JPS61103432A - Continuous blood pressure measuring method and apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a continuous blood pressure measuring method and apparatus for continuously measuring blood pressure based on pulse waves generated when a part of a living body is compressed.

Conventional technology Trends in blood pressure values (trends in changes over time) are used as one of the vital signs (biological information) when investigating the autonomic nervous system reflex function of a living body during exercise or when understanding the medical condition of a patient undergoing surgery. . The blood pressure measurement method for obtaining the trend of blood pressure values generally involves measuring blood pressure based on the occurrence and disappearance of Korotkoff sounds or changes in the size of pulse waves while changing the pressure of a cuff that compresses a part of the living body. Blood pressure values are repeatedly and continuously measured by repeatedly executing a blood pressure measurement cycle in which the following steps are performed. However, such blood pressure “~1
Since the measurement cycle requires a period of at least ten seconds, it was not possible to observe changes in blood pressure values in detail.

On the other hand, the cuff pressure can be adjusted to around the systolic or diastolic blood pressure value based on the presence or absence of a clicking sound on the roller 1, changes in the size of the pulse wave, or changes in the size of the waves on the arterial surface wall. A method has been considered in which the blood pressure value is precisely and continuously measured by adjusting the pressure. For example, this is described in Japanese Patent Application No. 163599/1989 filed by the present applicant.

Problems to be Solved by the Invention However, in such a conventional continuous blood pressure measurement method, a part of the living body is compressed with pressure near the systolic blood pressure value during the blood pressure measurement time, which hinders blood pressure circulation. Continuous blood pressure measurement over a long period of time was not desirable, as this caused pain to the person being measured. Further, since the pressure of the cuff is adjusted to either the diastolic blood pressure value or the systolic blood pressure value, there is also the inconvenience that the systolic blood pressure value and the diastolic blood pressure value cannot be continuously measured at the same time.

Means for Solving the Problems The present invention has been made to solve the above problems, and its gist is to continuously generate pulse waves generated when a part of a living body is compressed. This is a continuous blood pressure measurement method for measuring blood pressure during continuous blood pressure measurement, in which the blood pressure value is determined and memorized while changing the compression pressure on the part of the living body, and the pressure is maintained at a relatively low constant value to measure the pulse. Continuously collect pulse waves, find the correspondence between the magnitude of the earliest part of the series of pulse waves and the stored blood pressure value, and determine from that correspondence the magnitude of the pulse wave following the first part. The purpose is to continuously obtain blood pressure values based on the size.

Here, the systolic blood pressure value and/or diastolic blood pressure value may be used as the blood pressure value, and the maximum value and/or minimum value of the pulse wave may be used as the magnitude of the pulse wave corresponding to the blood pressure value. It is desirable to find the blood pressure value and the correspondence between the blood pressure value and the size of the pulse wave, but it is desirable to calculate the average blood pressure value, which is the average value of the systolic blood pressure value and the diastolic blood pressure value, and other blood pressure values, and It is also possible to use the average value of the maximum value and minimum value of the pulse wave or other values as the magnitude of the pulse wave that corresponds to the blood pressure value.

In addition, a device suitably used to carry out such a continuous blood pressure measurement method includes (a compression means for compressing a part of a living body;
b) a pulse wave sensor that collects a pulse wave generated when the part of the living body is compressed by the compression means, and fc) determining a blood pressure value while changing the pressure applied to the part of the living body by the compression means. (d) compression means for maintaining the compression pressure by the compression means at a relatively low constant value following the determination of the blood pressure value by the measurement means; (f) a pressure adjusting means, a correspondence determining means for determining a correspondence between the magnitude of the first one of the comparatively low compression pressures and the stored blood pressure value by the compression pressure adjusting means; continuous blood pressure value determining means for continuously determining a blood pressure value based on the magnitude of the pulse wave following the first pulse wave from the correspondence relationship;

