JPH10314129A - Automatic blood pressure measuring instrument with pulse wave propagation speed information measuring function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the measurement precision of pulse wave propagation speed information as much as possible in an automatic blood pressure measuring instrument with a pulse wave propagation speed information measuring function, by which the blood pressure value of aliving body is decided based on a heart beat synchronizing signal generated from the living body in process where the oppressive pressure of a cuff wound around a part of the living body is changed. SOLUTION: When the electrocardi-guide waveform of the living body is detected by an electrocardi-guide device 70 through an electrode which is brought into contact with the living body and the cuff pulse wave of the living body is detected by a pressure sensor 40, time difference TDRP from the R-wave of the electrocardi-guide waveform till the lower peak point of cuff pulse wave is calculated by a time difference calculating means 82 and a propagation speed calculating means 84 calculates cuff pulse wave propagation speed VM1 based on the time difference TDRP. Then, the average value of the three beat portion of cuff pulse wave propagation speed VM1 which is successively calculated after judgement that the change value of the propagation speed VM1 is equal to below a prescribed value by a change value judging means 86, is decided as the propagation speed VM2 of pulse wave which is propagated in the artery of the living body in a propagation speed deciding means 87.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse wave propagation speed or a pulse wave propagation time based on a heartbeat synchronization signal generated from a living body in a process of changing a compression pressure of a cuff wound around a part of the living body. The present invention relates to an automatic blood pressure measurement device having a function of measuring pulse wave propagation velocity information, such as measuring pulse wave propagation velocity information and determining a blood pressure value of a living body.

[0002]

2. Description of the Related Art As an apparatus for measuring a blood pressure value of a living body, for example, a compression pressure of a cuff wound around a part of the living body is gradually reduced at a predetermined speed, and a Korotkoff sound generated in this slow pressure lowering process is reduced. An automatic blood pressure measurement device based on the Korotkoff sound system that determines the blood pressure value based on the cuff pressure at the time of occurrence and disappearance, and a well-known oscillometric system based on the change in the amplitude of the pulse synchronous wave generated during the slow down process An automatic blood pressure measurement device or the like that determines a blood pressure value by using a computer is known. As an oscillometric automatic blood pressure measuring device, for example, there is an automatic blood pressure measuring device described in Japanese Patent Application Laid-Open No. 6-292660.

By the way, in the automatic blood pressure measurement apparatus as described above, for example, an electrocardiographic electrode for detecting an electrocardiographic lead waveform is provided at a tip end of the subject to support the right arm of the subject to be projected from the cuff. A second armrest is provided to be inclined upward in the direction of the back of the cuff, supports the left arm of the subject, and has an electrocardiographic electrode for detecting an electrocardiographic lead waveform at the distal end. Since the armrest is provided horizontally on the left side of the main body, the pulse is measured from a predetermined site generated at each cycle of the electrocardiographic waveform detected from the wrist of the right arm and the wrist of the left arm simultaneously with the blood pressure measurement. With a pulse wave propagation speed information measurement function that calculates the time difference to the rising part generated in each cycle of the synchronization wave and can also measure the propagation speed information of the pulse wave propagating in the artery of the living body based on the time difference Automatic blood pressure measurement Device has been considered.

According to such an automatic blood pressure measuring device with a function of measuring pulse wave velocity information, the pulse wave velocity information is measured simultaneously with the measurement of blood pressure, so that the pulse wave velocity information and the arteriosclerosis degree of the subject are measured. Is known to be closely related to chronic hypertension patients who take antihypertensive drugs on a daily basis. It is possible to evaluate continuously.

[0005]

However, the pulse wave propagation velocity information measured by such an automatic blood pressure measurement apparatus having a function of measuring pulse wave velocity information is such that the compression pressure of the cuff is substantially equal to the average blood pressure value of the subject. In the period when the pressure value is equal to or higher than the equivalent pressure value, the cuff pressure is increased as the compression pressure decreases,
If pulse wave velocity information is measured from the electrocardiographic lead waveform and the pulse synchronizing wave detected at an appropriate time without considering the change in the compression pressure of the cuff, the reliability of the measurement accuracy is significantly lacking.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a heartbeat generated from a living body in a process of changing the compression pressure of a cuff wound around a part of the living body. An object of the present invention is to improve the measurement accuracy of pulse wave propagation velocity information as much as possible in an automatic blood pressure measurement apparatus having a function of measuring pulse wave velocity information of a type that determines a blood pressure value of a living body based on a synchronization signal.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the gist of the present invention is to provide a heartbeat synchronization generated from a living body in a process of changing a compression pressure of a cuff wound around a part of the living body. An automatic blood pressure measurement device having a function of measuring a blood pressure of a living body based on a signal, wherein a pulse wave propagating in an artery of a portion of the living body upstream of the cuff is detected. A first pulse wave sensor,
(B) a second pulse wave sensor for detecting a pulse wave generated in the cuff in the process of changing the compression pressure of the cuff; and (c) a pulse wave generated every period of the pulse wave detected by the first pulse wave sensor. And calculating pulse wave propagation velocity information related to the propagation velocity of the pulse wave based on a time difference from a predetermined part to a rising part generated in each cycle of the pulse wave detected by the second pulse wave sensor. Speed information calculating means; and (d) change value determining means for determining whether a change in the propagation speed information of the pulse wave calculated by the propagation speed information calculating means with respect to the cuff pressure has become a predetermined value or less; (E) the biological value is determined based on at least one of a plurality of pieces of propagation speed information for which the change in the propagation speed information of the pulse wave with respect to the cuff pressure is determined to be equal to or less than a predetermined value. Of the pulse wave propagating in the artery A propagation velocity information determining means for determining 播速 degree information is to include.

