JPH10328150A - Pulse wave propagation speed information measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly accurately measure pulse wave propagation speed information such as pulse wave propagation speed or pulse wave propagation time in spite of how much the arteriosclesis of person to be measured are hardened. SOLUTION: Concerning this instrument, a maximum inclined line determining means 86 determines a maximum inclined line LKmax passing a maximum inclination point Kmax of heartbeat synchronizing wave and having the inclination of that maximum inclination point Kmax and a base line determining means 88 determines a base line BL connecting the rising side minimum point and falling side minimum point of heartbeat synchronizing wave. Then, a reference point determining means 90 determines an intersection TS of these maximum inclined line LKmax and base line BL as a reference point TS for measuring the pulse wave propagation speed. Therefore, since the reference point TS is determined so as not to be affected by reflected waves in pulse waves, the setting position of reference point TS is not dispersed even for the person to be measured which advances arteriosclerosis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse wave velocity information measuring apparatus for measuring pulse wave velocity information such as the propagation velocity or time of a pulse wave propagating in an artery of a living body.

[0002]

2. Description of the Related Art For example, in order to estimate the arteriosclerosis, blood pressure value, peripheral resistance, etc. of a living body, information on the propagation velocity of a pulse wave propagating in an artery of the living body has been obtained. As one of the methods, for example, a pulse wave sensor that presses an artery from the skin of a living body to detect a pulse wave generated from the artery is used.
There is known a method of determining a propagation velocity based on a pulse wave generation time difference detected by a pulse wave sensor provided at a location. This is the pulse wave velocity measuring device described in Japanese Patent Application Laid-Open No. 60-220037. In the conventional pulse wave propagation velocity information measuring device, the reference point for determining the time difference is often determined based on the rising start point of the pulse wave, but this rising start point is a gentle curve. In many cases, it was difficult to accurately detect the rising start point. Therefore, based on the maximum amplitude point of the pulse wave, for example, the maximum amplitude point of the pulse wave itself may be used as the reference point, or a point corresponding to 1/5 of the maximum amplitude in the rising part of the pulse wave may be set as the reference point. Has been proposed.

[0003]

By the way, a pulse wave propagating in an artery is formed by combining a traveling wave and a reflected wave generated when the traveling wave is rebounded by a blood vessel wall such as a blood vessel bifurcation. However, as shown in FIG. 5, since the influence of the reflected wave on the pulse wave is generally small, the maximum amplitude point of the pulse wave may be estimated as the maximum amplitude point of the traveling wave.
However, as the arteriosclerosis progresses, the influence of the reflected wave in the pulse wave gradually increases as shown in FIG. 11, and the maximum amplitude point of the pulse wave is determined based on the maximum amplitude point of the reflected wave. If the reference point is determined based on the maximum amplitude point of the pulse wave, the maximum amplitude point of the reflected wave greatly changes depending on the degree of arterial stiffness, or the shape of the artery at the site where the pulse wave is detected. It was inevitable that there would be variations in the set locations.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a pulse wave in which a high measurement accuracy is maintained regardless of the degree of arterial stiffness of a subject. It is an object of the present invention to provide a propagation speed information measuring device.

[0005]

SUMMARY OF THE INVENTION A first aspect of the present invention for achieving the above object is that a pair of heartbeat synchronous wave sensors respectively detected from a pair of heartbeat synchronous wave sensors attached to a part of a living body. In the pulse wave velocity information measuring device that measures pulse wave velocity information related to the propagation velocity of the pulse wave propagating in the artery of the living body based on the time difference of generation of the heartbeat synchronous wave,
(A) maximum slope determining means for determining a maximum slope that passes through the maximum slope of the heartbeat synchronization wave and has a slope of the maximum slope, and (b) a minimum point on the rising side of the heartbeat synchronization wave. (C) determining the intersection of the maximum slope determined by the maximum slope determination and the baseline determined by the baseline determination. Reference point determining means for determining a reference point for determining the time difference.

[0006]

According to the first aspect of the present invention, the maximum slope line which passes through the maximum slope point of the heartbeat synchronous wave and has the slope of the maximum slope point is determined by the maximum slope line determining means, and the heart rate is determined by the baseline determination means. A baseline connecting the minimum point on the rising side and the minimum point on the falling side of the synchronous wave is determined, and the intersection of the maximum slope line and the baseline is determined as a reference point for determining the time difference by the reference point determining means. You. Therefore, since the reference point which is not affected by the reflected wave in the pulse wave is determined, even in the subject who has advanced arteriosclerosis, the set point of the reference point does not vary and propagates in the artery of the living body. The measurement accuracy of the pulse wave propagation velocity information can be improved as much as possible.

[0007]

According to a second aspect of the present invention, there is provided a computer system comprising: a pair of heartbeat synchronous wave sensors respectively mounted on a part of a living body; A pulse wave propagation velocity information measuring device for measuring pulse wave propagation velocity information related to a propagation velocity of a pulse wave propagating in an artery of a living body based on a time difference of generation of the heartbeat synchronous wave, wherein (d) Maximum slope determining means for determining a maximum slope line passing through the maximum slope point and having the slope of the maximum slope point; and (e) passing the maximum amplitude point of the heartbeat synchronous wave and rising of the heartbeat synchronous wave Amplitude line determining means for determining a maximum amplitude line having a slope parallel to a base line connecting the minimum point on the falling side and the minimum point on the falling side; (f)
From the intersection of the maximum slope line determined by the maximum slope line determination means and the maximum amplitude line determined by the maximum amplitude line determination means, a vertical heartbeat synchronous wave that is lowered perpendicular to the maximum amplitude line. And a reference point determining means for determining a reference point for determining the time difference based on the intersection.

