JP2000000218A - Blood pressure monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blood pressure monitoring system capable of being easily mounted on a living body and accurately monitoring a blood pressure without putting burdens on the living body so much. SOLUTION: The amplitude Amp of photoelectric pulse waves detected by a photoelectric pulse wave sensor 40 is calculated in an amplitude calculation means 64, the fluctuation rate F of the amplitude Amp is calculated from a fluctuation range R and an average value Av between the prescribed beat numbers of the amplitude Amp in a fluctuation rate calculation means 72, and blood pressure measurement by a blood pressure measurement means 60 is operated in the case that the fluctuation rate F of the amplitude calculated by the fluctuation rate calculation means 72 exceeds a predetermined judgement reference value TH1 in a fluctuation rate abnormality judgement means 74. Thus, since the fluctuation of the blood pressure is continuously monitored without using a cuff 10, the execution of the blood pressure measurement by the cuff 10 in a short cycle for reducing the delay of blood pressure monitoring is dissolved, and thus, the burdens on the living body are reduced. Also, there is a merit that the photoelectric pulse wave sensor 40 can be mounted on the surface skin of the living body without many restrictions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blood pressure monitoring device for continuously monitoring the blood pressure of a living body based on the fluctuation of the amplitude of a peripheral pulse wave of the living body.

[0002]

2. Description of the Related Art A blood pressure monitoring device for monitoring a blood pressure value of a living body for a relatively long period of time has a cuff wound around a part of the living body, and the compression pressure of the cuff is changed to change the pressure of the body. Generally, the blood pressure measuring means for measuring the blood pressure value is automatically started at a predetermined cycle. This is because the blood pressure measurement value measured by the blood pressure measurement means using the cuff can be relatively reliable.

[0003] However, in the case of such an automatic blood pressure monitoring device, if the automatic start cycle is shortened in order to eliminate the delay in blood pressure monitoring, the frequency of pressing the cuff against the living body increases, so that a heavy burden is imposed on the living body. is there. In addition, when the frequency of compression by the cuff becomes extremely high, congestion may occur and an accurate blood pressure value may not be obtained.

Therefore, it is required that pulse wave propagation speed information such as the propagation time or propagation speed of a pulse wave propagating in an artery of a living body has a substantially proportional relationship with the blood pressure value BP (mmHg) of the living body within a predetermined range. Using the blood pressure value BP of the living body measured in advance and the pulse wave propagation velocity information, for example, EBP = α (D
T) + β (α is a negative value) or EBP = α
(V _M ) + β (where α is a positive value), the coefficients α and β in a relational expression are determined in advance, and the estimated blood pressure value is determined from the relational expression based on the sequentially detected propagation velocity information. There has been proposed a blood pressure monitoring device that monitors the blood pressure value of a living body by obtaining an EBP and activates blood pressure measurement by a cuff when the estimated blood pressure value EBP is abnormal. For example, this is the blood pressure monitoring device described in Japanese Patent Application Laid-Open No. Hei 10-43147 filed by the present applicant.

[0005]

However, when calculating the estimated blood pressure value from the pulse wave velocity information as described above, at least two places on the living body are required to calculate the pulse wave velocity information. Must be installed. For example, as a first pulse wave detection device, a plurality of electrodes for detecting a Q wave or an R wave in an electrocardiographic lead waveform corresponding to a timing at which blood in the heart starts to be pumped toward the aorta are provided on a predetermined body of the living body. And a photoelectric pulse wave detection probe for detecting a pulse wave transmitted to a peripheral artery is attached to a fingertip of a living body or the like as a second pulse wave detection device.
For this reason, the mounting of the pulse wave detection device on a living body is relatively troublesome, and the body movement of the living body during blood pressure monitoring is also limited.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object the purpose of being able to easily attach to a living body without imposing a great burden on the living body.
An object of the present invention is to provide a blood pressure monitoring device capable of accurately monitoring blood pressure.

The present inventor has conducted various studies on the background of the above circumstances, and as the blood pressure value decreases, the fluctuation of the amplitude of the volume pulse wave in the peripheral part of the living body, that is, the volume during a predetermined period or a predetermined number of beats, It was found that the variation or the amplitude fluctuation of the pulse wave became large. The present invention has been made based on such knowledge, and monitors changes in the blood pressure value of a living body based on fluctuations in the amplitude of the volume pulse wave to avoid blood pressure measurement by the cuff as much as possible. It is like that.

[0008]

That is, the gist of the present invention to achieve the above object is to measure a blood pressure value of a living body using a cuff that changes a pressure applied to a part of the living body. A blood pressure monitoring device comprising a blood pressure measurement unit, wherein the blood pressure measurement device activates the blood pressure measurement by the blood pressure measurement unit based on a change in the pulse wave of the living body exceeding a predetermined determination reference range, and (a) A plethysmogram detection device for detecting a plethysmogram in the peripheral part of the living body, and (b) amplitude calculating means for sequentially calculating the amplitude of the plethysmogram detected by the plethysmogram detection device, (c) Fluctuation value calculation means for calculating the fluctuation value of the amplitude calculated by the amplitude calculation means, (d)
A blood pressure measurement activation unit that activates blood pressure measurement by the blood pressure measurement unit based on a fluctuation value of the amplitude calculated by the fluctuation value calculation unit exceeding a predetermined determination reference range.

[0009]

Thus, the amplitude of the plethysmogram detected by the plethysmogram detecting device is calculated by the amplitude calculating means, and the fluctuation value of the amplitude calculated by the amplitude calculating means is calculated by the fluctuation calculating means. Is calculated, and the blood pressure measurement activation means activates the blood pressure measurement by the blood pressure measurement means based on the fact that the fluctuation value of the amplitude calculated by the fluctuation value calculation means exceeds a predetermined judgment reference range. Therefore, since the fluctuation of the blood pressure is continuously monitored without using the cuff, the blood pressure measurement by the cuff is not performed in a short cycle in order to reduce the delay of the blood pressure monitoring. Is reduced. Further, there is an advantage that the plethysmogram detection device can be mounted on the epidermis of a living body without much restriction.

[0010]

In another aspect of the present invention, preferably, the fluctuation value calculating means calculates a difference between a maximum value and a minimum value of the amplitude sequentially calculated by the amplitude calculating means during a predetermined period or a predetermined number of beats. The fluctuation value is calculated by dividing by the average value of the amplitude during the predetermined period or the predetermined number of beats. In this manner, as the fluctuation value, the ratio of the range of the amplitude variation between the predetermined period or the predetermined number of beats to the average value of the amplitude during the predetermined period or the predetermined number of beats is calculated. There is an advantage that a fluctuation value that is not affected by the mounting state of the device and individual differences is calculated.

Preferably, the fluctuation value calculating means calculates, as a fluctuation value, a variation coefficient of the amplitude sequentially calculated by the amplitude calculating means during a predetermined period or a predetermined number of beats. According to this configuration, since the variation coefficient represents the variation of the amplitude during the predetermined period or the predetermined number of beats as a relative degree of dispersion, the fluctuation coefficient is not affected by the mounting state of the volume pulse wave detection device and individual differences. There is an advantage that the value is calculated.

[0012]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block 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 includes a cuff 10 having a rubber bag in a cloth band-shaped bag and wound around a patient's upper arm 12, for example, and a cuff 10 connected to the cuff 10 through a pipe 20. It has a pressure sensor 14, a switching valve 16, and an air pump 18 connected thereto. 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 22.
And the pulse wave discrimination circuit 24. Static pressure filter circuit 22 includes a low pass filter, steady pressure or cuff pressure P _C to discriminate the cuff pressure signal SK representative of the in the cuff pressure signal SK to the A / D converter 2 is included in the pressure signal SP
6 to the electronic control unit 28.

The pulse wave discrimination circuit 24 includes a band pass filter, and a pulse wave signal SM which is a vibration component of the pressure signal SP.
₁ is discriminated in frequency and the pulse wave signal SM ₁ is supplied to the electronic control unit 28 via the A / D converter 29. The cuff pulse wave represented by the pulse wave signal SM ₁ is a pressure vibration wave, that is, a cuff pulse wave generated from a brachial artery (not shown) and transmitted to the cuff 10 in synchronization with the heartbeat of the patient. 14 and the pulse wave discrimination circuit 24 function as a cuff pulse wave sensor.

The electronic control unit 28 includes a CPU 30, R
The microcomputer 30 includes a so-called microcomputer having an OM 32, a RAM 34, an I / O port (not shown), and the like. The CPU 30 executes signal processing using a storage function of the RAM 34 according to a program stored in the ROM 32 in advance. Thus, a drive signal is output from the I / O port to control the switching valve 16 and the air pump 18 and to control the display contents of the display 36.

The photoelectric pulse wave sensor 40 functioning as a plethysmogram detecting device is configured in the same manner as that used for detecting a pulse in order to detect a plethysmogram (plethysmograph) of a peripheral blood vessel of a living body. In the housing 42 capable of accommodating a part of a living body such as a fingertip, red light or infrared light in a wavelength band that can be reflected by hemoglobin, preferably a wavelength of about 800 nm that is not affected by oxygen saturation. And a light receiving element 46 provided on the side of the housing 42 facing the light emitting element 44 and detecting light transmitted through a part of the living body. And outputs a photoelectric pulse wave signal SM ₂ corresponding to the blood volume in the capillary, and supplies the signal to the electronic control device 28 via the A / D converter 48. The photoplethysmographic signal SM ₂ is a signal that pulsates every beat and corresponds to the amount of hemoglobin in capillaries in the epidermis, that is, the blood volume.

FIG. 2 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 FIG. 2, the blood pressure measurement unit 60 starts blood pressure measurement at every preset blood pressure measurement period, and sets the compression pressure of the cuff 10 wound around the upper arm of the living body by the cuff pressure control unit 62 to a predetermined target pressure. pressure value P _CM (e.g., pressure values of about 180 mmHg) in the slow the buck period is caused to slow decreasing after that is rapidly raised to a rate of about 3 mmHg / sec, represented by the pulse-wave signal SM ₁ which is successively taken Systolic blood pressure value BP _SYS , mean blood pressure value BP using well-known oscillometric method based on changes in pulse wave amplitude
_MEAN , diastolic blood pressure BP _DIA, etc. are determined, and the determined systolic blood pressure BP _SYS , average blood pressure BP _MEAN , diastolic blood pressure BP _{DIA and the} like are displayed on the display 36.

The amplitude calculating means 64 includes the photoelectric pulse wave sensor 40
Calculates the amplitude intensity of volume pulse wave of peripheral blood vessels detected by
I do. Pulse wave signal output from the photoelectric pulse wave sensor 40
SM _TwoIs pulsating every beat as shown in FIG.
Therefore, the amplitude calculating means 64 calculates the rising point of the pulse wave.
a and the peak b of the pulse wave are detected, and the detected peak b
Pulse wave signal strength SM_TwoAnd pulse wave signal SM at rising point a
_TwoFrom the difference, the pulse wave amplitude Amp is calculated.

The amplitude storage means 66 sequentially stores the pulse wave amplitudes Amp sequentially calculated by the amplitude calculation means 64 in an amplitude storage area (not shown) of the RAM 34. The fluctuation range calculation means 68 calculates the maximum amplitude Amp _MAX and the minimum amplitude Amp of the amplitude Amp for a predetermined period or a predetermined number of beats including the latest pulse wave amplitude Amp from the pulse wave amplitude Amp stored in the amplitude storage area of the RAM 34. determining the amplitude Amp _MIN, the difference between the maximum amplitude Amp _MAX and the minimum amplitude Amp _MIN (Amp
_MAX− Amp _MIN ) is calculated as a variation in amplitude during a predetermined period or a predetermined number of beats, that is, a fluctuation range R. The amplitude Amp of the peripheral pulse wave calculated by the amplitude calculation means 64 changes every beat, and the variation of the amplitude Amp of the pulse wave during a predetermined period or a predetermined number of beats changes in relation to the blood pressure of the living body. However, the lower the blood pressure, the greater the variation in the amplitude Amp of the pulse wave. That is, the lower the blood pressure, the more unstable the amplitude Amp of the pulse wave. Therefore, the lower the blood pressure of the living body, the larger the fluctuation range R becomes.

The average value calculating means 70 outputs, from among the amplitudes Amp stored in the amplitude storage area of the RAM 34, the amplitude Am for the same predetermined period or the same number of beats as the fluctuation range calculating means 68.
An average value Av of p is calculated. The fluctuation rate calculation means 72
As shown in Expression 1, the fluctuation rate F (%) is calculated by dividing the fluctuation range R calculated by the fluctuation range calculation means 68 by the average value Av calculated by the average value calculation means 70. Since the fluctuation rate F functions as a value representing the fluctuation of the amplitude of the pulse wave, that is, the fluctuation value, in this embodiment, the fluctuation rate calculating means 72
Functions as the fluctuation value calculating means.

[0022]

## EQU1 ## F = R / Av

The fluctuation range R calculated by the fluctuation range calculating means 68 not only changes in relation to blood pressure, but also fluctuates due to fluctuations in factors affecting the absolute value of the pulse wave amplitude Amp. In other words, the fluctuation rate F calculated by the fluctuation rate calculating means 72 is calculated based on the fluctuation range R and the fluctuation range R, although the fluctuation varies depending on the part (wearing state) of the photoelectric pulse wave sensor 40 or individual differences. Since the ratio is converted into the ratio to the average value Av of the range, the influence of the mounting site of the photoelectric pulse wave sensor 40 or the individual difference is removed.

The fluctuation rate abnormality judging means 74 also functions as blood pressure measurement starting means, and judges an abnormality of the fluctuation rate F calculated by the fluctuation rate calculating means 72, and judges the abnormality of the fluctuation rate F. Based on this, the blood pressure measurement by the blood pressure measurement means 60 is started. That is, when the fluctuation rate F calculated by the fluctuation rate calculation means 72 exceeds a predetermined reference range, the abnormality of the fluctuation rate F is determined, and based on the determination that the abnormality of the fluctuation rate F is determined. The blood pressure measurement by the blood pressure measurement means 60 is started.

FIG. 4 is a flowchart for explaining the main control operation of the electronic control unit 28. Step SA1 of FIG. (Hereinafter omitted steps.) After the initial process of clearing the counter and register (not shown) in is executed in SA2, from the pulse wave signal SM ₂ supplied from the photoelectric pulse wave sensor 40, one It is determined whether the rising point a and the peak b of the pulse wave have been detected.

While the determination in SA2 is denied, S
A2 but is repeatedly executed, if affirmative been followed in SA3 corresponding to the amplitude calculating unit 64, the pulse wave signal SM ₂ detected peak b in SA2 intensity and peak a pulse wave signal SM ₂ Difference from intensity is pulse wave amplitude Amp
In SA4 corresponding to the following pulse wave amplitude storage means 66, the pulse wave amplitude Amp calculated in SA3 is calculated as RA
It is stored in an amplitude storage area (not shown) of M34.

S corresponding to the following fluctuation range calculating means 68
At A5, of the pulse wave amplitudes Amp sequentially stored in the amplitude storage area of the RAM 34, the amplitude A for a predetermined number of beats including the pulse wave amplitude Amp stored at SA4 in this routine.
The difference (Amp _MAX −Amp _MIN ) between the maximum amplitude Amp _MAX and the minimum amplitude Amp _{MIN of} mp is calculated as the fluctuation range R. The average value Av of the amplitude is calculated.

Next, S corresponding to the fluctuation rate calculating means 72
In A7, the fluctuation rate F is calculated by dividing the fluctuation range R calculated in SA5 by the average value Av of the amplitude calculated in SA6, that is, by the equation (1). FIG.
It is a figure explaining an example of the fluctuation of the fluctuation rate F which fluctuates according to the fluctuation of the blood pressure. As shown in FIG.
The fluctuation rate F sequentially calculated in 7 changes in accordance with the change in the blood pressure value BP. That is, the fluctuation rate F increases as the blood pressure value BP decreases.

[0029] In SA8 corresponding to the subsequent fluctuation rate abnormality determination unit 74, whether or not exceeds the determination reference value TH ₁ the calculated fluctuation rate F is determined experimentally in advance in SA7, i.e. fluctuation rate F is abnormal It is determined whether it is a value.
In the example shown in FIG. 5, before the time t ₁ , the fluctuation rate F does not exceed the determination reference value TH ₁ , so
The determination at A8 is denied. If the determination in SA8 is denied in such a manner, in subsequent SA9, the previous cuff 1
It is determined whether or not the elapsed time since the blood pressure measurement by 0 has been performed has passed a preset cycle of about 20 minutes, that is, a calibration cycle. When the determination at SA9 is denied, SA2 and subsequent steps are repeatedly executed.

However, if the above SA8 judgment is affirmed, for example, as shown at time t ₁ in FIG. 5, when the fluctuation rate F exceeds the judgment reference value TH ₁ , it corresponds to the blood pressure fluctuation. Since the fluctuation rate F fluctuating is an abnormal value, the blood pressure measurement using the cuff 10 is started in the SA 10 corresponding to the blood pressure measurement unit 60 after the character or symbol indicating the blood pressure abnormality is displayed on the display 36. The measured blood pressure value is displayed on the display 36. Also, SA9
Is determined, that is, when the calibration cycle has elapsed, SA10 is also executed.
After the execution of SA10, SA2 and subsequent steps are repeatedly executed.

As described above, according to the present embodiment, the amplitude Amp of the photoplethysmogram detected by the photoplethysmogram sensor 40 is calculated by the amplitude calculation means 64 (SA3), and the amplitude Amp is calculated for a predetermined number of beats. Fluctuation range R and average value Av
Is calculated by the fluctuation range calculation means 68 (SA5) and the average value calculation means 70 (SA6), and the fluctuation rate calculation means 7
2 (SA7), the fluctuation rate F of the amplitude Amp is calculated from the fluctuation range R and the average value Av, and the fluctuation rate abnormality determination means 74 (SA8) calculates the fluctuation rate
2 blood pressure measurement by the blood pressure measuring means 60 (SA10) when the fluctuation rate F of the calculated amplitude exceeds the determination reference value TH ₁ predetermined by (SA7) is allowed to start.
Therefore, since the fluctuation of the blood pressure is continuously monitored without using the cuff 10, the blood pressure measurement by the cuff 10 is prevented from being executed in a short cycle to reduce the delay of the blood pressure monitoring. Is reduced. In addition, there is an advantage that the photoelectric pulse wave sensor 40 can be mounted on the epidermis of a living body without much restriction.

Further, according to the present embodiment, the fluctuation rate calculating means 72 (SA8) determines the maximum value Am of the amplitude Amp sequentially calculated by the amplitude calculating means 64 (SA3) between the predetermined number of beats.
the difference between the p _{MA X} and the minimum value Amp _MIN (Amp _MAX -Amp
_MIN ), that is, the fluctuation rate F is calculated by dividing the fluctuation range R by the average value Av of the amplitude between the predetermined number of beats. Therefore, as the fluctuation value, the fluctuation range R of the amplitude between the predetermined number of beats is calculated. Since the fluctuation rate F, which is the ratio of the amplitude between the predetermined number of beats to the average value Av, is calculated, there is an advantage that a fluctuation value that is not affected by the mounting state of the photoelectric pulse wave sensor 40 and individual differences is calculated. .

Next, another embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, portions common to the above-described embodiments will be denoted by the same reference numerals and description thereof will be omitted.

FIG. 6 is a functional block diagram for explaining a main part of the blood pressure monitoring control operation of the electronic control unit 28 of the blood pressure monitoring device to which another embodiment of the present invention is applied. In the blood pressure monitoring device of this embodiment, the mechanism and circuit configuration of the device are common to those of the above-described embodiment of FIG. 1, and the blood pressure monitoring method by the electronic control device 28 is different. The functional block diagram shown in FIG. 6 differs from the functional block diagram shown in FIG. 2 in that the standard deviation calculation means 68, the fluctuation rate calculation means 72, and the fluctuation rate abnormality determination means 74 are used instead of the standard deviation calculation. Means 76,
Variation coefficient calculating means 78 and variation coefficient abnormality determining means 80
Is different from FIG. 2 described above. Less than,
The differences will be mainly described.

The standard deviation calculating means 76 includes the amplitude storing means 6
6, the standard deviation σ of the pulse wave amplitude Amp during a predetermined period including the latest pulse wave amplitude Amp or a predetermined number of beats is calculated from the pulse wave amplitude Amp stored in the amplitude storage area of the RAM 34. As described above, the lower the blood pressure, the more unstable the amplitude Amp of the pulse wave. Therefore, the standard deviation σ of the amplitude Amp of the pulse wave for a predetermined period or a predetermined number of beats increases as the blood pressure decreases.

The variation coefficient calculating means 78 calculates a variation coefficient CV (%) for a predetermined period or a predetermined number of beats. That is, the variation coefficient calculating means 78 calculates the standard deviation σ of the pulse wave amplitude Amp during a predetermined period or a predetermined number of beats calculated by the standard deviation calculating means 76, as shown in Expression 2.
The coefficient of variation CV (%) is calculated by dividing by the average value Av calculated by the average value calculating means 70. Since the variation coefficient CV functions as a value representing the fluctuation of the amplitude of the pulse wave, that is, the fluctuation value, in the present embodiment, the fluctuation coefficient calculating means 78 functions as the fluctuation value calculating means. Incidentally, the average value calculating means 70 of this embodiment is used.
Is calculated by the standard deviation calculating means 7.
6 is the average value Av of the pulse wave amplitudes during the same predetermined period or predetermined number of beats.

[0037]

## EQU2 ## CV = σ / Av

The standard deviation .sigma. Calculated by the standard deviation calculating means 76 not only changes in relation to blood pressure but also changes due to a change in a factor affecting the absolute value of the pulse wave amplitude Amp. That is, the photoelectric pulse wave sensor 4
The variation coefficient CV is represented by the ratio of the standard deviation σ to the average value Av. Or the effects of individual differences have been removed.

The variation coefficient abnormality determining means 80 also functions as blood pressure measurement starting means, and determines an abnormality of the variation coefficient CV calculated by the variation coefficient calculating means 78.
The blood pressure measurement by the blood pressure measurement means 60 is activated based on the determination that the variation coefficient CV is abnormal. That is, the variation coefficient C calculated by the variation coefficient calculating means 78
When V exceeds a predetermined reference range, abnormality of the variation coefficient CV is determined, and based on the determination of the abnormality of the variation coefficient CV, blood pressure measurement by the blood pressure measurement unit 60 is started.

FIG. 7 is a flowchart for explaining the main part of the blood pressure monitoring operation of the electronic control unit 28 of this embodiment. In the drawing, SB1 to SB4 represent SA1 of the above-described embodiment.
Through the same processing as in steps SA4 to SA4, the pulse wave amplitude Amp is calculated for each pulse wave, and the pulse wave amplitude A
mp is stored in an amplitude storage area (not shown) of the RAM 34.

SB corresponding to the subsequent standard deviation calculating means 76
At 5, in the pulse wave amplitude Amp sequentially stored in the amplitude storage area of the RAM 34, the amplitude Am between a predetermined number of beats including the pulse wave amplitude Amp stored in SB4 of the current routine.
The standard deviation σ of p is calculated, and in SB6 corresponding to the subsequent average value calculating means 70, the average value Av of the amplitude over the same predetermined number of beats as in SB5 is calculated.

SB corresponding to the following variation coefficient calculating means 78
In step 7, the standard deviation σ calculated in step SB5 is divided by the average value Av of the amplitude calculated in step SB6, that is, the variation coefficient CV is calculated according to the equation (2). Then, it is determined whether or not the variation coefficient CV calculated in SB7 has exceeded a criterion range experimentally determined in advance, that is, whether or not the variation coefficient CV is an abnormal value.

