JPH03123535A - Electronic sphygmomanometer - Google Patents

Abstract

PURPOSE:To obtain a highly reliable apparatus with a highly accurate checking by arranging a point detection means to detect points between a maximum blood pressure and a minimum blood pressure based on the generation and the vanishing of a Korotokov sound and a judging means for judging validity of points and a display means. CONSTITUTION:A microcomputer 50 is made up of a CPU 51 for computation and control, an ROM 52 for storing a control program and an RAM for auxiliary memory and the RAM 53 has a pulse wave memory section 53a which stores at least a maximum peak value of a pulse wave and a pulse wave five beats before and after generation and vanishing points of a Korotkov sound made to correspond to a pressure cuff and bag. Then, the generation and vanishing of a Korotkov sound are detected from a korotkov sound recognition signal from a Korotkov sound detector section 10 and furthermore, generation and vanishing points of the Korotkov sound are checked from a peak value of a pulse wave data from a pulse wave detector section 30. Then, a pressure of the pressure cuff and bag at the generation and vanishing points of the Korotkov sound are shown on an LCD display section 70 as blood pressure value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic sphygmomanometer, particularly an electronic sphygmomanometer using both the Korotkoff method and the oscillometric method.

[Prior Art] An electronic blood pressure monitor that measures blood pressure by compressing a part of a living body with a cuff first pressurizes the cuff to a pressure higher than the person's systolic blood pressure, then depressurizes the body while applying pressure to the compression part. The Korotkoff method recognizes blood pressure by using a sensor to detect the onset and disappearance of the Korotkoff sounds generated by the cuff, and the blood pressure is determined by observing temporal changes in the magnitude of the cuff oscillation arterial wave signal superimposed on the cuff pressure signal. Oscillometric methods for determining values are known.

Of these, the one that has a better correlation with the auscultation method is the Korotkoff method blood pressure monitor, which uses the same Korotkoff sounds. However, the frequency band of the Korotkoff sound signal overlaps with the rubbing sound of a rubber tube, the rubbing sound of a cuff, etc., and may be misrecognized due to noise mixed in during measurement.

As a method for dealing with these problems, there is an oscillometric method that uses a pulse wave signal, since the cuff vibration arterial wave superimposed on the cuff pressure signal has a different frequency band from the above-mentioned scraping sound. However, the correlation with the auscultation method was not very good because the detected signals were different.

In order to compensate for the shortcomings of both of these methods, a blood pressure monitor has been proposed in which blood pressure values are determined independently using both methods, and the reliability of the blood pressure values is checked by comparing the measurement results (Japanese Patent Application Laid-open No. 1983-1999-1). No. 171539).

[Problems to be Solved by the Invention] However, in the conventional example described above, only blood pressure values obtained independently are compared, so although the accuracy is higher than that of a blood pressure monitor with only one type, the check is rough. Therefore, a check method with higher accuracy is desired.

The present invention eliminates the drawbacks of the conventional art and provides a highly reliable electronic blood pressure monitor with highly accurate checks.

Furthermore, by determining blood pressure values during pressure increase and pressure reduction, a more accurate check can be performed and a more reliable electronic blood pressure monitor is provided.

[Means for Solving the Problem] In order to solve this problem, the electronic blood pressure monitor of the present invention measures blood pressure by applying pressure with a cuff that is a part of a living body. or a point detection means for detecting a point between the systolic blood pressure and the diastolic blood pressure based on disappearance, and determining the validity of the point based on the pulse wave height at the point and the change in pulse wave height before and after the point. and a display means for displaying a blood pressure value in accordance with the determination result of the determining means.

Here, the point detection means detects each point at the time of pressurization and depressurization, and determines the validity of the point based on the difference between the blood pressure value at the time of pressurization and the blood pressure value at the time of depressurization.

[Operation] In this configuration, the validity of the systolic blood pressure and diastolic blood pressure points recognized by the Korotkoff method can be determined within a certain range by utilizing the fact that there is a change in the vascular volume under the cuff at the point where the Korotkoff sound occurs and disappears. Increase the reliability of measurement results by making judgments based on accuracy.

Embodiment FIG. 1 is a block diagram showing the configuration of an electronic blood pressure monitor according to this embodiment.