[0008]

In this way, the maximum gradient line determining means determines the maximum gradient line that passes through the maximum gradient point of the heartbeat synchronous wave and has the gradient of the maximum gradient point, and determines the maximum amplitude line. When the maximum amplitude line passing through the maximum amplitude point of the heartbeat synchronization wave and having a slope parallel to the base line connecting the minimum point on the rising side and the minimum point on the falling side of the heartbeat synchronization wave is determined by the reference, By a point determining means, a reference point for determining the time difference is determined based on an intersection of a perpendicular heartbeat synchronous wave dropped perpendicularly to the maximum amplitude line from an intersection of the maximum slope line and the maximum amplitude line. Is done. Therefore, since the reference point which is not affected by the reflected wave in the pulse wave is determined, even in the subject whose arteriosclerosis has progressed, there is no variation in the setting of the reference point, and the reference point propagates through the artery of the living body. The measurement accuracy of the pulse wave propagation velocity information can be improved as much as possible.

[0009]

A third aspect of the present invention to achieve the above object is to provide a third aspect of the present invention comprising a pair of heartbeat synchronous wave sensors respectively detected from a pair of heartbeat synchronous wave sensors attached to a part of a living body. A pulse wave propagation velocity information measuring device for measuring pulse wave propagation velocity information related to a propagation velocity of a pulse wave propagating in an artery of a living body based on a time difference of occurrence of a heartbeat synchronization wave. Is provided as a reference point for determining the time difference.

[0010]

According to the third aspect of the present invention, the reference point which is not affected by the reflected wave in the pulse wave is determined. Therefore, even in the subject whose arteriosclerosis has progressed, the set point of the reference point varies. Therefore, the measurement accuracy of the propagation speed information of the pulse wave propagating in the artery of the living body can be improved as much as possible.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view showing an automatic blood pressure measuring device 8 with a pulse wave velocity information measuring function.

In FIG. 1, a box 10 is provided with a through hole 14 into which a right arm 12 of a subject is inserted. In the through hole 14, a bag-shaped flexible cloth and a rubber bag are provided. A belt 16 which is provided with a cuff 15 formed on the inner peripheral surface thereof and held in a cylindrical shape is provided. Further, a first armrest 17 for supporting the right arm 12 of the subject protruding from the through-hole 14 is provided at the rear side of the through-hole 14 so as to be inclined upward, and a tip of the first armrest 17 is provided. In order to detect an electrocardiographic waveform generated with the action potential of the myocardium of the subject, the electrode 18 is disposed so as to be in good contact with the wrist of the right arm 12 of the subject. . The first armrest 17 keeps the muscles from the elbow to the wrist of the right arm 12 of the subject constantly relaxed so that an accurate ECG waveform can always be detected from the wrist of the subject. It has an optimal support surface shape that supports the entire area from the elbow to the wrist so that it can be leaned. On the left side of the box 10, a second armrest 19 for supporting the left arm 13 of the subject is provided horizontally. In order to detect the electric induction waveform, the electrode 18 is disposed so as to make good contact with the wrist of the left arm 13 of the subject. The second armrest 19 is also similar to the first armrest 17 so that the muscles from the elbow to the wrist of the left arm 13 of the subject are continuously relaxed from the elbow to the wrist. It has an optimal support surface shape to support it. An operation switch 20, a stop switch 24, a printer 26, a card insertion slot 28, and the like are provided on an operation panel 20 of the box 10, and a systolic blood pressure indicator 32, a diastolic blood pressure indicator 34, a pulse A number display 36 and a time display 38 are provided, respectively.

FIG. 2 is a block diagram for explaining a circuit configuration of the automatic blood pressure measuring device 8. In FIG. 2, the cuff 15 is connected to a pressure sensor 40, a switching valve 42, and an air pump 44 via a pipe 46. The switching valve 42 is configured to supply a pressure into the cuff 15 to allow a pressure to be supplied. It is configured to be able to switch between three states: a state, a slow discharge state in which the cuff 15 is gradually discharged, and a rapid discharge state in which the cuff 15 is rapidly discharged. Also, the cuff 15 is provided on the inner peripheral surface, and the belt 1 is wound around a cylindrical shape.
One end of 6 is fixed, and the other end is configured to be tightened by a drum 50 driven by a DC motor 48 with a speed reducer. The pressure sensor 40 detects the pressure in the cuff 15 and supplies a pressure signal SP representing the pressure to the static pressure discrimination circuit 52 and the pulse wave discrimination circuit 54, respectively.

