JPH06319708A - Electronic hemomanometer - Google Patents

Abstract

PURPOSE:To measure blood pressure with a high accuracy even with respect to a person generating a difference between the blood pressure value measured in a peripheral part and that measured in an upper arm part by correcting the difference. CONSTITUTION:After the max. blood pressure is estimated (ST11) and the min. blood pressure is estimated (ST15), the pulse waveform of one pulse at the time of the estimation of the max. blood pressure is subjected to secondary differentiation and the ratio (waveform strain) of the depth D(1) of the first trough of the obtained secondary differentiated waveform and the depth D(2) of the second trough thereof is computed and, corresponding to this tatio. the estimated max. and min. blood pressures are corrected (ST17).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic sphygmomanometer which is devised to improve accuracy.

[0002]

2. Description of the Related Art In a conventional electronic sphygmomanometer, a cuff is attached to an arm or the like, a cuff is pressurized by a pump or the like to stop blood flow in an artery, and then a slow depressurization of the cuff pressure is performed, and the depressurization is performed. The pulse wave amplitude value of the pulse wave component obtained in the process is calculated, and a predetermined algorithm is applied to the change in the cuff pressure and the pulse wave amplitude sequence to determine the systolic blood pressure (SYS) and the diastolic blood pressure (DIA). . This algorithm is, for example, the pressure at the point where the threshold and the envelope, which is a predetermined ratio, intersect the maximum pulse wave of the pulse wave amplitude curve (envelope) in the process of increasing the pulse wave amplitude value in the depressurization process. The pressure at the point where the envelope and the threshold value, which is a predetermined ratio of the maximum pulse wave, intersect the envelope in the amplitude decreasing process is determined as the minimum blood pressure.

[0003]

The conventional electronic blood pressure monitor described above applies the same algorithm to every person who measures.
On the other hand, in people who may have arteriosclerosis or stenosis, there is a possibility that the hemodynamics in the peripheral region may differ, affecting the pulse wave, and changing the pulse wave amplitude value calculated from the pulse wave component. However, when the blood pressure value is determined by the envelope obtained from this, there is a problem in that there is a difference between the blood pressure value measured by the auscultation method in the upper arm.

The present invention has been made by paying attention to the above-mentioned problems, and even a person who has a difference in measurement between the peripheral part and the upper arm due to arteriosclerosis, stenosis, etc. It is an object of the present invention to provide an electronic sphygmomanometer that can be corrected to perform highly accurate measurement.

[0005]

The electronic sphygmomanometer according to claim 1 has a cuff, a pressurizing means for pressurizing the cuff, a depressurizing means for depressurizing the pressure inside the cuff, and the cuff. From the pressure detection means for detecting the fluid pressure inside, the pulse wave component detection means for detecting the pulse wave component included in the output signal of this pressure detection means, and the pulse wave component detected by this pulse wave component detection means A pulse wave amplitude value calculating means for calculating the pulse wave amplitude value, and a blood pressure value determining means for determining the systolic blood pressure and the diastolic blood pressure based on the output signal of the pulse wave amplitude value calculating means and the output signal of the pressure detecting means. In the provision, the pulse wave waveform information detecting means for detecting the waveform information of the pulse wave, the waveform parameter extracting means for extracting a predetermined waveform parameter from the detected waveform information, and the determination based on the extracted waveform parameter. blood And a blood pressure value correcting means for correcting the values.

In this electronic sphygmomanometer, the systolic blood pressure and the diastolic blood pressure are determined from the cuff pressure and the envelope curve of the pulse wave amplitude obtained in the process of changing the cuff pressure by pressurizing the cuff to a predetermined pressure and then depressurizing the cuff. To be done. Also, in the process of changing the cuff pressure, pulse wave waveform information is detected, and from the obtained waveform information, characteristic waveform parameters such as waveform distortion and pulse wave width are extracted, and based on this waveform parameter, the determination is made. Systolic blood pressure,
Correct the blood pressure value such as the lowest blood pressure value.

