JPH04295334A - Monitoring device for blood pressure - Google Patents

Abstract

PURPOSE:To surely measure highest blood pressure and also to prevent the pain of a testee due to pressure and the time required for measurement from increasing more than needed when using a blood pressure monitoring device which repeats blood pressure measurement wherein cuff pressure exerted by a pressurizing device is dropped from target cuff pressure. CONSTITUTION:The rise of the pressure of a cuff 10 is temporarily stopped at first target cuff pressure by a controller 29 and a pulse wave indicated by a pulse wave signal SM is detected and the amplitude of the pulse wave is found, and second target cuff pressure is determined on the basis of the amplitude of the pulse wave and from the relation between amplitude preset for each subject and the second target cuff pressure. Because the amplitude of the pulse wave obtained under fixed pressure conditions is related to the highest blood pressure value of a testee, the second target cuff pressure can be decided as a necessary minimum value corresponding to the highest blood pressure value of the testee, on the basis of the amplitude of the pulse wave and from the above relation.

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 that repeatedly measures blood pressure values, and more particularly to a blood pressure monitoring device that measures blood pressure values by lowering the compression pressure of a compression device.

0002

[Background Art] A living body is compressed by a compression device such as a cuff, and blood pressure is measured based on pulse waves, Korotkoff sounds, etc. that are sequentially obtained during the pressure reduction process, and such blood pressure measurements are repeated at predetermined intervals. Blood pressure monitoring devices of this type are known.

0003

By the way, in such a blood pressure monitoring device, the compression pressure of the compression device is normally set to a relatively high constant target compression pressure (for example, 1
However, if the systolic blood pressure value of the living body is higher than the certain target compression pressure, the blood pressure cannot be measured and the blood pressure measurement must be repeated.

[0004] On the other hand, the target compression pressure is increased to a constant pressure higher than the previously measured systolic blood pressure value, but in this case, the However, if the currently measured systolic blood pressure value is lower than the previous systolic blood pressure value, the target compression pressure will become unnecessarily large and the burden of compression on the subject will increase. There are disadvantages in that the voltage becomes unnecessarily large and the pressure increase time and thus measurement time become unnecessarily long.

The present invention was made against the background of the above-mentioned circumstances, and its purpose is to measure the blood pressure value by lowering the compression pressure of the compression device from the target compression pressure, and to In a blood pressure monitoring device that repeatedly measures blood pressure, the target compression pressure can be determined to the minimum necessary value according to the patient's systolic blood pressure value, and the systolic blood pressure value can be reliably measured and the amount of pressure caused by compression can be reduced. It is an object of the present invention to provide a blood pressure monitoring device that can prevent unnecessary increases in the burden on the measurer and measurement time.

[0006]

[First Means for Solving the Problems] The gist of the first invention for achieving the above object is to provide a compression device that is attached to a living body and compresses it, and to apply compression pressure of the compression device to the living body. After increasing the pressure to a predetermined target compression pressure,
The blood pressure value is measured by lowering the compression pressure,
A blood pressure monitoring device that repeatedly measures the blood pressure value at predetermined intervals, the device comprising: (a) prior to increasing the compression pressure to the target compression pressure, the living body is kept at a predetermined constant pressure; a pulse wave detection means for detecting a pulse wave generated from within the living body in synchronization with the heartbeat when pressed;
(b) amplitude calculating means for calculating the amplitude of the pulse wave detected by the pulse wave detecting means; and (c) based on the amplitude of the pulse wave, calculating the target compression pressure from a predetermined relationship for each living body. and target compression pressure determining means.

[0007]

[Operation and Effects of the First Invention] According to the blood pressure monitoring device configured as described above, before the compression pressure is increased to the target compression pressure, the pulse wave detection means presses the living body at a predetermined constant pressure. As a result, a pulse wave generated from within the living body in synchronization with the heartbeat is detected, and the amplitude of the pulse wave is calculated by the amplitude calculation means. Then, based on the amplitude of the pulse wave, the target compression pressure determining means determines the target compression pressure from a predetermined relationship for each subject. In this case, since the amplitude of the pulse wave obtained under a certain pressure condition is related to the systolic blood pressure value, the amplitude of the pulse wave obtained under a certain pressure condition is used for each blood pressure measurement. If the target compression pressure is determined from a predetermined relationship for each subject, the target compression pressure can be determined to the minimum necessary value according to the systolic blood pressure value of the subject. Thereby, the systolic blood pressure value can be measured reliably, and the burden on the person to be measured due to compression and the measurement time can be prevented from increasing unnecessarily.

