JPH01214341A - Blood pressure monitor apparatus - Google Patents

Abstract

PURPOSE:To enhance the measuring accuracy of blood pressure by selecting which is to be used, the pulse wave before the start of oppression or that after the start of oppression in determining the relation with a blood pressure value and always calculating a blood pressure value on the basis of the actual pulse wave detected from the determined relation. CONSTITUTION:The pulse wave before the start of oppression by a cuff 10 stored in the first ring buffer 40 and that after the start of oppression by the cuff 10 stored in the second ring buffer 42 are compared with each other and it is judged whether the cuff 10 and a pulse wave sensor 32 are mounted on the same arm, that is, the pulse wave sensor 32 is mounted on the artery extending downstream from the cuff 10 and a method for calculating the corresponding relation between a blood pressure value and the magnitude of a pulse wave is selected and, from the corresponding relation determined by the method, a blood pressure value is continuously determined on the basis of an actual pulse wave. Since it can be selected which is to be used, the pulse wave before the start of oppression or that after the start of oppression in determining the relation between the pulse wave and the blood pressure value, the relation between the blood pressure value and the pulse wave is accurately calculated regardless of the mount positional relation between the cuff 10 and the pulse wave sensor 32 and the measuring accuracy of blood pressure is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a blood pressure monitoring device that can automatically detect the mounting position of a pulse wave sensor.

BACKGROUND TECHNOLOGY In general, the blood pressure value of a living body is measured by compressing a part of the living body with a cuff, while the pulse wave generated from the artery in the peripheral part of the living body is detected by a pulse wave sensor, and the actual measured value is measured. The correspondence relationship between the blood pressure value and the pulse wave detected by the pulse wave sensor is appropriately determined, and the blood pressure value of the living body is constantly calculated based on the actual pulse wave from that relationship. A blood pressure monitoring device of the type that monitors the blood pressure value of the living body has been considered.

In such conventional blood pressure monitoring devices, depending on the mounting conditions of the cuff and pulse wave sensor, that is, whether or not the pulse wave sensor is mounted on an artery extending downstream from the part of the living body to which the cuff is mounted. When determining the correspondence between actual blood pressure values and pulse waves, there are two methods: one method uses pulse waves detected before the start of compression of a living body with a cuff for blood pressure measurement, and the other uses pulse waves detected after the start of compression. Which of the methods to use is set in advance.゛This is because when the pulse wave sensor is attached on an artery extending downstream from the cuff, the magnitude of the pulse wave detected by the pulse wave sensor becomes small and distorted when the cuff is compressed during blood pressure measurement. Therefore, if the pulse wave after the start of compression is used, the above-mentioned correspondence relationship cannot be obtained accurately.

Problems to be Solved by the Invention However, in the conventional devices described above, the operation of the pulse wave sensor is often preset on the assumption that the pulse wave sensor is not attached to the artery extending downstream from the cuff. In such a case, if the person measuring the pulse wave sensor accidentally attaches it to the artery extending from the cuff, the blood pressure value and the pulse wave size can be determined based on the small and distorted pulse wave after the start of compression. There was a problem in that the correspondence relationship between the two was determined, making it impossible to obtain sufficient accuracy in blood pressure measurement.

Means for Solving the Problems The present invention has been made with the above circumstances in mind, and its gist is to measure the blood pressure of a living body by compressing a part of the living body with a cuff. A blood pressure measuring means for measuring blood pressure and a pulse wave sensor for detecting a pulse wave generated from an artery in a peripheral part of a living body are provided, and the blood pressure value measured by the blood pressure measuring means and the pulse wave detected by the pulse wave sensor are A blood pressure monitoring device of the type that appropriately determines the relationship, constantly calculates the blood pressure value of the living body based on the actual pulse wave from the relationship, and monitors the blood pressure value of the living body based on the calculated blood pressure value, (a) a first storage means for storing a pulse wave before the start of compression by the cuff; (b) a second storage means for storing a pulse wave after the start of compression by the cuff; and (C) the first storage means. The pulse wave stored in the cuff is compared with the pulse wave stored in the second storage means, and if the latter is smaller than the former, the pulse wave sensor is attached on an artery extending downstream from the cuff. determination means for determining that the
(dlIf the determination by the determining means is affirmative, the relationship between the pulse wave stored in the first storage means and the blood pressure value measured by the blood pressure measuring means is determined, and the determination by the determining means is denied. In such a case, the relationship between the pulse wave stored in the second storage means and the blood pressure value measured by the blood pressure measuring means is determined, and from that relationship, the blood pressure value of the living body is constantly calculated based on the actual pulse wave. and a calculation means for performing the calculation.