[0008]

In this way, when the first pulse wave sensor and the second pulse wave sensor detect the pulse wave of the living body in the process of changing the compression pressure of the cuff, the propagation speed information calculating means sets the first pulse wave sensor to the second pulse wave sensor. A time difference from a predetermined portion generated at each cycle of the pulse wave obtained by the first pulse wave sensor to a rising portion generated at each cycle of the pulse wave obtained by the second pulse wave sensor is calculated, and based on the time difference, The propagation speed information of the pulse wave is calculated. Then, based on at least one of a plurality of pulse wave propagation speed information determined by the change value determining means that a change in the propagation speed information with respect to the cuff pressure is equal to or less than a predetermined value, the propagation speed information is determined. The propagation speed information of the pulse wave propagating in the artery of the living body is determined by the means. Therefore, regardless of the change in the compression pressure of the cuff, the pulse wave propagation velocity information in the region where the pulse wave propagation velocity information sequentially calculated always shows a substantially constant value is finally determined as the pulse wave propagation velocity information. Therefore, the measurement accuracy of the pulse wave propagation velocity information is improved.

[0009]

More preferably, the propagation speed information determining means determines that the change in the pulse wave propagation speed information with respect to the cuff pressure is less than a predetermined value by the change value determining means. And determining the propagation speed information of the pulse wave propagating in the artery of the living body from the average value calculated based on the propagation speed information. According to this configuration, an appropriate one of the plurality of pieces of propagation speed information for which the change of the propagation speed information with respect to the cuff pressure is determined to be equal to or less than the predetermined value is determined as the final propagation speed information. The measurement accuracy of the pulse wave propagation velocity information is further improved as compared with the case where the measurement is performed.

[0010]

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 the section, the electrode 18 is disposed so as to be in good contact with the wrist of the right arm 12 of the subject in order to detect an electrocardiographic waveform generated with the activity of the subject's heart.
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. Further, a second armrest 19 for supporting the left arm 13 of the subject is provided on the left side of the box 10, and an electrocardiographic wave of the subject is also provided at the tip of the second armrest 19. The electrode 18 is arranged so as to contact the wrist of the left arm 13 of the subject in order to detect the wobble. In addition, like the first armrest 17, the second armrest 19 also extends between the elbow and the wrist so that the muscles from the elbow to the wrist of the subject's left arm 13 can be constantly relaxed. It has an optimal support surface shape for overall support. The start switch 2 is provided on the operation panel 20 of the box 10.
2, stop switch 24, printer 26, card slot 2
8 and the like, and a display panel 30 is provided with a systolic blood pressure display 32, a diastolic blood pressure display 34, a pulse rate display 36, and a time display 38, respectively.

FIG. 2 is a block diagram illustrating a circuit configuration of the automatic blood pressure measurement device 8. In the figure, cuff 1
5 is connected to a pressure sensor 40, a switching valve 42, and an air pump 44 via a pipe 46.
2 includes three states: a pressure supply state in which the supply of pressure into the cuff 15 is allowed, 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. It is configured to be switchable. Further, the cuff 15 is provided on the inner peripheral surface, and the belt 16 is wound in a cylindrical shape.
Is fixed at one end and the other end is a DC motor 48 with a reduction gear.
It is configured to be tightened by the drum 50 driven by the. 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 has a low-pass filter, discriminates a cuff pressure signal SK representing a steady pressure, ie, a cuff pressure, contained in the pressure signal SP, 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 an unshown brachial artery and transmitted to the cuff 15 in synchronization with the heartbeat of the subject, and includes the cuff 15 and the pressure sensor 4.
0 and the pulse wave discrimination circuit 54 function as a second pulse wave sensor.

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, at the time of blood pressure measurement, 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 the air pump 4
4, the upper arm is compressed by the cuff 15 and then the switching valve 42 is driven to gradually reduce the compression pressure of the cuff 15, and the pulse wave signal SM ₁ and the cuff pressure obtained in the slow down process. Based on the signal SK, a blood pressure value is determined by an oscillometric method, and the blood pressure value is displayed on the systolic blood pressure display 32 and the diastolic blood pressure display 34, and simultaneously 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. Since the electrocardiographic waveform, particularly the R wave, corresponds to the rising point of the starting point of the aortic pressure waveform, the electrocardiographic guiding device 70 and the electrode 18 cycle the pulse wave at the most upstream part in the artery. It functions as a first pulse wave sensor for performing dynamic detection.