[0008] As the predetermined relationship, for example, the relationship between the amplitude of the pulse wave and the target compression pressure is used.

[0009]

[Second means for solving the problem] A compression device is provided that is attached to a living body to compress it, and after increasing the compression pressure of the compression device to a predetermined target compression pressure, the compression pressure is lowered. A blood pressure monitoring device of the type that measures a blood pressure value by causing the blood pressure to rise and repeatedly measures the blood pressure value at predetermined intervals, the device comprising: (a) prior to increasing the compression pressure to the target compression pressure; a pulse wave detection means for detecting a pulse wave generated from within the living body in synchronization with the heartbeat by pressing the living body with a predetermined constant pressure;
) upper peak value determining means for determining the upper peak value of the pulse wave detected by the pulse wave detecting means; and (c) based on the upper peak value of the pulse wave, from a predetermined relationship for each living body. and target compression pressure determining means for determining the target compression pressure.

0010

[Operation and Effects of the Second Invention] According to the blood pressure monitoring device configured as described above, before increasing the compression pressure to the target compression pressure, the pulse wave detection means presses the living body at a predetermined constant pressure. As a result, a pulse wave generated from within the living body in synchronization with the heartbeat is detected, and the upper peak value of the pulse wave is determined by the upper peak value determining means. Then, based on the upper peak value of the pulse wave, the target compression pressure determining means determines the target compression pressure from a predetermined relationship for each subject. In this case, since the upper peak value of the pulse wave obtained under constant pressure conditions is related to the systolic blood pressure value, based on the upper peak value of the pulse wave obtained under constant pressure conditions for each blood pressure measurement, If the target compression pressure is determined from a predetermined relationship for each subject, the target compression pressure can be determined to the minimum necessary value according to the systolic blood pressure value of the subject. Thereby, the systolic blood pressure value can be measured reliably, and the burden on the person to be measured due to compression and the measurement time can be prevented from increasing unnecessarily.

[0011] As the predetermined relationship, for example, the relationship between the upper peak value and the target compression pressure is used.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

In FIG. 3, reference numeral 10 denotes a rubber bag-shaped cuff that is wrapped around the upper arm of a human body, and constitutes the compression device of the present invention. The cuff 10 has a pressure sensor 12
, an air pump 14, a rapid exhaust valve 16, and a slow exhaust valve 18 are connected via piping 22, respectively. Pressure sensor 12 supplies a pressure signal SP representing the pressure within cuff 10 to static pressure discrimination circuit 24 and pulse wave discrimination circuit 26, respectively. The static pressure discrimination circuit 24 includes a low-pass filter, discriminates a cuff pressure signal SK representing steady pressure included in the pressure signal SP, and transmits the cuff pressure signal SK to the control device 29 via the A/D converter 28. supply to The pulse wave discrimination circuit 26 is equipped with a bandpass filter, and the pressure signal SP
The pulse wave signal SM representing the pulse wave included in the A/D converter 32
is supplied to the control device 29 via. This pulse wave is a pressure vibration wave of the cuff 10 that is generated in synchronization with the heartbeat of the subject.

The control device 29 includes a CPU 30 and a ROM 34.
, a RAM 36, an output interface 40, and the like. C.P.
U30 executes signal processing using the storage function of RAM 36 according to a program stored in advance in ROM 34, and controls air pump 14, rapid exhaust valve 16, and slow exhaust valve 18 via a drive circuit (not shown). At the same time, by performing a series of blood pressure measurement operations, the cuff 10
The cuff pressure is temporarily stopped at a predetermined constant pressure, the pulse wave is detected, the amplitude of the pulse wave is calculated, and the current target cuff pressure is determined from a predetermined relationship based on the amplitude. While increasing the pressure to the target cuff pressure, blood pressure values such as the systolic blood pressure value and the diastolic blood pressure value are determined based on the pulse wave signal SM and cuff pressure signal SK that are sequentially obtained in the process of lowering the blood pressure from the target cuff pressure. The display 38 shows the blood pressure value
The blood pressure measurement is repeated at predetermined intervals and the measured blood pressure values are sequentially displayed on the display 38. Therefore, in this embodiment, the control device 29 constitutes a pulse wave detection means, an amplitude calculation means, and a target compression pressure determination means.