Operation and Effect of the Invention By doing this, as shown in the claim correspondence diagram of FIG. The determination means compares the pulse wave after the start of compression with the cuff, thereby determining whether or not the pulse wave sensor is attached on an artery extending downstream from the part of the living body to which the cuff is attached; Depending on the determination, the calculation means selects whether to determine the relationship with the blood pressure value using the pulse wave before the start of compression or the pulse wave after the start of compression. Based on the determined relationship, the blood pressure value is constantly calculated based on the actual pulse wave detected by the pulse wave sensor.

Therefore, in the blood pressure monitoring device of the present invention, the relationship between the blood pressure value and the pulse wave is accurately determined regardless of the relationship between the attachment position of the cuff and the attachment position of the pulse wave sensor, so that the accuracy of blood pressure measurement is sufficient. This means that you can get a high amount of money.

Embodiments Below, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 is a diagram illustrating the configuration of the blood pressure monitoring device of this embodiment. In the figure, a rubber bag-shaped cuff 10 that is wrapped around and compresses the upper arm of a living body has a microphone inside. 12 are provided. In addition, the cuff 10 has
Pressure sensor 14. Switching valve 16. and an electric pump 18 are connected to each other via piping 19. The microphone 12 detects pulse sounds (Korotkoff sounds) generated from the upper arm of the living body, and supplies a pulse sound signal SO representing the pulse sounds to the bandpass filter 20 . The band pass filter 20 passes a signal having a frequency component of, for example, about 30 to 80 Hz, and converts the passed pulse sound signal SO into an A/
It is supplied to the CPU 24 via the D converter 22. The pressure sensor 14 detects the pressure within the cuff 10 (cuff pressure P) and outputs a cuff pressure signal sp representing the cuff pressure P to the CPU 24.

The switching valve 16 is used to adjust the cuff pressure P by switching between three states: a pressure supply state, a rate-limiting evacuation state, and a rapid evacuation state between the cuff 10 and the electric pump 18. That is,
In the pressure supply state, the rate-limiting exhaust port and rapid exhaust port of the switching valve 16 are closed, pressure is supplied from the electric pump 18 to the cuff 10, and when the cuff pressure P reaches a predetermined target cuff pressure, rate-limiting exhaust is performed. The inside of the cuff 10 is evacuated from a rate-limiting exhaust port equipped with a restriction at a predetermined speed suitable for a predetermined blood pressure measurement.
At the same time as the blood pressure is measured during the rate-determining blood pressure lowering period, the state is switched to the rapid evacuation state, and the inside of the cuff 10 is rapidly evacuated from the rapid evacuation port.

The CPU 24 connects the ROM 26 .
RAM28. Connected to I10 port 27, RO
RAM28 according to the program stored in advance in M26
Execute signal processing while using the temporary memory function of 0N10F to drive circuit 31 connected to electric pump 18.
Controlling the start and stop of the electric pump 18 by supplying the F signal and controlling the power supply to the electric pump 18 from the drive circuit 31, and outputting a command signal to the switching valve 16 to execute the switching operation. The cuff pressure P is adjusted as described above. At the same time, the CPU 24 executes a series of blood pressure measurement operations, and determines the cuff pressure P at the time when the Korotkoff sound occurs and disappears as the systolic blood pressure value and the diastolic blood pressure value, respectively, based on the pulse sound signal SO and the cuff pressure signal SP. At the same time, the determined blood pressure value is displayed on the blood pressure display 29. As shown in FIG. 3, the blood pressure display 29 has a horizontal axis 21 and a vertical axis 23 representing time and blood pressure (ts
A bar graph 25 whose upper end A and lower end B represent the systolic blood pressure value and the diastolic blood pressure value, respectively, is successively and continuously displayed on a cathode ray tube provided with a two-dimensional chart representing Hg.