FIG. 3 is a functional block diagram for explaining a main control function of the electronic control unit 58 in the automatic blood pressure measurement device 8. In the figure, the pressure increase 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). (Pressure value), and the switching pressure of the cuff 15 is gradually reduced by 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. Thereby, the compression pressure of the cuff 15 is rapidly discharged. The blood pressure determination means 80 determines the cuff pulse wave sampled by the pulse wave discrimination circuit 54 via the pressure sensor 40 (corresponding to the second pulse wave sensor) in the slow pressure lowering process of gradually lowering the compression pressure of the cuff 15. The systolic blood pressure value SBP and the diastolic blood pressure value DBP of the subject are determined by a well-known oscillometric method based on the change in the amplitude, and the pulse rate HR is calculated based on the cuff pulse wave generation interval.

The time difference calculating means 82 is provided for each of the cycles of the cuff pulse wave sequentially detected by the pressure sensor 40 from a predetermined portion generated at each cycle of the electrocardiogram waveform detected by the electrocardiograph 70. time difference to the reference point or the rising portion occurs, for example, sequentially calculates the time difference TD _RP from R-wave of the ECG waveform as shown in FIG. 4 to the lower peak of the cuff pulse wave. In addition, as the rising portion of the cuff pulse wave, in addition to the lower peak point, a point rising by a predetermined amplitude value from the lower peak point, or a maximum slope point of the cuff pulse wave (the maximum peak of the differential waveform of the cuff pulse wave) Etc.) are used. Then, the propagation speed calculating means 84 calculates the propagation speed V _M1 (m / sec), which is the propagation speed information of the cuff pulse wave, based on the time difference TD _RP actually calculated from the preset equation 1. Is done. In Equation 1, L is the distance (m) from the left ventricle via the aorta to the pressed part of the pressure sensor 40, and T
_PEP is a pre-ejection period (sec) from the R wave of the electrocardiographic lead waveform to the lower peak point of the aortic root pulse. For the distance L and the pre- _ejection period T _PEP , values experimentally obtained in advance are used. In the present embodiment, the time difference calculating means 82 and the propagation velocity calculating means 84 function as pulse wave propagation velocity information calculating means.

[0018]

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

The change value judging means 86 determines the mutual change value of the propagation speed V _M1 of the cuff pulse wave sequentially calculated by the propagation speed calculating means 84, that is, the change amount or the change rate is equal to or less than a predetermined value, for example, 0. It is determined whether it has become 1 (m / sec) or less or 3% or less. Propagation velocity determining means 87 functioning as propagation velocity information determining means is provided in a region where the change value determining means 86 determines that the mutual change value of the cuff pulse wave propagation velocity V _M1 has become equal to or less than a predetermined value (see FIG. 5). (Corresponding to a horizontal portion of the propagation velocity V _M1 represented), the average value of the first three beats of the propagation velocity V _M1 of the cuff pulse wave calculated by the propagation velocity calculation means 84 is calculated in the artery of the living body. It is determined as the propagation speed V _M2 of the propagating pulse wave.

Further, the corrected propagation speed calculating means 89 functioning as the corrected propagation speed information calculating means, based on the diastolic blood pressure value DBP and the pulse rate HR determined by the blood pressure determining means 80 from the previously stored equation (2). modify a preset constant pressure value BP _t (e.g. 80 mmHg) and corrected to the value at the pulse rate HR _t (e.g. 70 bi ─ DOO / min) (normalized) and the modified propagation velocity information of the cuff pulse wave has The propagation speed V _M3 (m / sec) is calculated. In Equation 2, the coefficient A is calculated by the coefficient value determining means 88 as
Is a coefficient value proportional to the propagation speed V _M2 and inversely proportional to the diastolic blood pressure value DBP. Here, the constants B, C, and D in Expression 3 and the constant E in Expression 2 are experimentally obtained in advance.

[0021]

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

[0022]

A = BV _M2 −C (DBP) + D

[0023] Further, the apparatus is used as an expected propagation speed information determining means.
The expected propagation speed deciding means 90 which can function is the change value judging means 8
6, the propagation velocity V of the cuff pulse wave_M1The mutual change value of
After it is determined that the value has become equal to or less than the value, the propagation speed calculating means 8
The propagation velocities V of the plurality of cuff pulse waves sequentially calculated by
_M1Is calculated next by the propagation velocity calculating means 84 based on
Expected propagation velocity V_M1’(△ in FIG. 5)
Is determined based on Equation 4. The expected propagation speed
V_M1’Is determined, that is, once the change value of the propagation velocity
After the value falls below the specified value, the propagation speed
If the change value of the degree exceeds a predetermined value, the pulse wave correcting means 92
Corrects the pulse wave used for blood pressure determining means 80
Is done. The pulse wave correcting means 92 includes a propagation velocity calculating means 84
Velocity V of cuff pulse wave actually calculated by_M1(FIG. 5
And the expected propagation velocity V_M1ΔV
_M1That is, the difference ΔV calculated from Expression 5_M1Based on
The amplitude correction value X calculated from Equation 6 set in advance
₁ Only this time propagation speed V _M1The actual cuff vein calculated
Add to the wave amplitude value. That is, it is shown by a solid line in FIG.
Amplitude correction value X indicated by the broken line₁ Add
Or calculated from Equation 7 set in advance.
Pressure correction value X_Two Only this time propagation speed V_M1Was calculated
The pressure value in the cuff 15 at the time when the cuff pulse wave is generated
To be added, ie, the cuff pulse wave shown by a solid line in FIG.
Is moved to the position indicated by the broken line to
Correct the cuff pulse wave used in the setting means 80. This
Here, the constants F and G in Expressions 6 and 7 are experimentally obtained in advance.
It is what is done. Also, the blood pressure determination pulse wave correcting means 93
Is, for example, the expected propagation velocity determining means 90 and the pulse wave
And a correcting means 92.