The operation of the blood pressure monitoring apparatus of this embodiment will be explained below with reference to the flowcharts shown in FIGS. 1 and 2.

When the power is turned on, an initial process (not shown) is executed, and then step S1 is executed to determine whether a starting switch (not shown) has been turned on. If this judgment is negative, it will be in a standby state, but if it is affirmative, step S2 will be executed.
Both the rapid exhaust valve 16 and the slow exhaust valve 18 are closed, and the air pump 14 is driven to begin increasing the pressure within the cuff 10. Next, step S3 is executed, and the cuff pressure P is set to a predetermined relatively low first target cuff pressure Pm1.
(For example, a pressure of about 20 to 30 mmHg) It is determined whether or not the pressure has been reached. If this judgment is negative, steps S2 and S3 are repeatedly executed, but if the first target cuff pressure Pm1 is reached and the judgment of step S3 is affirmative, the following step S4 is executed, Pressurization within the cuff 10 is stopped.

Next, by executing step S5, 1
When one pulse wave is detected, step S6 is executed to calculate the amplitude A of the detected pulse wave. In the subsequent step S7, it is determined whether the relationship between the pulse wave amplitude A and the second target cuff pressure Pm2 has been determined in step S19, which will be described later. Since this determination is initially denied, step S8 is skipped and step S9 is executed to resume pressurization within the cuff 10, and step S10 is executed to increase the cuff pressure P.
It is determined whether or not exceeds the second target cuff pressure Pm2. This second target cuff pressure Pm2 corresponds to the target compression pressure in the claims, and is initially set to a relatively high constant initial value (for example, a pressure of about 180 mmHg).

If the determination in step S10 is negative, steps S9 and S10 are repeatedly executed, but if the cuff pressure P reaches the second target cuff pressure Pm2 and the determination in step S10 is affirmative. In this case, the following step S11 is executed, so that the air pump 1
4 is stopped, and the slow exhaust valve 18 is opened to start slow pressure reduction at a predetermined pressure reduction rate. Next, step S
Step S12 is executed to start detecting a pulse wave to measure the blood pressure value, and step S13 is executed,
It is determined whether a pulse wave is detected. If this determination is negative, steps S12 and S13 are repeatedly executed, but if the determination is affirmative, the blood pressure value determination routine of subsequent step S14 is executed. In this blood pressure value determination routine, well-known methods are used to determine blood pressure values such as the systolic blood pressure value and the diastolic blood pressure value based on the magnitude of the detected pulse wave and the cuff pressure P at the time the pulse wave was detected. Blood pressure values such as the systolic blood pressure value and the diastolic blood pressure value are determined according to the oscillometric blood pressure value determination algorithm. That is, the cuff pressure P at the time when the maximum value of the pulse wave amplitude obtained sequentially during the blood pressure lowering process occurs is determined as the mean blood pressure value, and the cuff pressure P at the inflection point of the pulse wave amplitude on the higher pressure side than this mean blood pressure value is determined as the mean blood pressure value. The pressure P is determined as the systolic blood pressure value, and the cuff pressure P at the inflection point of the pulse wave amplitude on the lower pressure side than the average blood pressure value is determined as the diastolic blood pressure value. Next, by executing step S15, it is determined whether or not the blood pressure measurement has been completed, and if the blood pressure measurement has not been completed yet, steps S12 to S15 are performed.
is executed repeatedly. After blood pressure measurement is completed, proceed to step S.
If the determination in step S15 is affirmative, the next step S16
By executing this, the rapid exhaust valve 16 is opened and the pressure inside the cuff 10 is rapidly evacuated, and the blood pressure value determined by executing step S17 is displayed on the display 38. FIG. 5 is a diagram showing an example of a change in the cuff pressure P from the time when the pressure inside the cuff 10 starts to be increased until the time when the inside of the cuff 10 is evacuated after blood pressure measurement is performed.

