JPH05111467A - Electr0nic hemomanometer - Google Patents

Abstract

PURPOSE:To make exact blood pressure measurement by estimating the shape of the smaller max. blood pressure region from the shape of the max. blood pressure region of the pulse wave envelope obtd. from the pressure pulse wave of the larger pulse wave-generating cuff pressure when there are two peaks in the pulse wave envelope and if the differential value thereof is above a prescribed value. CONSTITUTION:The deviation (difference) DELTAPCmax of the two pulse pressure peaks P1, P2 is calculated and SYS, DIA are determined in an ordinary manner when the two pulse pressure peaks appear. The value obtd. by subtracting the DELTAPCmax from the SYS is determined as the corrected max. blood pressure value SYS'. Namely, the deviation in the pulse pressure peaks is determined as the insufficient quantity of compressing force. This insufficient quantity of the compressing force is subtracted from the max. blood pressure value determined by an ordinary calculation. The blood pressure value is calculated by estimating the shape of the max. blood pressure region of the smaller cuff pressure from the shape of the max. blood pressure region of the pressure pulse wave envelope obtd. from the pressure pulse wave of the larger pulse wave-generating cuff pressure. As a result, the blood pressure value of only the artery to which the cuff pressure is sufficiently transmitted is obtd. and the reliability of the measured blood pressure is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic blood pressure monitor for measuring blood pressure from a wrist or the like having two main arteries.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view showing the structure of a wrist. There are two main arteries of the wrist, a radial artery A and an ulnar artery B, and a radius A1 and an ulna B1 exist behind them. In recent years, an electronic blood pressure monitor for wrists has been proposed that measures blood pressure by compressing the artery of the wrist with a cuff to prevent blood flow.

[0003]

The electronic blood pressure monitor for the wrist is
The blood pressure is measured by pressing the wrist artery with a cuff. When the wrist artery is pressed with a cuff, the compression force from the back of the hand is transmitted to each artery by two bones. However, the compression force is transmitted only from the palm side of the hand, and it is difficult to completely transmit the cuff pressure to each artery. If the cuff is not properly attached,
The pressure pulse wave detected from the cuff tends to be a pressure pulse wave at a pressure different from the actual cuff pressure. As shown in FIG. 8, when the radial artery A and the ulnar artery B are uniformly compressed by the cuff 1, as shown in FIG. The pulse wave envelope X (array of amplitude values for changes in cuff pressure of each pulse wave) X is obtained. However,
As indicated by 0, when the same pressure is not applied to each artery due to the cuff misalignment, that is, when the radial artery A is correctly compressed and the ulnar artery B is not correctly compressed, Generates pressure pulse waves at different pressures. 11A is a pulse wave envelope X1 indicating the pulse wave amplitude of the radial artery A, and FIG. 11B is a pulse wave envelope X2 indicating the pulse wave amplitude of the ulnar artery B. Then, the cuff 1 detects each as a pressure pulse wave having a different shape. That is,
As shown in (c) of FIG. 11, since they are detected in an overlapping manner, the pulse wave envelope X3 has a shape in which the peak of the pulse wave amplitude value appears twice. In a conventional electronic sphygmomanometer (sphygmomanometer for wrists), the peak side of the pulse wave amplitude value is used as a reference, and the cuff pressure on the high side corresponding to the amplitude value of 1/2 of the peak value is calculated as the maximum blood pressure value and the peak value. Since the cuff pressure on the lower side corresponding to the 0.7 amplitude value is determined as the diastolic blood pressure, the two peak pulse wave envelopes had a disadvantage in the reliability of the measured blood pressure value.

The present invention solves the above problems and provides an electronic sphygmomanometer capable of performing accurate blood pressure measurement even when a pulse pressure peak appears twice due to a cuff wearing deviation or the like. To aim.

[0005]

In order to achieve this object, the electronic sphygmomanometer of the present invention has the following configuration. The electronic sphygmomanometer includes a cuff, a pressurizing means for pressurizing the cuff, a pressure reducing means for reducing the pressure inside the cuff, a pressure detecting means for detecting the fluid pressure in the cuff, and an output signal of the pressure detecting means. A pulse wave component detecting means for detecting the contained pulse wave component, a pulse wave amplitude value calculating means for calculating the amplitude value of each pulse wave from the pulse wave component detected by this pulse wave component detecting means, and this pulse wave amplitude A blood pressure value determining means for determining a systolic blood pressure value and a diastolic blood pressure value based on the output signal of the value calculating means and the output signal of the pressure detecting means,
Peak number determination means for determining whether or not there are two peaks in the pulse wave envelope of the array of the calculated pulse wave amplitudes corresponding to changes in the cuff pressure, and two peaks when there are two peaks. A difference value calculating means for calculating a difference in cuff pressure corresponding to the peak pulse wave amplitude, and a pulse wave envelope obtained from a pressure pulse wave having a larger pulse wave generating cuff pressure when the difference value is a predetermined value or more. And an envelope estimating means for estimating the shape of the systolic blood pressure region of the pulse wave envelope of the smaller pulse wave cuff pressure from the shape of the systolic blood pressure region, and using this estimated pulse wave envelope Make a decision.

In the electronic blood pressure monitor having such a structure,
When two pulse pressure peaks are detected due to the displacement of the cuff or the like, the shift between the peaks of the two detected pulse wave envelopes is calculated. Then, the pulse wave envelope that should be originally obtained is estimated from the shift (difference) between the peaks of the pulse wave envelope. In other words, from the shape of the systolic blood pressure region of the pulse wave envelope obtained from the pressure pulse wave of the artery of the one with a large pressure pulse wave cuff pressure (the one with insufficient cuff compression force), the one with a small pressure pulse generation cuff pressure (cuff pressure). Estimate the shape of the systolic blood pressure region of the pressure pulse wave envelope of the artery (of which the compression force is not insufficient). Then, a blood pressure value is determined by applying a predetermined algorithm based on the estimated pulse wave envelope. As a result, the blood pressure value of only the artery to which the cuff pressure has been sufficiently transmitted can be obtained, and highly reliable blood pressure measurement can be performed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 6 is a block diagram showing a specific embodiment of the air system and measuring circuit of the electronic blood pressure monitor according to the present invention. A pressurizing pump (pressurizing means) 4, a rapid exhaust valve 5, a slow exhaust valve 6 and a pressure sensor (pressure detecting means) 3 are connected to the cuff 1 via a tube 2. For the pressure sensor 3, for example, a diaphragm pressure converter using a strain gauge or a semiconductor pressure conversion element is used. The pressurizing pump 4 and the rapid exhaust valve 5 are controlled by a CPU (Central Processing Unit) 9 described later. The output signal (analog amount) of the pressure sensor 3 is amplified by the amplifier 7 and converted into a digital value by the A / D converter 8. The CPU 9 takes in the output signal of the pressure sensor 3 converted into a digital value by the A / D converter 8 at a constant cycle. At the same time, the pulse wave component (pulse wave signal) appearing on the output signal of the pressure sensor 3 is also taken into the CPU 9. This CPU
Reference numeral 9 has a function of calculating a pulse wave amplitude value and a function of calculating a systolic blood pressure value and a diastolic blood pressure value from the obtained pulse wave amplitude value (pulse wave envelope). For example, the blood pressure is determined by setting the cuff pressure at the point where the pulse wave amplitude is 50% and 70% of the maximum value on the high pressure side and the low pressure side from the maximum pulse wave amplitude point (peak value) to the maximum blood pressure value (SYS) and the minimum value, respectively. The blood pressure value (DIA) is used. Also,
The CPU 9 has a function of displaying the determined blood pressure value on the display device 10.

Further, the CPU 9 has a function of determining whether or not the pulse pressure peak of the pressure pulse wave detected from the cuff 1 is detected (appeared) twice, and the cuff if the pulse pressure peak is not detected twice. A function of calculating the difference (deviation) of the cuff pressure corresponding to the peaks of the two pulse pressure peaks when the normal blood pressure determination processing is executed assuming that the wearing is correct and the pulse wave peak appears twice. , And a function of estimating a pulse wave envelope that should be originally obtained from the calculated difference in pulse pressure peaks, and a function of executing blood pressure determination processing based on the estimated pulse wave envelope.

FIG. 1 is a main flow showing a specific processing operation of the electronic blood pressure monitor of the embodiment. When the power switch is turned on, a measurement preparation process is performed [step (hereinafter referred to as ST) 1]. If the power switch is pressed again, S
The determination at T2 is turned on, the measurement is stopped, and the power is turned off at ST11. When measuring, the power switch is not pressed, so the determination in ST2 is OFF and the measurement state is entered. S
At T3, it is determined whether the pressure switch has been pressed. When the measurer presses the pressure switch, the determination in ST3 is O
N, the pressurizing process is executed. That is, the pressurizing pump 4 is driven to pressurize the cuff 1 wrapped around the wrist (ST
4). And after this cuff pressurization reaches a predetermined pressure,
The pressurizing process is terminated, and the pulse wave detecting process is executed at the cuff slow speed exhaust stage (ST5). In ST6, it is determined whether or not the pulse wave detection is completed. If sufficient pulse wave amplitude data (pulse wave envelope) for blood pressure calculation has not been obtained, the determination in ST6 is NO and the pulse wave detection process is continued. If sufficient pulse wave amplitude data for blood pressure calculation is obtained, this ST
The determination of 6 is YES, and the process proceeds to next ST7.

In ST7, it is determined whether or not the pulse pressure peak of the pressure pulse wave detected from the cuff 1 has been detected (appeared) twice. If the cuff 1 is worn correctly and the pulse pressure peak is 1
If it appears only once, the determination in ST7 is N.
When it becomes O, the process proceeds to ST9 and the normal blood pressure value determination process is executed. On the other hand, if the cuff 1 is worn poorly and two pulse pressure peaks P1 and P2 appear (detect) as shown in FIG. 4, the determination in ST7 is YES and the envelope estimation process is executed ( ST8). That is, the deviation (difference) / ΔPC _max between the pulse pressure peaks P1 and P2 detected twice is calculated, and the pulse wave envelope that should be originally obtained is estimated from the difference between the pulse pressure peaks. Then, the blood pressure value determination process is performed based on the estimated pulse wave envelope (ST9), and the determined blood pressure value is displayed on the display 10 (ST10).

FIG. 2 is a sub-flowchart showing a concrete processing operation of the envelope estimation processing of the main flow when two pulse pressure peaks appear. The pulse wave envelope shape should have the same shape when individually extracting the arteries with insufficient compression force and insufficient compression force, and the shape of the pressure portion higher than the pulse pressure peak of the envelope curve of the artery with insufficient compression force is defined. It can be considered as it is as the envelope shape of the artery of which compression force is not insufficient.

[0012] Therefore, to detect the appearance pulse pressure peak twice, ST7 main flow If it is determined YES, and calculates the two shift pulse pressure peak P1, P2 (differential) · ΔPC _max (ST21). Then, SYS and DIA are determined as usual (ST22). Then, from the determined SYS, ΔP
C _max is subtracted, and the obtained value is used as the original systolic blood pressure value (corrected correct systolic blood pressure value SYS '). That is, the deviation of the peak of the pulse pressure is taken as the amount of compression force insufficiency, and this amount of pressure force insufficiency is subtracted from the systolic blood pressure value normally calculated to obtain SYS '(see FIG. 4).

FIG. 3 is a sub-flowchart showing a concrete processing operation of the envelope estimating processing of the main flow when two pulse pressure peaks appear. Pulse pressure peak 2
If the number of times of occurrence is detected and ST7 of the main flow is estimated to be YES, the difference (difference) / Δ between the two pulse pressure peaks P1 and P2
PC _max is calculated (ST31). Then, DIA is obtained from the peak P1 generated at a low pressure, and SYS is obtained from the peak P2 generated at a high pressure. Then, ΔPC _max subtraction is performed only for the obtained SYS (ST3
2). That is, the systolic blood pressure is calculated from the pulse pressure peak P2 generated at high pressure, and the systolic blood pressure is calculated from the pulse pressure peak P1 generated at low pressure, and the compressive force shortage amount is subtracted only for the systolic blood pressure.

In the above, the reason why the envelope with the lower pressure is adopted is that when the cuff 1 compresses an artery and the cuff pressure is not sufficiently transmitted to the artery and the compression force becomes insufficient, the pressure is applied to the artery. In order to apply the cuff pressure, a higher cuff pressure is required than if the cuff pressure was sufficiently transmitted to the artery. That is, when the compression force is insufficient, it is more than when the compression force is not insufficient.
The pulse wave will be detected with a high cuff pressure. Therefore, the pulse wave envelope moves to a higher pressure than when the compression force is not insufficient, and the blood pressure value is displayed high. Therefore, the envelope is selected so that the compression force is not insufficient, that is, the pressure is low (see FIG. 5).

Thus, when the pulse pressure peak is detected twice, the pressure pulse wave is obtained from the shape of the systolic blood pressure region of the pressure pulse wave envelope obtained from the pressure pulse wave of the artery having the larger pressure pulse wave cuff pressure. Estimate the shape of the systolic blood pressure region of the pressure pulse wave envelope of the artery with the smaller generated cuff pressure, and calculate the blood pressure value, and as a result, obtain the blood pressure value only in the artery with the sufficiently transmitted cuff pressure. It is possible to improve the reliability of the measured blood pressure.

In the above embodiment, the case where the pulse pressure peak appears twice has been described, but the pulse pressure peak may be detected three times or more. For example, blood pressure may be measured at a site having three or more arteries. In the wrist, the main arteries are the radial artery and the ulnar artery, but actually there are also small arteries such as the anterior interosseous artery and the posterior interosseous artery. When a pulse wave is detected from these arteries, the peak may be detected three times or more. In such a case, from the shape of the systolic blood pressure region of the pressure pulse wave envelope obtained from the point where the peak cuff pressure becomes maximum, the pressure pulse wave that should be obtained from the point where the peak cuff pressure occurs is minimum The blood pressure is determined by estimating the shape of the systolic blood pressure region of the envelope.

Further, even when the pulse wave level changes during measurement due to physiological factors such as respiration, a plurality of peaks may be detected. However, the deviation of the peak pressure in this case is small. Therefore, when measuring the blood pressure, when the pulse pressure peak appears twice, it is higher than the pulse pressure peak generated at the higher pressure only when there is a certain difference in the cuff pressure at the time of occurrence of each peak. By estimating the pulse wave envelope that should be originally obtained from the pulse wave envelope obtained from the pressure range, it can be determined whether or not it is due to a physiological factor.

[0018]

As described above, according to the present invention, it is determined whether or not the peak of the pulse wave envelope appears twice, and when the peak appears twice, the two detected pulse wave envelopes are detected. The cuff pressure difference corresponding to the peak is calculated as a deviation, the pulse wave envelope that should be originally obtained from this peak difference is estimated, and the blood pressure value is determined based on this estimated pulse wave envelope, so the cuff pressure is determined. It is possible to obtain the blood pressure calculation value only for the artery to which the pressure is sufficiently transmitted, the accuracy of the blood pressure value for the difference in the cuff wearing state is improved, and the high reliability of the measured blood pressure can be obtained.
It has an excellent effect of achieving the object of the invention.

[Brief description of drawings]

FIG. 1 is a main flowchart showing a processing operation of an electronic blood pressure monitor according to an embodiment.

FIG. 2 is a sub-flowchart showing a specific main part processing operation of the embodiment electronic blood pressure monitor.

FIG. 3 is a sub-flowchart showing another specific main part processing operation of the electronic blood pressure monitor of the embodiment.

FIG. 4 is an explanatory diagram for calculating an accurate blood pressure value from the peaks of two pulse wave envelopes.

FIG. 5 is an explanatory diagram for calculating an accurate blood pressure value from the peaks of two pulse wave envelopes.

FIG. 6 is a block diagram showing a circuit configuration example of an example electronic blood pressure monitor.

FIG. 7 is an explanatory diagram showing a cross-sectional state of the wrist.

FIG. 8 is an explanatory diagram showing a state in which the cuff is properly worn on the wrist.

FIG. 9 is an explanatory diagram showing a pulse wave envelope curve when the cuff wearing state is accurate.

FIG. 10 is an explanatory diagram showing a case where the cuff wearing state is incorrect.

FIG. 11 is an explanatory diagram showing pulse wave envelopes when the compression force is appropriate and when it is not.

[Explanation of symbols]

 1 cuff 3 pressure sensor 9 CPU

Front Page Continuation (72) Inventor Toshiyuki Kobayashi 17 Chudo-Teraminami-cho, Shimogyo-ku, Kyoto Science Center Building Inside Omron Life Science Laboratory Co., Ltd. Omron Life Science Research Institute Co., Ltd.

Claims (1)

[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 the fluid pressure in the cuff, and an output signal of the pressure detecting means. A pulse wave component detecting means for detecting the contained pulse wave component, a pulse wave amplitude value calculating means for calculating the amplitude value of each pulse wave from the pulse wave component detected by this pulse wave component detecting means, and this pulse wave amplitude In an electronic sphygmomanometer comprising a blood pressure value determining means for determining a systolic blood pressure value and a diastolic blood pressure value based on the output signal of the value calculating means and the output signal of the pressure detecting means, the calculated value corresponding to the change of the cuff pressure is calculated. Peak number determination means for determining whether or not there are two peaks in the pulse wave envelope of the array of pulse wave amplitudes, and when there are two peaks, the cuff pressures corresponding to the two peak pulse wave amplitudes are determined. Difference value calculating means for calculating the difference, and the difference value is a predetermined value or less. In the above case, the shape of the systolic blood pressure region of the pulse wave envelope obtained from the pressure pulse wave with the larger pulse wave generation cuff pressure is changed to the shape of the systolic blood pressure region of the pulse wave envelope with the smaller pulse wave generation cuff pressure. An electronic sphygmomanometer including: an envelope estimating unit for estimating the blood pressure, and determining the blood pressure value using the estimated pulse wave envelope.