[0024]

[Equation 4] _VM1 '= [( _VM1 ) _in + ... + ( _VM1 )
_i-1 + ( _VM1 ) _i ] / (n + 1)

[0025]

[Expression 5] ΔV _M1 = V _M1 −V _M1 '

[0026]

X ₁ = F (ΔV _M1 )

[0027]

X ₂ = −G (ΔV _M1 )

The blood pressure determination ending means 94 outputs the propagation speed V of the cuff pulse wave sequentially calculated by the propagation speed calculating means 84.
_{When M1} exceeds a predetermined allowable range of the propagation velocity V _M1 set in advance for each pressure value in the cuff 15, that is, in a region within the one-dot chain line in FIG. The blood pressure determination ends. This allowable range is a range in which the propagation speed V _M1 cannot be absolutely exceeded in normal blood pressure measurement, and is obtained experimentally in advance.

FIG. 7 is a flowchart for explaining the main control operation of the electronic control unit 58. In step SA1 in the figure (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, this routine is ended. If the determination is affirmed, the magnetic card 74 is determined in SA2.
Is read.

At 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
_It is determined whether ₁ and the diastolic blood pressure value DBP ₁ have been determined. If this judgment is denied, SA7 to SA7
9 is repeatedly executed. However, if this determination is affirmed, in subsequent SA10, the measured systolic blood pressure value SBP ₁ , diastolic blood pressure value DBP ₁ , and average blood pressure value M
BP ₁ , pulse rate HR ₁ and measurement date and time are stored in the storage device 6
8 is stored for each subject in the blood pressure value storage area 69 and displayed on the systolic blood pressure display 32, the diastolic blood pressure display 34, and the pulse rate display 36, respectively.

[0034] Subsequently, in SA11 corresponding to the propagation velocity determining means 87, 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 coefficient value determining means 88, the propagation speed V _M2 determined in SA11 and the diastolic blood pressure value DBP ₁ determined in SA8 are calculated from Expression 3 stored in advance.
, The coefficient A in Equation 2 stored in advance is determined.

Subsequently, in SA13 corresponding to the corrected propagation velocity calculating means 89, S3 is calculated from the previously stored equation (2).
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. 9, 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 on the lower side, the artery determined according to FIG. 10 from the measurement date and time, blood pressure value, pulse rate, and the corrected propagation velocity _VM3 . Hardness list 104, trend graph 1
06 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. 8 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. In FIG. 8, in SB1, the time at which the R wave of the electrocardiographic lead waveform is generated is read. Next, at SB2, under the peak point of the pulse wave signal SM ₁ is whether or not it is detected is determined.
If the judgment is negative, but subsequently SB2 is repeated, if the judgment is affirmative, in a subsequent SB3, the time the lower peak point of the pulse wave signal SM ₁ is generated is read.

Next, in SB4 corresponding to the time difference calculating means 82, as shown in FIG. 4, the time difference TD _RP from R-wave of the ECG waveform to the lower peak point of the cuff pulse wave is calculated. Subsequently, at SB5 corresponding to the propagation velocity calculating means 84, the SB4
, The propagation speed V _M1 of the cuff pulse wave is calculated based on the time difference TD _RP actually obtained in
66 is temporarily stored in the first storage area.

Next, S corresponding to the blood pressure determination ending means 94
In B6, whether propagation velocity V _M1 of the cuff pulse wave calculated exceeds the possible predetermined tolerance of the propagation velocity V _M1 that is set in advance it is determined at SB5. That is,
It is determined whether or not the propagation speed V _M1 exceeds the maximum allowable curve or the minimum allowable curve represented by the one-dot chain line in FIG. If this determination is affirmed, the determined blood pressure value is clearly suspicious, and the SB7 corresponding to the boost control means 78 is executed in order to perform the measurement again.
The switching valve 42 is switched to the rapid exhaust pressure state, the rapid exhaust pressure in the cuff 15 is started, and at SB8, the display indicating that the measurement should be performed again is made by the printer 26 to the recording paper 1.
The magnetic card 74 is sent out from the card insertion slot 28 at SB9.

