JPH10201724A - Automatic sphygmometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitablly determine an objective pressure for pressing an organism even if the blood pressure of the organism may be largely changed compared to the last time. SOLUTION: A blood pressure of an organism is estimated from a previously set relationship based on transmission time Td of pulse wave transmitting in artery of the organism by an estimated blood pressure determining means 76, and an objective pressing value PM is determined by an objective pressure value determining means 78 based on an estimated blood pressure determined by an estimated blood pressure determining means 76; when the blood pressure is measured, a cuff pressure is quickly raised till the objective pressing value PM is reached. Therefore, on this apparatus, even if the blood pressure of the organism is largely changed compared to the blood pressure at the last time, regardless of the change of the last blood pressure in value, the objective pressing value PM for pressing the arm is suitably determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic blood pressure measuring device for automatically measuring a blood pressure value of a living body.

[0002]

2. Description of the Related Art A change in a pulse synchronizing wave generated in a process of rapidly increasing a compression pressure of a cuff attached to a living body to a predetermined target pressure value and thereafter gradually reducing the compression pressure of the cuff at a predetermined speed. There is known an automatic blood pressure measurement device of a type that measures a blood pressure value of a living body based on the blood pressure. Since the target pressure value is assumed to be a state in which the artery is stopped at the start of the blood pressure measurement, the target pressure value needs to be determined to be higher than the systolic blood pressure value of the living body. It is often set to a value sufficiently higher than the value, for example, a constant value of about 180 mmHg. However, the systolic blood pressure value of the living body varies greatly, and for a living body with low blood pressure, the burden and measurement time due to the pain caused by applying excessive compression becomes unnecessarily large, or for a living body with high blood pressure. In some cases, measurement becomes impossible due to insufficient compression, so that a re-boost operation or a re-measurement operation is required.

[0003] On the other hand, on the premise that measurement is repeatedly performed on a certain living body, a predetermined margin value is added to the previously measured systolic blood pressure value to determine a target pressure value. It has been proposed to ensure that the pressure for compressing a part of the living body at the time of measurement exceeds the systolic blood pressure of the subject by the margin. For example, the blood pressure measuring device described in Japanese Patent Application Laid-Open No. Sho 58-46937 is such a device.

[0004]

The above-mentioned conventional automatic blood pressure measuring device is based on the premise that the blood pressure value of the living body does not change from a general change range compared with the previous measurement. Indeed, it works effectively in the range where holds. However, the blood pressure value of the living body does not always change within a general change range, but may change abruptly compared with the previous measurement due to various causes. In such a case, similarly to the above, it is possible to avoid inconvenience such as giving pain to the subject by applying excessive pressure, or making measurement impossible due to insufficient compression. Did not.

The present invention has been made in view of the above circumstances, and an object of the present invention is to set a target pressure for compressing a living body even if the blood pressure of the living body has changed abruptly compared to the previous measurement. An object of the present invention is to provide an automatic blood pressure measurement device whose value is appropriately determined.

[0006]

Means for Solving the Problems The gist of the present invention to achieve the above object is to rapidly increase the compression pressure of a cuff attached to a living body to a predetermined target pressure value,
An automatic blood pressure measurement device of a type that measures a blood pressure value of a living body based on a change in a pulse synchronizing wave generated in a process of gradually reducing the compression pressure of the cuff at a predetermined speed,
(A) estimated blood pressure value determining means for estimating a blood pressure value of a living body based on a propagation time or a pulse wave propagation velocity of a pulse wave propagating in the artery of the living body from a preset relationship; and (b) estimating the blood pressure value. Target pressure value determining means for determining the target pressure value based on the estimated blood pressure value determined by the blood pressure value determining means.

[0007]

In this way, the blood pressure value of the living body can be determined by the estimated blood pressure value determining means based on the propagation time or the pulse wave propagation speed of the pulse wave propagating in the artery of the living body from a preset relationship. Is estimated, and the target pressure value determining means
The target pressure value is determined based on the estimated blood pressure value determined by the estimated blood pressure value determining means. As described above, when measuring the blood pressure, the target pressure value is determined based on the estimated blood pressure value, so that the target pressure value is determined irrespective of the blood pressure change from the previous measurement. Even if it changes abruptly compared to the time, the target pressure value of the compression on the living body is appropriately determined.

[0008]

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 diagram illustrating a configuration of a blood pressure monitoring device 8 to which the present invention has been applied.