[0007]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a block diagram showing a circuit configuration of an electronic sphygmomanometer in which the present invention is implemented. This electronic sphygmomanometer includes a cuff 1 worn on a finger, a pressurizing pump 2 for pressurizing the cuff 1, an exhaust valve 3 for depressurizing the cuff 1,
A pressure sensor 4 that detects the air pressure of the cuff 1 and converts it into an electric signal, an amplifier 5, a bandpass filter 6, an AD converter 7 that converts the output of the pressure sensor 4 into a digital signal, and a pressure pump. 2. A CPU 8 that controls the exhaust valve 3 and the like, and executes processing such as blood pressure determination and correction by a signal taken from the AD converter 7, and a display 9 that displays the systolic blood pressure, the diastolic blood pressure, and the like. It is composed of a power switch 10 and a pressure switch 11.

In this electronic sphygmomanometer, the blood pressure is measured by the procedure shown in the flow chart of FIG. With the power on,
When the pressurizing switch 11 is turned on [step ST (hereinafter abbreviated as ST) 1], the pressurizing pump 2 is turned on to start pressurizing (ST2). During pressurization, the pressure of the cuff 1 increases.
Eventually, when the cuff pressure reaches a predetermined target value (ST3),
Turn off the pressure pump 2, open the exhaust valve 3 (ST4),
Slow-speed exhaust is started (ST5). As a result, the cuff pressure gradually decreases. Even in the process of decreasing the cuff pressure, the cuff pressure is read (ST6), the pulse wave is extracted (ST7), and the pulse wave amplitude value is calculated (ST8). Then, the processes of ST6 to ST9 are repeated until the maximum amplitude of the pulse wave is detected (ST9). When the pulse wave amplitude rises as the cuff pressure decreases, and eventually falls, the maximum amplitude is obtained, and the determination in ST9 "whether the maximum amplitude is detected" is YES, and then the maximum pulse wave amplitude is used as a reference. For example, the cuff pressure corresponding to the pulse wave amplitude corresponding to 0.5 on the cuff pressure side is estimated as the systolic blood pressure (ST1
0), the estimated systolic blood pressure Ps ′ is stored (ST1
1).

After that, the cuff pressure reading (ST12) and the pulse wave extraction (ST13) are continued, and the maximum pulse wave amplitude is used as a reference.
For example, when a pulse wave amplitude of 0.7 is obtained (ST14), the cuff pressure at that time is estimated to be the minimum blood pressure (ST15), and the estimated minimum blood pressure value Pd 'is stored (ST16). Subsequently, a blood pressure correction process is executed on the estimated blood pressure value (ST17). This processing is a feature of the present invention and will be described later in detail. When the correction process is completed, the exhaust valve 3 is opened wide to perform rapid evacuation (ST18), the blood pressure value is displayed on the display 9 (ST19), and the measurement is completed.

Next, details of blood pressure correction will be described. Two types of correction methods will be described below. First, the first correction processing procedure will be described with reference to the flowcharts of FIGS. 3 and 4.
Since the systolic blood pressure estimation value Ps ′ and the diastolic blood pressure estimation value Pd ′ obtained by the blood pressure value estimation in FIG. 2 are stored, when ST17 is entered, one pulse near the systolic blood pressure value Ps ′ of the extracted pulse wave component is stored. The wave component Wps 'is extracted (ST21), and in order to clarify the inflection point of this pulse wave component Wps', the second-order differentiation is performed to obtain the waveform Wps (ST22). Next, for this secondary differential waveform Wps, a valley is searched from the rising edge of the waveform (ST23), and when the first valley is found (ST23).
24) [see (b) of FIG. 6], the depth of the valley is D (1)
(ST25). If the second valley is found (ST
26) and determine whether the valley is above the baseline (= 0) (S
T28), if it is above the baseline, the distance from the baseline to the valley bottom is D (2) (ST29) [see (c) of FIG. 6]. If the valley is below the baseline, the depth of the valley is D. (2) (ST30) [see (d) of FIG. 6]. If the second valley is not found in ST26, D (2) = 0 is set (ST27).

When D (1) and D (2) are obtained, D
ip ratio = D (2) / D (1) is obtained (ST31),
The ratio K is used as a parameter of the waveform distortion, and the value is divided into cases to give a constant R. That is, when the ratio K is smaller than 0, R = 2 (ST32, ST33), K
= 0, R = 3 (ST34, ST35), 0 <
When K ≦ 0.25, R = 4 (ST36, ST3
7), if 0.25 <K ≦ 0.5, R = 5 (ST
38, ST39), and if 0.5 <K ≦ 0.75, R =
6 (ST40, ST41), R = 7 if 0.75 <K ≦ 1 (ST42, ST43), and R = 8 if K> 1 (ST42, ST44).

The constant R obtained as described above has already been calculated,
The correction value Y is obtained by substituting the correction function Y = α1 · R + β1 stored in advance. That is, Ys ← α1sR +
β1s and Yd ← α1d + β1d are obtained (ST45).
Then, using the calculated correction values Ys and Yd, the systolic blood pressure SYS = Ps′−Ys and the diastolic blood pressure DIA = Pd′−Y.
Determine d. The correction coefficient α1s used here is
β1s, α1d, and β1d are numerical values shown in FIG.

Next, the second correction processing procedure will be described with reference to the flowchart of FIG. Also in this case, when entering this process,
The one-beat pulse wave waveform Wps 'in the vicinity of the estimated systolic blood pressure value Ps' of the detected pulse wave component is extracted (ST51), and this pulse wave waveform W is extracted.
The second-order differentiation is applied to ps' to obtain the waveform Wps (ST5
2). Next, the first maximum point at the rising edge of the waveform is calculated (ST5
3, ST54), and as the trailing edge of the waveform, the last minimum point is searched (ST55, ST56) [see (a) and (b) of FIG. 6], and the pulse width W of the original pulse wave waveform is obtained (ST57). The correction value is obtained by substituting the pulse width W of this waveform into a correction function Ys = α2 · W + β2 that has been calculated and stored in advance. That is, Ys = α2sW + β2s, Yd = α
2dW + β2d is calculated (ST58), and first the correction value Y
Substituting s and Yd into the following equation, systolic blood pressure SYS = Ps′−
Ys and diastolic blood pressure DIA = Pd′−Yd are calculated to obtain a corrected blood pressure value (ST59). The correction coefficients α2s, β2s, α2d, β2d used here are the values shown in FIG. 7.

Both of the above two correction methods may be executed in ST17, or either one may be adopted. Here, FIG. 8 shows the correlation coefficient before and after the measurement by the auscultation method on the upper arm and the blood pressure value measured by the finger (measurement value by the photoelectric pulse wave method). However, in FIG. 8, error = finger blood pressure value−upper arm blood pressure value. From the table shown in FIG. 8, the correlation coefficient after correction is higher by about 0.1 as compared with before correction, and the correction can bring the measurement closer to the auscultation method in the upper arm.

[0015]

According to the present invention, since the blood pressure value is determined by the conventional blood pressure determination means, a means for correcting the blood pressure value is provided according to the shape of the pulse wave waveform in each individual.
Only the person who made the error can be corrected. Further, in measuring the blood pressure of a finger, the blood flow that flows out during the process of decreasing the cuff pressure is reflected by the influence of peripheral resistance and the like, which affects the hemodynamics, the waveform is deformed, and the shape of the envelope is changed. As a result, the difference caused in the blood pressure value with the upper arm due to the auscultation method is corrected by catching the phenomenon with the waveform, so that the inconvenience due to the difference can be eliminated.

Further, when arteriosclerosis or stenosis caused by a hypertensive patient occurs between the upper arm and the peripheral portion, when a difference occurs between the measured value on the upper arm and the blood pressure value measured on the wrist or finger, The inconvenience can be eliminated by capturing and correcting the phenomenon with a waveform.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an electronic sphygmomanometer in which the present invention is implemented.

FIG. 2 is a flowchart for explaining the overall operation of the electronic blood pressure monitor.

FIG. 3 is a flow chart for explaining details of a blood pressure value correction routine of the flow chart of FIG.

FIG. 4 is a flowchart for explaining details of the blood pressure value correction routine in the flowchart of FIG. 2 together with FIG. 3;

FIG. 5 is another flowchart for explaining the details of the blood pressure value correction routine of the flowchart of FIG.

6 is a waveform diagram for explaining blood pressure value correction in FIGS. 3, 4, and 5. FIG.

FIG. 7 is a diagram showing correction coefficients of the embodiments shown in FIGS. 3, 4, and 5;

FIG. 8 is a diagram showing a relationship between an upper arm blood pressure value obtained by auscultation and a finger blood pressure value obtained by a finger-type blood pressure monitor (photoplethysmograph).

[Explanation of symbols]

 1 cuff 2 pressurizing pump 3 exhaust valve 4 pressure sensor 7 A / D converter 8 CPU

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[Procedure amendment]

[Submission date] April 7, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art In a conventional electronic sphygmomanometer, a cuff is attached to an arm or the like, a cuff is pressurized by a pump or the like to stop blood flow in an artery, and then a slow depressurization of the cuff pressure is performed, and the depressurization is performed. The pulse wave amplitude value of the pulse wave component obtained in the process is calculated, and a predetermined algorithm is applied to the change in the cuff pressure and the pulse wave amplitude sequence to determine the systolic blood pressure (SYS) and the diastolic blood pressure (DIA). . The algorithm, for example, the maximum amplitude pulse wave amplitude curve in the pulse wave amplitude value increase process in pressure reduction process (envelope)
Is to determine the diastolic blood pressure of the intersection point is a threshold value is a predetermined percentage of the maximum amplitude envelope in the predetermined ratio systolic blood pressure of the point threshold value intersect a pulse wave amplitude reduction process .

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

The present invention has been made in view of the above-mentioned problems, and even in a person who has a difference between the measurement in the peripheral portion and the measurement in the upper arm due to arteriosclerosis or stenosis, blood
Corrects the gap generated by the pulse wave waveform that captures the behavioral information ,
It is an object of the present invention to provide an electronic sphygmomanometer capable of highly accurate measurement.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

[0005]

The electronic sphygmomanometer according to claim 1 has a cuff, a pressurizing means for pressurizing the cuff, a depressurizing means for depressurizing the pressure inside the cuff, and the cuff. From the pressure detection means for detecting the fluid pressure inside, the pulse wave component detection means for detecting the pulse wave component included in the output signal of this pressure detection means, and the pulse wave component detected by this pulse wave component detection means A pulse wave amplitude value calculating means for calculating the pulse wave amplitude value, and a blood pressure value determining means for determining the systolic blood pressure and the diastolic blood pressure based on the output signal of the pulse wave amplitude value calculating means and the output signal of the pressure detecting means. And a predetermined waveform parameter obtained from the detected waveform information.
Parameter that represents the waveform width or waveform distortion
Waveform parameters to be calculated as parameters or both
It is provided with a calculating means and a blood pressure value correcting means for correcting the determined blood pressure value based on the calculated waveform parameter.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

In this electronic sphygmomanometer, the blood pressure is measured by the procedure shown in the flow chart of FIG. With the power on,
When the pressurizing switch 11 is turned on [step ST (hereinafter abbreviated as ST) 1], the pressurizing pump 2 is turned on to start pressurizing (ST2). During pressurization, the pressure of the cuff 1 increases.
Eventually, when the cuff pressure reaches a predetermined target value (ST3),
Turn off the pressure pump 2, close the exhaust valve 3 (ST4),
Slow-speed exhaust is started (ST5). As a result, the cuff pressure gradually decreases. Even in the process of decreasing the cuff pressure, the cuff pressure is read (ST6), the pulse wave is extracted (ST7), and the pulse wave amplitude value is calculated (ST8). Then, the processes of ST6 to ST9 are repeated until the maximum amplitude of the pulse wave is detected (ST9). When the pulse wave amplitude rises as the cuff pressure decreases, and eventually falls, the maximum amplitude is obtained, and the determination in ST9 "whether the maximum amplitude is detected" is YES, and then the maximum pulse wave amplitude is used as a reference. For example, the cuff pressure corresponding to the pulse wave amplitude corresponding to 0.5 on the cuff pressure side is estimated as the systolic blood pressure (ST1
0), the estimated systolic blood pressure Ps ′ is stored (ST1
1).

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

After that, the cuff pressure reading (ST12) and the pulse wave extraction (ST13) are performed , the pulse wave amplitude calculation (ST14) is continued, and a pulse wave amplitude of, for example, 0.7 is obtained based on the maximum pulse wave amplitude. When used (ST1 5), the cuff pressure at that time was estimated as diastolic blood pressure (ST1 6), stores the minimum blood pressure estimate value Pd '(ST1 7). Subsequently, to the estimated blood pressure value, it executes a blood pressure value correcting process (ST1 8). This processing is a feature of the present invention and will be described later in detail. When the correction process is completed, open the exhaust valve 3 wide,
Rapid exhaust with (ST1 9), the display unit 9 to display the blood pressure value (ST 20), and ends the measurement.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

Next, details of blood pressure correction will be described. Two types of correction methods will be described below. First, the first correction processing procedure will be described with reference to the flowcharts of FIGS. 3 and 4.
Since the systolic blood pressure estimation value Ps ′ and the diastolic blood pressure estimation value Pd ′ obtained by the blood pressure value estimation in FIG. 2 are stored, when ST17 is entered, one pulse near the systolic blood pressure value Ps ′ of the extracted pulse wave component is stored. The wave component Wps 'is extracted (ST21), and in order to clarify the inflection point of this pulse wave component Wps', the second-order differentiation is performed to obtain the waveform Wps (ST22). Next, for this secondary differential waveform Wps, a valley is searched from the rising edge of the waveform (ST23), and when the first valley is found (ST23).
24) [see (b) of FIG. 6], the depth of the valley is D (1)
(ST25). If the second valley is found (ST
26) and determine whether the valley is above the baseline (= 0) (S
T28), if it is above the baseline, the distance from the baseline to the valley bottom is D (2) (ST29) [see (c) of FIG. 6]. If the valley is below the baseline, the depth of the valley is D. (2) (ST30) [see ( b ) in FIG. 6]. If the second valley is not found in ST26, D (2) = 0 is set (ST27).

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Further, when arteriosclerosis or stenosis caused by a hypertensive patient occurs between the upper arm and the peripheral portion, when a difference occurs between the measured value on the upper arm and the blood pressure value measured on the wrist or finger, By capturing and correcting the phenomenon with the waveform, it becomes a difference
It is possible to eliminate the inconvenience. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 8, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 4

[Correction method] Change

[Correction content]

[Figure 4]

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

Claims (3)

[Claims] 1. A cuff, a pressurizing means for pressurizing the cuff, a depressurizing means for reducing the internal pressure of the cuff, a pressure detecting means for detecting a fluid pressure in the cuff, and an output signal of the pressure detecting means. A pulse wave component detecting means for detecting the included pulse wave component, a pulse wave amplitude value calculating means for calculating a pulse wave amplitude value from the pulse wave component detected by the pulse wave component detecting means, and this pulse wave amplitude value calculating means An electronic sphygmomanometer comprising: a blood pressure value determining means for determining the systolic blood pressure and the diastolic blood pressure based on the output signal of the means and the output signal of the pressure detecting means, and a pulse wave waveform information detecting means for detecting the waveform information of the pulse wave. A waveform parameter extracting means for extracting a predetermined waveform parameter from the detected waveform information, and a blood pressure value correcting means for correcting the blood pressure value determined based on the extracted waveform parameter. Electronic blood Pressure gauge. 2. The waveform parameter extracting means, a second derivative processing means for subjecting the detected waveform information to a second derivative, and a waveform for calculating the distortion of the original pulse wave waveform from the depth of the valley of the second derivative waveform. And a blood pressure value correction means,
The electronic blood pressure monitor according to claim 1, wherein the blood pressure value is corrected based on the calculated waveform distortion. 3. The waveform parameter extracting means, which is a second derivative processing means for subjecting the detected waveform information to a second derivative, and a rising edge and a falling edge of the original pulse wave waveform from the second derivative waveform to obtain a width. The electronic sphygmomanometer according to claim 1, further comprising: a pulse wave width calculating means for calculating the blood pressure value, wherein the blood pressure value correcting means corrects the blood pressure value based on the calculated pulse wave width.