JPH0326968B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention uses a vibration method (oscillometric method) that extracts and calculates arterial pulse wave components for each heartbeat superimposed on cuff pressure to measure systolic and diastolic blood pressure values. ) concerning electronic blood pressure monitors.

[Background Art] Conventionally, in this type of electronic sphygmomanometer using the vibration method, which extracts the arterial pulse wave component superimposed on the cuff pressure and determines the maximum and diastolic blood pressure values based on the change, the blood pressure measurement operation is The end point is the point at which an arterial pulse wave value smaller than a predetermined value obtained by multiplying the maximum value of the extracted arterial pulse wave value (hereinafter abbreviated as maximum pulse wave value) by a predetermined ratio appears, or the point at which the arterial pulse wave value The point was defined as the point when the pulse wave value suddenly decreased. However, in such conventional methods, unstable arterial pulse waves can be obtained due to arrhythmia (e.g., extrasystole, absent pulse, alternans, etc.) or sudden fluctuations in the blood pressure value itself during measurement. In this case, there was a problem in that the arterial pulse wave temporarily attenuated before the actual maximum pulse wave value appeared, and the blood pressure measurement ended erroneously, making it impossible to obtain a normal blood pressure value.

[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to provide an electronic blood pressure monitor that can prevent erroneous measurements due to temporary attenuation of arterial pulse waves caused by arrhythmia, etc. It is about providing.

[Disclosure of the Invention] (Structure) The present invention provides a cuff that is attached to the main part of a subject to prevent blood flow, a pressurizing means that increases the pressure inside the cuff,
An exhaust means for gradually lowering the pressure inside the cuff, a pressure sensor for converting the pressure inside the cuff into an electrical signal, a pressure information separation means for extracting an arterial pulse wave value and a cuff pressure value from the pressure sensor output, and a pressure information separation means for extracting an arterial pulse wave value and a cuff pressure value from the pressure sensor output. The maximum
In an electronic blood pressure monitor comprising a blood pressure determination means for determining the diastolic blood pressure value and a display means for displaying both determined blood pressure values, the maximum and diastolic blood pressures are temporarily determined based on previously extracted arterial pulse wave values. A blood pressure determining means is formed by a first blood pressure determining means and a second blood pressure determining means that determines whether the blood pressure value calculated by the first blood pressure determining means will not be changed thereafter and determines the maximum and diastolic blood pressures. and the second blood pressure determination means sequentially calculates the predetermined termination determination reference value and the arterial pulse wave value extracted by the pressure information separation means during the termination determination period provided after the determination by the first blood pressure determination means is completed. When a predetermined number of arterial pulse wave values smaller than the termination criterion value are consecutively extracted by comparison,
Alternatively, it is possible to determine the end of the measurement and determine the minimum and systolic blood pressure when no arterial pulse wave value greater than the end determination reference value appears, thereby preventing erroneous measurements due to temporary attenuation of the arterial pulse wave due to arrhythmia, etc. The system is designed to provide an electronic blood pressure monitor.

Embodiment 1 FIG. 1 shows the basic configuration of an embodiment of the present invention, which includes a cuff 2 that is attached to the main part of the subject (for example, the upper arm) 1 for blood ischemia, and a cuff 2 that increases the pressure inside the cuff 2. a pressurizing means 3 that gradually lowers the pressure inside the cuff 2, a pressure sensor 5 that converts the pressure inside the cuff 2 into an electrical signal, and a low-pass filter that removes noise signals from the output of the pressure sensor 5. 6
and an A/D converter 7 that samples the output of the low-pass filter 6 and converts it into a digital value.
An arterial pulse wave extraction means 8a that digitally extracts an arterial pulse wave value V from the pressure value (digital value) output from the A/D converter 7 during the gradual evacuation period, and a cuff pressure value obtained by removing the arterial pulse wave from the pressure value. Pressure information separation means 9 equipped with cuff pressure extraction means 8b for extracting P by digital calculation, and memory for storing arterial pulse wave values V and cuff pressure values P corresponding to the pulse waves extracted by the pressure information separation means 9. A blood pressure system comprising a means 10, a calculating means 11 for appropriately reading and comparing values stored in the storing means 10, and a blood pressure determining means 12 for determining maximum and diastolic blood pressure values from the calculation results calculated by the calculating means 11. Determining means 13;
A display means for appropriately displaying the maximum and diastolic blood pressure values, the pumping speed determined by the blood pressure determining means 13, the pumping speed and pulse values output from the pulse monitor 14, and the cuff pressure output from the cuff pressure monitor 15. 1
It consists of 6. Moreover, the blood pressure determining means 13
The first blood pressure determining means temporarily determines the systolic and diastolic blood pressures based on the previously extracted arterial pulse wave values V, and the first blood pressure determining means determines whether the blood pressure values calculated by the first blood pressure determining means will not be changed thereafter. and a second blood pressure determining means that determines the maximum and diastolic blood pressures, and the second blood pressure determining means makes a predetermined end determination during the end determination period provided after the first blood pressure determining means completes the determination. The reference value and the arterial pulse wave value V extracted by the pressure information separation means 9 are sequentially compared, and when a predetermined number of arterial pulse wave values V smaller than the termination determination reference value are successively extracted, or the termination determination is made. When an arterial pulse wave value V greater than the reference value does not appear, it is determined that the measurement is complete, and the minimum and systolic blood pressures are determined. In addition, pressure information separation means 9,
Storage means 10, calculation means 11, blood pressure determination means 13
Both monitors 14 and 15 are microcomputers 18 using CPU, ROM, RAM, etc.
It is formed in