In FIG. 1, a blood pressure monitoring device 8 has a rubber bag in a cloth band bag, for example, an upper arm 12 of a patient.
And a pressure sensor 14, a switching valve 16, and a cuff 10 connected to the cuff 10 via a pipe 20, respectively.
And an air pump 18. This switching valve 16
Switches between three states: a pressure supply state in which the supply of pressure into the cuff 10 is permitted, a slow discharge state in which the cuff 10 is gradually discharged, and a rapid discharge state in which the cuff 10 is rapidly discharged. It is configured to be.

The pressure sensor 14 detects the pressure in the cuff 10 and outputs a pressure signal SP representing the pressure to the static pressure discriminating circuit 2.
2 and the pulse wave discrimination circuit 24. The static pressure discriminating circuit 22 has a low-pass filter, discriminates a cuff pressure signal SK representing a steady pressure included in the pressure signal SP, that is, a cuff pressure, and converts the cuff pressure signal SK into an A / D converter 26.
To the electronic control unit 28 via the Pulse wave discrimination circuit 2
Reference numeral 4 denotes a band pass filter, which discriminates a pulse wave signal SM ₁ which is a vibration component of the pressure signal SP in frequency, and converts the pulse wave signal SM ₁ via the A / D converter 30 into the electronic control unit 2.
8 The cuff pulse wave represented by the pulse wave signal SM ₁ is
These are pressure vibration waves generated from a brachial artery (not shown) and transmitted to the cuff 10 in synchronization with the heartbeat of the patient.

The electronic control unit 28 includes a CPU 29, R
The microcomputer 29 includes a so-called microcomputer including an OM 31, a RAM 33, an I / O port (not shown), and the like. The CPU 29 executes signal processing using a storage function of the RAM 33 according to a program stored in the ROM 31 in advance. Thus, a drive signal is output from the I / O port to control the switching valve 16 and the air pump 18.

The pressure pulse wave detection probe 34 is connected to the cuff 10.
At the portion of the upper arm 12 of the patient on the downstream side of the artery, the open end of the housing 36 having a container shape is
In a state facing the wrist 8, it is detachably attached to the wrist 42 by the wearing band 40. Inside the housing 36, a pressure pulse wave sensor 46 is provided via a diaphragm 44 so as to be relatively movable and protrudable from an open end of the housing 36.
A pressure chamber 48 is formed by the diaphragm 6 and the diaphragm 44 and the like. The pressure chamber 48 is supplied with pressurized air from an air pump 50 via a pressure regulating valve 52, whereby the pressure pulse wave sensor 46 applies a pressing force P corresponding to the pressure in the pressure chamber 48. _HD against the body surface 38.

The pressure pulse wave sensor 46 is configured by arranging a large number of semiconductor pressure-sensitive elements (not shown) on a pressing surface 54 of a semiconductor chip made of, for example, single crystal silicon. By being pressed onto the radial artery 56 on the surface 38, a pressure vibration wave, that is, a pressure pulse wave generated from the radial artery 56 and transmitted to the body surface 38 is detected, and a pressure pulse wave signal SM representing the pressure pulse wave is detected. ₂ is supplied to the control device 28 via the A / D converter 58. The lower waveform in FIG. 2 shows an example of the pressure pulse wave detected by the pressure pulse wave sensor 46.

The CPU 29 of the electronic control unit 28
According to a program stored in the ROM 31 in advance.
A drive signal is output to the air pump 50 and the pressure regulating valve 52,
The pressure in the pressure chamber 48, that is, the pressing force of the pressure pulse wave sensor 46 on the skin is adjusted. Thereby, when monitoring the blood pressure, the optimum pressing force P _HDP of the pressure pulse wave sensor 46 is determined based on the pressure pulse waves sequentially obtained in the pressure change process in the pressure chamber 48, and the optimum pressing force of the pressure pulse wave sensor 46 is determined. The pressure regulating valve 52 is controlled so as to maintain P _HDP .

The electrocardiographic lead device 60 continuously detects an electrocardiographic lead waveform indicating the action potential of the myocardium, a so-called electrocardiogram, through a plurality of electrodes 62 attached to a predetermined portion of a living body. A signal indicating an electrocardiographic lead waveform is supplied to the electronic control unit 28. The upper waveform in FIG. 2 shows an example of an ECG waveform detected by the ECG device 60.