Further, a pulse wave sensor 32 is connected to the CPU 24 via an A/D converter 34. As shown in FIG. 4, the pulse wave sensor 32, which is composed of a semiconductor strain sensor or a piezoelectric element for converting the pulsation of the artery into an electrical signal, has a band 3 provided with a pair of fasteners (not shown) at both ends thereof.
The band 36 is attached to the radial bone near the wrist of the living body, where it is easy to collect pulse waves. The radial artery located on the bone is locally pressed with a constant pressure of, for example, about 10 to 100 mHg.

The pulse wave sensor 32 detects a pulse wave from the radial artery, and sends a pulse wave signal SM representing the pulse wave to the CP via the A/D converter 34.
Supply to U24. Then, the pulse wave signal SM is stored in RAM2.
Predetermined numbers are sequentially stored in the two first ring buffers 40 and second ring buffers 42 provided in the CPU 24.
The average value of the magnitude of a predetermined number of pulse waves and the actual blood pressure stored in one of the first and second ring buffers 40 and 42 selected according to the wearing state of the cuff 10 and the pulse wave sensor 32 Correspondence with values is now required. That is, in the first ring buffer 40,
Pulse waves detected immediately before compression of the living body by the cuff 10 are sequentially stored, and pulse waves detected after the start of compression are sequentially stored in the second ring buffer 42. When the sensor 32 is attached to the cuff 10, that is, when the pulse wave sensor 32 is attached on the artery extending downstream from the cuff 10, based on the pulse wave stored in the first ring buffer 40, The correspondence between the blood pressure value and the pulse wave is determined, and if not, the correspondence is determined based on the pulse wave in the second ring buffer 42.

Therefore, in this embodiment, the first ring buffer 40 serves as the first storage means, and the second ring buffer 40 serves as the first storage means.
2 function as second storage means. In this embodiment, the number of buffers in the first and second ring buffers 40 and 42 in the RAM 28 is eight each, but this number is equal to the respiratory cycle or an integral multiple thereof (in this embodiment). This is the number of pulse waves that occur within a period approximately equivalent to the length of (double). Further, a pulse signal CK of a predetermined frequency is supplied to the CPtJ 24 from a clock signal source 38.

The operation of this embodiment will be explained below according to the flowchart shown in FIG.

First, when a power switch (not shown) is turned on, step S1 is executed, and it is determined whether a start/stop button (not shown) has been pressed, that is, whether a start/stop signal is being supplied to the CPU 24. When the activation stop signal is output after the cuff 10 is wrapped around the upper arm of the living body, step S2 is executed, and the count content T of the timer is reset to zero, after which the clock signal is supplied again from the clock signal source 38. starts counting the pulse signals CK. Next, step S3 is executed, and each time a pulse wave is detected by the pulse wave sensor 32, the detected pulse wave is stored in the first ring buffer 40, and in the following step S4, the pulse wave sensor 32 It is determined whether the detected pulse wave has reached the predetermined number, that is, eight beats. That is,
The determination in step S4 is negative until eight consecutive pulse waves are detected and stored in the first ring buffer 40, and step S3 is executed each time. When individual pulse waves are stored sequentially,
Step S5 continues at the same time that the determination in step S4 is affirmed and the storage operation of the first ring buffer 40 is stopped.
is executed.

When step S5 is executed, the switching valve 16 is switched to a pressure supply state, and pressurized fluid is supplied from the electric pump 18 to the cuff 10. This increases the cuff pressure P, and in step S6 it is determined whether the cuff pressure P has reached a predetermined target cuff pressure P1. Further, in step S5, immediately after the start of compression of the upper arm, a series of pulse waves detected by the pulse wave sensor 32 starts to be sequentially stored in the second ring buffer 42 in the RAM 28 by a predetermined number. Note that the target cuff pressure P1
is set at a pressure higher than the predicted systolic blood pressure value of the living body, for example, about 180 mHg, and when the cuff pressure P reaches the target cuff pressure P1, step S7 is subsequently executed.

