¹ and T ² at that time are converted into T ¹ _t and T
^It is stored in RAM 4 as _2t . In step SP26, the CPU 1 stops the injection of the physiological saline by the injector 11 and returns to the main routine of FIG.

In step SP15, the CPU 1 controls the injector drive circuit 10 to inject a specific amount of the specific dye into the living body 17 from the injector 12 via the catheter 13. In step SP16, the CPU
1 detects the light quantity data T ^1, T ² based on the light passing through the implanted bio-17 specific dye, using the first (14) described _{above, C d (t) = {} logT 2 (t 1) / T ² (t ₅ )} / {K ¹ _d · K ² _Hb · α} {(logT ¹ (t ₁ ) / T ¹ (t ₅ ) −K ¹ _Hb / K ² _Hb (logT ² (t ₁ ). / T ² t ₅ )) is calculated, and in step SP18, the blood dye concentration Cd (t) obtained by the above calculation is displayed on the display device 5 and printed by the printer 6. The above-mentioned α is a predetermined value representing C _Hb .

[0020]

As described above, according to the present invention, the light having the wavelength absorbed by the specific dye is injected into the blood when the transparent liquid is injected and when the specific dye is injected into the blood. Since the blood dye concentration is measured according to the light amount data obtained by irradiating the living body with light of a wavelength that is not absorbed and a predetermined calculation formula, the blood dye concentration can be accurately measured without assuming a bloodless state. It can be measured well.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of the present invention.

FIG. 2 is a schematic block diagram of an embodiment of the present invention.

FIG. 3 is a flow chart of a main routine for explaining the operation of the embodiment of the present invention.

FIG. 4 is a flowchart for explaining a calibration operation in the embodiment of the present invention.

[Explanation of Codes] 1 CPU 2 I / O Port 3 ROM 4 RAM 5 Display 6 Printer 7 Operating Unit 8 Calibration Key 9 Start Key 10 Injector Drive Circuit 11, 12 Injector 13 Catheter 14 LED Drive Circuit 15, 16 Light Emitting Diode 17 living body 18 photodiode 19 preamplifier 20 amplifier 21 A / D converter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G01N 33/483 C 7055-2J

Claims (1)

[Claims] 1. A blood dye concentration measuring device for measuring a dye concentration in blood of a living tissue, the first device for injecting a transparent liquid into the blood of the living tissue.
Second injection means for injecting a specific dye into the blood of the living tissue
Injection means, light source means for irradiating the living tissue with first light having a wavelength that is absorbed by the specific dye, and second light having a wavelength that is not absorbed, and the living body is irradiated with the light source means by the light source means. Photoelectric conversion means for outputting first and second photoelectric conversion signals corresponding to the first and second light obtained from a tissue, and sampling the first and second photoelectric conversion outputs from the photoelectric conversion means For sampling the output of the sampling means at each wavelength when a transparent liquid is injected into the blood of the living tissue by the first injecting means, and the second injecting means to identify in the blood of the living tissue Blood dye provided with a calculating means for calculating the blood dye concentration by substituting the output of the sampling means at each wavelength when the dye is injected into a predetermined arithmetic expression Degree measurement device.