JPS63238847A - Electronic hemomanometer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention is a vibration method (
This relates to an electronic blood pressure monitor using the oscillometric method.

[Prior art] A typical electronic blood pressure monitor uses an auscultation method (Ribaroch-Korotkoff sound method) to determine blood pressure by detecting arterial blood flow sounds (Korotkoff sounds) using a microphone built into the cuff. An electronic sphygmomanometer (oscilloscope) using a vibration method (oscilloscope) that extracts and calculates the arterial pulse wave component of each heartbeat that is superimposed on the cuff pressure and determines the peak and diastolic blood pressure periods.
For example, JP-A-60-106 (Publication No. 11, JP-A-Sho.
9-95033, etc.).

[Problem to be Solved by the Invention] FIG. 13 shows a blood pressure monitor using an auscultation method, in which a cuff 2' having a built-in rubber bladder 20 and a Korotkoff sound sensor 26 is shown.
a tube 2 wrapped around the upper arm 1 and connected to the rubber bladder 20
Air is supplied to the upper arm 1 by means of a pressurizing means 3 formed of a pressurizing rubber bulb 22, etc., and the artery of the upper arm 1 is blood-blocked. After that, exhaust means 4
The air in the rubber sac 20 is gradually evacuated and depressurized by the constant speed evacuation function of the rubber sac 20, thereby transitioning from arterial ischemia to a bleeding state, and the Korotkoff sound sensor 26 detects the Korotkoff sound generated from the artery during the arterial compression operation. , blood pressure monitor body 3
0, the maximum and diastolic blood pressures are determined based on the appearance and disappearance of Korotkoff sounds, and the maximum and diastolic blood pressure values are displayed on the display means 1G. In the figure, 17 is an operation switch.

However, since the electronic blood pressure monitor using the auscultation method described above has the Korotkoff sound sensor 26 inside the cuff 2, it feels uncomfortable when the cuff 2 is attached to the upper arm 1 and pressure is increased or decreased, and it is difficult to measure blood pressure accurately. In order to do this, the Korotkoff sound sensor 26 had to be placed precisely at the arterial position, and the cuff 2' was difficult to attach. Furthermore, since the Korotkoff sound sensor 26 also detects noise emitted from the upper arm 1 and the cuff 2, there is a problem in that malfunctions are likely to occur.

In order to solve these problems, an electronic blood pressure monitor using a vibration method has been proposed, which extracts and calculates arterial pulse wave components to determine blood pressure. , the cuff pressure from the output of the pressure sensor that detects the pressure inside the cuff and the arterial pulse wave superimposed on the cuff pressure are respectively extracted using filter means (low-pass filter, band-pass filter, etc.) consisting of an analog signal processing circuit. A pressure information separation means is formed to separate the pressure information, and the pressure information separated by the pressure information separation means is digitized by an A/D converter, and is used for noise removal and blood pressure determination in a digital calculation means configured using a CPU. A comparison calculation is performed to determine the maximum and diastolic blood pressures, and the determined maximum and diastolic blood pressures are displayed on the display means, and the pressure information separation means is configured with an analog signal processing circuit to separate the pressure information. Since the filter means constituting the means was formed from so-called hardware, there were problems in that the circuit configuration was complicated, the overall shape could not be made smaller, making it difficult to carry, and it was impossible to reduce the price. .

The present invention has been made in view of the above points, and its purpose is to enable the cuff to be easily worn without any discomfort;
Moreover, it is an object of the present invention to provide an electronic sphygmomanometer that has a simple configuration, can be made smaller and less expensive, and can reduce errors in blood pressure measurement due to whisker-like noise and distortion of pulse wave waveforms.