In step S7, the electric pump 18 is stopped, the switching valve 16 is switched to the rate-limiting exhaust state, and the cuff pressure P is gradually lowered. In such a state, the blood pressure measurement routine of step S8 corresponding to the blood pressure measurement means of this embodiment is executed, and the Korotkoff sound represented by the pulse sound signal SO during the rate-determining blood pressure drop period of the cuff lO is generated and disappeared. Based on the cuff pressure signal SP
From the actual systolic blood pressure value H (mHg) and diastolic blood pressure value L
(mHg) is determined and these actual blood pressure values H and L are stored in RAM 28. Next, step S9
is executed to determine whether or not the systolic and diastolic blood pressure values have been determined, and when both the systolic and diastolic blood pressure values are determined, step SIO is immediately executed to switch the switching valve 16 to the rapid exhaust state. cuff 10
If the determination is negative, step S8 is executed again and the blood pressure measurement operation is performed again.

In the following step Sll, the first ring buffer 4
A series of predetermined number (8 pieces) of pulse waves M1 stored in 0.
...The average value A of each highest value of M.

mmx and the average value A 21j @X of the highest values of the eight pulse waves m, ..., ms stored so far in the second ring buffer 42, and their average value A1' A difference α between ``0 and A 2II * In other words, if it is determined that the pulse wave sensor 32 is attached near the cuff 10 and the patient's wrist, step S13 is executed, but if it is determined that α is less than the predetermined value α. , i.e. cuff 1
If it is determined that the pulse wave sensor 32 and the pulse wave sensor 32 are worn on different arms, step S14 is executed. The judgment in step 312 is that if the cuff 10 and the pulse wave sensor 32 are worn at the time of opening the hospital, the pulse wave detected by the pulse wave sensor 32 will start when the cuff 10 starts compressing the upper arm. Since it is small and distorted, a predetermined value α is set between the average value A1'ml1X of the highest values of the pulse waves before the start of compression and the average value A2'''1x of the highest values of the pulse waves after the start of compression.

This is done based on the above differences. Therefore, in this embodiment, step S12 corresponds to the determination means.

In addition, in the determination in step S12, it is of course possible to compare the average values of the respective minimum values of the pulse waves.

If it is determined in step 312 that the cuff 10 and pulse wave sensor 32 are attached to the hospital, step S13
is executed. In step S13, step 3
In addition to the average value A and wax calculated in 11,
The average values A, mLn of the lowest values of the pulse waves Ml...M before the start of compression of the upper arm by the cuff 10 stored in the first ring buffing fur 40 are calculated, and the average values are calculated. A.

A relational expression for determining the systolic blood pressure value SYS and the diastolic blood pressure value DIA based on @tx and A, @@n, respectively: % and at are determined as constants in the formula % (1). That is,
By substituting the actual blood pressure values H and L determined in step S8 into the systolic blood pressure value SYS and the diastolic blood pressure value DIA, these constants are calculated.

Here, since it is known that a proportional relationship exists between the systolic blood pressure value and the highest value of the pulse wave, and between the diastolic blood pressure value and the lowest value of the pulse wave, the constant 1 and a are the blood pressure value Y
In the case where the magnitude of the pulse wave is taken as the X-axis, the slope and the intercept of the Y-axis are respectively shown. Note that even when the magnitude of the pulse wave is zero, the blood pressure value is not necessarily zero, so by adding the Y-intercept a, the relationship between the blood pressure value and the pulse wave becomes more accurate. Become.

Further, in step S12, the average value A , @a
The difference α between X, A, and wax is the predetermined value α. If it is determined that the pulse wave sensor 32 is smaller than , the cuff 10 and the pulse wave sensor 32 are worn on different arms, so step S14 is executed. In step S14, step Sll
In addition to the average value A calculated in , IIIX, the second
Pulse wave m1 after the start of compression by the cuff 10 stored in the ring buffer 42...m.

The average value Az′″i″ of each minimum value of is calculated, and based on these average values A2′″ax and A 2m in, the following formula (3
) and (4) to a constant! and at are determined.

5YS=Kz−A, “”+a, ・−・(3)
DIA=Kt-At""+a, ・-・(4)
As described above, when the correspondence between the blood pressure values SYS and DIA and the magnitude of the pulse wave is determined according to the determination by the determination means in step S12, the correspondence relationship between the blood pressure values SYS and DIA and the magnitude of the pulse wave is then stored in the second ring buffer 42 in step S15. Latest pulse wave m
, it is determined whether a pulse wave is detected or not,
If it is determined that the pulse wave m has been detected, the subsequent step S16 is executed, and the pulse wave m and the immediately following pulse wave m are read, and the highest values m, , X and lowest values m and i of the pulse wave m are read.

is determined. Then, in step S17, the blood pressure value SY has already been determined in step S13 or 314.
Since the correspondence relationship between S and DIA and the pulse wave size has been determined, these maximum value m5ex and minimum value m, i
11 into equations (1) and (2) when the cuff 10 and pulse wave sensor 32 are attached to the hospital, and (3) when the cuff 10 and pulse wave sensor 32 are attached to different arms.

By substituting each into equation (4), the systolic blood pressure value S
YS and the diastolic blood pressure value DIA are estimated, and in step 318 the systolic blood pressure value SYS and the diastolic blood pressure value DIA are displayed on the blood pressure display 29.

Therefore, in this embodiment, step S13. Step S14. Step S16. and step S17
corresponds to the calculation means.

In step S19, it is determined whether the start/stop push button has been operated again. If it is determined that the re-operation has been performed, the process returns to step S1, but if it is determined that the re-operation has not been performed, step S20 is executed and the count content T of the timer becomes the predetermined count content T0. It is determined whether or not it has been reached. This counting content T0 corresponds to the time interval at which al+ or 2 and a2 are re-determined in order to correct the correspondence determined in step S13 or S14, and for example, every 5 to 10 minutes. Set. Therefore, when the count content T reaches To, steps 82 and subsequent steps are executed again, but since the count content T has not yet reached To at this stage, steps 315 and below are executed. m.

A series of pulse waves m, following. 2m1. Each time ... is detected, the systolic blood pressure value SYS and the diastolic blood pressure value DIA are estimated and displayed continuously.

As described above, in the process of repeating the operations from step 315 onwards, the count content T of the timer reaches T in step S20. When it is determined that the actual systolic blood pressure value H and the diastolic blood pressure value newly determined in step S8 are determined, steps 82 and subsequent steps are executed again.
Step S
13 or S14, 1 and aI+ or 2 and a2 are again determined as constants of the correspondence equation. Then, based on the new correspondence, blood pressure values are continuously determined and displayed based on the highest and lowest values of the series of pulse waves.

As described above, in the blood pressure monitor device of this embodiment,
The pulse wave before the start of compression by the cuff 10 stored in the first ring buffer 40 and the pulse wave after the start of compression by the cuff 10 stored in the second ring buffer 42 are stored in step S1.
2, it is determined whether the cuff 10 and the pulse wave sensor 32 are attached to the hospital, that is, whether the pulse wave sensor 32 is on the artery extending downstream from the cuff 10.
It is determined whether or not the device is being worn, and according to the determination, a method for determining the correspondence between the blood pressure value and the magnitude of the pulse wave is selected, and from the correspondence determined by the selected method, Blood pressure values are determined continuously based on actual pulse waves. Therefore, according to this embodiment, it is possible to select whether to use the pulse wave before the start of compression or the pulse wave after the start of compression when determining the relationship between the pulse wave and the blood pressure value. Since the relationship between the blood pressure value and the pulse wave can be accurately determined regardless of the mounting position of the blood pressure sensor 10 and the pulse wave sensor 32, sufficiently high accuracy in blood pressure measurement can be obtained.