A Korotkoff sound sensor 2 is provided on the peripheral side of the cafe and cuff that compresses a part of the living body, and the signal from the Korotkoff sound sensor 2 is input to the Korotkoff sound detection unit 10, and after being amplified by an amplifier 11, the frequency band is controlled. Bandpass filter 1
2 to a comparator 13, and a value above a certain threshold from a threshold input circuit 14 is determined to be a Korotkoff sound. This Korotkoff sound recognition signal is input manually to the microcomputer 50.

On the other hand, the signal from the pressure sensor 21 connected to the cafe is input to the pressure detection section 20, and after being amplified by the amplifier 22,
It is connected to the A/D converter 33 and its digital output is input to the microcomputer 50. Further, after the signal from the pressure sensor 21 is amplified by the amplifier 20, it is input to the pulse wave detection unit 30, passed through a bandpass filter 31 that limits the frequency band in order to remove DC components and cancel noise, and then amplified again by the amplifier 32. It is connected to the A/D converter 33 and its digital output is input to the microcomputer 50.

The microcomputer 50 includes a CPU 5 for calculation and control.
1, a ROM 52 for storing a control program, and a RAM 53 for auxiliary storage.The RAM 53 stores at least the maximum pulse wave value and the pulse waves of 5 beats before and after the point of occurrence and extinction of the Korotkoff sound in association with the cuff. The pulse wave storage section 53a has a pulse wave storage section 53a. The microcomputer 50 operates with power supplied from the power supply section 60, detects the occurrence and extinction of Korotkoff sounds from the Korotkoff sound recognition signal from the Korotkoff sound detection section 10, and further detects the pulse wave data from the pulse wave detection section 30. Check the point at which the Korotkoff sound occurs and disappears from the wave height. Then, the cuff pressure at the point where the Korotkoff sound occurs and disappears is displayed on the LCD display section 70 as a blood pressure value.

The microcomputer 50 also controls the air supply pump 42 . Rapid exhaust valve 43.
The pressure inside the cafe is controlled by driving the bypass valve 45 and the like. A surge tank 46a and a fluid resistance 46b are provided as a pulsation prevention filter 46 between the cuff 1 and the air pump 42. The microcomputer 50 controls these pumps and valves while monitoring the cuff pressure to achieve a predetermined change in cuff pressure. 47 is a constant speed exhaust valve during pressure reduction.

Example of measurement only during decompression> When measuring the points at which Korotkoff sounds occur and disappear in a continuous manner using a blood pressure monitor equipped with the cuff oscillation arterial wave detection unit 30, the cuff pressure value at the point of occurrence is used as the systolic blood pressure value or the point at which Korotkoff sounds disappear. It has the function of setting the cuff pressure value at the point of occurrence as the diastolic blood pressure value, or the pressure value at the point of disappearance as the systolic blood pressure value in the case of measurement during pressure increase, and the point at which the Korotkoff sound occurs, 5 before and after including the disappearance point
The validity of the systolic blood pressure point and diastolic blood pressure point recognized by the Korotkoff method using the flow shown below with a sphygmomanometer that has the function of storing the maximum value of the pulse wave size and the maximum value of the pulse wave size for each pulse. Check.

FIG. 2 is a diagram showing the measurement principle of the blood pressure monitor of this embodiment, which measures blood pressure only when the pressure is reduced.

The first point at which Korotkoff sounds occur consecutively as a result of depressurization after pressurization is defined as the systolic blood pressure point. From the pulse wave height values of 5 beats before and after this point, calculate the difference in order by △
S1□, △S1□△S 13. ΔSI4 is set, and the validity of the systolic blood pressure point is checked based on the peak value at the systolic blood pressure point and their difference value.

Further decompression is continued, and the first point at which the Korotkoff sounds disappear continuously is defined as the diastolic blood pressure point.

From the pulse wave height values of five beats before and after this point, the difference is taken and the difference is sequentially △Dr, △D2. △D3. ΔD4, and the validity of the diastolic blood pressure point is checked based on the peak value at the diastolic blood pressure point and the difference value between these values.

The operation of the electronic sphygmomanometer of this embodiment will be described in detail below in accordance with flowcharts showing the operating procedure of the electronic blood pressure monitor of this embodiment shown in FIGS.

FIG. 3 shows the main flow of the electronic blood pressure monitor of this embodiment.

First, in step Sll, initialization such as setting the pressure to zero is performed. In step SL2, pressurization is started, and in step 313, it is checked whether the predetermined pressure is higher than the systolic blood pressure value. If it is, pressurization is stopped, and step S14
Start depressurizing. At the same time as the start of depressurization, step S1
5, storage of the pulse wave in the pulse wave storage section 53a is started.

In step S16, a time point at which Korotkoff sounds occur continuously is found, and in step S17, this time point is stored as a systolic blood pressure point.

Next, in step S18, it is checked whether it is the maximum value of the pulse wave, and if the maximum value is detected, this maximum wave height value M is stored in step S19. In step S20, validity is checked based on the difference between the peak value at the systolic blood pressure point and the previous and subsequent peak values.

FIGS. 4A and 4B are flowcharts showing two examples of checking the systolic blood pressure value in step S20.

In step S31, the pulse wave height value at the systolic blood pressure point is set to A% (for example, 3%) of the maximum wave height value stored in step S19.
0%) or more. If not, the validity of the measured systolic blood pressure value is questionable, so the systolic blood pressure value is displayed blinking in step S34. If it is A% or more, the process advances to step S32 and the difference value △SI□ or △S
I3 is set to the maximum value M to a predetermined value B (for example, B=0.10<B<
1) is checked, and in the following cases, the display blinks in step S34.The peak value is greater than or equal to the maximum value M(7)A% and the difference value is △8, 2 or △S.
13 is larger than the maximum value M multiplied by the predetermined value B, the measured systolic blood pressure value is deemed to have validity, and the systolic blood pressure value is displayed normally in step S33.

In FIG. 4B, the check in step S36 is performed instead of the check in step S32 in FIG. 4A.

In step S36, α, = △S++/△S1□ β1=△S1□/△SI3 γ1=△S13/△S14 It is.

Returning to FIG. 3, the process proceeds to step S21, in which the disappearance of the Korotkoff sounds is continuously checked, and in step S22, the time of disappearance is stored as the diastolic blood pressure point. Subsequently, in step S23, the validity of this diastolic blood pressure is checked.

FIGS. 5A and 5B are flowcharts showing two examples of checking the diastolic blood pressure value in step S23.

First, in step S41, the pulse wave height value at the diastolic blood pressure point is 0% (
For example, it is checked whether it is greater than or equal to 40%. If it is not 0% or more, it is determined that there is a problem with the validity of the diastolic blood pressure, and the diastolic blood pressure value is displayed blinking in step S44. If it is larger than 0%, the process proceeds to step 842, where the difference value ΔD2 or ΔD3 is set to the maximum value M by a predetermined value D (for example, D=0.10<
It is checked whether the value is greater than the value multiplied by D<1), and if it is not greater, the display is blinked in step S44. If the peak value is greater than 0% of the maximum value M, the difference value △D2 or △D
3 is larger than the maximum value M multiplied by a predetermined value, the diastolic blood pressure value is normally displayed in step S43.

FIG. 5B replaces step S42 in FIG. 5A with step S4.
6 was replaced.

In step S46, α2=△D2/△D1 β2=△D3/△D2 γ2=△D4/△D3 It is.

<Example of measurement during pressurization and depressurization> For blood pressure monitors that measure the diastolic and systolic blood pressures during pressurization, and then measure the diastolic blood pressure using the Korotkoff method when depressurizing again, the lowest pressure on the pressure booster clock side is measured as shown in the flow below. Compare the blood pressure value and the diastolic blood pressure value on the decompression watch side. Since the range of blood pressure fluctuation in a living body is usually about 10-odd mmHg at rest, if the difference between the two is within 10-odd mmHg, it will be slower than when the pressure increases. Measures at decompression speed and displays the highly accurate diastolic blood pressure during decompression.If the distance is more than 10 mmHg, check the diastolic blood pressure in the same way as above and display the more reasonable one of the two. However, if both are judged to be valid, the diastolic blood pressure value at the time of decompression is displayed with priority as the diastolic blood pressure for the above-mentioned reason.

When checking the validity of the diastolic blood pressure during pressurization, it is empirically determined that the pulse wave just before the point where Korotkoff sounds occur is relatively stable, and that the ratio of this pulse wave to the maximum value of the pulse wave is within a certain range. By checking, the validity of the diastolic blood pressure point during pressurization is checked.

FIG. 6 is a diagram showing the principle of measuring blood pressure not only when the pressure is reduced but also when the pressure is increased, thereby achieving more reliable blood pressure measurement.

First, the occurrence of the Korotkoff sound during pressurization is defined as the diastolic blood pressure point during pressurization, and the disappearance of the Korotkoff sound is defined as the systolic blood pressure point.

Furthermore, the disappearance of the Korotkoff sound during decompression is defined as the diastolic blood pressure point during decompression. Here, the pulse wave height values of five beats before and after each point are memorized, and the validity of the blood pressure value is determined by the pulse wave height value at each point, the presence of a pulse wave before the point, or the difference value between the pulse wave height values. Check. Furthermore, regarding diastolic blood pressure,
Based on the diastolic blood pressure during pressurization, it is possible to perform more accurate measurement during depressurization, and by performing the measurement twice, it is possible to minimize the possibility that the diastolic blood pressure cannot be measured.

7 to 9 are flowcharts showing the operating procedure of the electronic blood pressure monitor of this embodiment.

FIG. 7 shows the main routine.

First, in step S5L, initialization such as zero setting of the pressure value is performed. Step S52. 20mmH for S53
Rapid pressurization is performed up to 20 mmHg, and when the pressure reaches 20 mmHg, it is switched to medium speed pressurization in step S54, and storage of pulse waves corresponding to the cuff pressure in the pulse wave storage section 53a is started in step S55.

In step S56, the occurrence of consecutive Korotkoff sounds is checked, and if they occur, the first point is stored as the diastolic blood pressure point during pressurization in step S57. Next, in step S58, the maximum value M of the pulse wave is detected, and in step S59, the maximum value M and the average blood pressure value are stored. After the maximum value M of the pulse wave occurs, the process switches to low-speed pressurization in step S60, checks for disappearance of the Korotkoff sounds in step S61, sets the point of disappearance as the systolic blood pressure point in step S62, and checks the systolic blood pressure value in step S63. .

FIG. 8 is a flowchart of checking the systolic blood pressure value in step S63.

In step S71, it is checked whether the peak value of the pulse wave at the systolic blood pressure point is greater than or equal to A% of the maximum value stored in step S59. A blinking display is performed in S74. A
% or more, a check is performed in step S72 based on the difference value between the five pulse waves before and after, and if it is not within a predetermined range, a blinking display is performed in step S74.

Note that in step S72 α3=△S22/△Sol β, = △S23/△S2□ γ, = △S24/△S23 It is.

If it is A% or more and within the predetermined range, the systolic blood pressure is displayed normally in step S73.

Returning to step S64 in FIG. 7, step S64. S
65, α from the average blood pressure stored in step S59. Perform rapid depressurization to a higher value (eg, 20 mmHg).

When the mean blood pressure reaches 00, the process switches to low-speed decompression in step S66, and checks for disappearance of the Korotkoff sound in step S67.

In step S68, the vanishing point is set as the diastolic blood pressure point during depressurization, and in step S69, its validity is checked together with the diastolic blood pressure point during pressurization stored in step S57. FIG. 9 is a flowchart showing the procedure for checking the diastolic blood pressure value in step S69.

First, in step S81, the difference between the diastolic blood pressure value during pressurization and the diastolic blood pressure value during depressurization is determined, and it is checked whether this difference is smaller than several mmHg. If it is smaller, a more accurate diastolic blood pressure value during decompression will be displayed. If the difference between the time of pressure increase and the time of pressure reduction is large, the process advances to step S82 to check whether there is a measured value of the diastolic blood pressure during pressure reduction, and if there is, the process proceeds to step S83. In S84, the validity of the diastolic blood pressure at the time of decompression is checked, and if it is appropriate, the process proceeds to step S95, where the diastolic blood pressure value at the time of depressurization is displayed.

Furthermore, in step S84 α4=△DD, /△D　D　+ β4=△DD3/△D　D　2 γ4=△DD4/△D　D　s It is.