FIG. 4 is a functional block diagram for explaining a main control function of the electronic control unit 28 in the blood pressure monitoring device 8. In the figure, the cuff pressure control means 68 performs a compression pressure of the cuff 10, that is, a cuff pressure P _C when measuring the blood pressure.
Rapidly boosts to the target pressure value P _M determined by target pressure value determining means 78 will be described later, after which the cuff 10
Is gradually reduced at a predetermined speed, for example, a speed of about 3 mmHg / sec. When the determination of the blood pressure value by the blood pressure determining means 70 described later is completed in the process of reducing the pressure, the compression pressure of the cuff 10 is released to the atmospheric pressure. . Figure 5 shows a variation of the cuff pressure P _C which is controlled by the cuff-pressure changing means 68.

The blood pressure determining means 70 determines the systolic blood pressure value of the patient by an oscillometric method based on the change in the amplitude of the cuff pulse wave obtained as the pressure oscillation of the cuff 10 during the above-mentioned slow pressure reduction process of the compression pressure of the cuff 10. Determine BP _SYS and diastolic blood pressure value BP _DIA . For example, the cuff pressure when the change rate of the cuff pulse wave amplitude is the maximum is determined as the systolic blood pressure value BP _SYS and the diastolic blood pressure value BP _DIA .

The propagation time calculating means 72 calculates a pulse wave propagation time Td (msec) between the electrocardiographic lead waveform detected by the electrocardiographic lead device 60 and the pressure pulse wave detected by the pressure pulse wave sensor 46. Are sequentially calculated. Here, the pulse wave propagation time T
As shown in FIG. 2, d is calculated from the phase difference delay time from the R wave of the electrocardiographic lead waveform to the time when the differential waveform of the pressure pulse wave shows a peak value. 5 shows the pulse wave transit time from to the radial artery of the wrist.

The transit time blood pressure correspondence relation determining means 74 calculates the transit time Td calculated by the transit time calculating means 72.
And a blood pressure value BP determined by the blood pressure determining means 70, for example, a systolic blood pressure value BP _SYS, is determined in advance for a predetermined subject. This correspondence is determined, for example, at the time of the previous blood pressure measurement. FIG. 3 is a diagram for exciting the above-mentioned correspondence, where EBP _SYS = A (1 / T
d) It is expressed by + B formula. Here, EBP _SYS is an estimated systolic blood pressure value, A is a constant indicating a slope, and B is a constant indicating an intercept.

The estimated blood pressure value determining means 76 calculates the actual pulse wave transit time calculated by the transit time calculating means 72 from the correspondence shown in FIG. based on td, sequentially determined for each one heartbeat the estimated systolic blood pressure EBP _{SY S} of the measurement subject.

The target pressure value determining means 78 calculates an estimated blood pressure value determined by the estimated blood pressure value determining means 76 based on a preset relationship shown in, for example, Expression 1 or Expression 2, for example, an estimated systolic blood pressure value EBP _SYS of the subject. based on, determines a target pressure value P _M (mmHg). That is, the estimated systolic blood pressure value E determined by the estimated blood pressure value determining means 76.
By multiplying BP _SYS by a preset constant α or adding a preset pressure value β (mmHg),
To calculate a target pressure value P _M. This constant α or pressure value β
Is experimentally determined in advance so as to be necessary and sufficiently higher than the systolic blood pressure value BP _SYS of the living body regardless of the variation of the estimated systolic blood pressure value EBP _SYS .

[0022]

[Equation 1] P _M = α · EBP _SYS

[0023]

## EQU2 ## P _M = EBP _SYS + β

FIG. 6 is a flowchart for explaining a main part of the control operation of the electronic control unit 28 of the blood pressure monitoring device 8 of the present embodiment. In the figure, in step SM1 (hereinafter, the steps are omitted), it is determined whether or not a blood pressure measurement start operation is performed by a start switch (not shown).
If the determination of SM1 is denied, the process is suspended. If the determination is affirmed, the electrocardiogram waveform detected by the electrocardiography device 60 and the pressure Based on the pressure pulse wave detected by the pulse wave sensor 46, the propagation time Td is calculated for each beat.