In addition, in this example, the average value of each of the highest and lowest values of eight pulse waves obtained within a time longer than the breathing cycle of the living body, that is, a time approximately equivalent to two breathing cycles. is calculated, the actual blood pressure values H and L of the living body are measured, and the actual blood pressure values H and L are measured.
The correspondence relationship between the average value of the highest value and the average value of the lowest value is determined, and the blood pressure values SYS and DIA are determined from the correspondence relationship based on the pulse waves detected after determining the correspondence relationship. Therefore, according to this embodiment, the correspondence between the blood pressure value and the pulse wave size is determined using the average value of eight pulse waves generated within a time period longer than the breathing cycle of the living body. The correspondence relationship is hardly affected by the respiration of the living body,
This allows for high blood pressure measurement accuracy.

Furthermore, according to this embodiment, the blood pressure value can be monitored simply by compressing a part of the living body at regular time intervals, compared to a method that continuously compresses a part of the living body at a relatively high pressure. As a result, even when blood pressure is measured continuously over a long period of time, pain caused to the living body such as discomfort and congestion can be significantly reduced. Furthermore, since the systolic blood pressure value and the diastolic blood pressure value of the living body can be measured simultaneously and continuously for each pulse of the artery, there is an advantage that highly dense medical information can be obtained.

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

As shown in FIG. 6, step 513 or step S
A state in which the correspondence relationship between the brachial blood pressure value determined in step 14 and the pulse wave seems to have deviated, for example, when body movement at the pulse wave detection unit near the wrist or a change in peripheral blood flow resistance is determined from the pulse wave. , step S21 may be provided to recalculate the relationship. When the pressure condition of the pulse wave sensor 32 changes due to body movement of the pulse wave detection unit, or when the peripheral blood flow resistance changes due to contraction or expansion of the peripheral blood vessels, the brachial blood pressure value and the radial artery wave are This is because the correspondence relationship with the determined blood pressure value deviates. The above step S21 is
For example, it is provided between steps S16 and 317 in FIG. 5 to determine whether there is an abnormality in the radial pulse wave. This step S21
For example, regarding the body movement of the pulse wave detection unit, the amplitude of the radial pulse wave, the magnitude from the base line (for example, the zero volt line) to the peak value of the radial pulse wave, is determined by the unit time (for example, 5 seconds).
It is determined that there is an abnormality when there is a change of 50% or more within the range.

Alternatively, when the generation timing of the radial pulse wave deviates from the normal generation cycle by, for example, 30% or more, it is determined to be abnormal. Regarding the change in peripheral blood flow resistance, as shown in Figure 7, the value indicating the position of the notch (for example, the size A from the notch to the upper peak value) with respect to the radial pulse wave. /The size B) from the notch to the lower peak value is 30% within unit time.
It is determined that there is an abnormality when the value changes more than that. Alternatively, it is determined that there is an abnormality when the rate of change (slope) of a part of the radial pulse wave corresponding to the cardiac diastole (falling part C after the notch) changes significantly.

Although one embodiment of the present invention has been described above based on the drawings,
The present invention can also be suitably implemented in other embodiments.

In the above embodiment, the pulse wave before the cuff 10 starts compressing the living body and the pulse wave after the compression starts are stored in the first memory in the RAM 28.
and the second ring buffer 42 respectively, one ring buffer having a predetermined number of buffers, for example 16, is provided in the RAM 28, and the half of the ring buffer is divided into two to determine the pulse rate before the start of compression. The first ring buffer 40 may be used to store pulse waves, and the remaining half may be used as a second ring buffer 42 to store pulse waves after the start of compression.

In addition, in the above embodiment, when determining the blood pressure value continuously from the correspondence relationship between the blood pressure value and the pulse wave, the pulse wave is read every time the pulse wave is detected, and the pulse wave is immediately read based on the pulse wave. Although the blood pressure value is determined, for example, the storage operation of the second ring buffer 42 is continued even after the correspondence relationship is determined, and a series of pulse waves detected after the correspondence relationship is determined is stored in the second ring buffer 42. By sequentially storing the pulse waves in the second ring buffer 42, the blood pressure value may be determined from the above relationship using the latest pulse wave among the pulse waves in the second ring buffer 42.