Next, by executing step S18, the amplitude A of the pulse wave calculated in step S6 and the second
It is determined whether the relationship between the target cuff pressure Pm2 and the target cuff pressure Pm2 has been determined. Since the determination in step S18 is initially negative, a relationship determination routine for determining the relationship is executed in step S19. In this relationship determination routine, for example, the pulse wave amplitude A1 calculated in the first blood pressure measurement cycle and the systolic blood pressure value SYS1 measured in the first blood pressure measurement cycle
, the amplitude A2 of the pulse wave calculated in the second blood pressure measurement cycle, and the systolic blood pressure value SYS2 measured in the second blood pressure measurement cycle.
and the second target cuff pressure Pm2 is determined. FIG. 4 is a diagram showing an example of the relationship, and ΔP indicates a necessary and sufficient amount of pressure increase to be added to the systolic blood pressure value in order to measure the systolic blood pressure value.

Next, step S21 is executed to determine whether or not the starting switch has been turned off. If this judgment is denied, step S2
3 is executed for a predetermined period of time (for example, 5
~10 minutes) have elapsed. Step S
If the judgment in step S22 is negative, the standby state is entered, but if the judgment is affirmative, steps S2 and subsequent steps are executed again and the process returns to step S2.
The second blood pressure measurement begins. Since the relationship between the amplitude A and the second target cuff pressure Pm2 is not determined in the first blood pressure measurement cycle, in the second blood pressure measurement cycle, step S8 is performed in the same manner as in the first blood pressure measurement. is skipped and the predetermined 180
The pressure is increased to the second target cuff pressure Pm2 of approximately mmHg, and blood pressure measurement is performed, and the step S18
The determination is negative and the relationship determination routine of step S19 is executed, so that the amplitude A and the second target cuff pressure Pm
2 is determined.

In the third blood pressure measurement cycle after the relationship has been determined in this way, the determination in step S7 is affirmed and step S8 is executed, so that the relationship calculated in step S6 in this cycle is Based on the amplitude A3, the amplitude A and the second target cuff pressure Pm2 are calculated.
The current second target cuff pressure Pm2 is determined from the predetermined relationship between While the blood pressure is increased to that value and blood pressure measurement is performed, step S18
The determination is affirmative and step S20 is executed, whereby the relationship between the amplitude A and the second target cuff pressure Pm2 is corrected based on the current amplitude A3 and the systolic blood pressure value SYS3. Correction of this relationship is performed, for example, by determining a regression line. That is, in the third blood pressure measurement cycle, a regression line is determined based on three data points in the two-dimensional coordinates shown in FIG. 4 (the third point is not shown in FIG. 4), and this regression line is corrected. It is said that the relationship is Thereafter, blood pressure measurements are repeated at predetermined intervals in the same manner, and the relationship between the amplitude A and the second target cuff pressure Pm2 is successively corrected. The target cuff pressure Pm2 is determined, and the blood pressure values measured in the process of lowering the blood pressure from the determined second target cuff pressure Pm2 are sequentially displayed on the display 38. Note that as blood pressure measurements are repeated, the number of data points increases, and the regression line is successively determined based on all accumulated data points. On the other hand, if the starting switch is turned OFF and the determination in step S21 is affirmative, step S23 is executed and the second
After the target cuff pressure Pm2 is returned to the initial value and the above relationship is cleared, the process returns to step S1.

As described above, according to this embodiment, during each blood pressure measurement cycle, the pressure increase in the cuff 10 is temporarily stopped and the pulse wave is collected with a constant pressing force of about 20 to 30 mmHg, and the pulse wave is collected. The amplitude A of is calculated, and
The relationship between the amplitude A and the second target cuff pressure Pm2 is the amplitude A.
and the systolic blood pressure value SYS in the initial blood pressure measurement cycle for each subject. After the relationship is determined, the amplitude A determined in the current blood pressure measurement cycle is determined based on that relationship. Based on this, the second target cuff pressure Pm2 for the current blood pressure measurement cycle is determined. In this case, since the amplitude of the pulse wave obtained under a constant pressure condition is related to the systolic blood pressure value, the amplitude A and second
Based on the relationship for each subject with the target cuff pressure Pm2, the second
If the target cuff pressure Pm2 is determined, the second
The target cuff pressure Pm2 can be determined to the minimum necessary value according to the systolic blood pressure value of the subject. As a result, the systolic blood pressure value can be measured reliably, and the burden on the person to be measured due to compression and unnecessary increases in pressure increase time t1 (see Figure 5) and measurement time t2 (see Figure 5) can be avoided. A blood pressure monitoring device is provided that can prevent blood pressure.

According to this embodiment, the pulse wave amplitude A and the systolic blood pressure value SY obtained in the current blood pressure measurement cycle are
Since the predetermined relationship between the amplitude A and the second target cuff pressure Pm2 is sequentially corrected based on S, the second target cuff pressure Pm2 in the next blood pressure measurement cycle can be more preferably set to the minimum necessary value. The above effect can be obtained even more favorably.

Further, according to this embodiment, the second target cuff pressure Pm is maintained while the pressure increase in the cuff 10 is temporarily stopped at a constant pressure.
2 is configured so that the pulse wave for determining the pulse wave is detected, there is an advantage that there is no need to separately provide a pulse wave detection means for detecting the pulse wave under constant pressing conditions.

In the above embodiment, the above relationship and the second target cuff pressure Pm2 are determined based on the amplitude of one pulse wave obtained when the pressure increase in the cuff 10 is temporarily stopped. However, it is not necessary to do so, for example, based on the average amplitude value of multiple pulse waves obtained during the stop of pressurization, or based on the pulse wave obtained from a pulse wave sensor installed in the radial artery, etc. The above relationship and the second target cuff pressure Pm2 may be determined based on the amplitude.

Furthermore, in the above embodiment, the relationship between the amplitude A and the second target cuff pressure Pm2 is determined in the initial blood pressure measurement cycle. You can also do that. Even in this case, if the relationship is corrected based on the amplitude A and the systolic blood pressure value data, the second target cuff pressure Pm2 can be adjusted to the minimum necessary level according to the patient's systolic blood pressure value after correction. The value can be determined. In this case, the above relationship may change not in a linear manner but in a curved manner.

Furthermore, in the embodiment described above, step S20
In step S, the relationship between the amplitude A and the second target cuff pressure Pm2 is corrected.
Even if 20 is not provided, some effects of the present invention can be obtained.

Furthermore, in the above embodiment, the current second target cuff pressure Pm2 is determined based on the current amplitude A from the predetermined relationship between the amplitude A and the second target cuff pressure Pm2. However, this is not necessarily necessary; for example, by adding a predetermined pressure increase amount ΔP' to the systolic blood pressure value measured in the previous blood pressure cycle, the second target cuff pressure Pm2 in the current blood pressure measurement cycle can be determined. In a blood pressure monitoring device configured to determine the current pressurization amount ΔP' and thus the second target cuff pressure based on the current amplitude A from a predetermined relationship between the amplitude A and the pressurization amount ΔP'. It can also be configured to determine Pm2,
Or the amplitude difference ΔA between the amplitude A obtained during the previous blood pressure measurement and the amplitude A obtained during the current blood pressure measurement.
Based on this, the pressure increase amount ΔP' and thus the second target cuff pressure Pm2 can be determined from a predetermined relationship between the amplitude difference ΔA and the pressure increase amount ΔP'. Even in the latter case, the amplitude difference ΔA suitably reflects the fluctuation of the systolic blood pressure value, and therefore, by determining the pressure increase amount ΔP' from a predetermined relationship based on the amplitude difference ΔA, the pressure increase amount can be determined. ΔP' and thus the second target cuff pressure Pm2 can be determined to the minimum necessary value according to the systolic blood pressure value of the subject.

Furthermore, in the above embodiment, the predetermined relationship between the amplitude A and the second target cuff pressure Pm2 is configured to be corrected based on the amplitude A and the systolic blood pressure value data. However, this is not necessarily necessary; for example, the blood pressure may be lowered during the period from the start of blood pressure reduction in the cuff 10 until the cuff pressure P falls to the currently measured systolic blood pressure value SYS (period indicated by R in FIG. 5). It is also possible to configure the correction based on the amount, time, or pulse wave number detected during the period R.