However, if the determination in SB6 is denied, it is determined in subsequent SB10 whether the amplitude value of the cuff pulse wave is smaller than the maximum pulse wave amplitude value up to that time. That is, the amplitude value of the cuff pulse wave newly newly detected is compared with the maximum pulse wave amplitude value stored so far. If this determination is denied, that is, if the detected amplitude value is larger than the previous maximum pulse wave amplitude value, in SB15, the amplitude value is updated as a new maximum pulse wave amplitude value. Is terminated.
Since the amplitude of the cuff pulse wave becomes maximum when the pressure value in the cuff reaches the average blood pressure value, the maximum pulse wave amplitude value is updated one after another until the pressure value in the cuff reaches the average blood pressure value.

However, if the determination in SB6 is affirmative, the cuff pressure pressure value has exceeded the average blood pressure value that produces the maximum pulse wave amplitude, and therefore, it corresponds to the subsequent change value determination means 86. In SB11, a mutual change value between the propagation speed V _M1 calculated in SB5 and the propagation speed V _M1 calculated one cycle ago stored in the first storage area of the RAM 66, that is, a change amount or a change rate. Is less than a predetermined value, for example, 0.1 (m / sec) or less, or 3
% Is determined. If the judgment is affirmative, in a subsequent SB12, propagation velocity V _M1 calculated in SB5 is temporarily stored in the second storage area of the RAM 66. Then, the expected propagation speed determining means 9
0 in SB13 corresponding to the second
Based on the plurality of propagation velocities V _M1 stored in the storage area, the expected propagation velocity V _M1 ′ of the cuff pulse wave that is expected to be calculated next from Equation 4 (see the mark △ in FIG. 5). Is determined, and is temporarily stored in the third storage area of the RAM 66.

However, if the determination in SB11 is denied, in SB14 corresponding to the following pulse wave correcting means 92, the propagation speed V _{M1 of} the current cuff pulse wave calculated in SB5 (marked with ● in FIG. 5). Prediction) determined based on Equation 4 using a plurality of propagation speeds up to the propagation speed V _M1 calculated one cycle before and stored as the latest one in the third storage area of the RAM 66. Based on the difference ΔV _M1 from the propagation velocity V _M1 ′ (corresponding to the symbol △ in FIG. 5), that is, the difference ΔV _M1 calculated from Equation 5,
Only the amplitude correction value X ₁ calculated from
_M1 is added to the calculated amplitude value of the cuff pulse wave, or a pressure correction value X calculated from Equation 7 set in advance.
₂ only by this propagation velocity V _M1 is added to the pressure value in the cuff 15 at the time of occurrence of the cuff pulse wave is calculated, the blood pressure determining means 80 cuff pulse wave modification used in is performed.

As described above, according to the present embodiment, the electrocardiographic lead waveform of the living body is detected by the electrocardiographic lead device 70 through the electrode 18 which comes into contact with the living body, and the pressure sensor 40 (corresponding to the second pulse wave sensor) is detected. ), When a cuff pulse wave of the living body is detected, the time difference TD _RP from the R wave of the electrocardiographic lead waveform to the lower peak point of the cuff pulse wave is calculated in SB4 corresponding to the time difference calculation means 82, and the propagation velocity is calculated. At SB5 corresponding to the means 84, the propagation speed V _M1 of the cuff pulse wave is calculated based on the time difference TD _RP . And this propagation speed V
SB1 corresponding to the change value determination means 86 determines that the adjacent mutual change value of _M1 is equal to or less than a predetermined value, and then three beats from the beginning of the propagation speed V _M1 of the cuff pulse wave sequentially calculated in SB5. Is the propagation speed determining means 8
In SA11 corresponding to 7, the propagation speed V _M2 of the pulse wave propagating in the artery of the living body is finally determined. Therefore, regardless of the change in the compression pressure of the cuff 15, the pulse wave velocity V _M1 in the region where the sequentially calculated pulse wave velocity V _M1 always shows a substantially constant value finally becomes the pulse wave velocity V _{M M2}
Therefore, the measurement accuracy of the pulse wave velocity is improved.

Further, according to the present embodiment, the corrected propagation velocity calculating means is obtained from the previously stored equation 2 based on the diastolic blood pressure value DBP and the pulse rate HR determined in SA8 corresponding to the blood pressure determining means 80. SA13 corresponding to 89
In, 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.

In addition, the corrected propagation velocity V _M3 measured by this device is determined by the SA1 corresponding to the coefficient value determining means 88.
In SA2, based on Equation 3 stored in advance, SA1
The coefficient A is determined by using the propagation speed V _M2 determined in step 1 and the diastolic blood pressure value DBP measured in SA8, and the coefficient A determined in other words, that is, a coefficient that takes into account the influence of individual differences in arterial stiffness. Therefore, it is possible to use the measured pulse wave propagation velocity as an index representing individual differences in arterial stiffness.

According to the present embodiment, the pulse wave velocity is measured simultaneously with the measurement of blood pressure, and the pulse wave velocity can be directly used as an index indicating the change over time in arterial stiffness. Since more biological information is provided to the subject, it is possible to judge the health condition from multiple angles. 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.

Further, since the pulse wave propagation velocity has been conventionally measured by attaching a pulse wave sensor to the carotid artery and the hip artery using a dedicated fixing device, considerable skill is required in searching for an optimal pressure. And it was very difficult for the subject to measure himself, but the automatic blood pressure measurement device 8 of this embodiment
According to the method, the pulse wave propagation velocity can be easily measured without special skill, so that the subject can measure the pulse wave velocity.

[0048] Furthermore, modifications may be calculated propagation velocity V _M3, since those that have been modified to a value in the preset constant pressure value BP _t and pulse rate HR _t, based on Equation 8, is set in advance compared to only those were fixed to the value at a given blood pressure BP _t was, by an amount affected by the pulse rate is eliminated, thereby enabling more accurate evaluation.

[0049]

[Equation 8] _{V M3 = V M2 + A (} BP t -DBP)

According to the present embodiment, the propagation speed V
_When the change value of _M1 becomes equal to or less than a predetermined value, the change value determining means 86
Based on the propagation velocities V _M1 of the plurality of pulse waves sequentially calculated by SB5 corresponding to the propagation velocity calculating means 84 after being determined by SB11 corresponding to SB13, the expected propagation velocity V of the cuff pulse wave that is expected to be calculated next
_M1 'is determined and SB14 corresponding to the pulse wave correcting means 92
Thus, based on the difference ΔV _M1 between the propagation speed V _M1 of the cuff pulse wave actually calculated by SB5 and the expected propagation speed V _M1 ′, the amplitude value X calculated from the preset expression 6
_The current propagation velocity V _M1 is added to the calculated amplitude value of the cuff pulse wave by 1 or the pressure value X ₂ calculated from the preset equation 7 at the time of generation of this cuff pulse wave. By adding to the cuff pressure value, the cuff pulse wave used in SA8 corresponding to the blood pressure determining means is corrected.
Therefore, even if the blood pressure value changes for each heartbeat for some reason during the blood pressure measurement, the blood pressure value is appropriately corrected, so that an accurate blood pressure value determination is always performed, and the blood pressure measurement accuracy is seriously affected. Will not be affected.

According to the present embodiment, the propagation speed V
_{If M1} exceeds a predetermined allowable range of the propagation speed V _M1 set in advance for each compression pressure value of the cuff 15, that is, if it exceeds the region within the dashed line in FIG.
The blood pressure determination by SA8 corresponding to the blood pressure determination end means 9
The process is terminated by SB6 corresponding to No. 4. Therefore, even if the blood pressure value changes for each heartbeat for some reason during blood pressure measurement, if the change is far beyond the allowable amount and abnormal, the blood pressure value determination is terminated, so that the blood pressure measurement is terminated. The accuracy is not significantly affected.

While the embodiment of the present invention has been described with reference to the drawings, the present invention can be applied to other embodiments.

[0053] 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 A time difference from a predetermined portion generated every cycle of the pulse wave obtained by the first pulse wave sensor to a rising portion generated every cycle of the pulse wave obtained by the second pulse wave sensor;
That is, the propagation time TD _RP may be used instead. In this case, the change value determination means 86
Instead of the mutual change value of the propagation velocity V _M1 of the cuff pulse wave, determined change amount or rate of change of the propagation time TD _RP cuff pulse wave whether it is below a predetermined value. As the propagation speed information determining means, a propagation time determining means is used in place of the propagation speed determining means, and from the region where it is determined that the mutual change value of the propagation time TD _RP of the cuff pulse wave has become equal to or less than a predetermined value, The average value of the first three beats of the propagation time TD _RP of the cuff pulse wave is determined as the propagation time TD _RP2 of the pulse wave propagating in the artery of the living body.

In this case, the propagation speed calculating means 84 and the corresponding SB5 are not required. In this case, the pulse wave propagation time TD is calculated based on the diastolic blood pressure value DBP and the pulse rate HR instead of the corrected propagation speed calculating means 89.
A corrected pulse wave propagation velocity information calculating means for correcting the _RP, that is, a corrected pulse wave transit time calculating means is used. The modified pulse wave transit time calculating means calculates the modified pulse wave _transit time TD _RP2 based on the diastolic blood pressure value DBP measured by the blood pressure determining means 80 and the pulse rate HR, for example, according to Equations 9 and 10. Here, the constant B ′ in Equation 10 is
C ′ and D ′ and the constant E ′ in Expression 9 are experimentally obtained in advance.

[0055]

[Equation 9] TD_RP2 = (TD_RP-T_PEP) L / ｛L + A ’
(BP_t−DBP) + E ′ (HR _t-HR)｝

[0056]

A ′ = B ′ × L / (TD _RP −T _PEP ) −C ′
(DBP) + D '

In this case, the expected propagation speed determining means
An expected propagation time determination means is used in place of step 90,
Expected propagation time TD to be calculated_RP'To the formula
11 is determined. In this case, the pulse wave correcting means 92
Is the actual propagation time TD of the cuff pulse wave_RPAnd expected propagation time T
D_RP'And the difference ΔTD_RPThat is, it is calculated from Equation 12.
ΔTD_RPIs calculated from Equation 13 set in advance based on
Output amplitude correction value X ₁ ’, This time propagation time TD_RPBut
It is added to the calculated amplitude value of the cuff pulse wave, or
Pressure correction value X calculated from Equation 14 to be set_Two ’
Only this time of propagation TD_RPOf the calculated cuff pulse wave
The pressure value in the cuff 15 at the time of
With this, the cuff pulse wave used for the blood pressure determining means 80 is corrected.
Correct it properly. Here, the constants F 'in Expressions 13 and 14,
G 'is previously determined experimentally.