[Means for Solving the Problems] The electronic sphygmomanometer of 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 a cuff that gradually increases the pressure inside the cuff. a pressure sensor that converts the pressure inside the cuff into an electrical signal, an A/D converter that samples the pressure sensor output and converts it into a digital value, and an A/D converter that gradually outputs the air during the evacuation period. Arterial pulse wave extraction means for digitally extracting an arterial pulse wave value from a pressure value; and pressure information separating means, comprising a cuff pressure extraction means for digitally extracting a cuff pressure value from which the arterial pulse wave has been removed from the pressure value. and a storage means for storing arterial pulse wave values and cuff pressure values corresponding to the pulse waves extracted by the pressure information separation means, and the pressure values stored in the storage means are appropriately read out and compared with each other to calculate the maximum, In an electronic blood pressure monitor comprising a blood pressure determining means for determining the diastolic blood pressure value and a display means for displaying both determined blood pressure values, the value of the pulse wave rise start point of the pressure value output from the A/D converter is set to an offset value. The arterial pulse wave extraction means is configured to calculate the area value of the pulse wave as follows, and take the value obtained by dividing the area value by the area calculation period as the arterial pulse wave value.

(Function) The present invention is configured as described above, and since it does not use a cuff with a built-in microphone like an electronic blood pressure monitor using auscultation, the cuff can be easily worn without any discomfort, and it can also be used to improve blood pressure in the arteries. Since the pulse wave value is extracted by digital calculation, the configuration is simpler than the conventional vibration method that performs analog signal processing, making it easier to downsize and lower the price. In addition, since the area value of the pulse wave is calculated and the value obtained by dividing the area value by the area calculation period is used as the arterial pulse wave value, compared to the case where the peak value of the pulse wave is taken as the arterial pulse wave value, the Erroneous measurements are not performed due to the influence of foreign noise, and
Moreover, even if the resolution of the A/D converter is low and the peak value is not sampled, the blood pressure measurement error can be reduced. Furthermore, even if the area calculation period is extended due to distortion of the pulse waveform due to foreign noise, etc., the effect of the distortion of the pulse waveform does not appear on the arterial pulse wave value.
Blood pressure judgment errors due to pulse wave waveform distortion are reduced,
Provides more accurate blood pressure measurement.

(Example) Figures 1 to 4 show an example of the present invention.
In FIGS. 2 and 4, a cuff 2 that is wrapped around and attached to the upper arm 1 of the subject has a built-in rubber bag 20, and a pressurizing hand made of a rubber ball 22 is connected to the rubber bag 20 via a tube 21. Pat 3 is connected and by the suppression operation of the rubber bulb 22;
91! II It is possible to pressurize until blood is drawn.

The pressure inside the cuff 2 pressurized in this manner is gradually exhausted by the exhaust means 4 having an exhaust valve, and blood pressure is measured by the blood pressure monitor main body 30 during this gradual exhaustion period.

A blood pressure monitor main body 30 to which one end is connected to the rubber bladder 20 and the other end of the tube 21 is connected includes a pressure sensor 5 that converts the pressure within the cuff 2 into an electrical signal as shown in FIGS. 2 and 3; A low-pass filter 6 that removes noise contained in the output of the pressure sensor 5, and an A/D converter that samples the noise-removed output of the pressure sensor 5 at a predetermined period (a period sufficiently shorter than the pulse wave) and converts it into a digital value. 7, an arterial pulse wave extraction means 8a for extracting an arterial pulse wave value V by digital calculation from the pressure value (digital value) outputted from the A/D converter 7 during the gradual exhaust period, and an arterial pulse wave extraction means 8a for removing the arterial pulse wave from the pressure value. Pressure information separation means 9 equipped with cuff pressure extraction means 81) for extracting cuff pressure value P by digital calculation, and arterial pulse wave value V and cuff pressure value P corresponding to the pulse wave extracted by pressure information separation means 9. Storage means 1o for storing
and a blood pressure determination means comprising a calculation means 11 for appropriately reading values stored in the storage means 10 and performing comparison calculations, and a blood pressure determination means 12 for determining maximum and diastolic blood pressure values from the calculation results calculated by the calculation means 11. 13, maximum and diastolic blood pressure values, exhaust speed determined by the blood pressure determining means 13, exhaust speed value and pulse rate output from the pulse monitor 14,
The display means 16 displays the cuff pressure outputted from the cuff pressure monitor 15 as appropriate, and the operation switch section 17 for controlling the blood pressure measurement operation and the display means 16 are arranged on the front side of the blood pressure monitor main body 30. There is. Here, the pressure information separation means 9, the storage means 10, the calculation means 11, the blood pressure determination means 13, and both monitors 14 and 15 are formed by a microcomputer 18 using a CPU, ROM, RAM, and the like. As a means for pressurizing and exhausting the cuff 2, a cuff pressure control means 19 is used which automatically controls a pressurizing pump and an electromagnetic exhaust valve according to a predetermined program set in a microcomputer 18, as shown by imaginary lines in the figure. It may be provided.