Note that the first blood pressure determination means for temporarily determining the maximum and diastolic blood pressures temporarily determines the maximum and diastolic blood pressures based on the maximum value or increase/decrease of the previously extracted arterial pulse wave values (the first blood pressure determination means temporarily determines the maximum and diastolic blood pressures). For example, the systolic blood pressure is determined based on the maximum value or increase in the extracted arterial pulse wave value, and the diastolic blood pressure is determined based on the maximum value of the extracted arterial pulse wave value. Determined based on the value or amount of decrease.

The basic operation of the first embodiment is as follows. Now, the cuff 2 is attached to the upper arm 1 of the person to be measured, and by appropriately pressurizing and depressurizing with the pressurizing means 3 and exhausting means 4, arterial ischemia is achieved, and the arterial counter pressure at the time of opening is reduced by cuff 2. The cuff pressure signal is transferred to the pressure sensor 5 by air conduction through the tube 21, and electrically converted together with the static pressure (cuff pressure) to obtain an internal cuff pressure signal consisting of an analog signal as shown in FIG. 3a. Next, after filtering this cuff internal pressure signal as much as possible using a low-pass filter 6, the pressure value converted into a digital value by an A/D converter 7 is sent to a microcomputer 1.
Sent to 8th. In the microcomputer 18,
The information separating means 8 separates and extracts the arterial pulse wave component and the cuff pressure component, which are seen as a phenomenon of arterial counterpressure, from the pressure value output from the A/D converter 7, and the extracted arterial pulse wave value V and The cuff pressure value P is stored in the storage means 10, and the calculation means 11 of the blood pressure determination means 13 performs a comparison calculation,
The blood pressure determining means 12 determines the systolic blood pressure period and the diastolic blood pressure period, and at the same time reads the cuff pressure value P corresponding to the maximum and diastolic blood pressure period from the storage means 10, and displays this cuff pressure value P as the maximum and diastolic blood pressure value. Means 1
6. Here, the best
The diastolic blood pressure timing is determined based on the highest and lowest judgment boundary values V〓(α×Vmax) and V〓(β×Vmax) obtained by multiplying the maximum value Vmax of the arterial pulse wave value V by predetermined ratios α and β. , as shown in Figure 3, the systolic blood pressure period is
This is the time (point A) when the arterial pulse wave value V begins to exceed the highest judgment boundary value V〓, and the diastolic blood pressure period is after the maximum value Vmax of the arterial pulse wave value V and below the lowest judgment boundary value V〓. This is the time (point C) when the arterial pulse wave value V decreases the most before the arterial pulse wave value V appears.

FIG. 2 is a flowchart showing the end operation of blood pressure measurement. The arterial pulse wave value V, which is now successively separated and extracted by the pressure information separation means 8, gradually increases from the measurement start point and reaches the maximum pulse at point B. After the wave value Vmax is obtained, the arterial pulse wave value V begins to decrease, and during this increase/decrease process, the first blood pressure determining means determines the maximum pulse wave value.
Maximal and diastolic blood pressure will be tentatively determined by extracting Vmax. On the other hand, in the second blood pressure determining means,
A timer and an artery that measure the elapsed time from the time when the extracted arterial pulse wave value V becomes smaller than a separately set termination determination reference value Vγ (same as the determination boundary value V〓 in the embodiment) during the termination determination period. A counter that counts the number of pulse waves is operated, and the period until the measured value of the timer exceeds a predetermined time or the count value of the counter exceeds a predetermined number is defined as an end determination period. During this termination determination period, if an arterial pulse wave value V exceeding the termination determination reference value Vγ is not extracted, the end of the measurement is determined, the end of the blood pressure measurement operation is displayed on the display means 16, and the maximum and diastolic blood pressures are determined. The person to be measured will be informed of this. On the other hand, if the termination determination reference value Vγ is exceeded during the termination determination period, the termination determination period is immediately canceled and the first blood pressure determining means is configured to correct the determination of the maximum and diastolic blood pressure again. .