[0058]

TD _RP ′ = [(TD _RP ) _in +... + (T
D _RP ) _i-1 + (TD _RP ) _i ] / (n + 1)

[0059]

ΔTD _RP = TD _RP −TD _RP ′

[0060]

X ₁ ′ = F ′ (ΔTD _RP )

[0061]

X ₂ ′ = −G ′ (ΔTD _RP )

In the above-described embodiment, the pulse wave velocity V _M1 is calculated from Equation 1 based on the time difference TD _RP from the R wave of the electrocardiographic lead waveform to the lower peak point of the cuff pulse wave. The time difference TD _RP is the time difference from the Q wave or S wave of the electrocardiographic lead waveform to the point where the pulse rises by a predetermined amplitude value from the lower peak point of the cuff pulse wave, or the Q wave or R wave of the electrocardiographic lead waveform And the time difference from the maximum slope point of the cuff pulse wave to the maximum slope point.

Further, in the equation (1) of the above-described embodiment, T
_{The PEP} was defined as a pre-ejection period (sec) from the R wave of the electrocardiographic lead waveform to the lower peak point of the cuff pulse wave, but the lower peak point of the cuff pulse wave from the Q wave or S wave of the electrocardiographic lead waveform. May be defined as the pre-ejection period up to. Since the mutual time difference between the Q point, the R point, and the S point in the electrocardiographic waveform is an extremely small value, it may be defined as such.

In the above embodiment, the right arm 12
Was configured to be inserted into the through hole 14,
The left arm 13 may be configured to be inserted into the through hole 14, and in this case, the through hole 14, the first armrest 17, the second armrest 19, and the like are provided at opposite positions. Further, in the above embodiment,
Although the first armrest 17 is provided to be inclined upward, the first armrest 17 may be separately provided in a horizontal state.
The armrest may be provided to be inclined upward. In short, it is only necessary that the muscles be designed so as to maintain a relaxed state.

In the above-described embodiment, the electrodes 18 are provided at the distal ends of the first armrest 17 and the second armrest 19, but need not be limited to this position. Can be changed to various installation positions. In short, it suffices if it is installed so that a stable ECG waveform can be detected from the right arm 12 and the left arm 13.

In the above embodiment, the cuff 15
Is automatically wound around the arm of the person to be measured, but an automatic blood pressure measuring device of the type in which the person is wound around the arm by himself is adopted. It does not matter, and the electrocardiographic lead waveform does not need to be detected from an electrode separately provided on the armrest, and is brought into contact with a predetermined part of the living body as in the past, for example, from a sucker-shaped electrocardiographic electrode. It may be configured to be detected.

In the above-described embodiment, the calculated corrected propagation velocity V _M3 is a predetermined fixed blood pressure value B
Although corrected to values at P _t and pulse rate HR _t , the calculated corrected propagation velocity V _M3 is corrected only to a value at a predetermined constant blood pressure value BP _t based on Equation 8. It may be done. Similarly, when used to correct propagation time as the correction propagation velocity information, but may be one that is only corrected to a value in the preset constant pressure value BP _t. The effect of the pulse rate on the pulse wave propagation velocity information is not as great as the effect of the blood pressure value, so that a necessary and sufficient effect can be obtained.

Expression 15 may be used instead of Expression 3 in the above embodiment. In short, it is only necessary that the coefficient A that is proportional to the propagation speed V _M2 and inversely proportional to the diastolic blood pressure value DBP is calculated.

[0069]

(Equation 15)

In SA15 of the above-described embodiment,
Is the arterial stiffness list 104 and the trend graph 10
6 was displayed, but the corrected pulse wave velocity information V_M3Also
Is TD _RP2 Is the list 104 and the trend graph
It may be configured to be displayed at 106.

Further, in the above-described embodiment, after it is determined in SB11 that the change value of the propagation speed _VM1 which is the propagation speed information of the cuff pulse wave sequentially calculated in SB5 is equal to or less than a predetermined value, the process proceeds to SB5. The average of three successive beats of the sequentially calculated cuff pulse wave propagation velocity V _M1 is determined as the propagation velocity V _M2 of the pulse wave propagating through the artery of the living body in SA11 corresponding to the propagation velocity determination means 87. However, any one of the velocities V _M1 of one arbitrarily extracted heart, instead of the average value, may be determined as the velocities V _M2 , or the number of beats of more than three beats to increase the accuracy. The propagation speed V _M2 may be calculated from the average value of the minutes. Similarly, in the case where the propagation time TD _RP is used as the propagation speed information, any of the arbitrarily extracted one-time propagation times TD _RP may be determined as the propagation time TD _RP2 instead of the average value. _{Alternatively, the} propagation time _TDRP2 may be calculated from an average value of more than three beats in order to further increase the accuracy.