Next, in SM3 corresponding to the estimated blood pressure value determining means 76, based on the actual propagation time Td from the correspondence shown in FIG. An estimated systolic blood pressure value EBP _SYS is determined. Further, in SM4 corresponding to the target pressure value determining means 78, based on the actual estimated systolic blood pressure EBP _SYS from the relationship shown in Equation 1 or Equation 2 is set in advance, the target pressure value P _M of the cuff 10 is determined Is done. Then, S corresponding to the cuff pressure control means 68
M5 to SM7 are executed.

[0026] First, the SM5, by air pump 18 is started and the switching valve 16 is a pressure supply state to allow supply of pressure to the cuff 10, the pressure P _C of the cuff 10 is raised rapidly . Then, the SM6, the pressure P _C of the cuff 10 whether exceeds the target pressure value P _M determined in the SM4 is determined. If the determination of SM6 is denied, rapid boosting is continued by repeatedly executing SM5 and subsequent steps. However, the cuff pressure P
If _C is increased beyond the above target pressure P _M, since the determination of SM6 is positive, the SM7, slow decreasing is started at a rate of about 3 mmHg / sec. T ₁ in FIG. 5 illustrates this point.

[0027] Then, the blood-pressure determining routine SM8 which corresponds to the blood pressure determining means 70 is executed for each occurrence of the pulse wave signal SM _1. In this SM8 blood pressure value determination routine,
Based on the change in the amplitude of the pulse wave represented by the pulse-wave signal SM _1, well-known oscillometric method systolic blood BP _SYS in accordance blood pressure determining algorithm, the mean blood pressure value B
P _{ME AN,} and with diastolic blood pressure BP _DIA are determined, such as pulse rate is determined based on the cuff pulse wave interval.
Subsequently, in SM9, whether or not the determination of the blood pressure value has been completed by executing the above SM8, that is, the systolic blood pressure value BP
_SYS, the average blood pressure value BP _{ME AN,} and the diastolic blood pressure value BP _DIA
Is determined. If the determination in SM9 is negative, the above SM7 and subsequent steps are repeatedly executed.

However, if the determination at SM9 is affirmative while the above SM7 and below are repeatedly executed, then at SM10, the systolic blood pressure value BP determined at SM8 is determined.
_SYS , mean blood pressure BP _MEAN , and diastolic blood pressure BP _DIA
After the display and the pulse rate are displayed on the display 32, the cuff pressure P _C is displayed in the SM11 corresponding to the cuff pressure control means 68.
Is set to the atmospheric pressure, and the compression of the living body by the cuff 10 is rapidly released.

Then, in SM12 corresponding to the propagation time blood pressure correspondence determination means 74, based on the systolic blood pressure BP _SYS determined in SM8 and the propagation time Td at that time, for the next blood pressure measurement, For example, the propagation time blood pressure correspondence shown in FIG. 3 is determined again.

As described above, according to the present embodiment, the estimated blood pressure value determining means 76 (SM3) uses the predetermined relationship based on the propagation time Td of the pulse wave propagating in the artery of the living body. the estimated blood pressure value EBP _SYS biological, the target pressure value determining means 78 (SM4), the target pressure value P _M on the basis of the estimated blood pressure value EBP _SYS determined by the estimated blood pressure value determining means 76 is determined, the blood pressure in the measurement, the cuff pressure P _C is then rapidly increased to reach this target pressure value P _M. Therefore, in the present embodiment, even if the blood pressure of the living body suddenly changes compared to the previous measurement, there is no relation to the change in the blood pressure value from the previous measurement,
Target pressure P _M of the pressure on the living body is appropriately determined.

Next, another embodiment of the present invention will be described. In the following description, the same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIGS. 7 and 8 are a functional block diagram showing a main part of the control function of the electronic control unit 28 and a flowchart showing a main part of the control operation of the electronic control unit 28 according to another embodiment of the present invention. As shown, the pulse wave transit time T
instead of d differs in that the pulse wave velocity V _P is used.

