JPH088908B2 - Electronic blood pressure monitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention is an electronic blood pressure monitor, and in the case where a systolic blood pressure value cannot be obtained due to insufficient cuff pressure, an appropriate re-pressure value is provided. The present invention relates to an electronic blood pressure monitor that calculates and re-pressurizes the cuff.

(B) Conventional technology In a conventional electronic blood pressure monitor, a pressurizing set value for pressurizing the cuff is usually set, and the pressurizing pump operates based on the pressurizing set value to pressurize the cuff. That is, it is set to block the brachial artery of the subject.

However, the compression pressure leading to arterial ischemia varies depending on the person to be measured, and even if the cuff is inflated to a preset pressure setting value, insufficient pressure will occur depending on the person to be measured. In some cases, there is a disadvantage that it is difficult to perform accurate blood pressure measurement.

For this reason, the current electronic sphygmomanometer causes insufficient cuff pressurization,
If the blood pressure value (maximum blood pressure value) cannot be determined, the sum of values obtained by adding a constant pressure (for example, 30 mmHg) to the initial pressurization setting value is used as the repressurization setting value. On the basis of this, the cuff is set to be re-pressurized.

(C) Problems to be Solved by the Invention The re-pressurization set value calculation means used in the conventional electronic blood pressure monitor has a constant pressure (for example, 30 mmHg) for a constant pressurization set value.
This is a method of obtaining a uniform summed value obtained by adding as the re-pressurization set value.

For this reason, when the cuff is inflated by this constant uniform re-pressurization set value, the pressure on the artery may be too strong depending on the person to be measured, which may cause congestion, and conversely, depending on the person to be measured. However, since the pressurization is still insufficient, accurate blood pressure measurement cannot be performed, and there is a disadvantage that re-pressurization is required.

The present invention solves the above problems and calculates the re-pressurization value corresponding to the systolic blood pressure value of the measurement subject when the cuff insufficiency is insufficient, and accurately based on the appropriate pressurization value. An object of the present invention is to provide an electronic blood pressure monitor that can perform accurate blood pressure measurement.

(D) Means and Actions for Solving Problems In order to achieve this object, the electronic sphygmomanometer of the present invention has the following configuration.

The electronic sphygmomanometer includes a pressurizing unit that pressurizes the cuff to a pressurizing set value, a depressurizing unit that depressurizes the pressure inside the cuff, and a pulse wave amplitude extracting unit that extracts the amplitude value of the pulse wave obtained from the living body when the cuff is depressurized. And a blood pressure determining means for performing blood pressure determination using the pulse wave amplitude value extracted by the pulse wave amplitude extracting means and the pressure value of the cuff by the pressure sensor, wherein the pulse wave amplitude extracting means extracts While detecting insufficient pressurization by the pulse wave amplitude value, provided repressurization set value calculation means for calculating the repressurization set value that is the target of repressurization when insufficient pressurization, the blood pressure determination means, The minimum blood pressure value is determined by using the pulse wave after the maximum value of the pulse wave amplitude extracted by the pulse wave amplitude extraction means during depressurization of the cuff, and the repressurization set value calculation means detects insufficient pressurization. When the maximum and the maximum value of the pulse wave amplitude extracted by the pulse wave amplitude extraction means It is characterized in that a systolic blood pressure value is predicted from the diastolic blood pressure value determined by the blood pressure determining means, a predetermined pressure is added to this diastolic blood pressure value, and the value obtained by this addition is set as a repressurization set value. .

In the electronic sphygmomanometer having such a configuration, when the cuff is pressurized to the pressurization set value and insufficient pressurization of the cuff is detected at the stage of shifting to the slow speed exhaust, that is, the pulse wave amplitude corresponding to the systolic blood pressure value. Insufficient cuff pressurization is detected when no value (for example, 50% of the maximum pulse wave amplitude value during the pulse wave amplitude increasing process) data is detected. When this insufficient cuff pressurization is detected, the maximum blood pressure value is predicted from the maximum pulse wave amplitude value and the minimum blood pressure value. Then, a constant pressure (for example, 30 mmHg) is added to this predicted systolic blood pressure value, and this added value is used as the re-pressurization set value.

 A prediction of systolic blood pressure (SYS) is obtained by SYS = 3 x Pm-2 x DIA.

Here, Pm is the maximum pulse wave amplitude value, and DIA is the minimum blood pressure value obtained as the cuff pressure corresponding to 70% of the maximum pulse wave amplitude value in the decreasing process of the pulse wave amplitude.

Therefore, if insufficient cuff pressurization occurs, the re-pressurization set value corresponding to the measured person can be calculated by predicting the systolic blood pressure value of the measured person. A re-pressurization set value can be obtained.

(E) Embodiment FIG. 3 is a block diagram showing a specific embodiment of the air system and measuring circuit of the electronic sphygmomanometer according to the present invention.

A pressurizing pump (pressurizing means) 3, a slow exhaust valve 4, a quick exhaust valve 5 and a pressure sensor (pressure detecting means) 6 are connected to the cuff 1 via a tube 2.

As the pressure sensor 6, for example, a diaphragm type pressure converter using a strain gauge, a semiconductor pressure conversion element, or the like is used, and the output signal (analog amount) of the pressure sensor 6 is used.
Is amplified by the amplifier 7 and converted into a digital value by the A / D converter 8. The CPU (Central Processing Unit) 9 takes in the output signal of the pressure sensor 6 converted into a digital value by the A / D converter 7 at a constant cycle and extracts the cuff pressure and the pulse wave component appearing on the cuff pressure signal. Take in.

The CPU 9 has a built-in memory for storing programs and measurement data, and also turns on the pressurizing pump 3 and the quick exhaust valve 4.
It has a function of turning on / off and a function of calculating a pulse wave amplitude value, and a function of determining blood pressure from cuff pressure data and the pulse wave amplitude value. Then, the determined blood pressure value is output by a command from the CPU 9 and displayed on the display device 10. Further, the CPU 9 detects insufficient cuff pressurization from the pulse wave amplitude value, predicts the systolic blood pressure value from the maximum pulse wave amplitude value and the diastolic blood pressure value, and adds a constant pressure (30 mmHg) to the predicted systolic blood pressure value. A control function is provided for calculating the summed value as a repressurization set value and driving the pressurizing pump 3 based on the repressurization set value.

The prediction of the systolic blood pressure value is calculated based on the generally known correlation equation between the maximum pulse wave amplitude value (Pm) and the systolic blood pressure value (SYS) and the diastolic blood pressure value (DIA). This correlation equation is It is expressed as follows, and from this equation (1), SYS = 3 × Pm-2 × DIA (2) is obtained. Based on this equation (2), the maximum blood pressure value is 30 mm
Hg) is added to obtain the re-pressurization set value.

FIG. 1 is a flowchart showing a specific processing operation of the electronic blood pressure monitor of the embodiment.

When the person to be measured wraps the cuff 1 around his upper arm [step (hereinafter referred to as "ST") 1] and turns on the start switch 11 of the instrument, the measurement is started (ST2). Here, quick exhaust valve 5
Then, the slow exhaust valve 4 is closed (ST3), the pressurizing pump 3 is operated, and the cuff 1 is inflated to the pressurizing set value (ST4).

In ST5, it is determined whether or not the cuff 1 has been inflated to the set pressure value. Now, assuming that the cuff 1 is inflated to the set pressure value, the determination in ST5 is YES, and the pressurizing pump 3
Drive stops (ST6). Then, the slow speed exhaust valve 4 is opened, and the slow speed exhaust is performed when the pressure inside the cuff 1 is, for example, about 3 mmHg / sec (ST7). In this depressurization process, the cuff pressure and the pulse wave component on the cuff pressure are sequentially taken into the CPU 9 at each sampling time (ST8).

ST9 detects that the cuff 1 is under-pressurized. That is, the pulse wave amplitude value obtained at the beginning of the stage of slow exhaust (pulse wave amplitude value in the increasing process) is lower than the maximum pulse wave amplitude value (about 3.0 mmHg), and the pulse wave amplitude value corresponding to the systolic blood pressure value (50% of the maximum pulse wave amplitude value on the high-pressure side) It is determined whether there is data.

If the initial pressurization setting value is a value sufficient for the ischemia of the subject, the determination in ST9 is YES, and normal blood pressure measurement is performed. That is, the maximum pulse wave amplitude value (Pm) is extracted (ST15), and the cuff pressure at the points where the maximum pulse wave amplitude value is 50% and 70% of the maximum value (peak value Pm) on the high pressure side and low pressure side, respectively. Is calculated as the systolic blood pressure value (SYS) and the diastolic blood pressure value (DIA) (ST15 and ST16), and after determining the blood pressure value, the quick exhaust valve 5 is opened (ST18) and the blood pressure value is displayed on the display 10. To end the measurement (ST19).