Below, the basic configuration and operation described in Section 2 will be explained in detail. First, the basic NII configuration and operation for measuring systolic and diastolic blood pressure using the vibration method are as follows.

Now, the cuff 2 is attached to the upper arm 1 of the subject and the pressurizing means 3 is applied.
And by appropriately pressurizing and depressurizing with the exhaust means 4, arterial ischemia and arterial counterpressure at the time of opening (co, unLer p
pressure) into the cuff 2, and the tube 21
It is transmitted to the pressure sensor 5 by air conduction through the air, and electrically converted together with static pressure (cuff pressure) to obtain a pressure signal consisting of an analog signal. Next, this pressure signal is filtered to the extent that it can be removed by a low-pass filter 6, and then the pressure value converted into a digital value by an A/D filter is sent to a microcomputer 18. Next, the microcomputer 18 separates the arterial pulse wave observed as a phenomenon of arterial counterpressure from the pressure value output from this A/D converter 7.
In addition to extracting, storing, and calculating, the systolic blood pressure period and the diastolic blood pressure period are determined, and at the same time, the values corresponding to the maximum and diastolic blood pressure periods of the separated and extracted cuff pressure are read and displayed on the display means 16 as the maximum and diastolic blood pressure values. . Here, in the embodiment, the arterial pulse is calculated so that the area value of the pulse wave is calculated using the pulse wave rise starting point value of the pressure value output from the A/D converter as an offset value to obtain the arterial pulse wave value. It forms a wave extraction means.

The cuff 2 shown in Fig. 4 adopts the shape specified by JIS, keeping in mind that the blood pressure value varies depending on the external shape of the cuff 2, especially its width, as was experienced by using it in the auscultation method. ing. Note that the blood pressure measurement device may be attached to a site other than the upper arm 1, such as the forearm, wrist, chest, thigh, lower leg, etc., as appropriate. Furthermore, the cuff may be wrapped around the tail of an animal other than the human body, such as a rabbit or a mouse. The internal structure of these cuffs 2 needs to be thin, have high compliance, and have high responsiveness in order to detect arterial counterpressure well, so the inner fabric 23 of the cuff 2 must be lightweight,
The rubber bag 20 is made to be stretchable, can withstand repeated pressures of 300 mmHH or more, and is designed to be as thin as possible. Furthermore, it is obvious that the best way to eliminate the influence of the inner fabric 23 is to eliminate the inner fabric 23 and apply the rubber bladder 20 directly to the body surface; in this case, the inner fabric 23 becomes unnecessary. This simplifies the configuration. By the way, another function of the cuff 2 is to transmit the detected arterial counter pressure to the tube 21 by air conduction, but in order to transmit the level of arterial counter pressure without attenuation,
In this embodiment, a method is adopted in which the air portion 25 of the rubber bag 20 has a constant volume regardless of the winding diameter, the deformation of the pressurized area during pressurization, or the pressurizing pressure. The structure has low compliance to prevent expansion. In addition,
Although the winding diameter may vary significantly depending on the body part, this can be easily accommodated by preparing several types of cuffs 2 with different winding diameters.