If there is no diastolic blood pressure during decompression or if it is not valid, it is checked in step S85 whether or not there is a diastolic blood pressure during pressurization, and if not, the existence of a diastolic blood pressure during decompression is checked again in step S86, and if there is no diastolic blood pressure. If both are absent, a message indicating that diastolic blood pressure cannot be measured is displayed in step S94. If there is a diastolic blood pressure at the time of decompression, in step S93, the diastolic blood pressure at the time of decompression is deemed to have a validity problem and is displayed blinking.

On the other hand, if there is a diastolic blood pressure during pressurization, step S87
．． S88. Its validity is checked in S90.

In step S87, α, = △UD+/△UD2 β5=△U　D　2　/△UD.

γ5=△UD, /△UD4 It is.

In step S91, the diastolic blood pressure value at the time of pressure increase is displayed as valid if it is within the range of step S87 and if there is a previous pulse wave and its wave height is within a predetermined range. . If there is no previous pulse wave, step S8
If there is a diastolic blood pressure during depressurization in step 9, it is displayed blinking in step S93, and if not, the diastolic blood pressure during pressurization is displayed blinking in step S92. Further, even if there is a previous pulse wave, if it is outside a predetermined range (greater than E and smaller than F), the diastolic blood pressure during pressurization is displayed blinking.

[Effects of the Invention] According to the present invention, a highly reliable electronic blood pressure monitor with highly accurate checks can be provided.

Furthermore, by determining blood pressure values during pressure increase and pressure reduction, a more accurate check can be performed and a more reliable electronic blood pressure monitor can be provided.

In other words, if a measurement error occurs during measurement due to friction noise with the rubber tube or clothing, it is possible to prompt the person taking the measurement again, and it is possible to avoid recognizing an incorrect blood pressure value. It has become possible.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of the electronic blood pressure monitor of this embodiment. Fig. 2 is a diagram showing the principle of an example in which measurement is performed only during decompression. Fig. 3 shows the operating procedure of the example in Fig. 2. Flowcharts, FIGS. 4A and 4B are flowcharts showing a check routine for the systolic blood pressure value in the example of FIG. 2, FIGS. 5A and 5B are flowcharts showing a check routine for the diastolic blood pressure value in the example in FIG. 2, Fig. 6 is a diagram showing the principle of an example in which measurement is performed during pressurization and depressurization, Fig. 7 is a flowchart showing the operating procedure of the example in Fig. 6, and Fig. 8 is a diagram showing the systolic blood pressure value in the example in Fig. 6. Flowchart Showing Check Routine FIG. 9 is a flowchart showing the check routine for the diastolic blood pressure value in the example of FIG. In the figure, 1...cuff, 2...Korotkoff sound sensor, 1
0...Korotkoff sound detection unit, 11...Amplifier, 12
... band pass filter, 13... comparator, 14.
...Threshold level generation circuit, 20...Pressure detection section, 21...Pressure sensor, 22...Amplifier, 31...
・Band pass filter, 32...Amplifier, 33...
A/D converter, 41... motor/valve drive unit, 42
...Rapid exhaust valve, 43...Air supply pump, 47.
・・Constant speed exhaust valve, 45 ・・Bypass valve, 46
...Anti-pulsation filter, 46a...Surge tank,
46b...Fluid resistor, 50...Microcomputer, 51...CPU, 52...ROM, 53...
- RAM, 52a... pulse wave storage section, 60... power supply section, 70... LCD display. Figure 4A Figure 4B Figure 5A Figure 5B Figure

Claims (2)

[Claims] (1) In an electronic sphygmomanometer that measures blood pressure by compressing a part of a living body with a cuff, a point detection means for detecting the point between the systolic blood pressure and the diastolic blood pressure based on the occurrence or disappearance of Korotkoff sounds; a determination means for determining the validity of the point based on the pulse wave height at the point and changes in pulse wave height before and after the point; and a display for displaying a blood pressure value in accordance with the determination result of the determination means. An electronic blood pressure monitor comprising: (2) The point detection means detects each point during pressurization and depressurization, and determines the validity of the point based on the difference between the blood pressure value during pressurization and the blood pressure value during depressurization. The electronic blood pressure monitor according to claim 1, characterized in that: