JPH11299750A - Blood pressure monitor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blood pressure monitor device which can monitor changes in blood pressure continuously without loading an organism excessively with burder and without limitting attachment to the organism. SOLUTION: Changes in pulse wave area caused by a change in heart beat are compensated at a pulse wave area compensation means 78 by the heart rate, and changes in lowering time caused by a change in heart beat are compensated at a peripheral resistance information compensation means 82 by the heart rate. When either of the compensated pulse wave area or the compensated lowering time exceeds the range of a specified criteria, a blood pressure measuring means 70 starts to measure blood pressure by a blood pressure measurement start means 84. Changes in blood pressure are continuously monitored without using a cuff and when the cuff is used to measure the blood pressure can accurately and securely determined, so there is no need to measure the blood pressure using the cuff with a short cycle not to delay the blood pressure monitoring, resulting in reducing the burden on an organism.

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 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 living 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.

On the other hand, a blood pressure measuring means for changing a compression pressure of a cuff attached to a living body, and measuring a blood pressure value of the living body based on a change of a pulse synchronizing wave generated in a process of changing the compression pressure; A pressure pulse wave sensor for detecting a pressure pulse wave generated by the artery of the living body when pressed by the artery, and a pressure pulse wave detected by the pressure pulse wave sensor by activating the blood pressure measuring means at a predetermined cycle. A pressure pulse wave blood pressure correspondence relationship determining means for determining a pressure pulse wave blood pressure correspondence relationship between the size of the blood pressure value and the blood pressure value measured by the blood pressure measurement means,
A blood pressure monitoring device including monitoring blood pressure value determining means for sequentially determining a monitoring blood pressure value based on an actual pressure pulse wave based on the pressure pulse wave blood pressure correspondence has been proposed. According to this, there is an advantage that a monitored blood pressure value is obtained for each beat, and a delay in blood pressure monitoring is eliminated. For example, a blood pressure monitoring device described in Japanese Patent Application Laid-Open No. 2-177937 is an example.

[0005]

However, according to the above-mentioned blood pressure monitor, the pressure pulse wave sensor is stably pressed from above the epidermis toward the artery in order to detect the pressure pulse wave generated from the artery of the living body. Is necessary, the place where the pressure pulse wave sensor is pressed is limited to the place where the artery is located just below the epidermis such as the wrist, so it may not be used depending on the diseased part of the living body, or a band etc. Even if the pressure pulse wave sensor is fixed to a living body by using the pressure pulse wave signal, the pressure pulse wave signal shifts due to the movement of the living body and the like, so that there is a problem that accurate monitoring may not be performed.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to place a burden on a living body without much burden and without restricting wearing on the living body.
An object of the present invention is to provide a blood pressure monitoring device capable of continuously monitoring a change in blood pressure.

The inventor of the present invention has conducted various studies on the background described above, and has found that the blood flow rate in the peripheral part of the living body changes in close relation to the change in the blood pressure value of the living body. The present invention has been made based on such findings, and has a peripheral blood flow (peripheral blood flow) or a peripheral blood flow obtained from a plethysmogram indicating a periodic change in the peripheral blood volume. Fluctuations in the blood pressure value of the living body are monitored based on the resistance, and blood pressure measurement by the cuff is avoided as much as possible.

[0008]

The first aspect of the present invention for achieving the above object is as follows.
A blood pressure measurement unit that measures a blood pressure value of the living body using a cuff that changes a compression pressure on a part of the living body, based on a change in a pulse wave of the living body exceeding a predetermined determination reference range. A blood pressure monitoring device that activates blood pressure measurement by the blood pressure measurement means, wherein (a) a plethysmogram detection device that detects a plethysmogram in a peripheral portion of the living body; and (b)
Pulse wave area calculating means for calculating the area of the volume pulse wave detected by the volume pulse wave detecting device; and (c) the blood pressure measuring means based on the fluctuation of the pulse wave area calculated by the pulse wave area calculating means. And a blood pressure measurement starting means for starting blood pressure measurement according to the present invention.

[0009]

According to the first aspect of the present invention, the peripheral blood flow which fluctuates in accordance with the fluctuation of the blood pressure is obtained by calculating the area of the volume pulse wave, and based on the fluctuation of the pulse wave area. Then, the blood pressure measurement by the blood pressure measurement means is activated by the blood pressure measurement activation means. 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]

A second aspect of the present invention to achieve the above-mentioned object is that a cuff for changing a pressure applied to a part of a living body is used for the living body. A blood pressure monitoring device of a type comprising a blood pressure measuring means for measuring a blood pressure value, wherein a blood pressure measurement by the blood pressure measuring means is started based on a fluctuation of a pulse wave of the living body exceeding a predetermined judgment reference range. (A) a plethysmogram detecting device for detecting a plethysmogram in a peripheral part of the living body; and (b) a plethysmogram detected by the plethysmogram detecting device varies in relation to peripheral vascular resistance. A peripheral resistance information calculating means for calculating the peripheral resistance information; and (c) a blood pressure measurement activating means for activating the blood pressure measurement by the blood pressure measuring means based on the fluctuation of the peripheral resistance information calculated by the peripheral resistance information calculating means. , Including A.

[0011]

In this way, the peripheral vascular resistance that fluctuates in response to the change in blood pressure can be obtained by calculating the peripheral resistance information from the plethysmogram. Based on this, the blood pressure measurement by the blood pressure measurement means is started by the blood pressure measurement start means. 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.

Here, preferably, the blood pressure monitoring device comprises:
A heartbeat information calculation unit that calculates the heartbeat information of the living body, and a pulse wave area correction unit that corrects the pulse wave area based on the heartbeat information, wherein the blood pressure measurement activation unit includes a pulse wave area correction unit. The blood pressure measurement by the blood pressure measurement means is started based on a change in the corrected corrected pulse wave area or its change value. In this way, the pulse wave area fluctuation due to the heartbeat fluctuation is corrected by the pulse wave area correction means, and the activation of the blood pressure measurement is determined based on the corrected pulse wave area or the change value thereof. Therefore, there is an advantage that it is possible to more accurately determine when to start the blood pressure measurement using the cuff.

Preferably, the blood pressure measurement starting means includes heart rate information calculating means for calculating heart rate information of the living body, and peripheral resistance information correcting means for correcting the peripheral resistance information based on the heart rate information. Starts the blood pressure measurement by the blood pressure measuring means based on the corrected peripheral resistance information corrected by the peripheral resistance information correcting means or the change value thereof. According to this configuration, the fluctuation of the peripheral resistance information due to the fluctuation of the heart rate is corrected by the peripheral resistance information correcting means, and the activation of the blood pressure measurement is determined based on the corrected peripheral resistance information or the change value thereof. Therefore, there is an advantage that it is possible to more accurately determine when to start the blood pressure measurement using the cuff.

[0014] Preferably, the blood pressure measurement starting means changes at least one of the corrected pulse wave area, the change value of the corrected pulse wave area, the corrected peripheral resistance information, or the change value of the peripheral resistance information. Based on the determination, the blood pressure measurement by the blood pressure measurement means is started. With this configuration, when it is determined that at least one of the corrected pulse wave area or its change value or the corrected peripheral resistance information or its change value has changed, blood pressure measurement is started, and thus blood pressure measurement is started. It has the advantage of being more reliably activated.

[0015]

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 which has a rubber bag in a cloth band-shaped bag and is wound around, for example, an upper arm 12 of a patient, and the cuff 10 is connected to the cuff 10 via 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 apparatus 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. Since the photoelectric pulse wave signal SM ₂ is a signal that pulsates every beat in accordance with the amount of hemoglobin in the peripheral capillaries, that is, the blood volume, the photoelectric pulse wave sensor 40 detects a heartbeat signal of a living body. It also functions as a heartbeat signal detection device.

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 70 starts the blood pressure measurement at every preset blood pressure measurement cycle, and sets the compression pressure of the cuff 10 wound around the upper arm of the living body by the cuff pressure control unit 72 to a predetermined target. 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 pulse wave area calculating means 74 is a photoelectric pulse wave sensor.
Calculates the area of plethysmogram of peripheral blood vessels detected by 40
I do. Pulse wave signal output from the photoelectric pulse wave sensor 40
SM _TwoIs pulsating every beat as shown in FIG.
Therefore, the pulse wave area calculating means 74 calculates, for example,
Signal SM_TwoThe intensity of the beat every beat or two or more beats
Pulse wave area A representing peripheral blood flow by integrating every number
Is calculated. Alternatively, as indicated by a predetermined broken line B
Area exceeding a certain reference value,
The rising of the next peak from the rising point of the peak
The area of the area surrounded by the line connecting the points and the pulse wave is every beat
Alternatively, it is calculated at every predetermined number of beats of two or more beats.
The area of the fluctuation component of the pulse wave may be mainly calculated.
Since the above peripheral blood flow changes in response to blood pressure fluctuations,
The pulse wave area A changes according to the blood pressure fluctuation.

