JPH067827B2 - Cuvette for biological simulation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention receives the light emitted from a light source unit through a sample at a light receiving unit, and detects the intensity of the transmitted light according to the above. The present invention relates to a biological simulation cuvette used in an analyzer that performs optical analysis of a sample by the output of a light receiving unit, and is particularly suitable for testing the measurement accuracy when measuring the oxygen saturation of blood in biological tissue. The present invention relates to a cuvette for biological simulation.

(Prior Art) A pulse oximeter measures the amount of transmitted light of each wavelength that changes when the thickness of the blood layer of arterial blood changes due to pulsation by irradiating living tissue with light of different wavelengths. The oxygen saturation of arterial blood is determined from these measurements. Such a pulse oximeter is calibrated by performing a measurement accuracy test in order to allow the manufacturer to evaluate the performance of the pulse oximeter produced by the manufacturer, to confirm the accuracy by the user, and in the event of a repair. There is a need.
The calibration of this pulse oximeter has been conventionally performed as follows. That is, a probe connected to the pulse oximeter is attached to the finger of the subject, and the oxygen concentration of the gas to be inhaled by the subject is arbitrarily changed to obtain a value when the measured value by the pulse oximeter is stable. Oxygen saturation. Next, the arterial blood when the measured value becomes stable is sampled, the oxygen saturation of the arterial blood is obtained by an invasive oximeter, and compared with the measured value by the pulse oximeter.

When a pulse oximeter is calibrated using a conventional living body as described above, it can be calibrated relatively accurately because it is a test method under actual usage conditions, but it has the following problems. It was In other words, (1) The pulse oximeter must be calibrated by the human body because the absorption characteristics of hemoglobin differ depending on the animal.

(2) When calibrating by the human body, time and place are limited, and it is not preferable to use the human body for calibrating the device.

(3) When the human body is used, various gas cylinders and gas mixers for producing inhaled gas are required, and a measuring instrument for the gas composition is also required, which makes the operation complicated.

(4) When changing the oxygen concentration of the gas to be inhaled by the subject, if the oxygen concentration is made too low, there is a danger of life, so the oxygen concentration range is limited.

(5) When testing a large number of pulse oximeters, or when it is desired to test frequently, it is practically impossible to carry out the test using the human body.

Because of the above problems, it is necessary to perform calibration without using a living body. As a method of calibrating the pulse oximeter without using a living body, a cuvette containing the collected blood is provided with a sample tank having two light-transmissive parallel flat plates as a part of the wall, and one of the flat plates is made of an elastic member. There has been considered a method of pulsating the internal pressure of the sample tank formed, and sandwiching the cuvette with a probe provided with a light emitting portion and a light receiving portion facing each other. However, according to this method, the relationship between the oxygen saturation of blood and the indicated value of the pulse oximeter is different from that in the human body, and there is a problem that accurate calibration cannot be performed.

(Problems to be Solved by the Invention) As described above, when the oxygen saturation of blood in living tissue is measured by the pulse oximeter using the conventional cuvette, the relationship between the indicated value of the pulse oximeter and the oxygen saturation. However, there is a problem that accurate measurement cannot be performed, which is different from the case where it is measured directly on a living tissue.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a biological simulation cuvette capable of performing accurate optical analysis.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention receives light emitted from a light emitting unit through a sample at a light receiving unit and determines the intensity of the transmitted light. In a biological simulation cuvette used in an analyzer that performs optical analysis of the sample by the output of the light receiving unit, two rigid plates at least a part of which are light transmissive, and a cuvette disposed between the rigid plates. A light-transmitting elastic plate, and a frame plate sandwiched between the elastic plate and the two rigid plates to form a closed space,
These rigid spaces are provided with openings provided in the rigid plate for injecting and discharging the sample and the light-scattering substance, respectively.

The biological simulation cuvette having the above-mentioned configuration includes an internal pressure changing means for periodically changing the internal pressure of any one of the sample and the light-scattering substance injected into the pair of closed spaces, or a closed state. It is preferable to provide temperature maintaining means for maintaining the temperature of the sample and the light-scattering substance injected into the space at a predetermined temperature.

(Operation) According to the above configuration, for example, when the discharge side opening of the closed space into which the sample is injected is closed and the internal pressure is periodically changed through the injection side opening, a pair of closed spaces is formed. The elastic plate that separates moves. That is, the thickness of the light-scattering substance increases or decreases in inverse proportion to the increase or decrease in the thickness of the sample. So, for example,
By sandwiching this cuvette with a probe having a light emitting part and a light receiving part and measuring with a paloximeter, it is possible to carry out a measurement equivalent to the case where the finger of a living body is sandwiched with the probe, and the pulse oximeter is used. Accurate calibration can be performed when the calibration is performed by comparing the measurement value of the meter with the measurement value of the invasive oximeter. Therefore, if the oxygen saturation of blood is measured using a pulse oximeter that is accurately calibrated as described above, correct measurement becomes possible.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment of the present invention.