In the above-described embodiment, the SB13
In the above, it is expected that the next calculation will be performed by using Expression 4 based on the plurality of propagation velocities V _M1 stored in the second storage area of the RAM 66, that is, using the moving average value. Although the expected propagation speed V _M1 ′ of the cuff pulse wave is sequentially determined, it is configured to determine the expected propagation speed V _M1 ′ of the cuff pulse wave using a so-called regression line instead of the moving average value. Is also good. Similarly, when the expected propagation time TD _RP ′ is used instead of the expected propagation velocity V _M1 ′, the expected propagation velocity TD _RP ′ of the cuff pulse wave is determined using a so-called regression line instead of the moving average value. It may be configured to do so.

In the above embodiment, the cuff 15
Although the blood pressure value was determined based on the change in the amplitude of the cuff pulse wave collected in the slow pressure step of gradually reducing the compression pressure of the cuff 15, in the slow pressure step of gradually increasing the compression pressure of the cuff 15 The blood pressure may be determined based on the cuff pulse wave to be collected.

Although the blood pressure value is determined by the oscillometric method in the above-described embodiment, the same effect can be obtained even if the blood pressure value is determined by the Korotkoff sound method. it can.

In the above-described embodiment, the electrocardiographic lead-in device 7
0 and the electrode 18 functioned as the first pulse wave sensor, but a carotid artery wave sensor for detecting a pulse wave of the carotid artery, a brachial artery sensor for detecting a pulse wave of the brachial artery, and the like are used as the first pulse wave sensor. You may be.

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 an automatic blood pressure measurement device 8 with a pulse wave propagation velocity information measurement function 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 of the electronic control device 58 of the embodiment in 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 a diagram showing a change tendency of the propagation speed _VM1 obtained by the control operation of the embodiment of FIG. 1 with respect to the pressure value in the cuff 15;

FIG. 6 is a diagram showing a change tendency of the amplitude value of the cuff pulse wave obtained by the control operation of the embodiment of FIG.

FIG. 7 is a flowchart illustrating a main part of a control operation of the electronic control device 58 of the embodiment of FIG. 1;

FIG. 8 is a flowchart showing an interrupt routine executed when an R wave of an electrocardiographic lead waveform is detected with respect to the main routine shown in FIG. 4;

FIG. 9 is a diagram showing an example of a display output by the printer 26 of the embodiment of FIG.

FIG. 10 is a diagram showing an example of a table used when converting the measured corrected propagation velocity _{VM3 back} into a predetermined arteriosclerosis degree.

[Explanation of Signs] 8: Automatic blood pressure measurement device with pulse wave propagation velocity information measurement function 15: Cuff 18: Electrode 40: Pressure sensor (second pulse wave sensor) 70: Electrocardiographic induction device 78: Boost control means 80: Blood pressure Determination means 82: Time difference calculation means 84: Propagation velocity calculation means 86: Change value determination means 88: Propagation velocity determination means 89: Modified propagation velocity calculation means 90: Expected propagation velocity determination means 92: Pulse wave correction means 93: Blood pressure determination Pulse wave correcting means 94: blood pressure determination ending means

Claims (2)

[Claims] 1. A pulse wave velocity of a type for determining a blood pressure value of a living body based on a heartbeat synchronization signal generated from the living body in a process of changing a compression pressure of a cuff wound around a part of the living body. In an automatic blood pressure measurement device with an information measurement function, a first pulse wave sensor for detecting a pulse wave propagating in an artery at a position upstream of the cuff of the living body, and a cuff in a process of changing a compression pressure of the cuff. A second pulse wave sensor for detecting a generated pulse wave, and a pulse wave detected by the second pulse wave sensor from a predetermined portion generated for each period of the pulse wave detected by the first pulse wave sensor. Propagation speed information calculating means for calculating pulse wave propagation speed information related to the propagation speed of the pulse wave based on a time difference to a rising portion generated in each cycle; and the pulse wave calculated by the propagation speed information calculating means Before propagation speed information Change value determining means for determining whether or not the change with respect to the cuff pressure is equal to or less than a predetermined value; and the change value determining means determining that the change in the propagation speed information of the pulse wave with respect to the cuff pressure is equal to or less than a predetermined value. Based on at least one of the plurality of pieces of propagation velocity information,
An automatic blood pressure measurement device with a pulse wave propagation speed information measuring function, comprising: a propagation speed information determining unit that determines propagation speed information of a pulse wave propagating in an artery of a living body. 2. The method according to claim 2, wherein the change value determination unit determines that a change in the pulse wave propagation speed information related to the pulse wave propagation speed with respect to the cuff pressure is equal to or less than a predetermined value. The pulse wave propagation velocity information measuring function according to claim 1, wherein the propagation velocity information of the pulse wave propagating in the artery of the living body is determined from an average value calculated based on the propagation velocity information. Blood pressure measuring device.