The heart rate information calculating means 76 generates heart rate information relating to the heart rate of the living body from the heart rate signal detected by the heart rate signal detecting device, that is, heart rate cycle TP, heart rate PR, pulse rate T
Calculate M, pulse rate MR, and the like. For example, the pulse wave sensor 4
Apart peak interval example between a predetermined portion of the resultant pulse waves from the photoelectric pulse-wave signal SM ₂ detected is measured by 0, inverse of ie cardiac cycle TP of the peak interval (1 /
TP) to obtain a heart rate PR (times / times) for one minute.
Minute).

The pulse wave area correcting means 78 calculates the peripheral pulse wave area A calculated by the pulse wave area calculating means 74 on the basis of the heart rate information calculated by the heart rate information calculating means 76. Normalize or correct to represent the flow rate. For example, the product of the heart rate PR calculated in the one heartbeat pulse wave area A and heartbeat information calculating unit 76 of the pulse wave signal SM ₂ calculated in pulse-wave area calculating means 74 as a correction pulse wave area A ' decide. The pulse wave area A fluctuates according to the blood pressure fluctuation, but also fluctuates when the heart rate fluctuates. For example, when the heart rate PR increases, that is, the heartbeat period TP decreases, the pulse wave area A for each beat decreases. However, since the heart rate PR is increasing, the blood flow in the peripheral blood vessels is not always decreasing. If the blood flow in the peripheral blood vessels has not decreased, it can be expected that the blood circulation volume has not decreased, so that blood pressure measurement by the cuff 10 is not required. Thus, a product of the pulse wave area A and the heart rate PR is obtained to calculate a corrected pulse wave area A 'representing the blood flow per minute.

As shown in FIG. 3, generally a single pulse wave
There is a minimum value D called a notch, and the minimum value D
Before the first peak top P₁, After the minimum D
2 Peak Top P_TwoThere is. 2nd peak top P_TwoNoah
Is a reflected wave due to an obstacle (resistance) in the blood vessel,
The greater the vascular resistance, the greater the reflected wave,
Chi second peak top P_TwoMountain with a bigger. That
First peak top P₁Period from to the minimum value D
R_time defined as the interval or falling period TR
Becomes shorter as the peripheral vascular resistance R increases,
It becomes longer as the tube resistance R becomes smaller. In addition, peripheral blood vessels
Since anti-R fluctuates in response to fluctuations in blood pressure,
The interval TR also reflects the change in blood pressure. Peripheral resistance information calculation means
80 is the volume pulse wave detecting device (photoplethysmographic sensor 40)
Vascular resistance R from the peripheral plethysmogram detected by
Peripheral resistance information that fluctuates in relation to
Measure TR. That is, the output from the photoelectric pulse wave sensor 40 is
Photoelectric pulse wave signal SM input _TwoThe first peak for each pulse wave
Cuptop P₁Is measured from the falling period TR to the minimum value D
Set.

The peripheral resistance information correcting means 82 converts the peripheral resistance information such as the descending period TR calculated by the peripheral resistance information calculating means 80 into a heartbeat signal detected by the heartbeat signal detecting device (photoelectric pulse wave sensor 40). The correction or normalization is performed based on the correction. For example, the product of the falling period TR and the heart rate PR calculated by the heart rate information calculating means 76 is determined as the corrected falling period TR '. The falling period TR fluctuates according to the fluctuation of the blood pressure, but also fluctuates when the heart rate fluctuates. For example, the heart rate PR increases,
That is, when the heartbeat period TP becomes shorter, the falling period TR for each beat becomes shorter. In this case, the falling period TR is shortened irrespective of the increase in the peripheral vascular resistance R. Therefore, the product of the falling period TR and the heart rate PR is obtained to calculate the corrected falling period TR ′ excluding the influence of the fluctuation of the heart rate PR.

The blood pressure measurement activating means 84, based on the determination that at least one of the corrected pulse wave area A 'and the corrected falling period TR' has changed, has been determined.
Activate blood pressure measurement by 0. That is, the blood pressure measurement activation unit 84 determines that the corrected pulse wave area A ′ corrected by the pulse wave area correction unit 78 is a predetermined reference range, for example, a moving average value A ′ _AV [= (( A ' _in
+... + A ′ _i−1 + A ′ _i ) / (n + 1)] or corrected pulse wave area abnormality determination means 86 which determines an abnormality based on a change in a predetermined value or a predetermined ratio from the previous blood pressure measurement by the cuff. And peripheral resistance information correcting means 82
The corrected falling period TR ′ corrected by the above is a predetermined reference range, for example, the moving average value TR ′ _AV [= (TR ′ _in +... + TR ′ _i−1 + T) of the corrected falling period TR ′.
R ′ _i ) / (n + 1)] or corrected peripheral resistance information abnormality determining means 88 for determining abnormality based on a change in a predetermined value or a predetermined ratio from the blood pressure measurement by the previous cuff, and the corrected pulse wave area abnormality The determination unit 86 determines whether the corrected pulse wave area A ′ is abnormal, or the corrected peripheral resistance information abnormality determination unit 88 determines the correction falling period T.
If it is determined that R ′ is abnormal, the blood pressure measurement unit 70
Activate blood pressure measurement by.

FIG. 4 shows the control operation of the electronic control unit 28.
6 is a flowchart for explaining the main part of FIG. Figure steps
This is illustrated in SA1 (hereinafter, steps are omitted).
No initial processing is performed to clear any counters or registers.
After that, in SA2 corresponding to the pulse wave area calculation means 74,
The photoelectric pulse wave signal SM output from the photoelectric pulse wave sensor 40 _Two
The pulse wave area A for each beat is calculated by integrating the intensity of
In SA3 corresponding to the peripheral resistance information calculating means 80, the photoelectric
Pulse wave signal SM_TwoThe first peak toe of the pulse wave obtained from
P₁From the minimum value D to the minimum value D every beat
Measured.

SA corresponding to the following heart rate information calculating means 76
In step 4, the peak interval of the pulse wave detected by the pulse wave sensor 40 is measured, and the reciprocal of the peak interval, that is, the reciprocal (1 / TP) of the heartbeat period TP is calculated to calculate the heart rate PR for one minute. .

SA corresponding to the following pulse wave area correction means 78
In step 5, in order to normalize the pulse wave area A affected by the heart rate information, the product of the pulse wave area A for each beat calculated in SA2 and the heart rate PR calculated in SA4 (A ×
PR), the corrected pulse wave area A ′ representing the blood flow per minute is determined.

Next, at SA6 corresponding to the peripheral resistance information correcting means 82, the product (TR × PR) of the falling period TR for each pulse wave measured at SA3 and the heart rate PR calculated at SA4 is obtained. The heart rate P
The corrected fall period TR ′ in which the influence of the fluctuation of R is removed is determined.

Subsequently, SA7 to SA8 corresponding to the blood pressure measurement starting means 84 are executed. That is, in SA7 corresponding to the corrected pulse wave area abnormality determining means 86, it is determined whether or not the corrected pulse wave area A 'determined in SA5 is abnormal, for example, based on the previous blood pressure measurement by the cuff and a predetermined value. Alternatively, the determination is made based on the fact that the state changed by a predetermined ratio (for example, up and down 5%) continuously exceeds a predetermined number of beats, for example, 20 or more.

If the determination at SA7 is negative,
SA8 corresponding to the corrected peripheral resistance information abnormality determining means 88 is executed. That is, whether or not the corrected falling period TR ′ determined in SA6 is abnormal is determined by, for example, a state in which the value has changed by a predetermined value or a predetermined ratio (for example, up and down 10%) from the previous blood pressure measurement by the cuff. The determination is made based on the number of consecutive beats exceeding a predetermined number of beats, for example, 20 or more.

If the determination in SA8 is negative, in SA9, the elapsed time since the blood pressure was measured 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 SA9 is denied, S
A2 and subsequent steps are repeatedly executed.

When the judgment at SA7 or SA8 is affirmative, the corrected pulse wave area A 'or the corrected fall period TR' that fluctuates in response to the blood pressure fluctuation is an abnormal value, indicating an abnormal blood pressure. After the characters or symbols are displayed on the display 36, the blood pressure measurement using the cuff 10 is started in SA10, and the measured blood pressure value is displayed on the display 36. Also, when the determination in SA9 is affirmed, that is, when the calibration cycle has elapsed, SA10 is also executed. After SA10 is executed,
SA2 and subsequent steps are repeatedly executed.

As described above, according to this embodiment, based on the fact that at least one of the peripheral pulse wave area A and the pulse wave falling period TR that fluctuate in response to the fluctuation of blood pressure fluctuates. Blood pressure measurement means 7 by blood pressure measurement activation means 84
A blood pressure measurement with 0 is activated. That is, the fluctuation of the pulse wave area A due to the fluctuation of the heartbeat is determined by the pulse wave area correcting means 78.
In (SA5), the fluctuation of the falling period TR due to the fluctuation of the heartbeat is corrected by the heart rate PR in the peripheral resistance information correction means 82 (SA6), and the corrected pulse wave area A ′ and the correction are corrected. Falling period T
If at least one of R ′ exceeds a predetermined judgment reference range, the blood pressure measurement activation unit 84 (SA7, SA
The blood pressure measurement by the blood pressure measurement means 70 (SA10) is started by 8). Therefore, the fluctuation of the blood pressure is continuously monitored without using the cuff, and the start time of the blood pressure measurement by the cuff is accurately and reliably determined. Therefore, the blood pressure measurement by the cuff is performed in order to reduce the delay of the blood pressure monitoring. Since the execution in a short cycle is eliminated, the burden on the living body 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.

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. 5 is a block diagram illustrating a circuit configuration of a blood pressure monitoring device 89 to which the present invention is applied. In the blood pressure monitoring device 89, a part for measuring blood pressure using a cuff is common to the blood pressure monitoring device 8 of the above-described embodiment, but a device for detecting a volume pulse wave is different. Hereinafter, the difference will be mainly described.

The pulse oximeter photoelectric pulse wave detection probe 90 (hereinafter, simply referred to as a probe) functions as a volume pulse wave detection device for detecting a volume pulse wave of a capillary blood vessel. The probe 90 is attached, for example, in close contact with a body surface 38 such as a patient's forehead by a not-shown attachment band or the like. The probe 90 includes a container-like housing 92 that opens in one direction, and the housing 9.
2 is provided at a portion located on the outer peripheral side of the inner surface of the bottom of LE2.
D and a plurality of first light-emitting elements 94a and second light-emitting elements 94b (hereinafter, simply referred to as light-emitting elements 94 unless otherwise specified) and a central portion of the bottom inner surface of the housing 92, and a photodiode or a phototransistor. A transparent resin 98 provided integrally with the housing 92 to cover the light emitting element 94 and the light receiving element 96; and a light emitting element 94 in the housing 92.
Between the light emitting element 94 and the light receiving element 96.
And a ring-shaped shielding member 100 that shields reflected light from the light-receiving element 96 toward the light-receiving element 96.

The first light emitting element 94a is, for example, 660
The second light emitting element 94b emits red light having a wavelength of about
Emits infrared light having a wavelength of about 800 nm, for example. The first light emitting element 94a and the second light emitting element 94b emit light alternately at a predetermined frequency for a fixed time according to a driving current from the driving circuit 101, and are irradiated from the light emitting elements 94 toward the body surface 38. The reflected light from the portion of the body where the capillaries are densely packed is received by the common light receiving element 96. Note that the wavelength of light emitted from the light emitting element 44 is not limited to the above value, and the first light emitting element 94a emits light having a wavelength at which the absorption coefficient between oxygenated hemoglobin and oxygen-free hemoglobin is significantly different from each other. May be any as long as they emit light having wavelengths at which their extinction coefficients are substantially the same, that is, light having wavelengths reflected by oxygenated hemoglobin and anoxicized hemoglobin.

The light receiving element 96 outputs a photoelectric pulse wave signal SM ₃ having a magnitude corresponding to the amount of received light via the low-pass filter 102. Light receiving element 96 and low-pass filter 10
An amplifier and the like are appropriately provided between the first and second circuits. Low pass filter 102 removes noise from the photoelectric pulse-wave signal SM ₃ input has a higher frequency than the frequency of the pulse wave,
And it outputs a signal SM ₃ whose noise is removed in the de-multiplexer 104. Since the photoelectric pulse wave represented by the photoelectric pulse wave signal SM ₃ is a volume pulse wave generated in synchronization with the pulse wave of the living body, the probe 90 also functions as a heartbeat signal detecting device for detecting a heartbeat signal of the living body. ing.

The demultiplexer 104 controls the first light emitting element 94a and the second light emitting element 94a in accordance with a signal from the electronic control unit 28.
By being switched in synchronization with the light emission of the light emitting element 94b, the electric signal SM _R based on the red light is transmitted through the sample hold circuit 106 and the A / D converter 109, and the electric signal SM _IR based on the infrared light is transmitted through the sample hold circuit 108. And an A / D converter 110 to sequentially supply them to an I / O port (not shown) of the electronic controller 112 for measuring oxygen saturation. Sample hold circuits 106 and 108
When sequentially outputting the input electric signals SM _R and SM _IR to the A / D converters 109 and 110, the A / D converters 109 and 1 for the previously output electric signals SM _R and SM _IR
The electric signals SM _R and SM _IR to be output next are held until the conversion operation at 10 is completed.

The CPU 30 of the electronic control unit 28 has a RAM
The measurement operation is performed according to a program stored in the ROM 32 in advance while utilizing the storage function of the drive circuit 34.
1 to output the control signal SLV to the light emitting elements 94a and 94b.
While for sequentially for a predetermined time increments emission at a predetermined frequency, their light-emitting element 94a, by switching the demultiplexer 104 outputs a switching signal SC in synchronization with the emission of 94b, the electric signal SM _R sample and hold circuit 106 And the electric signal SM _IR into the sample and hold circuit 10
8 each.

I / O (not shown) of the electronic control unit 28
Electrical signal SM from port_R, SM_IRWhen supplied sequentially,
The CPU 30 reserves a value for calculating the blood oxygen saturation.
From the stored arithmetic expression, the electric signal SM_R, SM_IRof
Calculates and displays the blood oxygen saturation of the living body based on the amplitude value
While the electric signal SM_R, SM _IR
Represents the blood pressure based on the plethysmogram as shown in FIG.
Changes are monitored. The method for determining the oxygen saturation and
For example, the applicant has filed and published a
Utilization of the determination method described in JP-A-3-15440
Is done.

FIG. 6 is a functional block diagram illustrating a main part of the blood pressure monitoring control operation of the electronic control device 28 when applied to the blood pressure monitoring device 89. The functional block diagram shown in FIG. 6 is different from the functional block diagram shown in FIG.
In that the corrected pulse wave area change value calculating means 120 and the corrected peripheral resistance information change value calculating means 122 are added, and that the blood pressure measurement activation means 124 has the corrected pulse wave area change value abnormality determining means 126 And the correction peripheral resistance information change value abnormality determination means 128. Hereinafter, the difference will be mainly described.

The corrected pulse wave area change value calculation means 120 calculates a change value ΔA 'of the corrected pulse wave area A' corrected by the pulse wave area correction means 78. This change value ΔA ′ is
For example, the moving average value A ′ _{AV of the} corrected pulse wave area or the corrected pulse wave area A ′ determined based on the pulse wave before a predetermined number of beats.
Is the rate of change or the amount of change. The corrected peripheral resistance information change value calculation means 122 calculates the change value ΔTR 'of the falling period TR' corrected by the peripheral resistance information correction means 82. The change value ΔTR ′ is, for example, a change rate or a change amount with respect to the corrected falling period TR ′ determined based on the moving average value TR ′ _{AV of the} corrected falling period or the pulse wave before a predetermined number of beats.

The blood pressure measurement activating means 124, based on the fact that at least one of the corrected pulse wave area change value ΔA 'and the corrected fall period change value ΔTR' has exceeded a predetermined judgment reference range, executes the blood pressure measurement means 70. Activate blood pressure measurement by. That is, the blood pressure measurement activation unit 124 performs the abnormality determination correction based on the fact that the corrected pulse wave area change value ΔA ′ calculated by the corrected pulse wave area change value calculation unit 120 exceeds the criterion range that is set experimentally in advance. Abnormality is determined based on the fact that the corrected fall period change value ΔTR ′ calculated by the pulse wave area change value abnormality determining means 126 and the corrected peripheral resistance information change value calculating means 122 exceeds a criterion range experimentally set in advance. A corrected peripheral resistance information change value abnormality determining means 128; and the corrected pulse wave area change value abnormality determining means 126 determines whether the corrected pulse wave area change value ΔA ′ is abnormal, or a corrected peripheral resistance information change value. When the abnormality determining unit 128 determines that the corrected fall period change value ΔTR ′ is abnormal, the blood pressure measurement by the blood pressure measuring unit 70 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 the present embodiment. In the drawing, SB1 to SB6 represent SA1 of the above-described embodiment.
By performing the same processing as in steps SA6 to SA6, the corrected pulse wave area A ', the corrected falling period TR', and the like are determined for each beat.

The subsequent correction pulse wave area change value calculating means 120
In corresponding SB7, the corrected pulse wave calculated in SB5
The change value ΔA ′ of the area A ′ is calculated. This corrected pulse wave front
The moving average of the corrected pulse wave area is used as the product change value ΔA ′.
Value A '_AV(= A ′)_i-A '_AV) Or
Change rate [= (A '_i-A '_AV) / A '_AV) Or place
Change rate with respect to the corrected pulse wave area A 'calculated before the constant number of beats
Alternatively, a change amount or the like is used. Subsequent corrected peripheral resistance information
At SB8 corresponding to the change value calculating means 122, the control goes to SB6.
The change value ΔTR ′ of the corrected fall period TR ′ calculated
Is calculated. As the corrected falling period change value ΔTR ′,
Is the moving average value TR 'in the corrected falling period. _AVStrange against
(= TR '_i-TR '_AV) Or change rate [= (T
R '_i-TR '_AV) / TR '_AV) Or before the specified number of beats
Or the rate of change with respect to the corrected fall period TR '
The amount of change is used.

Subsequently, steps SB9 to SB10 corresponding to the blood pressure measurement starting means 124 are executed. That is, in SB9 corresponding to the corrected pulse wave area change value abnormality determination means 126, it is determined whether the corrected pulse wave area change value ΔA ′ calculated in SB7 is abnormal or not. In order to judge whether or not the change has become a problem, the judgment is made based on the fact that the state exceeding the judgment reference range experimentally determined in advance is continued for a predetermined number of beats, for example, five or more beats.

When the determination at SB9 is negative,
SB10 corresponding to the corrected peripheral resistance information change value abnormality determination means 128 is executed. That is, whether or not the corrected fall period change value ΔTR ′ determined in SB8 is abnormal is determined in order to determine whether or not the blood pressure value of the patient has changed to a problem in monitoring the condition of the living body. The determination is made based on the fact that the state exceeding the criterion range determined experimentally in advance is continuous for a predetermined number of beats, for example, five or more beats.

If the determination at SB10 is negative,
In the following SB11, it is determined whether or not the elapsed time since the blood pressure measurement by the cuff 10 was performed last time has passed a preset set cycle of about 20 minutes, that is, a calibration cycle. If the determination at SB11 is negative, SB2 and subsequent steps are repeatedly executed.

When the determination at SB9 or SB10 is affirmative, the corrected pulse wave area change value ΔA ′ or the corrected fall period change value ΔTR ′ is an abnormal value, that is, it changes in response to the blood pressure change. Since the corrected pulse wave area A 'or the corrected falling period TR' changes abruptly, blood pressure measurement using the cuff 10 is started in SB12, and measurement is performed using the character or symbol indicating blood pressure abnormality and the cuff 10. The displayed blood pressure value is displayed on the display 36. Therefore, even if the blood pressure value does not reach the abnormal value, if the blood pressure value changes abruptly, the corrected pulse wave area change value ΔA ′ and the corrected fall period change value ΔTR ′ are determined to be abnormal, and SB12 is determined to be abnormal. Is executed. Also, when the determination in SB11 is affirmed, that is, when the calibration cycle has elapsed, the above SB12 is executed. After the execution of SB12, S2 and subsequent steps are repeatedly executed.

As described above, according to this embodiment, based on the fact that at least one of the peripheral pulse wave area A and the pulse wave falling period TR that fluctuate in response to the fluctuation of blood pressure fluctuates. The blood pressure measurement is started by the blood pressure measurement unit 70 by the blood pressure measurement start unit 124. That is, the change value Δ of the corrected pulse wave area A ′ corrected by the heart rate PR in the corrected pulse wave area change value calculating means 120 (SB7).
A ′ is calculated, and the corrected peripheral resistance information change value calculation means 12 is calculated.
2 (SB8), the change value ΔTR ′ of the corrected fall period TR ′ corrected by the heart rate PR is calculated, and the corrected pulse wave area change value ΔA ′ and the corrected fall period change value ΔT
If at least one of R ′ exceeds a predetermined judgment reference range, the blood pressure measurement activation unit 124 (SB9, S9)
By B10), the blood pressure measurement by the blood pressure measurement means 70 (SB12) is started. Therefore, the fluctuation of the blood pressure is continuously monitored without using the cuff, and the start time of the blood pressure measurement by the cuff is accurately and reliably determined. Therefore, the blood pressure measurement by the cuff is performed in order to reduce the delay of the blood pressure monitoring. Since the execution in a short cycle is eliminated, the burden on the living body is reduced. In addition, there is an advantage that the photoelectric pulse wave detection probe 90 can be mounted on the epidermis of the living body without much restriction.

Although 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 or the photoelectric pulse wave detecting probe 90 for measuring oxygen saturation is used as the volume pulse wave detecting device, but the impedance pulse wave sensor is used. You may be. This impedance pulse wave sensor includes at least two electrodes that are brought into contact with the epidermis of the living body at a predetermined interval,
It is configured to output an impedance pulse wave corresponding to the blood volume of the living tissue located between the two electrodes.

In the above embodiment, the photoelectric pulse wave sensor 40 and the photoelectric pulse wave detecting probe 90 functioning as a volume pulse wave detecting device also function as a heartbeat signal detecting device. By supplying pressure to the wound cuff 10 so as to slightly press the upper arm 12, the cuff pulse wave may be continuously detected, and the cuff pulse wave may be used as a heartbeat signal. An electrocardiographic guidance device, a heart sound microphone, or the like may be provided as a heartbeat signal detection device.