In such a continuous blood pressure measuring device, first, a blood pressure value is determined by the measuring means in the process of changing the compression pressure by the compressing means, and the determined blood pressure value is stored in the storage means. Next, the compression pressure by the compression means is maintained at a relatively low constant value by the compression pressure adjustment means, and in this state, a series of pulse waves are collected by the pulse wave sensor, and the correspondence determination means first collects the pulse waves. The correspondence relationship between the magnitude of the pulse wave collected and the blood pressure value stored in the storage means is determined, and the above-mentioned value is determined based on the magnitude of the pulse wave collected subsequent to the first pulse wave by the continuous blood pressure value determining means. Blood pressure values are continuously determined from the correspondence.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 1, reference numeral 10 denotes a bag-shaped cuff as a compression means for compressing the arm or the like of the subject, and the cuff 10 has a pressure sensor 12. cuff 1
14. Electric pump that supplies air into the 0 and increases its pressure.
A rapid exhaust electromagnetic valve 16 for rapidly reducing the pressure within the cuff 10 by 1" after blood pressure measurement is completed; and an exhaust flow restriction restrictor 18 for gradually decreasing the pressure within the cuff 10.
A solenoid valve 20 for rate-limiting exhaust is connected thereto.

The pressure sensor 12 is configured with an amplifier, and after amplifying the detected pressure, supplies a pressure signal SP representing the pressure to the low-pass filter 22 and the band-pass filter 24. The low-pass filter 22 removes vibration components such as pulse waves synchronized with the pulse of the human body from the pressure signal SP, and supplies the pressure signal SP representing the static pressure of the cuff 10 to the multiplexer 26 .

The band pass filter 24 is the low pass filter 22
On the contrary, a pulse wave signal SM obtained by extracting only the pulse wave component from the pressure signal SP is supplied to the multiplexer 26, and together with the pressure sensor 12, constitutes a pulse wave sensor. The pressure signal SP and pulse wave signal SM supplied to the multiplexer 26 are alternately applied to the A/D converter 3 in accordance with the timing signal ST supplied from the I10 boat 28.
0c=mi*h゛″:hv, 11″5″; ))Bv″
-゛(1°h?,: BE.

After being converted into force signal SPD and pulse wave signal SMD, I10
It is supplied to boat 28.

The I10 port 28 connects the CPU via the data bus line.
32. RAM34. It is connected to ROM36 and the CP
U32 utilizes the temporary storage function of RAM34 and stores it in ROM.
The signals supplied to the I10 boat 28 are processed according to a program prestored in the electric pump 14.36. Drive signals PD, MDI, and MD2 are supplied to the solenoid valves 16 and 20, respectively, and the above-mentioned timing signal S'T is supplied to the multiplexer 26. In addition, the display device 3
8 is supplied with a display signal DD from the I/○ port 28. This display device 38 displays a two-dimensional chart on a cathode ray tube provided with a two-dimensional chart in which a horizontal axis 40 and a vertical axis 42 represent time and blood pressure (non-Hg), respectively, as shown in FIG. 2, according to the supplied display signal DD. A bar graph 44 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. Note that a start/stop signal SC is supplied to the I10 port 28 by the closing operation (ON operation) of the start/stop switch 46, so that the device is started or stopped each time the start/stop switch 46 is operated. Further, the CPU 32 is supplied with a pulse signal CK of a predetermined frequency from a clock signal source 48.

Next, the operation of this embodiment will be explained 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 the start/stop switch 46 has been opened, in other words, whether the start/stop signal SC is being supplied to the I10 port 28. Ru. After the cuff 10 is wrapped around the subject's arm, start/stop switch 46
When the timer is opened, step S2 is executed, and the counting content T of the timer is reset to zero, and then counting of the pulse signal CK supplied from the clock signal source 48 is started again. Subsequently, step S3 is executed, and the solenoid valve 16
and 20 are closed, and the electric pump 14 is operated according to the drive signal PD. As a result, air is supplied into the cuff 0 and the cuff 10 represented by the pressure signal SPD
The static cuff pressure P increases, and in step S4 it is determined whether the cuff pressure P has reached a predetermined maximum pressure P1. This maximum pressure P1 is higher than the expected systolic blood pressure value of the subject, for example, 180 mml (
When the cuff pressure P reaches the maximum pressure P1, step S5 is subsequently executed.