However, as shown in FIG. 4, the pulse wave amplitude value (the pulse wave amplitude value in the increasing stage of the pulse wave amplitude) obtained at the beginning of the slow exhaust phase approaches the maximum pulse wave amplitude value (Pm). If
That is, the pulse wave amplitude value corresponding to the systolic blood pressure value cannot be detected,
If the systolic blood pressure cannot be determined, it is determined that the cuff 1 is under-pressurized and the determination in ST9 is YES. Here, the maximum pulse wave amplitude value (Pm) is extracted (ST10), and the minimum blood pressure value detected with the progress of the slow velocity exhaust (the low side of the maximum pulse wave amplitude value is detected).
Calculate the cuff pressure corresponding to 70% (ST11). Immediately after this calculation is completed, as shown in FIG. 4, the quick exhaust valve 5 is opened and the cuff 1 is rapidly depressurized (ST12). After that, based on the extracted maximum pulse wave amplitude value and the determined minimum blood pressure value (DIA), the systolic blood pressure value is predicted, and then the repressurization set value is calculated from this predicted systolic blood pressure value (ST13 and ST1).
Four).

FIG. 2 is a flowchart showing a specific example of calculating the repressurization setting value. The calculation of the re-pressurization set value is started from the work of predicting the systolic blood pressure value (ST21). The systolic blood pressure is predicted by SYS = 3 × Pm−2 × DIA, and the repressurization setting value (Ps) is calculated based on the predicted systolic blood pressure value. The re-pressurization set value is calculated by Ps = SYS + α. That is, the re-pressurization set value is calculated by adding a predetermined pressure (α), for example, 30 mmHg to the predicted systolic blood pressure value (ST22).

Thus, based on this re-pressurization set value, the pressurizing pump 3 is driven again, and the cuff 1 is inflated to the re-pressurization set value as shown in FIG. As a result of the execution, the most appropriate pressurization state corresponding to the measurement subject is obtained, and accurate blood pressure measurement is achieved.

(F) Effect of the Invention In the present invention, as described above, when insufficient pressurization of the cuff is detected, the systolic blood pressure value is predicted from the maximum pulse wave amplitude value and the diastolic blood pressure value, and the systolic blood pressure value is set to the predetermined pressure. Is calculated, the re-pressurization set value is calculated, and the cuff is re-pressurized based on this re-pressurized set value to perform blood pressure measurement. Values are obtained and accurate blood pressure measurements can be performed.

Therefore, as in the past, regardless of the systolic blood pressure value of the measurement subject, a re-pressurization setting value calculation method that adds a uniform constant pressure to the pressurization setting value is generated by the measurement subject. Excessive pressure with pain is given, the disadvantage of causing congestion is not allowed to be eliminated, repressurization becomes insufficient under pressure again, and disadvantages such as repeated pressure application can be overcome, etc. It has an excellent effect of achieving the object of the invention.

[Brief description of drawings]

FIG. 1 is a flow chart showing a concrete processing operation of the electronic blood pressure monitor of the embodiment, FIG. 2 is a flow chart showing a concrete example of calculating a repressurization set value in detail, and FIG. FIG. 4 is a block diagram showing an example of the air system and circuit configuration of the meter, and FIG. 4 is an explanatory diagram showing a state in which blood pressure is measured by the electronic blood pressure monitor of the embodiment. 1: Cuff, 6: Pressure detection means, 9: CPU.

Claims (1)

[Claims] 1. A pressurizing means for pressurizing a cuff to a pressurizing set value, a depressurizing means for depressurizing the pressure inside the cuff, and a pulse wave amplitude extracting means for extracting an amplitude value of a pulse wave obtained from a living body when the cuff is depressurized. And an electronic blood pressure monitor including a blood pressure determining means for determining blood pressure using the pulse wave amplitude value extracted by the pulse wave amplitude extracting means and the pressure value of the cuff by the pressure sensor, wherein the pulse wave amplitude extracting means Is provided with a re-pressurization set value calculation means for calculating a re-pressurization set value which is a target of re-pressurization when the pressurization is insufficient, and the blood pressure determination means. Is to determine the minimum blood pressure value by using the pulse wave after the maximum value of the pulse wave amplitude extracted by the pulse wave amplitude extraction means during decompression of the cuff, the re-pressurization set value calculation means, the insufficient pressurization When detected, the maximum of the pulse wave amplitude extracted by the pulse wave amplitude extraction means And a systolic blood pressure value determined by the blood pressure determining means, a systolic blood pressure value is predicted, a predetermined pressure is added to the systolic blood pressure value, and the value obtained by the addition is set as a repressurization set value. And an electronic blood pressure monitor.