[0030] Furthermore, in the above embodiment, the diameter of 20 to 30 mm
The current second target cuff pressure Pm2 is determined from a predetermined relationship based on the amplitude A of the pulse wave detected via the pulse wave discrimination circuit 26 at a constant pressure of approximately Hg. For example, as shown by the dashed line in FIG. 3, the pressure signal SP output from the pressure sensor 12 is
The pulse wave represented by the pressure signal SP is detected at the constant pressure in step S5 of the above embodiment, and the pulse wave represented by the pressure signal SP is detected in step S6 of the above embodiment. In addition to determining the peak value (highest value) on the wave, step S1 of the above-mentioned embodiment
9, the upper peak value and the second
The second target cuff pressure Pm2 may be determined based on the upper peak value obtained in the current blood pressure measurement cycle. Even in this case, since the upper peak value of the pulse wave obtained under certain pressure conditions is related to the systolic blood pressure value, the second target cuff pressure Pm2 is set to the minimum necessary value according to the patient's systolic blood pressure value. can be determined, and the same effect as the above embodiment can be obtained. In this case,
The control device 29 constitutes a pulse wave detection means, an upper peak value determination means, and a target compression pressure determination means.

Furthermore, in the above-mentioned embodiments, the case where the present invention is applied to an oscillometric type blood pressure monitoring device has been explained, but it goes without saying that the present invention can also be applied to a Korotkoff sound type blood pressure monitoring device. be.

[0032] In addition, various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a portion of a flowchart showing the operation of the apparatus of FIG. 3;

2 shows the remainder of the flowchart illustrating the operation of the apparatus of FIG. 3; FIG.

FIG. 3 is a block diagram showing a configuration example of a blood pressure monitoring device to which the present invention is applied.

FIG. 4 is a diagram showing an example of a relationship determined in the flowcharts shown in FIGS. 1 and 2;

5 is a diagram showing an example of changes in cuff pressure P in the flowcharts shown in FIGS. 1 and 2. FIG.

[Explanation of symbols]

10 Cuff (compression device) 29 Control device (pulse wave detection means, amplitude calculation means, target compression pressure determination means) 29 Control device (pulse wave detection means, upper peak value determination means, target compression pressure determination means)

Claims (4)

[Claims] Claim 1: A compression device that is attached to a living body and compresses it, and after increasing the compression pressure of the compression device to a predetermined target compression pressure, the blood pressure value is measured by lowering the compression pressure. The blood pressure monitoring device repeatedly measures the blood pressure value at predetermined time intervals, and presses the living body at a predetermined constant pressure before increasing the compression pressure to the target compression pressure. a pulse wave detection means for detecting a pulse wave generated from within the living body in synchronization with the heartbeat; an amplitude calculation means for calculating the amplitude of the pulse wave detected by the pulse wave detection means; A blood pressure monitoring device comprising target compression pressure determining means for determining the target compression pressure from a predetermined relationship for each living body based on the amplitude. 2. The blood pressure monitoring device according to claim 1, wherein the predetermined relationship is a relationship between the amplitude of the pulse wave and the target compression pressure. 3. A compression device that is attached to a living body and compresses it, and after increasing the compression pressure of the compression device to a predetermined target compression pressure, the blood pressure value is measured by lowering the compression pressure. The blood pressure monitoring device repeatedly measures the blood pressure value at predetermined time intervals, and presses the living body at a predetermined constant pressure before increasing the compression pressure to the target compression pressure. a pulse wave detection means for detecting a pulse wave generated from within the living body in synchronization with the heartbeat; an upper peak value determination means for determining the upper peak value of the pulse wave detected by the pulse wave detection means; A blood pressure monitoring device comprising target compression pressure determining means for determining the target compression pressure from a predetermined relationship for each living body based on the upper peak value of the pulse wave. 4. The blood pressure monitoring device according to claim 3, wherein the predetermined relationship is a relationship between the upper peak value and the target compression pressure.