JPH0426848B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a measuring device used for medical purposes, health care, sports, etc., and particularly relates to a device used for non-invasively measuring the specific resistance of blood. .

[Conventional technology]

BACKGROUND ART As a conventional body/extremity blood specific resistance measuring means, it is widely practiced to collect a small amount of blood from a human body and directly measure the specific resistance of this blood.

In addition, recently developed body and limb blood specific resistance measuring means involves wrapping multiple electrodes around the body and limb and immersing them in conductive liquid. The change in admittance of blood is measured while gradually changing the specific resistance of the liquid, thereby measuring the specific resistance of blood flowing through the limbs.

[Problem to be solved by the invention]

By the way, with the conventional means of measuring blood resistivity by drawing blood as described above, there is a problem that blood must be drawn from the subject every time a measurement is performed, which causes pain to the subject. Another problem is that it is difficult to measure changes in the specific resistance of the subject's blood.

In addition, the above-mentioned method of measuring resistivity from admittance changes requires immersing the test subject's limbs in a conductive liquid, which results in the problem that the measurement site is limited to relatively thin parts such as fingers. There is.

The present invention is an attempt to solve the above-mentioned problems.The present invention aims to solve the above-mentioned problems. By measuring changes in admittance or impedance of the same body limb and the same fluid due to changes in volume, the specific resistance of blood can be easily and continuously measured.
The purpose of the present invention is to provide a body limb blood specific resistance measuring device.

[Means to solve the problem]

In order to achieve the above object, the body limb blood specific resistance measuring device of the present invention includes a rigid outer cylinder and a flexible inner cylinder disposed inside the outer cylinder. It consists of a tank that has a volume-adjustable liquid storage part formed between it and an inner cylinder, and a limb receiving part formed inside the inner cylinder, and both the outer cylinder and the inner cylinder are electrically insulated. a plurality of external electrodes, each of which is made of a conductive material, in which the liquid has conductivity, and which are attached to the outer cylinder so as to be spaced apart from each other in the longitudinal direction thereof, and a support that projects inward from the outer electrode; Impedance of the liquid between the member, the internal electrode for body limb contact supported by the tip of the support member and exposed to the inner surface of the inner cylinder, and the external electrode, and the body limb between the internal electrodes. or means for measuring admittance,
The support member is composed of a cylindrical guide part and a rod-shaped part slidably fitted in the cylindrical guide part so as to expand and contract in the direction in which the support member protrudes. It is characterized in that the above-mentioned external electrode and internal electrode are respectively coupled to one side and the other side.

[Effect]

In the body limb blood specific resistance measuring device of the present invention described above,
When a limb is inserted into the limb receiving part inside the flexible inner cylinder, fluid between the outer cylinder and the inner cylinder changes as the volume of the limb changes due to blood pressure pulsations in blood vessels within the limb. The amount of liquid in the container changes.

In this way, changes in the conductive liquid whose liquid volume has changed and the admittance or impedance of the body limbs occur between the plurality of external electrodes attached to the outer tube and the plurality of internal electrodes attached to the inner tube. By measuring at the same time, the specific resistance of blood flowing through the limbs between the internal electrodes can be indirectly measured.

〔Example〕

Hereinafter, a body limb blood specific resistance measuring device as an embodiment of the present invention will be explained with reference to the drawings.
The figure is a schematic longitudinal sectional view, and Figure 2 is the − of Figure 1.
Cross-sectional view in the direction of arrows, Figure 3 is a partially enlarged view of Figure 2,
FIG. 4 is a schematic diagram showing changes in volume and admittance of the limb and electrolyte during measurement.

As shown in FIGS. 1 and 2, a rigid outer cylinder 11 is installed on the base member 10, and the outer cylinder 11
A flexible inner cylinder 12 is disposed inside the inner cylinder 1.
The peripheral edges of the flanged end portions 12a and 12b at both ends of the outer cylinder 11 are attached to the inner surface of the end portion of the outer cylinder 11 in a liquid-tight manner.

In this way, a liquid volume-adjustable liquid storage portion 13 is formed between the outer cylinder 11 and the inner cylinder 12, and the liquid storage portion 13 is communicated with the electrolyte tank 14. That is, an electrolytic solution W' as a conductive liquid is supplied into the liquid storage part 13, and this electrolytic solution may be physiological saline or a saline solution with a lower concentration. used.

Further, a pressure controller 15 is connected to the gas phase portion of the electrolyte tank 14, and the pressure controller 15 responds to a detection signal from a sensor 16 that detects the liquid pressure in the liquid storage portion 13.
By supplying operating pressure from the electrolyte tank 14 to the electrolyte tank 14, control is performed to maintain the liquid pressure at a predetermined value. That is, the electrolytic solution tank 14, the pressure controller 15, and the sensor 16 constitute a hydraulic pressure adjusting means.

The outer cylinder 11 is made of an electrically insulating material such as acrylic resin, and the inner cylinder 12 is a flexible member such as a rubber tube that has a limb receiving part B for receiving a limb A inside. . A pair of current applying external electrodes 1 are provided on the inner peripheral part of the outer cylinder 11 so as to be spaced apart from each other in the longitudinal direction.
7a, 17b and four voltage detection external electrodes 18a, 18 between the same electrodes 17a, 17b.
b, 18c, and 18d, and a pair of internal current applying electrodes 21a, 21b and a pair of internal current applying electrodes 21a, 21b are provided on the inner circumference of the inner cylinder 12 so as to be spaced apart from each other in the longitudinal direction. Four internal voltage detection electrodes 22a, 22b, 22c, 22d in
and four pieces each along the circumferential direction of the inner cylinder 12,
External electrodes 17a, 18a, 18b, 18c, 18
d, 17b in the longitudinal direction,
Each code 21a, 22a, 22b, 22c, 22
These electrodes are arranged in the order shown by d and 21b, and these electrodes can be connected to required terminals of a measuring device 19 that measures and records admittance or impedance.

Further, as shown in FIG. 3, each internal electrode is supported at a position 12 on the inner surface of the outer cylinder 11 where the external electrode is located by a supporting member 23 made of an insulating material, and this supporting member 23 It is composed of a cylindrical guide part 23a that can be expanded and contracted in the direction, and a rod-shaped part 23b that is slidably fitted into the cylindrical guide part 23a. The rear end of the cylindrical guide part 23a is connected to each of the external electrodes 17a, 17b, 18a, . The electrodes 17a, 17b, 18a, 18d and the internal electrodes 21a, 21b, 22a, 22d, which correspond to each other in the longitudinal direction, are connected to each other so that their positions do not shift, and are expandable and contractible in the radial direction. It has become impossible to prevent changes in the volume of the body and limbs.

Note that receiving portions 20a and 20b for the limbs A are provided at both ends of the base member 10, respectively.

And each external electrode 17a, 17b, 18a~
18d and each internal electrode 21a, 21b, 22a
-22d and the measuring device 19 include corresponding external electrodes 17a, 17b, 18a-18d.
Switches 24a, 24 for conducting and cutting off conduction between and each internal electrode 21a, 21b, 22a to 22d.
b, 24c, and 24d are provided. The liquid storage section 13 also includes a concentration adjustment mechanism 25 for the electrolytic solution W';
A resistivity measuring device 26 for the electrolytic solution W' and a pump 27 for stirring the electrolytic solution in the liquid storage section 13 are connected.

When measuring the specific resistance of blood flowing through the body and limb A using the body and limb blood resistivity measuring device having the above-described configuration, first, in the first method, an appropriate amount of electrolyte solution W is added to the liquid storage part 13. ' is supplied, and then, after the limb A is inserted into the limb receiving part B, the switch 24
a, 24b, 24c are open, that is, the admittance (or impedance) is changed independently for each external electrode 17a, 17b, 18a to 18d and each internal electrode 21a, 21b, 22a to 22d.
is being measured, the external electrode 17 for applying current
a, 17b, and the external electrode 21 for applying current
A required alternating current constant current is passed between a and 21b. Then, by the pressure controller 15,
Inside the liquid storage section, the inner cylinder 12 is in close contact with the body limbs,
In addition, the pressure is adjusted to a level that does not compress or close blood vessels in the limbs.