Furthermore, in the above embodiment, the pulse wave sensor 32 was mounted on the radial artery, but other arteries, such as the carotid artery and dorsalis pedis artery, which are located near the skin and where pulse waves are relatively easy to detect, may also be used. It can also be installed on top. At this time, cuff 10
If the cuff 1 is attached to the upper arm, the determination means
It is determined that the pulse wave 32 is not placed on the artery extending downstream from 0.

Further, in the above embodiment, the first ring buffer 40
The predetermined number of pulse waves stored in the second ring buffer 42 was eight, that is, the number that occurred within a time approximately equivalent to the length of two breathing cycles; It is only necessary to store three to four pulse waves obtained within a period of time, or more, preferably, the number of pulse waves that occur within a period of time that is an integral multiple of the respiratory cycle. Further, in the RAM 28, one pulse wave immediately before the start of compression by the cuff 10 and one pulse wave immediately before determining the correspondence between the blood pressure value and the pulse wave after the start of compression are stored, and each of the highest pulse waves of these pulse waves is stored. The correspondence relationship may be determined by substituting the value and the minimum value into the cutting allowances (1) and (2), respectively.

Further, in the above embodiment, the pulse wave sensor 32 is fixed on the radial artery near the wrist by the band 36 and is pressed against the radial artery with a constant pressing force.
On the other hand, for example, a cuff can be wrapped around the fingers of a living person's hand.
The cuff pressure is raised to a predetermined pressure, and a pressure sensor connected to the cuff detects the pressure vibration waves generated within the cuff in synchronization with the pulse of the living body, and a pulse wave signal corresponding to the pressure vibration waves is detected by the pressure sensor. The sensor may output the information to the CPU 24. At this time, the pressure supply to the cuff is controlled by a pressure regulating valve, and the CPU 24 calculates the magnitude of the pulse wave signal, such as amplitude and signal power, and detects whether or not the magnitude is saturated. When the cuff pressure reaches saturation, a command signal is output to the pressure regulating valve to maintain the cuff pressure at that point. Note that, instead of changing the cuff pressure so that the magnitude of the pulse wave signal is saturated, the cuff pressure may be controlled so that the inside of the cuff reaches a predetermined suitable pressure.

In addition, instead of the band 36, a fluid container that accommodates the pulse wave sensor 32, and a diaphragm made of rubber or the like that fixes the pulse wave sensor 32 so as to come into contact with the biological surface within the fluid container and seals the inside of the fluid container. The fluid container and diaphragm are fixed directly above the artery on the surface of the living body, and when pressure fluid whose pressure is regulated by a pressure regulating valve or the like is supplied into the fluid container, the pulse wave sensor 32 is activated by the action of the diaphragm. It is also possible to detect the pulse wave by pressing with a suitable pressing force. Also,
By providing the pulse wave sensor 32 inside the fluid container, on the fluid container, or outside the fluid container, and by blocking the contact surface of the fluid container with the living body with the diaphragm, the pulse wave sensor 32 is connected to the fluid in the fluid container and through the diaphragm. A pressure vibration wave corresponding to the wave may be detected by the pulse wave sensor 32.

For example, by fixing electrodes at two positions separated by a predetermined distance on a part of a living body such as a finger and passing a weak current through the finger, a vibration wave corresponding to a pulse wave can be generated from the impedance generated between the two electrodes. It may also be detected. Further, a light projector and a light receiver are provided above and below a relatively thin part such as a finger, and the light receiver receives the light projected to pass through the artery located in that part,
Pulsation in the artery can also be detected from changes in the wavelength of the received light.

In addition, in the above-mentioned example, the correspondence relationship between the actual blood pressure value and the pulse wave size is calculated on the premise that they are in a proportional relationship, but the blood pressure value is a quadratic function of the pulse wave size. The blood pressure value and pulse wave size of the living body being measured can be determined from among multiple types of data maps that express the correspondence relationship between the blood pressure value and the pulse wave size that has been programmed in advance. There is no problem in finding the correspondence in other ways, such as finding the correspondence by selecting one data map based on the data map.