In step S5, the electric pump 14 is stopped and the solenoid valve 20 for slow exhaust is activated by the drive signal MD2.
The air in the cuff 10 is gradually exhausted through the restrictor 18, and the cuff pressure P is slowly lowered. Then, in such a state, the blood pressure measurement routine of step S6 as a measuring means is executed, and the cuff pressure P is changed to the maximum based on the change in the magnitude of the pulse wave, which is the pressure vibration of the cuff 10 represented by the pulse wave signal SMD. Hypertension value H (mmHg
) and diastolic blood pressure value L (mmHg) are determined, and those blood pressure values H and L are stored in R as a storage means.
It is stored in AM34.

' ~ □ When the systolic blood pressure value H and the diastolic blood pressure value are determined in step S6, step S7 is executed next, and the cuff pressure P is lowered to a predetermined relatively low two constant pressure P2. It is decided whether or not it was done.

This constant pressure P2 is desirably set to a value lower than the hemostatic force of the veins of the subject, for example, 15 mmHg.
When the cuff pressure P reaches the second constant pressure P2, step S8 is executed and the solenoid valve 20 is closed. As a result, the compression pressure by the cuff 10, that is, the cuff pressure P
is maintained at a relatively low two constant pressure P2,
These steps S7 and S8 constitute compression pressure adjustment means.

Step 89 and subsequent steps are executed while the cuff pressure P is maintained at a constant pressure P2, and as shown in FIG. 4, a series of pulse waves MKI, MK2, . . . are sequentially read. Systolic blood pressure values sys based on their magnitude
and the diastolic blood pressure value DIA are continuously measured.

That is, first in step S9, the pulse wave signal SM
It is determined whether one pulse wave has been detected based on D, the pulse wave MKI for which the first pulse wave MKI is detected is read, and then step S10 is executed, and the read pulse wave MKI is read. From wave MKI to its highest value M1
(mmHg) and the minimum value ms (mmHg) are determined. Subsequently, step 311 is executed, and the maximum value Mmax (mmHg) and the minimum value Mmin of the pulse wave are determined.

Systolic blood pressure value 3YS based on (m+aHg)
(mmHg) and the diastolic blood pressure value DI A (mh), it is determined whether the constants Kmax and Kmin of the correspondence equation: % formula % (1) have already been determined. Constant K maX, and Kmj
If n, has already been determined, step 312 is executed, but since the constants Kmax and Kmin have not yet been determined at the stage when the first pulse wave MKI is read, step S13 is executed next. executed.

In step S13, the systolic blood pressure value H and the diastolic blood pressure value stored in the RAM 34 in step S6, and the pulse wave MK determined in step S10 are used.
From the maximum value M□ of I and ml, the above correspondence relational expression (1
) and the constant Kmax in (2).

and Kmin are determined as shown in the following formula: % formula % (3) Accordingly, the correspondence relation formulas (1) and (2) are specifically determined. That is, this step S13 constitutes a correspondence determining means for determining the correspondence between the magnitude of the pulse wave and the blood pressure value.

Next, step S14 is executed, and the display signal DD representing the systolic blood pressure value H and the diastolic blood pressure value is supplied to the display device 38, and a bar graph 44 representing the blood pressure values H and L is displayed on the cathode ray tube. . Next, step S15
is executed, and the start/stop switch 46 is operated again (OFFI).
It is determined whether or not the work was done. Start/stop switch 46
is operated again and the start/stop signal SC is not supplied, step S16 is executed, the solenoid valve 16 is opened, and the air in the cuff 10 is rapidly exhausted, but at this stage there is still sufficient air. Since the trend of blood pressure values has not been obtained, the start/stop switch 46 is not operated again. Therefore, step S17 is executed next, and the count content T of the timer becomes the predetermined count content T. It is determined whether or not it has been reached.

This counting content T. corresponds to the time interval for re-determining the correspondence relationship in order to optimize the correspondence relationship determined in step S13, and is set to, for example, about 5 to 10 minutes. Therefore, the count content T is T. If it reaches, step 81 and subsequent steps will be executed again, but at this stage immediately after the first pulse wave MKI is detected after blood pressure measurement, the count content T is still T. Since this has not been reached, steps 89 and subsequent steps are executed.

Pulse wave MK2 following the pulse wave MKI in step S9
When is detected, step 310 is subsequently executed, and the maximum value M2 (wit(g)) and minimum value m2 (mmHg) of the pulse wave MK2 are determined.In step 311, the step "
In S 13 constants Kmax and Kmin,
Since 1+lI has been determined, a YES judgment is made, and then step S12 is executed. In step S12, the systolic blood pressure value and diastolic blood pressure value corresponding to the maximum value M2 and minimum value m2 of the pulse wave MK2 are determined from the correspondence equations (1) and (2), and these blood pressure values are used to The blood pressure value is estimated to be the person's actual blood pressure value and displayed on the cathode ray tube in the next step S14.

Thereafter, step S15 or S], until the determination in step S7 becomes YES, step S9. SIO,SLl,S
12. SL, 1. The execution of S15 and S17 is repeated, and each time a pulse wave is detected, in other words, for each pulse of the artery, the correspondence relational expressions (1) and (2) are calculated based on the highest and lowest values of the pulse wave. The systolic blood pressure value and the diastolic blood pressure value are continuously measured. The step S12 constitutes continuous blood pressure value determination means that continuously determines the blood pressure value based on the magnitude of the pulse wave.

Then, the count content T of the timer is T. Reach step S
Every time the judgment in step 17 is YES, step 7 1
The execution from step S1 onwards is repeated, and based on the actual systolic blood pressure value and diastolic blood pressure value newly measured in step S6, and the highest value and lowest value of the pulse wave at the forefront detected in step S9, The constants Kmax and Kmin of the correspondence equations (1) and (2) are determined, and based on the maximum and minimum values of the pulse waves subsequently detected from the new correspondence equations (1) and (2). Continuous blood pressure measurements are taken repeatedly.

As described above, in this embodiment, once the actual systolic blood pressure value and diastolic blood pressure value of the subject are measured, the cuff 10
The cuff pressure P is maintained at a relatively low two constant pressure P2, and the systolic blood pressure and diastolic blood pressure values are continuously measured based on the maximum and minimum values of the pulse wave detected in this state. Blood pressure measurement can be performed continuously for a long time without obstructing blood circulation or causing pain to the person being measured. Here, as mentioned above, it is desirable to set the constant pressure P2 lower than the venous hemostatic pressure, but it may be set arbitrarily in consideration of the part where the cuff 10 is wound, the measurement time, the health condition of the subject, etc. For example, it is possible to set the pressure to a higher value than the diastolic blood pressure value of the subject.

In addition, in this embodiment, the systolic blood pressure value and the diastolic blood pressure value can be measured simultaneously and continuously for each pulse of the artery, compared to the conventional continuous blood pressure measurement method that could only measure either one at a time. , it is possible to obtain high-density medical information. Note that it is of course possible to continuously measure either the systolic blood pressure value or the diastolic blood pressure value, or it is also possible to continuously measure the average blood pressure value or other blood pressure values. can.

Furthermore, in this example, the constants Kmax and Km of the correspondence equations (1) and (2), which are the basis for calculating the systolic blood pressure value and the diastolic blood pressure value from the maximum and minimum values of the pulse wave, are
In, is newly calculated at regular time intervals, so the systolic blood pressure and diastolic blood pressure values obtained even during long-term continuous measurements can be calculated from the subject's actual systolic and diastolic blood pressure values. There is no risk of significant deviation.

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

For example, in step S6 of the embodiment described above, the actual blood pressure value of the subject is measured by the so-called oscillometric method based on changes in the magnitude of the pulse wave during the blood pressure lowering process of the cuff 10. Other blood pressure measurement methods, such as a method that detects Korotkoff sounds and determines the blood pressure value according to their presence, or a method that uses ultrasound to detect waves in the arterial surface wall and determines the blood pressure value according to changes in the amplitude of the waves. Furthermore, it is also possible to measure the blood pressure during the pressure increase process of the cuff 10.

Further, in the embodiment described above, the cuff 10 as a compression means is wound around the arm of the person to be measured, but by wrapping it around the finger of the hand and compressing it, the fingertip pulse wave can be detected. There is no problem even if it is detected. In that case, the pulse wave can be collected not only by pressure imaging of the cuff 10 described above but also by transmitted light.

Q Also, in the above example, the correspondence between the actual blood pressure value and the pulse wave size is determined on the premise that there is a proportional relationship between them, but it is assumed that the blood pressure value is a quadratic function of the pulse wave size. Based on the subject's blood pressure value and pulse wave size, it is possible to calculate the correspondence relationship expressed in There is no problem in finding the correspondence using other methods, such as finding the correspondence by selecting one piece of data.

Furthermore, in the above embodiment, the continuously measured systolic blood pressure value and diastolic blood pressure value 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. , and other various display means or recording means may be employed.

The above description is merely an example of the present invention, and the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit thereof.

Effects of the Invention As described in detail above, according to the continuous blood pressure measurement method or device of the present invention, once the blood pressure value of the subject is measured, the compression pressure is maintained at a relatively low constant value. Since the blood pressure value is continuously measured based on the size of the pulse wave detected under the condition, it is possible to measure blood pressure over a long period of time without causing pain to the person being measured. It also has the advantage of being able to simultaneously and continuously measure multiple blood pressure values such as the diastolic blood pressure value and the diastolic blood pressure value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the configuration of a continuous blood pressure measuring device that is an embodiment of the present invention. FIG. 2 is a diagram showing an example of the trend of blood pressure values displayed on the display device in the embodiment of FIG. 1. FIG. 3 is a flowchart illustrating the operation of the embodiment shown in FIG. FIG. 4 is a diagram showing an example of a pulse wave continuously detected in the embodiment of FIG. 1. 10: Cuff (compression means) 34, : RAM (memory means) Step S6: Measuring means

Claims (4)

[Claims] (1) A continuous blood pressure measurement method that continuously measures blood pressure based on pulse waves generated when a part of the living body is compressed, the blood pressure value being determined while changing the compression pressure on the part of the living body. This is stored, the compression pressure is maintained at a relatively low constant value, pulse waves are continuously collected, and the magnitude of the earliest part of the series of pulse waves is compared with the memorized blood pressure value. A continuous blood pressure measuring method characterized in that a correspondence is determined, and a blood pressure value is continuously determined based on the magnitude of the pulse wave following the first pulse wave from the correspondence. (2) The continuous blood pressure measuring method according to claim 1, wherein the blood pressure value is a systolic blood pressure value and/or a diastolic blood pressure value, and the magnitude of the pulse wave is its maximum value and/or minimum value. (3) The continuous blood pressure measuring method according to claim 1, wherein the blood pressure value is an average blood pressure value, and the magnitude of the pulse wave is the average value. (4) A continuous blood pressure measurement device that continuously measures blood pressure based on pulse waves generated when a part of a living body is compressed, comprising: a compression means for compressing the part of the living body; A pulse wave sensor that collects a pulse wave generated when a part of the living body is compressed, and a blood pressure value determined while changing the pressure applied to the part of the living body by the compression means, and the blood pressure value stored in a storage means. a measuring means for storing the blood pressure value; a compression pressure adjustment means for maintaining the compression pressure by the compression means at a relatively low constant value following the determination of the blood pressure value by the measurement means; and a compression pressure adjustment means for maintaining the compression pressure at a relatively low constant value by the compression pressure adjustment means. a correspondence determining means for determining a correspondence between the magnitude of the foremost part of a series of pulse waves collected when the blood pressure is maintained at a constant relatively low value and the stored blood pressure value; 1. A continuous blood pressure measurement device comprising continuous blood pressure value determining means for continuously determining a blood pressure value based on the magnitude of the pulse wave following the foremost pulse wave.