As shown in these figures, this cuvette is constructed by laminating a plurality of substantially rectangular plate-shaped members and fixing them with screws. In the figure, 1 is a rigid plate, 2 is a sheet, 3 is a surface board, 4 is a spacer that serves as a frame plate, and 5 is a diaphragm that is an elastic plate. These plates are laminated in the above-mentioned order, centering around the diaphragm. It consists of 9 layers vertically symmetrical. The nine plate-shaped members are firmly fixed by a plurality of screws 6 and a plurality of nuts 7 in a state of being closely stacked.

The rigid plate 1 is made of a stainless steel thick plate, and has a rectangular notch 1a opened at one side at the center. Two holes are provided on both sides of the notch 1a, and pipes 8 and 9 to be openings are fitted in these holes, respectively.

Sheet 2 is made of black neoprene sheet,
A notch 2a is formed in the center, and holes 2b are formed on both sides of the notch 2a at positions aligned with the notch 2a and the hole formed in the rigid plate 1, respectively.

The sheet 2 has a function of liquid-tightly sealing the rigid plate 1 and the surface board 3.

The surface board 3 is made of a thick plate of acrylic resin having a light-transmitting property and a light-scattering property, and a hole 3b is formed at a position aligned with the hole 2b formed on the sheet 2.
Further, a cutout portion 3a having a small depth is formed at a position aligned with the cutout portion 2a of the sheet 2.

The spacer 4 is made of a black neoprene thin plate, and has a hole 4a provided in the longitudinal direction in the central portion thereof to form a closed space which is a sample tank sandwiched between the surface board 3 and the diaphragm 5. is doing. Similar to the surface board 3, a small cutout 4b is also formed in the spacer 4.

The diaphragm 5 is made of a light-transmissive polyethylene film and has a small cutout 5a similar to the spacer 4.
Are formed.

The cutouts 3a, 4b, 5a are provided on one side of the cuvette 10 configured as described above as shown in FIG. This is because it is easy to position them in the central portion of the rigid plate 1.

Next, the operation of the cuvette 10 thus configured will be described together with the method of use. When the cuvette 10 is used, as shown in FIG. 4, the tubes 13a, 14a, 13 are connected to the tubes 8a, 9a, 8b, 9b through the opening / closing cocks 11a, 12a, 11b, 12b.
Connect b and 14b, and open / close cock in the middle of tube 13a.
Install 15. Then, the cuvette 10 is fixed in a vertically standing state. The cuvette 10 is set up vertically in this way because it is easy to remove the air inside the hole 4a that forms the closed space. Next, the operator inserts a pulse oximeter probe (not shown) into the cutout 3 shown in FIG.
The light emitting part 17 and the light receiving part 16 of the probe are fitted to a, 4b and 5a.
Are attached to the notches 1a of the rigid plate 1, respectively. When the probe is mounted on the cuvette 10 as described above, the light emitted from the light emitting portion 17 is emitted from the rigid plate 1 as shown by an arrow X in FIG.
And the notches 1a and 2a respectively formed in the sheet 2, the surface board 3, the hole 4a of the spacer 4, the diaphragm 5, the hole 4a of the spacer 4, the surface board 3, the rigid plate 1 and the sheet 2, respectively. It reaches the light receiving portion 16 through the notches 1a and 2a.

The operator opens the open / close cocks 11a, 12a, 15 shown in FIG. 4 to inject the sample into the one hole 4a. After the sample is filled in the hole 4a, the opening / closing cocks 12a and 15 are closed, and the opening / closing cock 11 is closed.
Open a. Similarly, a light-scattering substance in the other hole 4b,
For example, fill milk and open and close cock 11 after filling.
Open at least one of b and 12b and close the other. The tubes 13a, 14 are made of elastic material, and in this state, the operator operates the opening / closing cock 11 of the tube 13a.
When pinching between a and 15 with a fingertip and pressing, the hole 4a on the side filled with the sample is sealed, so the sample is pressed and the light scattering property filled in the other hole 4b through the diaphragm 5 Press the substance. In this way, the thicknesses of the two liquids of the sample and the light-scattering substance in the cuvette 10 can be changed in mutually opposite directions. When the operator releases this compression, the diaphragm 5 returns to its original state due to its elasticity.