The static pressure discriminating circuit 52 includes a low-pass filter, discriminates a cuff pressure signal SK representing a steady pressure included in the pressure signal SP, ie, a cuff pressure, and converts the cuff pressure signal SK into an A / D converter 56. To the electronic control unit 58 via The pulse wave discrimination circuit 54 includes a band-pass filter, and a pulse wave signal S which is a vibration component of the pressure signal SP.
The pulse wave signal SM ₁ to discriminate the M ₁ in frequency A / D
The electric power is supplied to the electronic control device 58 via the converter 60. The cuff pulse wave represented by the pulse wave signal SM ₁ is a pressure vibration wave generated from a brachial artery (not shown) and transmitted to the cuff 15 in synchronization with the heartbeat of the subject. In the present embodiment, the cuff 15
The pressure sensor 40 and the pulse wave discrimination circuit 54 function as a heartbeat synchronous wave sensor, and the cuff pulse wave corresponds to the heartbeat synchronous wave.

The electronic control unit 58 includes a CPU 62, R
The CPU 62 is configured by a so-called microcomputer including an OM 64, a RAM 66, and an I / O port (not shown). The CPU 62 processes an input signal according to a procedure stored in the ROM 64 in advance while using the temporary storage function of the RAM 66. To output drive signals and display signals. That is, when measuring the blood pressure, the CPU 62 drives the DC motor 48 with a speed reducer in accordance with a predetermined procedure to wind the cuff 15 around the upper arm of the living body, and drives the air pump 44 to cause the cuff 15 to move the upper arm. Portion, and then the switching valve 42 is driven to gradually reduce the compression pressure of the cuff 15. Based on the pulse wave signal SM ₁ and the cuff pressure signal SK obtained in the slow down process, the blood pressure is oscillometrically determined. The value is determined, and the blood pressure value is displayed on the systolic blood pressure display 32 and the diastolic blood pressure display 34, and at the same time, sequentially stored in the blood pressure value storage area 69 of the storage device 68. The storage device 68 is a magnetic disk,
It is constituted by a well-known storage device such as a magnetic tape, a volatile semiconductor memory, or a nonvolatile semiconductor memory.

The electrocardiography device 70 is connected to the right arm 12 of the subject.
Pair of electrodes 1 brought into contact with the wrist of the left arm 13 and the wrist of the left arm 13
Through 8, an electrocardiographic waveform indicating the action potential of the myocardium, that is, a so-called electrocardiogram is continuously detected, and a signal indicating the electrocardiographic waveform is supplied to the electronic control device 58. In the present embodiment, the electrocardiographic lead device 70 and the electrode 1
Reference numeral 8 functions as a heartbeat synchronous wave sensor, and the electrocardiographic lead waveform corresponds to the heartbeat synchronous wave.

FIG. 3 is a functional block diagram for explaining a main part of a control function corresponding to the first invention of the electronic control unit 58 in the automatic blood pressure measuring device 8. As shown in FIG. In FIG. 3, the pressure increasing control means 78 first switches the switching valve 42 to the pressure supply state and drives the air pump 44 to reduce the compression pressure of the cuff 15 to a predetermined target cuff pressure value P ₁ (for example, about 180 mmHg). The pressure value of the cuff 15 is gradually reduced by gradually switching the switching valve 42 to the slow exhaust pressure state. After the blood pressure measurement is completed, the switching valve 42 is switched to the rapid exhaust pressure state. By switching, the compression pressure of the cuff 15 is rapidly discharged. The blood pressure measuring means 80 is well known based on the change in the amplitude of the cuff pulse wave collected by the pulse wave discriminating circuit 54 via the pressure sensor 40 in the slow pressure lowering process of gradually lowering the compression pressure of the cuff 15. The systolic blood pressure SBP and the diastolic blood pressure DBP of the subject are determined by the oscillometric method, and the pulse rate HR is calculated based on the cuff pulse wave generation interval.

The time difference calculating means 82 detects the cuff pulse sequentially detected by the pressure sensor 40 from the R wave of the electrocardiographic lead waveform sequentially detected by the electrocardiographic lead device 70 as shown in FIG. sequentially calculates the time difference TD _RP to a predetermined reference point T _S to be described later generated in every period of the wave. Then, based on the time difference TD _RP actually calculated from the preset equation (1), the propagation speed calculation means 84 calculates the propagation speed V _M1 which is the propagation speed information of the cuff pulse wave.
(M / sec) is calculated. In Equation 1, L is the distance (m) from the left ventricle via the aorta to the pressure site of the pressure sensor 40, and T _PEP is the reference point T _S of the aortic origin pulse wave from the R wave of the electrocardiographic lead waveform. Pre-ejection period (s
ec). These distance L and pre-ejection period T _PEP
Is a value experimentally obtained in advance.

[0019]

## EQU1 ## _VM1 = L / ( _TDRP - _TPEP )

The maximum slope determining means 86 is shown in FIG.
The maximum slope point K of the cuff pulse wave_maxThat is,
The point where the differential waveform of the cuff pulse wave shows the maximum value is
Determined from the peak point, the maximum slope point K_maxTo
Passing and its maximum slope point K _maxMaximum inclination with inclination of
Oblique line L_Kmax(Corresponding to the broken line in the figure) is determined. Baseline decision maker
Step 88 is a minimum point on the rising side of the cuff pulse wave.
A baseline BL (see FIG. 1) connecting the
(Corresponding to the dotted line). The reference point determining means 90
The maximum inclination line L determined by the large inclination line determination means 86
_KmaxAnd the baseline BL determined by the baseline determining means 88
The time difference TD from the intersection of_RPReference point T for finding_S
To determine.