After such preparatory operations are performed, the electrolyte W' admittance (or impedance) between the voltage detection external electrodes 18b and 18c is determined.
Then, the measuring device 19 measures the admittance (or impedance) of the body and limb A between the voltage detection internal electrodes 22b and 22c.

At this time, the volume of limb A changes due to blood pressure pulsations in blood vessels in limb A. That is, as shown in FIG. 4, the voltage detection external electrodes 18b, 18
c or regarding the section L sandwiched between the voltage detection internal electrodes 22b and 22c, the volume of the electrolyte W' in the section L is Vs, the volume of the blood vessel, that is, the volume of blood, is Vb, and the admittance of the limb A is Ys,
Assuming Yb and Yt, each of the above values changes as follows due to blood pressure pulsation.

When blood flows into limb A in section L whose volume was initially (Vb + Vt), Vt is always considered to be constant regardless of the inflow of blood, so limb A
The volume of increases by the blood inflow ΔV, and (Vb + Vt
+ΔV). In addition, the volume of the section L including the body limbs A is always constant because the outer cylinder 12 is made of a rigid material, and the increase in volume of the body limbs A, ΔV, is the volume of the section L.
The electrolytic solution W' in the space decreases by ΔV and is filled up. In other words, the amount of blood increase in limb A and the amount of decrease in electrolyte W' are equal.

Along with the above-mentioned volume change, the admittance of the body limb A and the electrolyte W' also changes. If the admittance change measured at the voltage detection internal electrodes 22b and 22c is ΔYb, the tissue Vt of the limb A is always constant as described above, and Yt
does not change, that is, the volume change ΔV of limb A is entirely due to a change in blood volume. Therefore, it can be expressed as follows using ΔYb, specific resistance ρb of blood, and length l of section L.

|ΔV|=ρb・l ²・|ΔYb| Further, ΔV is expressed as |Δv|=ρs・l ²・|ΔYs| using the admittance change ΔYs and specific resistance ρs of the electrolytic solution W′. The following equation is derived from the above two equations.

ρb=|ΔYb/ΔYs|ρs In other words, the measuring device 19 measures the amplitude of the admittance change between the voltage detection external electrodes 18b and 18c and the amplitude of the admittance change between the voltage detection internal electrodes 22b and 22c. After the measurement, the electrolytic solution W' in the liquid storage part 13 is introduced into the resistivity measuring device 26, and the resistivity ρs of W' is measured.
ρb is calculated using the above relational expression.

Next, to explain the second blood specific resistance measurement method using this device, first, the switches 24a to 24
c is closed, each external electrode and each internal electrode are electrically connected, and each external electrode 17a, 17b, 18a to 18
d and each internal electrode 21a, 21b, 22a to 22d
The same preparatory operations as in the first method described above are carried out, with the combined admittance (or impedance) of

The admittance (or impedance) of the electrolyte W' between the voltage detection external electrodes 18b and 18c and the voltage detection internal electrode 22
The measurement device 19 measures the sum of the admittance (or impedance) of the body limb A between b and 22c.

At this time, when the admittance measured by the measuring device 19 is Y, Y is expressed as Y=Yb+Yt+Ys using the above-mentioned symbols. Furthermore, if the change in volume of limb A due to blood inflow is ΔV, based on the same principle as the first method, the amount of decrease in electrolyte W' is -ΔV, -ΔV=ρs・l ²・ΔYs ΔV= From the relational expression of ρb・l ²・ΔYb, the admittance of blood inflow
Let Y′ and its change be ΔY, then ΔY=Y′−Y=ΔV/l ² (1/ρb−1/ρs) is derived.

That is, if ρb=ρs, then ΔY=0 always holds true in the above equation, and the measured admittance will not show any change or amplitude due to blood pressure pulsations in the limbs. Therefore, during measurement, the measuring device 19 is used to connect the voltage detection external electrodes 18a to 18.
While measuring the sum of the admittances of d and voltage detection internal electrodes 22a to 22d, that is, Y, the concentration of W' is gradually changed by the electrolyte W' concentration adjustment mechanism 25, and the electrolyte stirring pump 27
An operation is performed to adjust the concentration of W' so that it is always uniform.

Then, the concentration of W' is adjusted so that the amplitude of admittance pulsations, that is, ΔY, disappears or ΔY is minimized. When ΔY disappears or becomes minimum, the concentration adjustment is stopped, the electrolytic solution W' is introduced into the resistivity measuring device 26, and ρs is measured. At this time, since ρs=ρb, the value of ρb is determined.

In addition, in this example, blood specific resistance is measured from admittance change in both methods, but since impedance is obtained as the reciprocal of admittance, blood specific resistance can be measured from impedance change using almost the same procedure. be able to.

In this way, in this example, there is no need to collect blood from the subject as in the past, so the specific resistance of the blood can be measured without causing pain to the subject, and the specific resistance of the blood can be measured without causing pain to the subject. It is possible to easily and continuously measure changing conditions. Also,
Because there is no need to immerse the subject's limbs in conductive liquid,
It has the advantage that the measurement site is not limited.

Further, in this device, when the switches 24a to 24d are open, the external electrodes 17a, 17b, 18a to 1
If measurement is performed using only the 8d, it can be used as a recently developed body and limb volume measurement device used to measure body and limb volume, blood pressure, and the like.

〔Effect of the invention〕

As described in detail above, according to the body limb blood specific resistance measuring device of the present invention, the following effects and advantages can be obtained.

(1) Since there is no need to collect blood from the subject, the specific resistance of blood can be measured without causing pain to the subject.

(2) Changes in the specific resistance of blood can be easily and continuously measured.

(3) Since there is no need to immerse the subject's limbs in conductive liquid, there is an advantage that the measurement site is not limited.

[Brief explanation of drawings]

FIG. 1 is a schematic longitudinal cross-sectional view showing a body limb blood specific resistance measuring device as an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the - arrow in FIG. The partially enlarged view, FIG. 4, is a schematic diagram showing changes in the volume and admittance of the body limb and electrolyte during measurement. 10... Base member, 11... Outer cylinder, 12...
Inner cylinder, 12a, 12b...Flanged end, 13
...Liquid storage section, 14...Electrolyte tank, 15...
...Pressure control, 16...Sensor, 17a, 17b...External electrode for current application, 1
8a, 18b, 18c, 18d... external electrode for voltage detection, 19... measuring instrument, 20a, 20b... receiving part, 21a, 21b... internal electrode for current application,
22a, 22b, 22c, 22d... Internal electrode for voltage detection, 23... Supporting member, 23a... Cylindrical guide portion, 23b... Rod-shaped portion, 24a, 24b, 24
c, 24d... Switch, 25... Concentration adjustment mechanism, 26... Specific resistance measuring device, 27... Electrolyte stirring pump, A... Body limb, B... Body limb receiving section,
W′...electrolyte.

Claims (1)

[Scope of Claims] 1. A liquid storage section with an adjustable liquid volume between the outer cylinder and the inner cylinder, comprising a rigid outer cylinder and a flexible inner cylinder disposed inside the outer cylinder. The outer cylinder and the inner cylinder are both made of an electrically insulating material, and the liquid is electrically conductive. and a plurality of external electrodes attached to the outer cylinder so as to be spaced apart from each other in the longitudinal direction thereof, a supporting member protruding inward from the external electrode, and the above-mentioned external electrode supported by the tip of the supporting member. An internal electrode for contacting a body limb exposed to the inner surface of the inner cylinder, and means for measuring the impedance or admittance of the liquid between the external electrodes and the body limb between the internal electrodes are provided, and the support The member is composed of a cylindrical guide part and a rod-shaped part slidably fitted in the cylindrical guide part so as to expand and contract in the projecting direction, and one of the cylindrical guide part and the rod-shaped part A body-extremity blood specific resistance measuring device, characterized in that the external electrode and the internal electrode described above are each coupled to the other. 2. The body-extremity blood specific resistance measuring device according to claim 1, wherein the support member is made of an insulating material and is provided with a switch that connects and disconnects the external electrode and the internal electrode. 3. Claim 1, wherein the liquid storage section is connected to a hydraulic pressure adjustment means that can adjust the hydraulic pressure within the liquid storage section.
Or the body limb blood specific resistance measuring device according to 2.