If such an operation is repeated, the thickness of the hole 4a filled with the sample due to the vibration displacement of the diaphragm 5 becomes
It changes as if by pulsating arterial blood. The light that reaches the light receiving unit 16 during this fluctuation is photoelectrically converted there, and is input to the pulse oximeter as an electric signal to analyze the sample.

Next, the analysis result of the sample obtained by the above operation will be described. In the living tissue of the tissues, the arterial blood in the tissue increases or decreases with the pulsation of the arterial blood pressure, and the tissues other than blood are eliminated by the increase in blood. Considering the state where the pulse oximeter probe is attached to the peripheral part of the finger such as the living body, the thickness of the arterial blood vessel increases due to the increase in arterial blood pressure, and as a result, between the light emitting part and the light receiving part of the probe The equivalent thickness of the sandwiched blood increases. On the other hand, tissues without blood other than arterial blood vessels and venous blood are compressed by this and excluded from the measurement target area of the probe. Here, both blood and tissue have a light-scattering property, and when blood increases, the tissue decreases.Therefore, light-scattering occurs between the light-emitting part and the light-receiving part of the probe that holds the living body at a certain distance. Sex does not change. However, in the conventional cuvette, since the thickness of the sample layer is simply changed, the coefficient relating to light scattering becomes larger than that in the case where the probe is attached to the actual living body.

However, when the cuvette according to this example is used, the thickness of the light-scattering substance is reduced by the increase in the thickness of blood, so that the measurement can be performed under the same conditions as the measurement of blood pulsation in the tissue.

According to this example, blood collected from a living body was placed in a cuvette, and the oxygen saturation was measured by a pulse oximeter, and the measured value was compared with the blood measured by an open oximeter. When performing calibration, it is possible to obtain the same value as when measured by the living body, and it is possible to test the accurate measurement accuracy of the pulse oximeter.

In the above examples, the measurement of oxygen saturation of arterial blood of the tissue of the living body was described, but when a dye was injected into the vascular system for diagnosis by the dye dilution curve method, the blood dye concentration was measured by a pulse oximeter. It can be applied when measuring from outside the body, and can also be used to measure other blood components.

Further, when the amount of venous blood changes, it can be applied to obtain the oxygen saturation of this venous blood.

Further, in the present embodiment, as a means for changing the pressure of the sample in the hole 4a, the case of using the method of pinching and pressing the tube 13a with a finger was described, but as shown in FIG. It is also possible to use a mechanism which is mounted on the top and rotates the eccentric cam 21 by contacting the tube 13a.

Also, since the light absorption coefficient in blood varies with temperature,
In order to obtain the same result as the human body, as shown in Fig. 6, the temperature bath
It is preferable to immerse the cuvette 10 in 30 and hold the blood in the cuvette 10 at a temperature of about body temperature for measurement.

Further, the material shape of each plate-shaped member shown in the above embodiment is not limited to them.

[Effects of the Invention] As described above, according to the present invention, the biological simulation cuvette has the two-chamber structure with the elastic film interposed therebetween. Therefore, when performing optical analysis based on the intensity of transmitted light passing through the sample. The apparatus can be calibrated without using a living body so that accurate measurement results can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a cuvette for biological simulation according to the present invention, FIG. 2 is a perspective view thereof, FIG. 3 is an exploded perspective view thereof, and FIG. 5 and 6 are views showing another embodiment of the present invention. 1 ... Rigid plate, 4 ... Spacer (frame plate) 4a ... Hole (closed space) 5 ... Diaphragm (elastic plate) 8, 9 ... Tube (opening) 10 ... Cuvette, 17 ... Light emitting part, 16 ... Light receiving part 21 … Cam (internal pressure changing means) 30… Insulation tank (temperature holding means)

Claims (3)

[Claims] 1. A living body used in an analyzer for receiving light emitted from a light emitting unit through a sample at a light receiving unit and performing optical analysis of the sample by the output of the light receiving unit according to the intensity of transmitted light. In a simulation cuvette, two rigid plates at least partially having a light transmitting property, an elastic plate having a light transmitting property disposed between these rigid plates, the elastic plate and the two rigid plates. And a frame plate sandwiched between them to form a closed space, and openings provided in the rigid plate for injecting and discharging the sample and the light-scattering substance into these closed spaces, respectively. A cuvette for biological simulation characterized by. 2. An internal pressure changing means for cyclically changing the internal pressure of either one of the sample and the optical confusion substance injected into the pair of closed spaces. 1) The biological simulation cuvette described above. 3. The biological simulation cuvette according to claim 1, further comprising temperature holding means for holding the temperature of the sample and the light-scattering substance injected into the closed space at a predetermined temperature.