The specific operation will be explained below. 3 and 4 show examples of changes in the arterial pulse wave value V during gradual evacuation, and FIG. 3 shows a case where the arterial pulse wave is stable. When a stable arterial pulse wave is obtained in this way, after starting the measurement,
The arterial pulse wave value V gradually increases and eventually reaches the maximum pulse wave value Vmax. The first blood pressure determining means determines the point A, which exceeds the predetermined value V at point B, as the systolic blood pressure period, and determines the cuff pressure value P at that period as the systolic blood pressure value. Next, after the maximum pulse wave value Vmax is obtained, the point C at which the arterial pulse wave value V decreases the most is determined to be the diastolic blood pressure period, and the cuff pressure value P at that point is determined to be the diastolic blood pressure.

Next, in the second blood pressure determining means, the arterial pulse wave value V
The timer starts measuring the elapsed time of the end determination period from point D, where V is smaller than the end determination reference value Vγ, and at the same time, the counter starts counting the number of arterial pulse wave values V. In the case of FIG. 3, since arterial pulse wave values V smaller than the termination determination reference value Vγ appear continuously during this termination determination period, blood pressure measurement is performed at point E where a predetermined number (four in the example) appear. The systolic and diastolic blood pressure values are determined and displayed on the display means 16.

Figure 4 shows a case where the arterial pulse wave is unstable; after the start of measurement, the arterial pulse wave value V increases between points A' and B', but temporarily decreases between points B' and D'. do. In this case, the maximum pulse wave value Vmax is provisionally determined at point B', and the first blood pressure determining means temporarily determines the maximum and diastolic blood pressures, so once the end determination period is entered, the end determination criteria Since an arterial pulse wave value V smaller than the value Vγ cannot be obtained four times in a row, and the arterial pulse wave value V exceeds the end judgment reference value Vγ at point A,
At this point, the end determination period is canceled, the maximum pulse wave value Vmax is extracted again at point B, the cuff pressure value P at point A is re-determined as the systolic blood pressure, and the diastolic blood pressure is re-determined at point C. After that, the end judgment reference value will be reached at point D.
Since an arterial pulse wave value V smaller than Vγ appears, the end determination period is started again, and the blood pressure measurement operation is ended at point E obtained four times in a row, and the maximum and diastolic blood pressure values are determined on the display means 16. Is displayed.

By the way, in this embodiment, a predetermined value V〓 obtained by multiplying the maximum pulse wave value Vmax by a predetermined ratio β is used as the end judgment reference value Vγ
However, it goes without saying that a preset constant value may be used as the termination determination reference value Vγ.

Embodiment 2 FIG. 5 is a diagram showing the operation of still another embodiment, in which the arterial pulse wave values extracted in a predetermined period after the maximum pulse wave value Vmax which is the maximum value among the sequentially extracted arterial pulse wave values V The maximum value ΔVmax of the decrease values ΔV obtained by calculating the difference between the pulse wave value V and the arterial pulse wave value V extracted immediately before that value is set as the termination criterion value Vγ, and in the illustrated example, it is the point C. The end determination period begins from point E, and the measurement operation ends at point E. Note that the decrease value ΔV does not necessarily have to be the difference from one beat before.

Embodiment 3 FIGS. 6 to 8 are diagrams showing the operation of still another embodiment, in which a predetermined value V〓 obtained by multiplying the maximum pulse wave value Vmax by a predetermined ratio β and a decrease value ΔV of the arterial pulse wave value V
The larger of the maximum values ΔVmax is set as the termination determination reference value Vγ.

Now, FIG. 6 is a flowchart showing the operation, and FIGS. 7 and 8 are diagrams showing the specific operation.
Fig. 7 shows the case where ΔVmax>V〓, ΔVmax is set as the end judgment reference value Vγ, and the end judgment period starts at point D when the arterial pulse wave value V becomes less than ΔVmax, and the end judgment period is started by the counter. The measurement operation is terminated at point E (before the timer time elapses) at which the count value of the arterial pulse wave reaches 4. Furthermore, Fig. 8 shows the case where V〓>ΔVmax, V〓 is set as the end judgment reference value Vγ, and the end judgment period is set at point D where the arterial pulse wave value V becomes less than V〓. The measuring operation is started and ends at point E (before the counter value reaches 4) after the timer time has elapsed.

