JPH05200030A - Apparatus for measuring degree of autonomic imbalance - Google Patents

Abstract

PURPOSE:To provide an apparatus capable of measuring the degree of a autonomic imbalance quantitatively. CONSTITUTION:In a living body generating orthostatic hypotension owing to a functional disorder of autonomic nerve, a maximum blood pressure value SYS change curve caused by tilt-up for example can be assumed as a primary delay transmitting function shown by an approximate curve CSYS, so that a time constant TSYS1 is determined on the basis of the intersection point (i) of a tangential line (a) at a point (p) of the approximate line CSYS from which blood pressure fall is started by the tilt-up and a tilt-up balanced blood pressure value line (e) of the analogous curve CSYS. Then the time constant TSYS1 represents quantatively the degree of autonomic imbalance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an autonomic nerve ataxia degree measuring apparatus for quantitatively measuring the degree of ataxia of an autonomic nerve in a living body.

[0002]

2. Description of the Related Art It is known that when autonomic nerve dysfunction occurs, it exhibits various symptoms such as so-called orthostatic hypotension in which blood pressure significantly decreases when standing up, such as autonomic imbalance. .. The diagnosis of orthostatic hypotension due to the dysfunction of the autonomic nerve is usually performed by standing up the patient in a recumbent state and then measuring the blood pressure value of the patient by a so-called auscultation method. In addition, as described in Japanese Utility Model Laid-Open No. 60-83603, which was filed by the applicant of the present invention earlier, and published, the trend of blood pressure values and the like which are repeatedly measured automatically using a cuff at the time of changing the posture is displayed. It is considered that the orthostatic hypotension is diagnosed based on recording on a recording medium and sequentially detecting the posture of the patient and displaying the posture on the recording medium.

[0003]

However, the conventional diagnosis of orthostatic hypotension based on the blood pressure value measured by such an auscultation method or an automatic blood pressure measuring device equipped with a cuff is qualitatively based on the change in blood pressure due to a change in posture. However, there is a drawback that it is difficult to objectively judge the orthostatic hypotension improving effect of a drug.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an autonomic nerve ataxia degree measuring apparatus capable of quantitatively measuring the ataxia degree of an autonomic nerve. is there.

[0005]

Means for Solving the Problems As a result of various studies, the present inventor has found that, in a patient with orthostatic hypotension due to dysfunction of the autonomic nerve, the patient's posture is erect at a predetermined angle with a recumbent posture. It was found that the blood pressure change curve when changing between different postures can be assumed as a first-order lag transfer function, and the time constant of the first-order lag transfer function quantitatively represents the degree of autonomic ataxia. ..

The present invention has been made on the basis of such findings, and its gist is to provide an autonomic nerve ataxia degree measuring device for quantitatively measuring the ataxia degree of an autonomic nerve of a living body. , As shown in the claim correspondence diagram of FIG.
(a) Blood pressure measuring means for measuring a plurality of times the blood pressure value of the living body, which changes in association with the posture of the living body changing between a predetermined first posture and a second posture standing upright from the first posture. And, (b) in order to quantitatively measure the degree of ataxia of the autonomic nerve, assuming a blood pressure change curve when the posture of the living body is a first-order lag transfer function, a plurality of blood pressure measuring means obtained by And a time constant determining means for determining the time constant of the first-order lag transfer function based on the individual blood pressure values.

[0007]