In the blood pressure measurement means 70 of the above-described embodiment, the blood pressure measurement is executed at every preset blood pressure measurement period and when the blood pressure measurement activation means 84 and 124 determine that the blood pressure measurement is activated. However, the execution of the blood pressure measurement for each blood pressure measurement cycle is not performed, and the blood pressure measurement activation unit 84
The blood pressure measurement may be performed only when the activation of the blood pressure measurement is determined in 124.

Further, the blood pressure measuring means 70 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.

In the above-described embodiment, the heart rate information per unit time is calculated by the heart rate information calculating means 76, and the pulse wave area A and the falling period T are calculated based on the heart rate PR.
Although R has been corrected, the pulse wave area A and the falling period TR may be corrected by dividing the pulse wave area or the falling period TR by the heart rate TP corresponding to the heart rate PR one-to-one. In the present invention, since the heartbeat and the pulse can be treated as equivalent, the pulse cycle TM may be used instead of the heartbeat cycle TP, or the pulse wave rate MR may be used instead of the heart rate PR.

[0061] In the illustrated embodiment, the peripheral resistance information calculation unit 80, the falling period is TR has been calculated, the degree or second peak top P of falling of the pulse wave from the second peak top P ₂ since the rate of change or variation in ₂ subsequent amplitude intensity of the pulse wave also corresponds to the peripheral resistance, rate of change or a change of the amplitude intensity of a pulse wave of the second peak top later may be calculated as the peripheral resistance information .

Further, in the above-described embodiment, the corrected pulse wave area A and the falling period TR (corrected pulse wave area A ′, corrected falling period T
R ′) or their change values (corrected pulse wave area change values Δ
A ′, the activation of the blood pressure measurement is determined based on the variation of the corrected falling period change value ΔTR ′), but the pulse wave area A and the falling period TR that are not corrected based on the heartbeat, or their change values are also determined. Since it reflects the fluctuation of the blood pressure, the blood pressure measurement activating means includes the pulse wave area A and the falling period T.
R, or at least one of the change values thereof is monitored, and the blood pressure measurement by the blood pressure measurement means 70 is started based on the fact that at least one of the monitored values exceeds a predetermined judgment reference range. It may be the one that causes it.

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 block diagram showing a configuration of a blood pressure monitoring device according to another embodiment of the present invention.

FIG. 6 is a functional block diagram for explaining a main part of a control function of the electronic control device according to the embodiment of FIG. 5;

FIG. 7 is a flowchart illustrating a main part of a control operation of the electronic control device according to the embodiment of FIG. 5;

[Description of sign]

8, 89: blood pressure monitoring device 40: photoelectric pulse wave sensor (volumetric pulse wave detecting device, heartbeat signal detecting device) 70: blood pressure measuring unit 74: pulse wave area calculating unit 76: heartbeat information calculating unit 78: pulse wave area correcting unit 80: peripheral resistance information calculation means 82: peripheral resistance information correction means 84, 124: blood pressure measurement activation means 86: corrected pulse wave area variation determination means 88: corrected peripheral resistance information abnormality determination means 90: photoelectric pulse wave detection probe (volume pulse) 120: corrected pulse wave area change value calculation means 122: corrected peripheral resistance information change value calculation means 126: corrected pulse wave area change value abnormality determination means 128: corrected peripheral resistance information change value abnormality determination means

Claims (4)

[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. Pulse wave area calculating means for calculating the area of the plethysmogram detected by the above, and blood pressure measurement starting for starting blood pressure measurement by the blood pressure measuring means based on the fluctuation of the pulse wave area calculated by the pulse wave area calculating means Means for monitoring blood pressure. 2. 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. Peripheral resistance information calculating means for calculating peripheral resistance information that varies in relation to peripheral vascular resistance from the plethysmogram detected by the method; and the blood pressure based on the fluctuation of the peripheral resistance information calculated by the peripheral resistance information calculating means. A blood pressure monitoring device comprising: a blood pressure measurement activation unit that activates blood pressure measurement by the measurement unit. 3. A heart rate information calculating means for calculating heart rate information of the living body, and a pulse wave area correcting means for correcting the pulse wave area based on the heart rate information, 2. The blood pressure monitoring device according to claim 1, wherein the blood pressure measurement by the blood pressure measurement unit is started based on a change in the corrected pulse wave area corrected by the wave area correction unit or a change value thereof. 4. A blood pressure measurement starting means for calculating the heartbeat information of the living body, and a peripheral resistance information correcting means for correcting the peripheral resistance information based on the heartbeat information, 3. The blood pressure monitoring device according to claim 2, wherein the blood pressure measurement by the blood pressure measurement unit is started based on the corrected peripheral resistance information corrected by the resistance information correction unit or a change value thereof.