Furthermore, in the above-mentioned embodiment, the slope and the Y-intercept a, or the slope 2 and the Y-intercept a2 were used in the correspondence between the blood pressure value and the pulse wave size, but now only the slope is used. It is okay to do so. In this case,
The proportional relationships between the systolic blood pressure (t! S Y S and the average value of each maximum value of the pulse wave, and the proportional relationship between the diastolic blood pressure value DIA and the average value of each minimum value of the pulse wave are respectively different, and two types of slopes are calculated. You can ask for it.

Furthermore, in the above embodiment, the blood pressure measuring means employs the previous method in which the blood pressure value is determined during the blood pressure lowering process of the cuff 10 based on the generation and disappearance of Korotkoff sounds collected by the microphone 12. , the oscillometric method that determines blood pressure values based on changes in the size of the pulse waves of the living body, and the ultrasound method that uses ultrasound to detect waves on the arterial surface wall and determines blood pressure values according to changes in the size of the waves. It is also possible to adopt other blood pressure measurement methods such as the above-mentioned method, and it is also possible to measure blood pressure during the process of increasing the pressure of the cuff 10.

In addition, in step S16 described above, the maximum value m, 18 and the minimum value m, i· of one pulse wave were determined, but the number obtained within a time equal to the respiratory cycle or an integral multiple thereof, for example, 8 It may also be determined by taking a moving average of the highest and lowest values of consecutive pulse waves.

In this way, the influence of negative layer breathing is removed, making it possible to monitor blood pressure with high accuracy.

Further, in the above embodiment, the continuously measured systolic and diastolic blood pressure values are displayed on the cathode ray tube, but they may also be printed and recorded on recording paper such as a chart at the same time. Various other display means or storage means may be employed.

The above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to claims of the present invention. FIG. 2 is a diagram illustrating the configuration of a blood pressure monitoring device that is an embodiment of the present invention. FIG. 3 is a diagram showing an example of the trend of blood pressure displayed on the blood pressure display in FIG. 2. Figure 4 is the second
It is a figure which shows the state in which the pulse wave sensor of the figure was attached to the wrist of a living body. FIG. 5 is a flowchart illustrating the operation of the apparatus of FIG. 2. FIG. 6 is a flowchart illustrating the main part of the operation of another embodiment of the present invention. FIG. 7 is a diagram illustrating the notch position of the pulse wave or the portion corresponding to the diastole phase of the heart. 10: Cuff 32: Pulse wave sensor 40: First ring buffer (first storage means) 42: Second
Ring buffer (second storage means) Applicant Corin Electronics Co., Ltd. No. 1 @ Figure 3 °C Group 6

Claims (1)

[Scope of Claims] Blood pressure measuring means for measuring the blood pressure of a living body by compressing a part of the living body with a cuff, and a pulse wave sensor for detecting pulse waves generated from peripheral arteries of the living body. , appropriately determines the relationship between the blood pressure value measured by the blood pressure measuring means and the pulse wave detected by the pulse wave sensor, and constantly calculates the blood pressure value of the living body based on the actual pulse wave from the relationship. , a blood pressure monitoring device configured to monitor the blood pressure value of the living body based on the calculated blood pressure value, comprising: a first storage means for storing a pulse wave before the start of compression by the cuff; and a first storage means for storing a pulse wave before the start of compression by the cuff; a second storage means for storing pulse waves, and a pulse wave stored in the first storage means and a pulse wave stored in the second storage means are compared, and if the latter is smaller than the former, , a determining means for determining that the pulse wave sensor is attached on an artery extending downstream from the cuff; and when the determination by the determining means is affirmative, the pulse wave sensor stored in the first storage means; The relationship between the pulse wave and the blood pressure value measured by the blood pressure measuring means is determined, and if the determination by the determining means is negative, the relationship between the pulse wave stored in the second storage means and the blood pressure value measured by the blood pressure measuring means is determined. Find the relationship with the blood pressure value,
A blood pressure monitoring device comprising: calculation means for constantly calculating the blood pressure value of the living body based on the actual pulse wave from the relationship.