According to the autonomic imbalance measuring apparatus having the above-mentioned configuration, the posture of the living body is related to the change between the predetermined first posture and the second posture standing upright from the first posture. The blood pressure value of the living body that changes due to the blood pressure measurement means is measured multiple times by the blood pressure measurement means, and the blood pressure change curve when the posture is changed is assumed by the time constant determination means to be a first-order lag transfer function. The time constant of the first-order lag transfer function is determined based on the measured blood pressure values. Since the time constant thus determined or a value based on the time constant quantitatively represents the degree of ataxia of the autonomic nerve, the degree of ataxia of the autonomic nerve can be quantitatively measured based on the time constant. Thereby, for example, the effect of improving the orthostatic hypotension of the drug can be objectively determined by observing the change in the degree of ataxia of the autonomic nerve quantitatively measured based on the time constant.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a diagram showing an example of an autonomic imbalance measuring apparatus according to the present invention, and 10 is a posture changing apparatus. The posture changing apparatus 10 includes a bed 15 rotatably provided on an upper end portion of a support column 12 by a shaft 14, and the bed 15 that supports the bed 15.
And a drive device 16 for rotating the same.
The drive device 16 includes, for example, a drive motor 20 having a speed reducer and an output shaft (not shown) of the drive motor 20.
And a pair of sprockets (not shown) provided on the shaft 14 so as not to rotate, and a chain 24 wound between both sprockets. In the present embodiment, the upright start push button switch (not shown) is turned on, whereby the bed 15 is rotated clockwise in FIG. 2 at a relatively moderate constant speed, and the living body on the bed 15 is rotated. 18 postures, for example, in FIG.
The horizontal posture shown in Fig. 4 can be changed from a horizontal posture to a standing posture at 45 °, and the control device 48 described later allows the bed to be laid when a predetermined time elapses after the living body 18 is completely erected. 15 is rotated counterclockwise in FIG. 2 at a relatively gentle constant speed,
The posture of the living body 18 on the bed 15 can be returned from the upright posture to the original horizontal position. In the present embodiment, the horizontal posture corresponds to the first posture, and the posture that stands at 45 ° (hereinafter, simply referred to as the standing posture) corresponds to the second posture.

A probe 26 for measuring blood pressure is attached to the wrist of the living body 18 on the bed 15. As shown in FIG. 3, the probe 26 has a container-like shape, and a housing 30 arranged so that its open end faces the surface of the wrist 28 of the living body 18, and the housing 30 can be attached to and detached from the wrist 28. A mounting band 32 for mounting and a surface pressure sensor 36 provided so as to be relatively movable in the housing 30 via the diaphragm 34 and projectable from the opening end of the housing 30 are provided, and the housing 30 and the diaphragm 34 are provided. The pressure chamber 38 is formed by the above. In the pressure chamber 38, the fluid supply source 4
A pressure fluid such as pressure air is supplied from 0 through the pressure regulating valve 42, whereby the surface pressure sensor 36 is pressed against the surface of the wrist 28 with a pressing force corresponding to the pressure in the pressure chamber 38. It

The surface pressure sensor 36 is equipped with a pressure detecting element (not shown) such as a pressure-sensitive die-dead on a pressing surface 44 of a semiconductor chip made of, for example, single crystal silicon.
By being pressed against the surface of the wrist 28, the radial artery 46
A pressure signal SM including a pressure pulse wave generated by the pressure sensor and transmitted to the surface of the wrist 28 is detected, and the pressure signal SM is supplied to the control device 48 via an A / D converter (not shown).

The controller 48 includes a CPU, ROM, RA
It is composed of a so-called microcomputer having an M, an I / O port, etc., and the CPU executes signal processing while utilizing the storage function of the RAM in accordance with a program stored in advance in the ROM, and a drive circuit (not shown). The pressure in the pressure chamber 38 is controlled by controlling the pressure regulating valve 42 via the pressure regulating valve 42, and the surface pressure sensor 36 is controlled based on the pressure pulse wave included in the pressure signal SM sequentially obtained in the step of gradually increasing pressure in the pressure chamber 38. The optimum pressure of the living body 18 is determined for each beat of the pressure pulse wave sequentially detected at the optimum pressure while controlling the pressure regulating valve 42 so as to maintain the optimum pressure. A value is determined, and the determined blood pressure value is displayed as a trend on the display / recording device 50 and recorded. Further, the CPU sets the time constant of the first-order lag transfer function represented by the blood pressure change curve when the posture of the living body 18 on the bed 15 is changed between the horizontal posture and the standing posture according to a program stored in advance in the ROM. The time constant thus determined is displayed and recorded on the display / recording device 50.

The operation of the autonomic imbalance measuring apparatus of this embodiment will be described below with reference to the flow chart of FIG.

When the power is turned on, an initial process (not shown) is executed and then step S1 is executed.
For example, the optimum pressing force of the surface pressure sensor 36 is determined on the basis of the pressure in the pressure chamber 38 in which the pressure pulse wave having the maximum amplitude is obtained in the process of gradually increasing the pressure in the pressure chamber 38, and the optimum pressing force is determined. To be held. Next, by executing step S2, it is determined whether the pressure signal SM is read and one pulse of the pressure pulse wave is detected. Step S2
If the determination is negative, step S2 is repeatedly executed, but if the determination is positive, step S3 is executed and the pressure signals at the upper peak and the lower peak of the pressure pulse wave detected at step S2. After the systolic blood pressure value SYS and the diastolic blood pressure value DIA are determined and stored based on the magnitude of the SM, step S4 is executed so that the determined blood pressure value is displayed as a trend on the display / recording device 50. To be recorded.

In the following step S5, it is determined whether or not the content of the flag F is "1". This flag F
Has its content set to "1" in step S8 described later. When the determination in step S5 is negative, step S6 is executed to determine whether or not the standing of the living body 18 from the horizontal posture (hereinafter referred to as tilt-up) has started. This determination is made, for example, based on whether or not the standing-up start pushbutton switch has been turned ON. If the determination in step S6 is negative, steps S2 and subsequent steps are repeatedly executed to determine and store the blood pressure values SYS and DIA for each beat of the pressure pulse wave, and the trend display is performed. If the determination is positive, step S7 is executed.

In step S7, it is determined whether or not a predetermined constant time α has elapsed since the tilt up was started. As shown in FIG. 5, this fixed time α includes a time in which the blood pressure value can reach a substantially equilibrium after the tilt-up is completed, and in consideration of the fainting of the living body 18 due to the decrease in blood pressure, for example, It is set to a value obtained by adding about 1 minute to the time required from the start of tilt-up to the completion. If the determination in step S7 is negative, steps S2 and subsequent steps are repeatedly executed to determine and store the blood pressure values SYS and DIA for each beat of the pressure pulse wave, and the trends are displayed, but the result is affirmative. In this case, step S8 is executed and the content of the flag F is set to "1" indicating that the predetermined time α has elapsed after the start of tilting up, and then step S9 is executed.

In step S9, the return rotation of the bed 10 is started, and the living body 18 is returned from the standing posture to the horizontal posture (hereinafter, tilt down).
In the following step S10, it is determined whether or not a predetermined fixed time β has elapsed since the tilt down was started. As shown in FIG. 5, the fixed time β includes a time in which the blood pressure value can reach a substantially equilibrium after the tilt down is completed, and is set to a value of, for example, about 1 to 1.5 minutes. If the determination in step S10 is negative,
Steps S2 and thereafter are repeatedly executed to determine and store the blood pressure values SYS and DIA for each beat of the pressure pulse wave, and the trend display is performed. At this time, since the determination in step S5 is affirmative, steps S6 to S9 are skipped.

If the determination in step S10 is affirmative, step S11 is executed to exhaust the pressure in the pressure chamber 38 of the probe 26, and then steps S12 and thereafter are executed, thereby showing in FIG. In this way, the time constant of the first-order lag transfer function represented by the blood pressure change curve when the posture of the living body 18 that causes orthostatic hypotension due to dysfunction of the autonomic nerve is changed between the horizontal posture and the standing posture is determined. It

That is, first, in step S12, a change curve (hereinafter referred to as SYS) of the systolic blood pressure value SYS when the posture of the living body 18 is changed from the horizontal posture to the standing posture and then changed from the standing posture to the horizontal posture again. approximate curve C _SYS and the diastolic blood pressure value DIA of the change curve changes as curve) (hereinafter, an approximation of that DIA change curve) curve C _DIA
Are determined respectively. In the next step S13, the tangent line a at the blood pressure drop start point p due to the tilt-up of the approximate curve C _SYS and the tangent line b at the blood pressure increase start point q due to the tilt-down are respectively determined, and the approximate curve C _DIA. The tangent line c at the blood pressure drop start point r due to the tilt up and the tangent line d at the blood pressure increase start point s due to the tilt down are respectively determined.

In the subsequent step S14, the equilibrium blood pressure value line e showing the systolic blood pressure value at which the systolic blood pressure value SYS has fallen to reach equilibrium by tilting up and the systolic blood pressure value SYS has risen to reach equilibrium by tilting down. The equilibrium blood pressure value line f indicating the systolic blood pressure value is determined based on the approximate curve C _SYS , and the equilibrium blood pressure value line g indicating the systolic blood pressure value at which the diastolic blood pressure value DIA has fallen to equilibrium by tilting up. And tilt down to lower blood pressure D
An equilibrium blood pressure value line h indicating the systolic blood pressure value at which IA has risen and reached equilibrium is determined based on the approximate curve C _DIA .

Next, in step S15, the time constant T _SYS1 of the change portion due to the tilt-up of the approximate curve C _SYS of the SYS change curve and the aforesaid value based on the intersection i of the tangent line a and the equilibrium blood pressure value line e. Tangent line b and equilibrium blood pressure value line f
The time constant T _SYS2 of the changing portion of the approximate curve C _SYS due to tilt down is determined based on the intersection j with the DIA change curve based on the intersection k between the tangent line c and the equilibrium blood pressure value line g. Of the approximate curve C _DIA based on the time constant T _DIA1 of the changed portion due to the tilt-up and the intersection l of the tangent line d and the equilibrium blood pressure value line h.
Time constant T of the changing part of _DIA due to tilt down
_DIA2 is decided respectively.

The above time constants T _SYS1 , T _SYS2 , T _DIA1 , T
_DIA2 quantitatively represents the degree of ataxia of the autonomic nerve of the living body 18. It should be noted that a change portion due to tilt up and a change portion due to tilt down of the approximate curve C _SYS of the SYS change curve, and a change portion due to tilt up and a change portion due to tilt down of the approximate curve C _DIA of the DIA change curve. Are the mathematical expressions 1
It is expressed as a first-order lag transfer function shown in. In Formula 1, x is a blood pressure value, A ₁ is an equilibrium blood pressure value, t is a time elapsed from the start of blood pressure drop or the start of blood pressure rise, T is a time constant, and the blood pressure value x when t is zero. (A ₁ +
A ₂ ) represents an initial blood pressure value, and A ₂ has a positive value when tilting up and a negative value when tilting down.

[0023]

[Formula 1] x = A ₁ + A ₂ · exp (-t / T)

Next, by executing step S16, the time constants T _SYS1 and T _SYS determined in step S15 are determined.
_SYS2 , T _DIA1 , and T _DIA2 are displayed and recorded on the display / recording device 50, respectively, and step S17 is executed to clear the contents of the flag F, and then the processing is terminated. In the present embodiment, the probe 26, the fluid supply source 40, the pressure regulating valve 42, and the control device 48 (more accurately, the portion of the control device 48 for executing steps S1 to S3, etc.) In addition to constituting the measuring means, the control device 48, more accurately, the above-mentioned steps S12 to S15 of the control device 48.
The part for executing the above constitutes the time constant determining means.

As described above, according to the autonomic imbalance measuring apparatus of the present embodiment, the living body 18 obtained by changing the posture of the living body 18 between the horizontal posture and the standing posture of 45 °.
Since it is possible to quantitatively measure the degree of ataxia of the autonomic nerves based on the time constant of the first-order lag transfer function represented by the blood pressure change curve of, for example, to improve orthostatic hypotension due to dysfunction of the autonomic nerves, When a drug is administered to No. 18, the orthostatic hypotension improving effect of the drug is objectively judged by observing the change in the degree of ataxia of the autonomic nerve quantitatively measured based on the above time constant. You can
Here, FIG. 6 and FIG. 7 show, for example, L-threo-3,4-dihydrox which is a precursor of noradrenaline as the above drug.
When yphenylserine (L-DOPS) is used, examples of changes in the time constant due to changes in the daily dose of the drug L-DOPS are shown, and FIG. 6 shows the time constant T _SYS1 during tilt-up, 7 shows changes in T _DIA1 , and FIG. 7 shows changes in time constants T _SYS2 and T _DIA2 when tilting down. In FIG. 6, the time constants T _SYS1 and T _DIA1 at the time of tilting up are medicines.
The doses of L-DOPS increased as the dose increased, and it was quantitatively shown that the decrease in blood pressure due to tilt-up was suppressed as the dose of L-DOPS increased. In addition, in FIG. 7, the time constants T _SYS2 and T _DIA2 at the time of tilting down become smaller as the dose of the drug L-DOPS increases, and as the dose of the drug L-DOPS increases. It is quantitatively shown that the return of blood pressure due to the tilt-down is promoted. This makes it possible to objectively judge the effect of the drug L-DOPS on improving orthostatic hypotension.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other modes.

For example, in the above embodiment, the time constant of the first-order lag transfer function represented by the approximate curve of the blood pressure change curve when the posture of the living body 18 is changed is at the intersection of the tangent line of the initial blood pressure value and the equilibrium blood pressure value line. However, the time constant may be determined based on the point on the approximate curve corresponding to the 63.2% value of the change from the initial blood pressure value to the equilibrium blood pressure value.

The equilibrium blood pressure value (A in the above equation 1)
₁ ), an initial blood pressure value (corresponding to A ₁ + A ₂ when t is zero in Expression 1), and three blood pressure values at any time between these two blood pressure values. A ₂ and the time constant T can be determined, or they can be obtained in the blood pressure change process from the first-order lag transfer function shown in Equation 1 without using the initial blood pressure value and the equilibrium blood pressure value. The time constant of the approximated curve may be obtained based on any three blood pressure values. In these cases, it is also possible to measure the above three blood pressure values with a blood pressure measuring device equipped with a cuff.

Further, in the above-mentioned embodiment, it was explained that the effect of improving the orthostatic hypotension by the drug can be objectively judged by observing the change of the time constant which quantitatively expresses the degree of ataxia of the autonomic nerve. The effect of the drug may be determined by dividing the size of the medicine in stages for each predetermined range and observing the change in the value indicating the range to which the actual time constant belongs. Since the value indicating the range to which this actual time constant belongs also quantitatively expresses the degree of ataxia of the autonomic nerve, the effect of the drug can be objectively judged.

Further, in the above embodiment, the time constants of the SYS change curve and the DIA change curve are determined at the time of tilting up and at the time of tilting down respectively.
The time constant of either one of the S change curve and the DIA change curve may be determined, the time constant of the mean blood pressure change curve may be determined, or at the time of tilt-up and tilt. The time constant may be determined at either one of the down times.

In the above embodiment, only the time constant determined this time is displayed and recorded.
This is not always necessary. For example, a plurality of time constants obtained each time the dose of the drug is changed are stored for each living body together with the dose of the drug, and the plurality of time constants are stored in FIG.
It may be displayed and recorded on a two-dimensional coordinate as shown in FIG. 7, or a plurality of time constants obtained at predetermined time intervals may be sequentially stored for each living body and the plurality of time constants may be stored. The constant may be displayed and recorded on the two-dimensional coordinates of the axis indicating the magnitude of the time constant and the time axis.

Further, in the above embodiment, the bed 15 is configured to change the posture of the living body 18 between the horizontal posture (first posture) and the standing posture at 45 ° (second posture). However, the first posture of the living body 18 changed by the bed 15 may be a posture inclined at a relatively small angle, and the second posture may be a posture standing at a predetermined angle other than 45 °. ..

In the above embodiment, the time constant of the first-order lag transfer function represented by the blood pressure change curve when the posture of the living body 18 is changed by the posture changing device 10 having the bed 15 is determined. However, this is not always necessary.For example, by determining the time constant of the first-order lag transfer function represented by the blood pressure change curve when the living body rises from the posture of sitting on the chair, the degree of ataxia of the autonomic nerve of the living body is determined. Can also be measured.

Further, in the above embodiment, the optimum pressing force of the surface pressure sensor 36 is determined and the blood pressure value is determined based on the pressure pulse wave sequentially detected at the optimum pressing force, but it is not always necessary. Alternatively, the surface pressure sensor 36 may be held at a predetermined pressing force, and the blood pressure value may be determined based on the pressure pulse wave sequentially detected by the pressing force.

Besides, the present invention can be variously modified without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of the present invention.

FIG. 2 is a diagram showing an example of a device for changing the posture of a living body.

FIG. 3 is a diagram showing an example of an autonomic dystonia degree measuring device of the present invention, and is a block diagram showing the configuration.

4 is a flow chart for explaining the operation of the apparatus of FIG.

FIG. 5 is a diagram showing an example of changes in blood pressure values when the posture of a living body is changed between a horizontal posture and a standing posture at 45 °, and is a diagram for explaining how to obtain a time constant. is there.

FIG. 6 is a diagram showing an example of changes in the time constant during tilt-up due to changes in the dose of the drug.

FIG. 7 is a diagram showing an example of a change in a time constant at the time of tilting down due to a change in the dose of a drug.

[Explanation of symbols]

18 living body {26 probe, 40 fluid supply source, 42 pressure regulating valve,
48 Control Device} Blood Pressure Measuring Means 48 Control Device (Time Constant Determining Means)

Claims (1)

[Claims] 1. An autonomic nerve ataxia degree measuring device for quantitatively measuring a degree of ataxia of an autonomic nerve of a living body, wherein the posture of the living body is a predetermined first posture and a second standing upright from the first posture. Blood pressure measuring means for measuring the blood pressure value of the living body that changes in association with a change in posture, and the posture of the living body changes in order to quantitatively measure the degree of ataxia of the autonomic nerve. And a time constant determining means for determining a time constant of the first-order lag transfer function on the basis of a plurality of blood pressure values obtained by the blood pressure measuring means. A device for measuring autonomic imbalance, characterized by: