JPH05305061A - Circulatory organ function measuring device - Google Patents

Abstract

PURPOSE:To provide a circulatory organ function measuring device capable of measuring the blood vessel physical quantity during the blood pressure mea surement. CONSTITUTION:A blood vessel is pressurized with a cuff, the blood cross sectional area and cross sectional area pulse wave are detected with a blood vessel volume sensor during the decompression process thereafter (ST1-ST4), the blood pressure is measured in this process, the blood pressure difference DELTAP between the maximal blood pressure and the minimal blood pressure is calculated (ST5, ST6), and the amplitude envelope e0 against the cuff pressure of the cross sectional area pulse wave is generated (ST10). This envelope is shifted by the calculated blood pressure difference DELTAP (ST10), this shift is repeated until the rising point cuff pressure of the envelope becomes 0 to obtain envelopes e0, e1,..., en (ST9-ST11), and these envelopes e0, e1,..., en are added to obtain the blood vessel physical quantity L0 (ST12).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circulatory organ function measuring device for non-invasively measuring a physical quantity indicating the degree of hardening of a blood vessel (the relationship between the pressure difference between the inside and the outside of the tube wall and the cross-sectional area of the blood vessel).

[0002]

2. Description of the Related Art Conventional methods for estimating the degree of arteriosclerosis include methods utilizing pulse wave velocity, biochemistry, and fundus findings.

[0003]

However, the measurement procedure is complicated, invasive, and the physical quantity (hereinafter referred to as vascular physical quantity) indicating the degree of arteriosclerosis is not directly measured. However, there was a problem as a quantitative evaluation method of arteriosclerosis. The present invention has been made in view of the above problems, and an object of the present invention is to provide a circulatory organ function measuring device capable of measuring a blood vessel physical quantity in the process of blood pressure measurement.

[0004]

Means and Action for Solving the Problems The circulatory organ function measuring device of claim 1 was invented on the basis of the theoretical basis described below. As shown in (i) of FIG. 1, the envelope e ₀ of the change component ΔA due to the pulsation of the blood vessel cross-sectional area.
Is the blood vessel physical quantity on the cuff pressure axis drawn when the cuff pressure is changed when the blood pressure does not pulsate and is constant at the systolic blood pressure value.
_0, likewise expressed by the difference between the L ₀ and L ₁ when the vessel physical quantity on the cuff pressure axis drawn when changing the cuff pressure was L ₁ when it is fixed in diastolic blood pressure without pulsation blood pressure. Also, L
_{Since 0} and L ₁ represent the characteristics of blood vessels, they have the same shape. The blood vessel physical quantity L ₀ is obtained as follows. First, set the cuff pressure at the rising point of the L ₀ and L ₁ curves to P
Let c ₀ and Pc _1, and let this blood pressure difference be ΔP. Since L ₁ does not exist in this cuff pressure section, e ₀ and L ₀ are equal.

Since L ₁ and L ₀ are curves of the same shape, Pc ₁
To Pc L ₁ of ₁ -DerutaP interval is determined by moving the L ₀ to the smaller of only the cuff pressure ΔP as the (ii) FIG. By adding the envelope e ₀ to this L ₁ , Δ
L ₀ up to Pc ₁ −ΔP is obtained. Next ΔPc ₁ −ΔP
Similarly, L _{1 in} the section of ΔPc ₁ −2 × ΔP is determined as shown in (iii) of FIG. 1 by moving L ₀ obtained by the above-described method by ΔP toward the smaller cuff pressure.
By adding the envelope e ₀ to this L ₁ , ΔPc ₁ −
L ₀ up to 2 × ΔP can be obtained. By repeating the same operation as described above n times, Pc ₀ to Pc ₁ −n × ΔP
The blood vessel physical quantity L ₀ in the section can be obtained. Also,
If this processing procedure is simplified, as shown in (iv) of FIG. 1, by adding all the envelope curves e ₀ , e ₁ , ... En obtained by moving the envelope curve e ₀ by ΔP toward the smaller cuff pressure, the blood vessel physical quantity L is added. You can ask for ₀ .

The circulatory organ function measuring apparatus according to claim 1 adopts this principle, and includes a cuff, a pressure control means for changing the cuff pressure, a pressure sensor for detecting the cuff pressure, and a measuring means for measuring the blood pressure. Or an input means for inputting a blood pressure value,
Volume detection means for detecting the arterial volume in the cuff living body or a physical quantity proportional to the volume, pulse wave extraction means for extracting a volume pulse wave synchronized with the heartbeat on the volume signal, and a process of gradually changing the cuff pressure Envelope creating means for creating an envelope by arranging one or a plurality of volume pulse wave amplitudes captured on the pressure axis, and one or a plurality of times with respect to the envelope while moving the envelope along the pressure axis. It is composed of adding means for performing addition twice, and the added value of the adding means is obtained as a physical quantity of blood vessel.

The circulatory function measuring apparatus according to a second aspect of the present invention is a cuff, pressure control means for changing the cuff pressure, a pressure sensor for detecting the cuff pressure, and blood pressure measurement for measuring blood pressure in the process of changing the cuff pressure. Means, a volume detection sensor for detecting the in-vivo arterial volume in the living body, and a pulse wave extracting means for extracting a volume pulse wave on a volume signal synchronized with the heartbeat, thereby capturing during pressurization or depressurization In a device having characteristic curve measuring means for measuring a pressure-blood vessel cross-sectional area and a volume curve proportional thereto from one pulse or a plurality of volume pulse wave amplitudes, a first curve of the pressure-blood vessel cross-sectional area and a volume curve proportional thereto is provided.
The pressure-blood vessel cross-sectional area and the proportional amount curve thereof are set so that the cross-sectional area at the second predetermined pressure point and the component proportional thereto coincide with the predetermined cross-sectional area with the predetermined pressure point of the above as a reference of the pressure axis. Means for obtaining a new normalized first pressure-vessel cross-sectional area and a volume curve proportional thereto, and an inclination angle at the third predetermined pressure point of the first pressure-vessel cross-sectional area and proportional volume curve, Alternatively, the degree of arteriosclerosis of each individual is quantitatively evaluated from an element proportional to it, or a change component of the cross-sectional area in a predetermined pressure section from the third predetermined pressure point to the fourth predetermined pressure point or an element proportional thereto. Equipped with means.

[0008]

The present invention will be described in more detail with reference to the following examples. <Embodiment 1> FIG. 2 is a block diagram showing a hardware configuration of a circulatory organ function measuring apparatus in which the present invention is implemented. This circulatory organ function measuring device includes a cuff 1 provided with a blood vessel volume sensor 2, a pressurizing pump 3 for pressurizing the inside of the cuff 1, a control valve 4 for reducing the air pressure inside the cuff 1, and a cuff 1. A pressure sensor 5 for detecting the air pressure of the
A low-pass filter 7, an A / D converter 8, a CPU 9 having various processing functions for measuring a circulatory organ function,
A switch 10 used for power-on, start, etc., an indicator 11, an amplifier 12 for amplifying a signal from the blood vessel volume sensor 2, a low-pass filter 13, and an A / D.
It is composed of a converter 14.

As the blood vessel volume sensor 2, a well-known impedance detection type or photoelectric type is used. In the impedance detection type, the inner surface of the cuff is provided with an application electrode at both ends of the center side and the peripheral side to apply an AC voltage, and a pair of detection electrodes is further provided between the application electrodes, and the impedance between the detection electrodes is set. The blood vessel volume is calculated by the detection.

Next, the software configuration and processing operation of the apparatus of this embodiment will be described with reference to the flow chart shown in FIG.
This will be described with reference to FIG. As shown in (i) of FIG. 7, it is assumed that the subject has a systolic blood pressure Ps and a diastolic blood pressure Pd. When the start switch is pressed, as shown in FIG. 3, first, in step ST (hereinafter referred to as ST) 1, variables are initialized. Here, n, m, and k are variables indicating pulse wave numbers and the like, ΔA * ma
x and ΔA * min represent all areas of variables for holding the maximum and minimum values of the amplitude of ΔA for each pulse wave. ST
At step 2, a signal is sent from the CPU 9 to the pressurizing pump 3 and the control valve 4, and the control valve 4 is closed. The cuff is pressurized while detecting the pressure Pc. When the pressurization reaches the target value, that is, when the pressurization is completed, the process shifts to the loop from ST3 to ST7. In ST3, a signal is sent from the CPU 9 to the control valve 4 to control the exhaust flow rate and gradually reduce the cuff pressure Pc until it becomes zero. In the process of decompression, in ST4, the blood vessel cross-sectional area pulse wave ΔA is detected (details will be described later). In ST5, blood pressure calculation processing by the oscillometric method is performed and the maximum blood pressure P
s and the minimum blood pressure Pd are determined. This blood pressure measurement may be the K-tone method. When the blood pressure value is determined, in ST6, the maximum blood pressure P
The pressure difference ΔP between s and the minimum blood pressure Pd is calculated, and Ps and ΔP are stored in the memory. In ST7, it is determined whether or not the cuff pressure Pc has become 0, and until it becomes 0, ST3, ..., ST
The process of 7 is repeated.

After the decompression is completed, in ST8, the above blood vessel cross section
By using the product pulse wave ΔA, the blood vessel disconnection as shown in (iii) of FIG.
Envelope e of area pulse wave ΔA₀(= ΔA (Pc) is obtained
(See below for details). As shown in FIG. 8, in ST10, the envelope e0
Is shifted toward the smaller cuff pressure by ΔP and the envelope e₀,
e₁, E₂, ..., e_n(= ΔA (Pc + n × ΔP) (n
= 0, 1, 2, ... K) (details will be described later). However
However, the number of shifts depends on the envelope e _nRising point
As shown in FIGS. 7 and 8, Pcn (n = 0, 1,
2, ... k), the maximum condition that satisfies Pcn ≧ 0
Defined as K times and ST9.

At ST12, when all envelopes e ₀ , e ₁ , ..., E _n are added for the range larger than 0, the blood vessel physical quantity A- as shown in FIG.
Obtain a Pt1 curve (details are given below). Next, details of the blood vessel cross-sectional area pulse wave ΔA detection routine in ST4 will be described with reference to the flowchart of FIG. 4 and FIG. 7.

When the routine of ST4 is entered, first, ST
The change in impedance Z of the living body under the cuff is detected by the blood vessel volume sensor 2 set in the cuff at 22, and the CPU 9
The amount of change in the blood vessel cross-sectional area is converted from the following equation within. Therefore, (i) of FIG.

[0014]

[Equation 1]

A blood vessel cross-sectional area waveform A as described above is obtained. ST2
By applying a high-frequency separation digital filter to the blood vessel cross-sectional area waveform A at 3, the pulsating component (blood vessel cross-sectional area pulse wave) ΔA superimposed on the blood vessel cross-sectional area waveform A is separated. ST24
Then, as shown in (ii) of FIG. 7, the point where the threshold level of ΔA changes from the low level to the high level is detected, and the pulse wave is divided into beats.

In ST25 and ST26, the maximum value in one pulse wave is detected and stored in ΔAmmax (m = 1, 2, ..., K), and in ST27 and ST28, the minimum value in one pulse wave is detected. And save as ΔAmmin (m = 1, 2, ..., K). S
At T29, the maximum amplitude of ΔA in the pulse wave immediately before the new pulse break generated in ST24 is calculated from the following equation, and Δ
Save in Am (m = 1, 2, ..., K).

ΔAm = ΔAmmax−ΔAmmin (m
= 1, 2, ..., K) In ST30, m is incremented by one. In ST31, the cuff pressure Pc at the point where the pulse separation occurs is Pcm (m =
Save to 1, 2, ..., k). In ST32, the time t at which the pulse break has occurred is stored in tm (m = 1, 2, ..., K). The number of times the pulse wave is detected in ST33 is stored in k.

Next, details of the envelope e ₀ creating routine in ST8 will be described with reference to the flowchart of FIG. 5 and FIG. In ST41, the initial value is assigned to the variable. ST4
In 2 increments m by one. ST43, ST4
ST42, ..., ST44 only k times of the pulse wave number detected in
Condition the loop to repeat. Figure 7 in ST44
The corresponding Pcm and ΔAm (m = 1, 2, ... K) are sequentially plotted on the Pc-ΔA graph as shown in (iii).

In ST45 and ST46, the average period of one pulse wave is obtained and stored in Δtmean. In ST47, as shown in (ii) of FIG. 7, the cuff pressure Pc Δtmean time before t1 is read from the memory, and the cuff pressure is S.
At T48, it is adopted as the cuff pressure Pc ₀ at the rising point of the envelope e ₀ as shown in (iii) of FIG. 7 and plotted on the Pc-ΔA graph.

In ST49, the points plotted in the previous step are interpolated by a straight line, and the envelope e ₀ is obtained as a function of the cuff pressure Pc as follows.

[0021]

[Equation 2]

Since it is complicated as it is, in the above description, e
_It was displayed as ₀ = ΔA (Pc). The operation of shifting the envelope en in the pressure axis direction by ΔP in ST10 is expressed by the following equation from the above-mentioned function e ₀ = ΔA (Pc).

[0023]

[Equation 3]

Total envelope e in ST12₀, E₁, ..., e
_nDetails of the addition routine are shown in the flowchart of FIG.
I will explain along. In ST51, the initial value is assigned to the variable.
However, A^*Is the storage area of the blood vessel cross-sectional area based on the physical quantity of the blood vessel
Means the whole. Envelope in ST52, 53, 54, 55
Line e_nThe envelope e₀Rising pressure Pc ₀From cuff pressure
Physical quantity of blood vessel is added to the smaller one by 1mmHg increments
Stored in the storage area Ar of the blood vessel cross-sectional area by. However, the pressure
The step width of 1 mmHg can be changed as required
Is.

In ST56, 57, 58, the above-mentioned step S
The processing of T52, 53, 54, 55 is repeated n + 1 times the number of times the envelope is shifted. ST59, 60, 61, 62
In total envelope e _0, e _1, ..., plotting the value Ar obtained by adding e _n in 1mmHg increments on A-Pc axis graph.
In ST63, the plotted points are interpolated with a straight line to obtain a function of the vascular physical quantity A-Pt1 with respect to the cuff pressure Pc as follows.

[0026]

[Equation 4]

The pressure axis is Pt = Ps- as shown in FIG.
By using the conversion formula of Pc, the cuff pressure axis Pc can be converted to the trans-mural pressure Pt axis. <Second Embodiment> The hardware configuration of the circulatory organ function measuring apparatus of this embodiment is the same as that shown in FIG.

The software configuration and processing operation of this embodiment are
According to the flowchart shown in FIG. 9, FIG.
Will be explained. In ST1, the pressure is increased to a target value above the systolic blood pressure. The blood pressure value is measured in ST3 of the depressurization process by the loop of ST2, ..., ST7, the blood pressure difference ΔP between the systolic blood pressure and the diastolic blood pressure is calculated in ST4, and the PA curve A-Ptr as shown in FIG. 10 is calculated in ST5 and ST6. To get

As shown in FIG. 10, the maximum inclination angle point ΔA-Ptr / ΔPtmax of A-Ptr is detected in ST8 and ST9.
Then, the trans-mural pressure (= blood vessel wall inner pressure−blood vessel wall outer pressure) Pt at that point is set to zero. P as shown in FIG.
t = P ₀ (P ₀ is the average value of the systolic blood pressure obtained statistically)
Assuming that the A-Ptr cross-sectional area at this time is Ar, the A-Ptr cross-sectional area component at Pt = P ₀ at ST10 is A ₀ (A ₀ is the statistically obtained Pt = P ₀ A-Pt normalized to match the average blood vessel cross-sectional area)
Create r '.

A-Ptr ′ = A-Ptr × (As / A ₀ ) As shown in FIG. 11, at ST 11, Pt = P ₁ (P ₁ is the average value of statistically obtained average blood pressure). The tilt angle α of A-Ptr 'is detected. There is a relationship as shown in FIGS. 12 and 13 between the inclination angle α of the PA curve and the degree of vascular hardening. Therefore, the standard deviation of the inclination angle α with respect to the plurality of basic data collected in advance is calculated in ST12, and the degree of hardening of the blood vessel is evaluated. That is, when the inclination angle α at the average blood pressure value P ₁ is small, it is evaluated that the degree of blood vessel hardening is high.

[0031]

According to the first aspect of the present invention, the cuff having the structure, the pressure control means for changing the pressure in the cuff (hereinafter referred to as the cuff pressure), the measuring means for measuring the blood pressure, or the blood pressure value is input. Input means, a pressure sensor to detect the cuff pressure, a volume detection sensor to detect the arterial volume in the body under the cuff, a pulse wave extraction means to extract a volume pulse wave synchronized with the heartbeat on the volume signal, and the volume Since the measuring means is used to measure the blood vessel physical quantity from the pulse wave and the blood pressure value, the effect that the blood vessel physical quantity can be easily measured in the normal blood pressure measurement process is obtained.

According to the second aspect of the present invention, the cuff and the pressure control means for changing the cuff pressure, the pressure sensor for detecting the cuff pressure, and the blood pressure measuring means for measuring the blood pressure in the process of changing the cuff pressure, By providing a volume detection sensor for detecting the arterial volume in the body under the cuff, and a pulse wave extracting means for extracting a volume pulse wave synchronized with the heartbeat on the volume signal, one pulse captured during pressurization or depressurization or In a device having characteristic curve measuring means for measuring a pressure-blood vessel cross-sectional area and a volume curve proportional thereto from a plurality of volume pulse wave amplitudes, a first predetermined pressure of the pressure-blood vessel cross-sectional area and a volume curve proportional thereto Using the point as a reference of the pressure axis, the pressure-vessel cross-sectional area and the proportional volume curve are normalized so that the cross-sectional area at the second predetermined pressure point and the proportional component thereof coincide with the predetermined cross-sectional area. First A means for obtaining a pressure-blood vessel cross-sectional area and a volume curve proportional thereto, and an inclination angle at a third predetermined pressure point of the first pressure-blood vessel cross-sectional area and a volume curve proportional thereto, or an element proportional thereto, or Since it is provided with a means for quantitatively evaluating the degree of arteriosclerosis of each individual from the change component of the cross-sectional area in a predetermined pressure section from the third predetermined pressure point to the fourth predetermined pressure point or an element proportional thereto. The pressure-vessel cross-sectional area and the amount curve proportional thereto can be quantitatively evaluated for the degree of arteriosclerosis of each individual.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a theoretical basis adopted by the circulatory organ function measuring apparatus according to claim 1.

FIG. 2 is a block diagram showing a hardware configuration of a circulatory organ function measuring device in which the present invention is implemented.

FIG. 3 is a flowchart for explaining a software configuration and a processing operation of the circulatory organ function measuring apparatus according to the first embodiment.

FIG. 4 is a flowchart showing in detail a processing routine for detecting a blood vessel cross-sectional area pulse wave in the flowchart.

5 is a flowchart showing in detail a processing routine for creating an envelope curve e ₀ of the flowchart of FIG.

FIG. 6 is a flowchart showing in detail a processing routine for adding all envelopes in the flowchart of FIG.

FIG. 7 is a diagram for explaining the operation of the circulatory organ function measuring apparatus according to the first embodiment.

FIG. 8 is a diagram for explaining the operation of the circulatory organ function measuring apparatus according to the first embodiment.

FIG. 9 is a diagram for explaining the software configuration and processing operation of the circulatory organ function measuring apparatus according to the second embodiment.

FIG. 10 is a view for explaining the operation of the circulatory organ function measuring apparatus according to the embodiment.

FIG. 11 is a view for explaining the operation of the circulatory organ function measuring apparatus according to the embodiment.

FIG. 12 is a view for explaining the operation of the circulatory organ function measuring apparatus according to the embodiment.

FIG. 13 is a view for explaining the operation of the circulatory organ function measuring apparatus according to the embodiment.

[Explanation of symbols]

 1 Cuff 2 Volume sensor 3 Pressurizing pump 4 Control valve 5 Pressure sensor 9 CPU

Claims (3)

[Claims] 1. A cuff, a pressure control means for changing the cuff pressure, a pressure sensor for detecting the cuff pressure, a measuring means for measuring blood pressure or an input means for inputting a blood pressure value, and an arterial volume in the living body under the cuff. Alternatively, a volume detecting means for detecting a physical quantity proportional to the volume, a pulse wave extracting means for extracting a volume pulse wave synchronized with a heartbeat on the volume signal, and one beat captured in the process of gradually changing the cuff pressure or Envelope creating means for arranging a plurality of volume pulse wave amplitudes on a pressure axis to create an envelope, and adding means for adding the envelope once or a plurality of times to the envelope while moving the envelope along the pressure axis. A circulatory organ function measuring device comprising: 2. A cuff, pressure control means for changing the cuff pressure, a pressure sensor for detecting the cuff pressure, blood pressure measuring means for measuring blood pressure in the process of changing the cuff pressure, and arterial volume in the living body under the cuff. By including a volume detection sensor for detecting the volume pulse and a pulse wave extracting means for extracting a volume pulse wave synchronized with the heartbeat on the volume signal, one or a plurality of volume pulse wave amplitudes captured during pressurization or depressurization In a circulatory organ function measuring device having characteristic curve measuring means for measuring a pressure-blood vessel cross-sectional area and a volume curve proportional thereto, a first curve of the pressure-blood vessel cross-sectional area and a volume curve proportional thereto is provided.
Of the pressure-vascular cross-section and the cross-sectional area at the second predetermined pressure point and a component proportional to the cross-sectional area at the second predetermined pressure point are equal to the predetermined cross-sectional area and the amount proportional thereto. Means for obtaining a new first pressure-vessel cross-sectional area and a proportional quantity curve proportional thereto by normalizing the proportional quantity curve, and a third predetermined pressure point of the first pressure-vessel cross-sectional area and proportional quantity curve Of the individual arteriosclerosis degree from the inclination angle at or the element proportional to it, or the change component of the cross-sectional area in the predetermined pressure section from the third predetermined pressure point to the fourth predetermined pressure point, or the element proportional thereto. A circulatory organ function measuring device comprising means for quantitatively evaluating 3. The first predetermined pressure point is a point of the maximum inclination angle of the pressure-vessel cross-sectional area and the proportional curve proportional thereto,
Alternatively, the circulatory organ function measuring device according to claim 2, which is a rising point.