[0033] That is, in SM21 corresponding to the propagation velocity calculating means 82, pulse wave velocity V _P of the living body, dividing the preset value L corresponding to the distance from the heart to the wrist in the pulse wave propagation time Td It is calculated by: Then, the estimated the blood pressure determining means 86 corresponding to SM31, for example the actual pulse wave velocity V _P from the correspondence relationship between the previously obtained pulse-wave propagation velocity V _P and blood pressure values BP _SYS in such the previous blood pressure measurement Systolic blood pressure value EB based on
P _SYS is determined. Then, the target pressure value determining means 78
In corresponding SM4, based on the actual estimated systolic blood pressure EBP _SYS from the relationship shown in Equation 1 or Equation 2 is set in advance, the target pressure value P _M of the cuff 10 is determined. When the blood pressure measurement is completed, the SM8 corresponding to the propagation speed blood pressure correspondence relation determination means 84 is referred to as SM8.
Based on the determined systolic blood pressure BP _{SY S} and the pulse wave propagation velocity V _P of the time in, for the next blood pressure measurement,
For example, the propagation speed blood pressure correspondence shown in FIG. 9 is determined again. Also in this embodiment, even if the blood pressure of the living body is changed rapidly as compared with the previous measurement, no relation to the change of blood pressure from the previous measurement, the target pressure value P _M of the pressure on the living body properly It is determined.

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

For example, the propagation time calculation means 72 or the propagation velocity calculation means 82 of the above-described embodiment calculates the R
Although it was calculated based on the time difference Td from the wave to the rise of the pressure pulse wave detected from the radial artery, for example,
It may be calculated based on the time difference from the cuff pulse wave detected through the cuff 10 wound around the upper arm to the rise of the pressure pulse wave of the radial artery.

In addition, the target pressure value determining means 78 of the above-described embodiment determines the cuff 1 based on the actual estimated systolic blood pressure value EBP _SYS from the relationship shown in Equation 1 or Equation 2 set in advance.
Although the target pressure value P _M 0 has been determined, it may be calculated based such as the estimated mean blood pressure EBP _MEAN. In this case, α or β used in Expression 1 or Expression 2 is experimentally obtained in accordance with the use of the estimated average blood pressure value EBP _MEAN .

Further, the blood pressure determining means 70 of the above-described embodiment is used.
(SM8), which had been determined blood pressure value according to the oscillometric method, the systolic blood pressure value the cuff pressure P _C at the time of generation and extinction of Korotkoff sounds BP _SYS and the diastolic blood pressure value BP
_The blood pressure value may be determined according to the Korotkoff sound method as _DIA .

In addition, the present invention can be variously modified without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a blood pressure monitoring device 8 according to an embodiment of the present invention.

FIG. 2 is a diagram exemplifying a pressure pulse wave detected by a pressure pulse wave sensor 46 and an electrocardiographic waveform detected by an electrocardiographic lead device 60 in the embodiment of FIG.

FIG. 3 is a diagram exemplifying a correspondence determined by a propagation time blood pressure correspondence determination unit in the present embodiment.

FIG. 4 is a functional block diagram for explaining a main part of a control function of the electronic control device of the embodiment of FIG. 1;

FIG. 5 shows a blood pressure measurement performed by the electronic control device 28 of the embodiment shown in FIG. 1;
Cuff pressure P controlled during _CTime change
It is a chart.

FIG. 6 is a flowchart for explaining a main part of a control operation of the electronic control device of the embodiment of FIG. 1;

FIG. 7 is a functional block diagram illustrating a main part of a control function of an electronic control unit according to another embodiment of the present invention.
FIG.

8 is a flowchart for explaining a main part of a control operation of the electronic control unit 28 in the embodiment of FIG. 7, and is a diagram corresponding to FIG.

9 is a diagram exemplifying a correspondence determined by a propagation speed blood pressure correspondence determination unit in the embodiment of FIG. 7;

[Explanation of symbols]

 8: Automatic blood pressure measuring device 10: Cuff 70: Blood pressure determining means 72: Propagation time calculating means 74: Propagation time blood pressure correspondence relation determining means 76, 86: Estimated blood pressure value determining means 78: Target pressure value determining means 82: Propagation speed calculation Means 84: Propagation velocity blood pressure correspondence relation determination means

Claims (1)

[Claims] 1. A pulse synchronizing wave generated in a process of rapidly increasing a compression pressure of a cuff attached to a living body to a predetermined target pressure value, and thereafter gradually reducing the compression pressure of the cuff at a predetermined speed. An automatic blood pressure measurement device of a type that measures a blood pressure value of a living body based on a change, based on a propagation time or a pulse wave propagation velocity of a pulse wave propagating in an artery of the living body from a predetermined relationship. Estimated blood pressure value estimating means for estimating the blood pressure value, and target pressure value determining means for estimating the target pressure value based on the estimated blood pressure value determined by the estimated blood pressure value determining means. Automatic blood pressure measurement device.