The change value determination section 92, adjacent one another change value of the propagation velocity V _M1 of the cuff pulse wave which is sequentially calculated by the propagation velocity calculating means 84, i.e., the amount of change or rate of change is less than a predetermined value, for example, It is determined whether it has become 0.1 (m / sec) or less or 3% or less. The propagation speed determining unit 94 determines, for example, the propagation speed calculating unit 84 from within the area where the change value judging unit 92 determines that the adjacent mutual change value of the cuff pulse wave propagation speed _VM1 has become equal to or less than a predetermined value.
From the beginning of the propagation speed V _M1 of the cuff pulse wave calculated by
The average value of the beat is determined as the propagation speed V _M2 of the pulse wave propagating in the artery of the living body.

Further, the corrected propagation speed calculating means 97
From pre-stored equation 2, the blood pressure based on the diastolic blood pressure DBP and pulse rate HR measured by the measuring means 80, preset constant pressure value BP _t (e.g. 80
mmHg) and corrected to the value at the pulse rate HR _t (e.g. 70 bpm) (normalized) to said cuff pulse wave modification propagation velocity V _M3 (m / sec) is calculated. In Equation 2,
Factor A is intended to be pre-determined based on Equation 3 by the coefficient value determining means 96, in proportion to the propagation velocity V _M2, is a coefficient value that varies in inverse proportion to the diastolic blood pressure DBP. Here, the constants B, C, and D in Expression 3 and the constant E in Expression 2 are obtained experimentally in advance.

[0023]

[Number 2] _{V M3 = V M2 + A (} BP t -DBP) + E (HR
_t- HR)

[0024]

A = BV _M2 −C (DBP) + D

FIG. 6 is a flow chart for explaining the main control operation of the electronic control unit 58. In step SA1 of FIG. 6 (hereinafter, the steps are omitted), it is determined whether or not the magnetic card 74 has been inserted into the card insertion slot 28 of the card reading device 72. If the determination in step SA1 is denied, the routine ends. If the determination is affirmed, the magnetic card 74 is determined in SA2.
Is read.

In the subsequent SA3, it is determined whether the read ID signal is a signal registered in the storage area of the storage device 68 in advance. If the determination in SA3 is denied, that is, if the ID signal recorded on the magnetic card 74 has not been registered, SA16 described later is executed, and the magnetic card 74 is sent out from the card insertion slot 28. However, when the determination in SA3 is affirmed, that is, when the magnetic card 7
If the ID signal recorded in No. 4 has already been registered,
In A4, it is determined whether the activation switch 22 for measuring blood pressure has been operated.

If the determination at SA4 is denied, the process waits until the determination is affirmed. However, if the determination in SA4 is affirmative, SA5 and SA6 corresponding to the boost control means 78 are executed. First, at SA5, the switching valve 42 is switched to the pressure supply state and the air pump 4
4 is driven and the cuff pressure P is set to a preset target cuff pressure P.
_After the pressure is increased to ₁ (for example, a pressure of about 180 mmHg), the air pump 44 is stopped. Next, SA6
, The switching valve 42 is switched to the slow exhaust pressure state to start slow pressure reduction in the cuff 15.

Subsequently, in SA7, the pulse wave signal SM
₁ is read, and it is determined whether or not one pulse wave is detected. If this determination is denied, SA7 is repeatedly executed.
Is executed, the blood pressure value determination routine of SA8 corresponding to is executed.
In this blood pressure value determination routine, based on the change in the amplitude of the pulse wave sequentially detected during the slow down process of the cuff pressure P,
The systolic blood pressure value SBP ₁ and the diastolic blood pressure value DBP according to a well-known oscillometric blood pressure value determining algorithm.
₁ and the average blood pressure value MBP ₁ are determined, and the pulse rate HR ₁ is determined based on the pulse wave generation interval.

Next, in SA9, the systolic blood pressure value SBP
₁ , Diastolic blood pressure DBP₁ , Mean blood pressure value MBP₁And pulse
Beat rate HR₁Is determined. This judgment
Is negative, SA7 to SA9 are repeatedly executed
Is done. However, if this judgment is affirmed,
At SA10, the measured systolic blood pressure value SBP
₁ , Diastolic blood pressure DBP₁ , Mean blood pressure value MBP₁ ,and
Pulse rate HR₁ And the measurement date and time are stored in the blood pressure value of the storage device 68.
The systolic blood pressure table is stored in the area 69 for each subject.
Indicator 32, diastolic blood pressure display 34, and pulse rate display 36.
Each is displayed.

[0030] Subsequently, in SA11 corresponding to the propagation velocity determining means 94, the average of the second of the propagation velocity V _M1 of the storage area are stored, the first three beats propagation velocity V _M1 described later RAM66 By calculating the value, the propagation speed V _M2 of the cuff pulse wave is determined. Then, in SA12 corresponding to the subsequent coefficient value determining means 96, the coefficient A in the previously stored equation 2 is replaced by the previously stored equation 3
From the propagation speed V _M2 and SA determined in SA11
It is determined based on the diastolic blood pressure DBP ₁ determined at 8.

Subsequently, at SA13 corresponding to the corrected propagation velocity calculating means 97, S
Diastolic blood pressure were measured in A8 DBP ₁ and pulse rate H
Based on R _1, the cuff pulse wave is corrected to a preset value at constant blood pressure BP _t and the pulse rate HR _t was,
That is, the normalized corrected propagation speed V _M3 is calculated.

Subsequently, the SA corresponding to the boost control means 78
At 14, the switching valve 42 is switched to the rapid exhaust pressure state, whereby the rapid exhaust pressure in the cuff 15 is started.
Then, in the subsequent SA15, as shown in FIG. 8, the systolic blood pressure SBP ₁ and the like are displayed and output on the recording paper 100 by the printer 26. That is, recording paper 1
At the upper left position on 00, the subject's name 102 is displayed, and below it, the artery determined according to FIG. 9 from the measurement date and time, blood pressure value, pulse rate, and the corrected propagation velocity _VM3 . List of degree of cure 104, trend graph 10
6 are sequentially displayed. As a method of determining the degree of arteriosclerosis, for example, it is determined by selecting a predetermined value of the degree of arteriosclerosis according to the calculated value of the corrected propagation velocity _VM3 based on a table as shown in FIG. This table is experimentally determined in advance, and the artery of the subject loses its flexibility as the value of the arteriosclerosis degree increases. In the trend graph 106, a bar line indicating the systolic blood pressure value and the diastolic blood pressure value at an upper end and a lower end respectively, a mark indicating a pulse rate, and a mark indicating a degree of arteriosclerosis correspond to the blood pressure measurement time on the horizontal axis, ie, time. Displayed along axis 108.
Then, when the subsequent SA16 is executed, the magnetic card 74 is sent out from the card insertion slot 28.

FIG. 7 shows the main routine of FIG.
It is a flowchart which shows the interruption routine performed when the R wave of an electrocardiogram lead waveform is detected. At SB1, the time at which the R wave of the electrocardiographic lead waveform is generated is read. Next, at SB2, whether the pulse wave signal SM ₁ is detected one beat is determined. If this determination is denied, SB2 is repeated. If this determination is affirmed, the maximum slope point of the cuff pulse wave shown in FIG. K _max is determined, for example, based on the point at which the differential waveform of the cuff pulse wave shows the maximum value, and the maximum slope point K
_The maximum slope line L _Kmax that passes through _max and has the slope of its maximum slope point K _max is determined. Next, baseline determination means 8
In SB4 corresponding to No. 8, a base line BL connecting the minimum point on the rising side and the minimum point on the falling side of the cuff pulse wave is determined. SB5 corresponding to the reference point determination means 90
, The maximum slope line L _Kmax determined in SB3
And the intersection with the base line BL determined in SB4 is determined as a reference point T _S for _{obtaining the} time difference TD _RP .

In the following SB6, the reference point T of the cuff pulse wave
_The time when _S occurred is read. Next, in SB7 corresponding to the time difference calculating means 82, as shown in FIG. 4, the reference point from the R-wave of the cuff pulse wave of the ECG waveform T _S
TD _RP is calculated. Subsequently, in SB8 corresponding to the propagation velocity calculating means 84, the propagation velocity V _M1 of the cuff pulse wave is calculated based on the time difference TD _RP actually obtained in SB7 from Equation 1 stored in advance, and , Are temporarily stored in the first storage area of the RAM 66.

Next, SB9 corresponding to the change value judging means 92
, The propagation speeds V _M1 and R calculated in SB8
Mutual change value of the propagation velocity V _M1 calculated in the previous cycle stored in the first storage area of the AM66, i.e. the variation or the rate of change is less than a predetermined value, for example, 0.1 (m /
sec) or less, or 3% or less. If this determination is denied, this routine is ended. If this determination is affirmed, the process proceeds to SB1.
At 0, the propagation speed V _M1 calculated at SB8 is temporarily stored in the second storage area of the RAM 66.

[0036] As described above, according to this embodiment, in SB3 corresponding to the maximum slope line determination unit 86, passes through the maximum inclination point K _max of the cuff pulse wave, and its maximum slope point K
A maximum slope line L _Kmax having a slope of _max is determined, and a base line BL connecting the minimum point on the rising side and the minimum point on the falling side of the cuff pulse wave is determined in SB4 corresponding to the base line determining means 88. Then, at SB5 corresponding to the reference point determining means 90, the maximum slope line L _Kmax and the base line BL
Reference point T to the intersection with calculates the time difference TD _RP
Determined as _S. Therefore, since the reference point T _{S which} is not affected by the reflected wave in the pulse wave is determined, even in the subject who has advanced arteriosclerosis, the set point of the reference point T _S does not vary, and the inside of the artery of the living body is not affected. Measurement accuracy of the propagation speed of the propagating pulse wave is improved as much as possible.

According to the present embodiment, the propagation speed V
_If the change value of _M1 is equal to or smaller than the predetermined value, the average value of three beats of the propagation speed V _M1 of the cuff pulse wave determined in SB9 corresponding to the change value determination means 92 is equal to SA11 corresponding to the propagation speed determination means 94. _Is determined as the propagation velocity V _M2 of the pulse wave propagating in the artery of the living body. Accordingly, regardless of the change in the compression pressure of the cuff 15, the propagation speed V _M1 calculated sequentially is calculated.
Since There always propagation velocity V _M1 of time as shown a substantially constant value is determined as the final propagation speed V _M2, the measurement accuracy of the pulse wave velocity is improved.

Further, in the present embodiment, the SA 13 corresponding to the corrected propagation velocity calculating means 97 is obtained from the previously stored equation 2 by the SA 13 corresponding to the blood pressure measuring means 80.
Blood pressure value DBP ₁ and pulse rate HR measured according to Eq.
Based on _1, modified propagation velocity V _M3 obtained by correcting the value (normalized) in the preset constant pressure value BP _t and pulse rate HR _t is calculated. Therefore, even if the blood pressure value and the pulse rate of the living body are slightly different each time it is measured, the pulse wave propagation velocity calculated by the present apparatus is equal to the corrected propagation velocity V _M3 at the constant blood pressure value and the pulse rate. Since the normalized pulse wave velocity is normalized, it is possible to directly use the measured pulse wave velocity as an index indicating a change over time in the arterial stiffness of the subject.

The corrected propagation speed V _M3 measured by this device is calculated by the SA 12 corresponding to the coefficient value determining means 96.
In, on the basis of Equation 3 to be pre-stored, the coefficient is determined from the lowest blood pressure value DBP ₁ Metropolitan measured in the propagation velocity V _M1 and SA8 calculated at SB8 A, i.e., the influence of individual differences in the degree of arteriosclerosis Is calculated using a coefficient that also takes into account the above, so that the measured pulse wave propagation velocity can be used as an index representing individual differences in arterial stiffness.

Further, according to the automatic blood pressure measuring device 8 of the present embodiment, the pulse wave propagation velocity is measured simultaneously with the blood pressure measurement, and the pulse wave propagation velocity is directly used as an index indicating the change over time in the degree of arteriosclerosis. Since the data is converted into a usable data, more biological information is provided to the subject, and the health condition can be more diversified. Further, the degree of arterial stiffness corresponding to the calculated pulse wave velocity is displayed as a trend graph, so that a temporal change can be more easily and accurately grasped.

Next, the main part of the control function corresponding to the second invention of the electronic control unit 58 in the automatic blood pressure measurement device 8 will be described with reference to the functional block diagram of FIG. Note that portions having the same configuration as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 10, the maximum amplitude line determining means 98
As shown in FIG. 11, the slope passing through the maximum amplitude point M _max of the cuff pulse wave and parallel to the base line connecting the minimum point on the rising side and the minimum point on the falling side of the cuff pulse wave is The maximum amplitude line L _Mmax (corresponding to the two-dot chain line in the figure) is determined. The reference point determining means 99 is provided with the maximum inclination line determining means 8.
6 maximum inclination line L _Kmax determined by (corresponding to dashed line in the figure), from the intersection point X ₁ between the maximum amplitude line L _Mmax which is determined by the largest amplitude line determination unit 98, with respect to the maximum amplitude line L _{Mm ax} the point corresponding to 1/5 of the amplitude values of the intersection point X ₂ of the cuff pulse wave of a perpendicular line which is lowered vertically is determined as the reference point T _S.

Next, the main part of the control operation of the electronic control unit 58 corresponding to the functional block diagram of FIG. 10 will be described. Since the main routine in this control operation is the same as that shown in FIG. 6, the description is omitted, and an interrupt executed when an R wave of an electrocardiographic lead waveform is detected with respect to the main routine in FIG. Only the routine will be described with reference to FIG. In FIG. 12, SC1 and SC2 are SB
1 to SB2.

Next, in SC3 corresponding to the maximum inclination line determining means 86, the maximum inclination point K _max of the cuff pulse wave shown in FIG. 11 is determined based on, for example, the point at which the differential waveform of the cuff pulse wave shows the maximum value. Is determined and its maximum slope point K
_The maximum slope line L _Kmax that passes through _max and has the slope of its maximum slope point K _max is determined. Next, in SC4 corresponding to the maximum amplitude line determining means 98, an inclination parallel to the base line passing through the maximum amplitude point M _max of the cuff pulse wave and connecting the minimum point on the rising side and the minimum point on the falling side of the cuff pulse wave. maximum amplitude line L _Mmax is determined with. At SC5 corresponding to the reference point determining unit 99, a maximum slope line L _Kmax determined in SC3, from the intersection X ₁ maximum amplitude line L _Mmax determined in SC4, the maximum amplitude line L
Prompts the amplitude value of the intersection point X ₂ of the cuff pulse wave of a perpendicular line which is lowered vertically to _Mmax, the amplitude value of the cuff pulse wave, for example, a reference point a point corresponding the cuff pulse wave to 1/5 T _S
Is determined as Then, the following SC6 to SC10
Are executed in the same manner as in SB6 to SB10 described above.

The largest as described above, according to this embodiment, which passes through the maximum inclination point K _max of the cuff pulse wave in SC3 corresponding to the maximum slope line determining means 86, having a slope of the maximum slope point K _max When the slope line L _Kmax is determined and the maximum amplitude line L _{Mmax that} is in contact with the maximum amplitude point M _max of the cuff pulse wave is determined in SC4 corresponding to the maximum amplitude line determination means 98, it corresponds to the reference point determination means 99. In SC5,
Intersection X ₁ between the maximum slope line L _Kmax and the maximum amplitude line L _Mmax
From the amplitude value of the intersection point X ₂ of the cuff pulse wave of a perpendicular line which is lowered vertically with respect to the maximum amplitude line L _Mmax, the point corresponding to, for example, 1/5 is determined as a reference point T _S. In this way, the reference point T _{S which is} not affected by the reflected wave in the pulse wave
Is determined, there is no variation in the setting of the reference point T _S even in the subject who has advanced arteriosclerosis, and the measurement accuracy of the propagation speed of the pulse wave propagating in the artery of the living body is improved as much as possible. Let me do.

Next, the main part of the control function corresponding to the third invention of the electronic control unit 58 in the automatic blood pressure measuring device 8 will be described with reference to the functional block diagram of FIG. Note that portions having the same configuration as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 13, the reference point determination means 76 determines the maximum slope point K _max of the heartbeat synchronization wave based on, for example, a point at which the differential waveform of the heartbeat synchronization wave shows the maximum value, and determines the maximum slope point _Kmax as the reference. Point T
Determined as _S.

Next, the main part of the control operation of the electronic control unit 58 corresponding to the functional block diagram of FIG. 13 will be described. Since the main routine in this control operation is the same as that shown in FIG. 6, the description is omitted, and an interrupt executed when an R wave of an electrocardiographic lead waveform is detected with respect to the main routine in FIG. Only the routine will be described with reference to FIG. In FIG. 14, SD1 and SD2 are SB
1 to SB2. Next, in SD3 corresponding to the reference point determining means 76, the maximum slope point K _max of the cuff pulse wave shown in FIG. 11 is determined based on, for example, the point at which the differential waveform of the cuff pulse wave shows the maximum value. , The maximum slope point K _max is determined as the reference point T _S. Then, the subsequent SD4 to SD8 are executed in the same manner as SB6 to SB10 described above.

[0048] As described above, according to this embodiment, in SD3 corresponding to the reference point determining unit 76, the maximum inclination point K _max of the cuff pulse wave is determined as a reference point T _S. Therefore, the reference point T _{S which is} not affected by the reflected wave in the pulse wave
Is determined, there is no variation in the setting of the reference point T _S even in the subject who has advanced arteriosclerosis, and the measurement accuracy of the propagation speed of the pulse wave propagating in the artery of the living body is improved as much as possible. Let me do.

Although various embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be applied to other embodiments.

[0050] For example, although in the foregoing embodiments, although the case of using the pulse wave velocity V _M1, V _M2 or V _M3 as pulse wave velocity information has been described, directly corresponding to the pulse wave velocity The propagation time TD _RP may be used instead. In this case, for example, the propagation speed calculating means 84 and the corresponding SB8, SC8 or SD
6 becomes unnecessary. In this case, the change value determination unit 92 and the corresponding SB9, the SC9 or SD7, whether the change value of the propagation time TD _RP instead change value of the propagation velocity V _M1 is equal to or less than a predetermined value is determined, change value from the determined region and equal to or less than a predetermined value, for example, the average value of the first three beats of propagation time TD _RP is determined arterial of the subject as a propagation time TD _RP1 pulse wave that propagates. In addition, instead of the corrected propagation speed calculating means 97, a corrected pulse wave propagation speed information calculating means for correcting the pulse wave propagation time TD _RP1 based on the diastolic blood pressure value DBP measured by the blood pressure measuring means 80 and the pulse rate HR. That is, the modified pulse wave transit time calculation means is used. The corrected pulse wave propagation time calculating means calculates the corrected pulse wave propagation velocity TD _RP2 based on the diastolic blood pressure value DBP measured by the blood pressure measuring means 80 and the pulse rate HR, for example, according to Equations 5 and 6. Further, based on a previously experimentally determined table of the corrected propagation times TD _RP2 and degree of arteriosclerosis, the value of a predetermined degree of arteriosclerosis is determined according to the calculated value of corrected propagation times TD _RP2.

[0051]

[Equation 4] TD_RP2 = (TD_RP1-T_PEP) L / ｛L +
A '(BP_t−DBP) + E (HR _t-HR)｝

[0052]

A ′ = B × L / (TD _RP1 −T _PEP ) −C (D
BP) + D

In the above-described embodiment, the propagation speed V _M1 is calculated by calculating the time difference TD _RP from the electrocardiographic lead waveform and the cuff pulse wave. The configuration may be such that the propagation speed V _M1 is calculated by calculating the time difference TD _RP from a pair of pulse waves respectively detected from a pair of pulse wave sensors. still,
In such a case, the reference point T for each pulse wave
_S is required.

Further, in the above-described embodiment, the intersection X of the maximum slope line L _Kmax and the maximum amplitude line L _Mmax in SC5.
₁ had been determined as a reference point T _S is a point of the cuff pulse wave that corresponds to 1/5 of the amplitude values of the intersection point X ₂ of the cuff pulse wave of a perpendicular line which is lowered vertically with respect to the maximum amplitude line L _Mmax However, for example, it may be 1/3 or 1/10 instead of 1/5, and the intersection itself corresponding to the foot of the perpendicular may be determined as the reference point T _S.

The present invention can be variously modified without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of an automatic blood pressure measurement device with a pulse wave velocity information measurement function 8 according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a circuit configuration of the embodiment of FIG. 1;

FIG. 3 is a functional block diagram illustrating a main part of a control function corresponding to the first invention of the electronic control unit 58 of the embodiment of FIG. 1;

FIG. 4 is a time chart for explaining a time difference TD _RP obtained by the control operation of the embodiment of FIG. 1;

FIG. 5 is an enlarged view of a cuff pulse wave for explaining a reference point T _S obtained by a control operation corresponding to the first invention in the embodiment of FIG. 1;

FIG. 6 is a flowchart illustrating a main part of a control operation corresponding to the first invention of the electronic control device 58 of the embodiment of FIG. 1;

7 is a flowchart showing an interrupt routine executed when an R wave of an electrocardiographic lead waveform is detected in the main routine shown in FIG. 6;

8 is a diagram showing an example of a display output by the printer 26 of the embodiment of FIG.

FIG. 9 is a diagram showing an example of a table used when converting the measured corrected propagation velocity _{VM3 back} into a predetermined arteriosclerosis degree.

FIG. 10 shows the second embodiment of the electronic control unit 58 of the embodiment of FIG.
FIG. 3 is a functional block diagram illustrating a main part of a control function according to the present invention.

11 is an enlarged view of a cuff pulse wave for explaining a reference point T _S obtained by a control operation corresponding to the second aspect of the embodiment of FIG. 1;

FIG. 12 shows the second embodiment of the electronic control unit 58 of the embodiment of FIG. 1;
FIG. 7 is a flowchart illustrating a main part of a control operation according to the present invention.
It is a flowchart which shows the interruption routine performed when the R wave of an electrocardiogram lead waveform is detected.

FIG. 13 shows the third embodiment of the electronic control unit 58 of the embodiment of FIG. 1;
FIG. 3 is a functional block diagram illustrating a main part of a control function according to the present invention.

FIG. 14 is a view showing the third example of the electronic control unit 58 of the embodiment of FIG. 1;
FIG. 7 is a flowchart illustrating a main part of a control operation according to the present invention.
It is a flowchart which shows the interruption routine performed when the R wave of an electrocardiogram lead waveform is detected.

[Explanation of symbols]

 8: Automatic blood pressure measurement device with pulse wave velocity information measurement function 15: Cuff (heart-rate synchronous wave sensor) 18: Electrode 70: electrocardiograph (heart-rate synchronous wave sensor) 76: Reference point determination means 86: Maximum slope determination Means 88: Baseline determination means 90: Reference point determination means 98: Maximum amplitude line determination means 99: Reference point determination means

Claims (3)

[Claims] 1. The method according to claim 1, further comprising: determining a propagation speed of a pulse wave propagating in an artery of the living body based on a time difference between a pair of heartbeat synchronous waves detected from a pair of heartbeat synchronous wave sensors attached to a part of the living body. In a pulse wave velocity information measuring device for measuring related pulse wave velocity information, a maximum inclination line determining means for determining a maximum inclination line passing through a maximum inclination point of the heartbeat synchronization wave and having an inclination of the maximum inclination point Baseline determining means for determining a base line connecting the minimum point on the rising side and the minimum point on the falling side of the heartbeat synchronizing wave; a maximum slope determined by the maximum slope determining means; And a reference point determining means for determining, as a reference point for determining the time difference, an intersection with the base line determined by the above. 2. The method according to claim 1, further comprising: determining a propagation speed of a pulse wave propagating in an artery of the living body based on a time difference between a pair of heartbeat synchronous waves detected from a pair of heartbeat synchronous waves sensors attached to a part of the living body. In a pulse wave velocity information measuring device for measuring related pulse wave velocity information, a maximum inclination line determining means for determining a maximum inclination line passing through a maximum inclination point of the heartbeat synchronization wave and having an inclination of the maximum inclination point And a maximum amplitude that determines a maximum amplitude line that passes through the maximum amplitude point of the heartbeat synchronization wave and has a slope parallel to a base line connecting the minimum point on the rising side and the minimum point on the falling side of the heartbeat synchronization wave. Line determining means, a perpendicular line vertically lowered with respect to the maximum amplitude line from an intersection of the maximum slope line determined by the maximum slope line determining means and the maximum amplitude line determined by the maximum amplitude line determining means. Said heartbeat A reference point determining means for determining a reference point for determining the time difference based on an intersection with a synchronous wave. 3. A propagation velocity of a pulse wave propagating in an artery of the living body based on a time difference between occurrences of a pair of heartbeat synchronous waves detected from a pair of heartbeat synchronous waves sensors attached to a part of the living body. In a pulse wave velocity information measuring device that measures related pulse wave velocity information, reference point determining means for determining a maximum slope point of the heartbeat synchronization wave as a reference point for determining the time difference is included. Pulse wave velocity information measuring device.