[Effects of the Invention] As described above, the present invention includes a cuff that is attached to the main part of a person to be measured, a pressurizing means that increases the pressure inside the cuff, and an exhaust system that gradually lowers the pressure inside the cuff. means, a pressure sensor that converts the pressure within the cuff into an electrical signal, and a pressure information separation means that extracts an arterial pulse wave value and a cuff pressure value from the pressure sensor output;
Storage means for storing arterial pulse wave values and cuff pressure values extracted by the pressure information separation means, and blood pressure determination for determining systolic and diastolic blood pressure values by appropriately reading and comparing the pressure values stored in the storage means. and a display means for displaying both determined blood pressure values, the electronic blood pressure monitor comprising: a first blood pressure determination means for temporarily determining the maximum and diastolic blood pressures based on previously extracted arterial pulse wave values; A blood pressure determining means is formed by a second blood pressure determining means that determines whether the blood pressure value calculated by the first blood pressure determining means will not be changed thereafter and determines the maximum and diastolic blood pressure, and the second blood pressure determining means The method sequentially compares a predetermined termination determination reference value with the arterial pulse wave value extracted by the pressure information separation means during the termination determination period provided after the determination by the first blood pressure determining means is completed, and determines the termination determination reference value. When a predetermined number of smaller arterial pulse wave values are consecutively extracted, or when no arterial pulse wave value larger than the end determination reference value appears, it is determined that the measurement is complete and the minimum and systolic blood pressures are determined. After tentatively determining the systolic and diastolic blood pressures by the first blood pressure determining means, the second blood pressure determining means determines whether the arterial pulse wave is stable after providing an end determination period. Since the maximum and diastolic blood pressures are determined, it is effective in preventing erroneous measurements due to temporary attenuation of arterial pulse waves caused by arrhythmia or sudden body movements.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of the present invention;
Figure 2 is a flowchart showing the same operation as above;
4 and 4 are explanatory diagrams of the same operation as above, FIG. 5 is an explanatory diagram of operation of another embodiment, FIG. 6 is a flowchart showing the operation of still another embodiment, and FIGS. 7 and 8 are same as above. FIG. 2 is a cuff, 5 is a pressure sensor, 9 is an information separation means, 10 is a storage means, 13 is a blood pressure determination means, 16
is a display means.

Claims (1)

[Claims] 1. A cuff that is attached to the main part of a person to be measured to prevent blood flow;
A pressurizing means for increasing the pressure within the cuff, an evacuation means for gradually decreasing the pressure within the cuff, a pressure sensor for converting the pressure within the cuff into an electrical signal, and an arterial pulse wave value and cuff pressure determined from the pressure sensor output. A pressure information separation means for extracting values, a storage means for storing arterial pulse wave values and cuff pressure values extracted by the pressure information separation means, and pressure values stored in the storage means are read out as appropriate and are compared and calculated. In an electronic sphygmomanometer comprising a blood pressure determining means for determining the maximum and diastolic blood pressure values and a display means for displaying both determined blood pressure values, the maximum and diastolic blood pressures are determined by determining the maximum value of the previously extracted arterial pulse wave value or A first blood pressure determination means that temporarily determines the blood pressure based on an increase or decrease, etc., and a second blood pressure that determines whether the blood pressure value calculated by the first blood pressure determination means will not be changed thereafter and determines the maximum and diastolic blood pressures. A blood pressure determining means is formed by the determining means, and the second blood pressure determining means extracts a predetermined end determination reference value and the pressure information separating means during an end determination period provided after the end of the determination by the first blood pressure determining means. When a predetermined number of arterial pulse wave values smaller than the termination criterion value are successively extracted, or when no arterial pulse wave value larger than the termination criterion value appears. An electronic blood pressure monitor characterized in that it determines the minimum and systolic blood pressure upon determining that measurement has ended. 2. The electronic blood pressure monitor according to claim 1, wherein a predetermined value obtained by multiplying the maximum value of the sequentially extracted arterial pulse wave values by a predetermined ratio is used as the termination determination reference value. 3. The electronic blood pressure monitor according to claim 1, wherein a preset constant value is used as the termination determination reference value. 4 Among the decrease values obtained by calculating the difference between the arterial pulse wave values extracted in a predetermined period after the maximum value of the sequentially extracted arterial pulse wave values and the arterial pulse wave value extracted immediately before that. 2. The electronic blood pressure monitor according to claim 1, wherein the maximum value of is set as the termination determination reference value. 5. Claim No. 5, characterized in that the larger of the predetermined value obtained by multiplying the maximum value of the extracted arterial pulse wave value by a predetermined ratio and the maximum value of the decrease value of the arterial pulse wave value is used as the termination determination reference value. The electronic blood pressure monitor according to item 1. 6. The cuff pressure value at the time when an arterial pulse wave value larger than a predetermined value, which is obtained by multiplying the maximum value of the extracted arterial pulse wave value by a predetermined ratio, begins to occur is defined as the systolic blood pressure value, and the arterial pulse wave value After the maximum value occurs,
Claims characterized in that the first blood pressure determining means is configured to calculate the amount of decrease in the arterial pulse wave value and temporarily determine the cuff pressure value at the time when the maximum amount of decrease occurs as the diastolic blood pressure value. The electronic blood pressure monitor described in paragraph 1.