If the determination in SB8 is negative, in SB9, the elapsed time since the blood pressure measurement was performed by the cuff 10 last time has passed the preset cycle of about 20 minutes, that is, the calibration cycle. Is determined. If the determination at SB9 is negative, S
B2 and subsequent steps are repeatedly executed.

However, if the SB8 determination is affirmative, the variation coefficient CV that varies in response to the blood pressure variation is an abnormal value, so that a character or symbol indicating an abnormal blood pressure is displayed on the display 36. After that, the blood pressure measurement using the cuff 10 is started in the SB 10 corresponding to the blood pressure measurement means 60, and the measured blood pressure value is displayed on the display 36.
Also, when the determination in SB9 is affirmed, that is, when the calibration cycle has elapsed, the above SB10 is executed. After the execution of SB10, the above SB2 and subsequent steps are repeatedly executed.

As described above, according to the present embodiment, the amplitude Amp of the photoelectric pulse wave detected by the photoelectric pulse wave sensor 40 is calculated by the amplitude calculating means 64 (SB3), and the variation coefficient calculating means 78 (SB7) In the amplitude calculation means 64
The variation coefficient CV between the predetermined number of beats of the amplitude Amp calculated in (SB3) is calculated, and the variation coefficient abnormality determination means 80 (SB
In 8), when the variation coefficient CV between the predetermined number of beats calculated by the variation coefficient calculating means 78 (SB7) exceeds a predetermined judgment reference range, the blood pressure measuring means 60 (SB10)
Blood pressure measurement is activated. Therefore, since the change in blood pressure is continuously monitored without using the cuff 10,
Since the blood pressure measurement by the cuff 10 is not performed in a short cycle in order to reduce the delay in blood pressure monitoring, the burden on the living body is reduced.

Further, according to the present embodiment, the variation coefficient calculating means 78 (SB8) calculates the variation coefficient C for a predetermined number of beats of the amplitude Amp sequentially calculated by the amplitude calculating means 64 (SB3).
V is calculated as a fluctuation value, and the variation coefficient CV
Represents the variation of the amplitude Amp between the predetermined number of beats as a relative variance. Therefore, there is an advantage that a fluctuation value which is not affected by the mounting state of the photoelectric pulse wave sensor 40 and an individual difference is calculated.

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

For example, in the above-described embodiment, the photoelectric pulse wave sensor 40 was used as the volume pulse wave detecting device. However, the photoelectric pulse wave detecting probe for measuring the oxygen saturation or a predetermined distance from the skin of the living body. An impedance pulse wave sensor that includes at least two electrodes that are in contact with each other and outputs an impedance pulse wave corresponding to the blood volume of the living tissue located between the two electrodes may be used.

Further, in the above-described embodiment, the blood pressure measuring means 60 is determined every predetermined blood pressure measuring cycle and when the fluctuation rate abnormality determining means 74 or the variation coefficient abnormality determining means 80 determines that the blood pressure measurement is to be started. Is performed, but the blood pressure measurement is not performed for each of the above-described blood pressure measurement cycles, and only when the fluctuation rate abnormality determination unit 74 or the variation coefficient abnormality determination unit 80 determines that the blood pressure measurement is started. The blood pressure measurement by the blood pressure measurement means 60 may be executed.

Further, the blood pressure measuring means 60 of the above-described embodiment is used.
Is configured to determine the blood pressure value based on a change state of the magnitude of the pressure pulse wave that changes according to the compression pressure of the cuff 10 according to the so-called oscillometric method, but according to the so-called Korotkoff sound method, The blood pressure value may be determined based on the Korotkoff sound that is generated and disappears according to the compression pressure of 10.

Further, the fluctuation rate abnormality of the first embodiment described above.
In SA8 corresponding to the determination means 74, the fluctuation rate F is set in advance.
The set reference value TH₁Only if it exceeds
It was determined that the failure rate F was abnormal. That is, the criteria
In the box, the lower limit is not set and only the upper limit is the judgment reference value.
TH₁Has been set as the reference value TH. ₁
Or its criterion value TH₁Judgment instead of
The lower limit of the reference range is set, and it is determined that the fluctuation rate F is abnormal.
May be specified. Also, the other embodiments described above
Also, only the upper or lower limit of the
Is set to determine whether the variation coefficient CV is abnormal.
You may.

In the first embodiment, when the fluctuation rate abnormality judging means 74 determines that the fluctuation rate R is converted into a ratio to the average value Av of the pulse wave, the fluctuation rate F is judged to be abnormal. Although the blood pressure measurement by the measuring means 60 has been activated, the fluctuation range R also indicates the variation in the amplitude of the volume pulse wave during a predetermined period or a predetermined number of beats.
That is, since it represents the fluctuation value, an abnormality in the fluctuation range R may be determined based on the fact that the fluctuation range R exceeds a predetermined range, and blood pressure measurement may be started.

In the above-described other embodiment, the variation coefficient abnormality judging means 80 sets the standard deviation σ to the average value A of the pulse wave.
The blood pressure measurement by the blood pressure measurement means 60 has been activated when it is determined that the variation coefficient CV converted to a ratio with respect to v is abnormal. Since the standard deviation σ exceeds the predetermined range, the abnormality of the standard deviation σ is determined and the blood pressure measurement is started. You may be made to.

Further, in the above-described embodiment, the fluctuation rate abnormality judging means 74 functioning as a blood pressure measurement starting means at every beat.
(SA8) or variation coefficient abnormality determination means 80 (SB8)
In the above, it was determined whether or not to start the blood pressure measurement. However, the start of the blood pressure measurement may be determined for every predetermined number of beats of two or more.

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 showing a configuration of a blood pressure monitoring device according to one embodiment of the present invention.

FIG. 2 is a functional block diagram illustrating a main part of a control function of the electronic control device of the embodiment of FIG. 1;

FIG. 3 is a diagram illustrating a photoelectric pulse wave detected by the photoelectric pulse wave sensor of the embodiment of FIG.

FIG. 4 is a flowchart illustrating a main part of a control operation of the electronic control device according to the embodiment of FIG. 1;

FIG. 5 is a diagram illustrating an example of a fluctuation in a fluctuation rate F that fluctuates in response to a fluctuation in blood pressure.

FIG. 6 is a functional block diagram illustrating a main part of a control function of an electronic control device according to another embodiment of the present invention.

FIG. 7 is a flowchart illustrating a main part of a control operation of the electronic control device according to the embodiment of FIG. 6;

[Description of sign]

 8: Blood pressure monitoring device 40: Photoplethysmographic sensor (volumetric pulse wave detecting device) 60: Blood pressure measuring means 64: Amplitude calculating means 68: Fluctuation range calculating means 72: Fluctuation rate calculating means (fluctuation value calculating means) 74: Fluctuation rate Abnormality determination means (blood pressure measurement activation means) 76: Standard deviation calculation means 78: Variation coefficient calculation means (fluctuation value calculation means) 80: Variation coefficient abnormality determination means (blood pressure measurement activation means)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihiro Yokoseki 2007-1 Kobayashi-shi, Aichi Prefecture, Japan Korin Co., Ltd. F-term (reference) 4C017 AA08 AA09 AB01 AB03 AC03 AC27 AD01 BC11 BD05 BD06 CC01 DD11 FF08

Claims (1)

[Claims] 1. A blood pressure measuring means for measuring a blood pressure value of a living body using a cuff for changing a compression pressure on a part of the living body, wherein a variation of a pulse wave of the living body is set to a predetermined reference range. A blood pressure monitoring device that activates blood pressure measurement by the blood pressure measurement means based on the detection of a volume pulse wave, wherein the volume pulse wave detection device detects a volume pulse wave in a peripheral portion of the living body, and the volume pulse wave detection device. Amplitude calculating means for sequentially calculating the amplitude of the plethysmogram detected by the above; a fluctuation value calculating means for calculating a fluctuation value of the amplitude calculated by the amplitude calculating means; and an amplitude calculating section for calculating the amplitude value calculated by the fluctuation value calculating means. A blood pressure measurement activation unit that activates blood pressure measurement by the blood pressure measurement unit based on a fluctuation value exceeding a predetermined determination reference range.