In addition, the resonance frequency of the acoustic system closed by the tube 21 that transmits pressure from the cuff 2 to the pressure sensor 5 and the pressure control device is
The frequency is set sufficiently higher than the frequency of the arterial pulse wave (2 to 10 Hz), so that even if the resonant frequency changes due to variations in the component parts, it does not affect the band of the arterial pulse wave. In order to transmit the arterial counterpressure without attenuation, the tube 21 is used in this example to reduce the volume.
The length of the tube 21 is made around 50 cm, and the hardness of the tube 21 made of rubber is increased to prevent inflation due to arterial counterpressure.
It is set so that there is no contraction. Furthermore, it may be arranged near ε, 20, or it may be arranged in consideration of the responsiveness and frequency characteristics of the diaphragm so that arterial counterpressure can be reliably detected.

In addition, the low-pass filter placed before the A/D converter 7 has a cutoff range of 10 to 20H.
The static pressure (cuff pressure ) and arterial counterpressure.

In addition, the sampling interval of the A/D converter 7 is set to about 10 to 100 samples/second, which can resolve the arterial counterpressure, and the conversion speed (sample hold time) is set to 172 to 3/4 of the sag-pulling interval, as much as possible. The length is set so that noise at a level that cannot be removed by the low-pass filter 6 can be smoothed. 5 Next, the operation of each means configured in the microcomputer 18 is as follows. First, the pressure information extraction means 9 extracts the difference between the arterial pulse wave component contained in the pressure value, which is a digital value converted from A/D by the A/D converter 7, and the cuff pressure component. They are separated and extracted as an arterial pulse wave value V and a cuff pressure value P. That is, the 7th curve shows the pressure curve of the pressure value output from the A/D converter 7, and the J curve A is the cuff pressure curve during gradual evacuation. , Curve B is an arterial pulse wave curve superimposed on Curve A, and in the present I-child sphygmomanometer, the maximum and diastolic blood pressure values are determined only by the data of the 7th pressure surface. Here, in the arterial pulse wave extracting means 8a, the area value of the arterial pulse wave is obtained from the curve B by digital calculation, and the arterial pulse wave value V of -heartbeat is obtained. In the cuff pressure extraction means 8b, the curve A obtained by removing the arterial pulse wave component from the pressure curve in FIG. 7 is extracted by digital calculation and replaced with a numerical value, and the cuff pressure value P corresponding to each arterial pulse wave value V is It is designed to be.

5 and 6 are 70-charts showing an example of digital calculation that allows easy separation of the arterial pulse wave value V and the cuff pressure value P from the pressure value shown in the pressure curve of FIG. 7. That is, in FIG. 8, the pressure value P at the starting point of pulse wave rise
Read Ba5e and its time (time from the start of sampling to the start point of pulse wave rise) tBase, read the pressure value P Peak at the pulse wave peak point and its time (time from the start of sampling to peak point P eak) tPeak, and calculate these four values. The arterial pulse wave value ■ and the cuff pressure value P are determined by digital calculation using the values of . FIG. 9 is an explanatory diagram of the operation of the pressure information separation means 9, in which (a) is a pressure curve, (b) is an extracted arterial pulse wave value, and (c) is an extracted cuff curve. The pressure value P is shown.

FIG. 10 and FIG. 11 show the arterial pulse wave extraction means 8 of the embodiment.
It is a diagram illustrating the specific operation of a, and shows the pressure value P B at the pulse wave rise starting point of the pressure value output from the A/D converter 7.
The area value Vs of the pulse wave is calculated using a5e as an offset value, and the value obtained by dividing the area value by the area calculation period is set as the arterial pulse wave value V.

That is, the arterial pulse wave extraction means 8a extracts an arterial pulse wave value V for each heartbeat based on the pressure value taken into the microcomputer 18 (digital value output from the A/D converter 7), and extracts the arterial pulse wave value V by the vibration method. Although it is designed to obtain data for determining the peak and diastolic blood pressure periods, the pulse wave component included in the pressure information detected by the pressure sensor 5 is at most 5.
This is a vibration of mmHgp-p, which is not only difficult to extract, but also makes it easy for blood pressure judgment errors to occur because there is not much difference in level from noise caused by pressure fluctuations that occur when you move your body. . Therefore, in this embodiment, the smoothing effect of area calculation is used to make the blood pressure determination more resistant to noise, and the value obtained by dividing the area value by the area calculation period is used as the arterial pulse wave value. , which is designed to reduce measurement errors due to waveform distortion.

An example of area calculation in the arterial pulse wave extraction means 8a is shown below.

In the specific example shown in FIG. 10(a), the pressure value PBa5e at the start point of the rise and rise, which is the offset value, and the time value tPeak at the pulse wave peak point are determined, and the pressure curve, PBa5e straight line, and t
The area value Vs of the diagonally shaded portion surrounded by the Peak straight line is calculated.

In the specific example of FIG. 10 (,b), the pressure value PBa5e at the start point of pulse wave rise, which is the offset value, is determined, and the area value VS of the diagonally shaded portion surrounded by the PBa5e straight line and the pressure value curve is determined.

1 Here, in the example in the same figure (,), the area of the part where the pulse wave rises steeply is calculated, and there is no need to calculate the area of the part where the pulse wave rises slowly, which is affected by the exhaust speed. Therefore, the area calculation becomes easy, and the area value Vs corresponding to the arterial pulse wave, which is not affected by the pumping speed, can be obtained.

In addition, in the example of (b) in the same figure, the pressure value P at the starting point of pulse wave rise
After Ba5e has been determined, it is sufficient to simply add the pressure differences until the pressure value becomes less than P Ba5e.The area calculation is simple, and the absolute value of the area is also smaller than the example in the same figure (, ). It's getting bigger.

As mentioned above, in the examples shown in Figures (, a) and (b), by devising the area calculation method, it is not necessarily necessary to memorize the pressure value of the entire pulse wave, and the pressure value It is possible to reduce the storage capacity of the storage means for temporarily storing
FIG. 2 is a diagram illustrating the operation of calculating the value Vs/T (average pulse pressure) obtained by dividing the area value Vs calculated as described above by the area calculation period T and determining the arterial pulse wave value V. Now, the first
The calculation of the area value Vs in the specific examples shown in FIGS. 1(a) and (b) is the same as in the specific examples shown in FIGS. 10(a) and (b), but
In the case of the example shown in FIG. 11(a), the time value tBase of α at the beginning of the pulse wave rise is also determined, and the area calculation period T is calculated as T = tPe
The average pulse pressure, that is, the arterial pulse wave value v (=Vs/T) is calculated as ak -tBase. On the other hand, in the case of the example shown in FIG. 11(b), the time value tBase at the start point of pulse wave rise and the pressure value P Ba5 after the start point of pulse wave rise
The time t1 on the pressure curve with the same pressure as e is found, the area calculation period T is set to T = t, -tBase, and the average pulse pressure, that is, the arterial pulse wave value V (=Vs/T) is calculated. There is.

FIG. 12 shows an example of time-varying changes in the area value Vs, area calculation period T, and arterial pulse wave value V (-Vs/T) calculated based on the pressure value output from the A/D converter 7. As is clear from the figure, even if the average pulse pressure Vs/T is the arterial pulse wave value V, the maximum value of the arterial pulse wave value V is the same as when the area value Vs is the arterial pulse wave value V. It has been confirmed that the tendency of the arterial pulse wave value V to gradually change during the exhaustion period, which monotonically increases until the time tma when V max is calculated and then monotonically decreases, is not lost, and is effective in determining blood pressure using the vibration method. It was done.

In this embodiment, the output of the pressure sensor 5 is converted into a digital value by the A/D converter 7, and the pressure information separation means 9 digitally calculates the pressure value to obtain the arterial pulse wave value.
Since the pressure information separation means 9 and the blood pressure determination means 13 can be formed by so-called software using the same digital calculation circuit, the configuration becomes simpler, and the cuff pressure value P is separated and extracted. This means that miniaturization and cost reduction can be easily achieved. Furthermore, in the present invention, the arterial pulse wave is extracted such that the area value Vs of the arterial pulse wave is calculated, and the value Vs/T obtained by dividing the area value Vs by the area calculation period T is set as the arterial pulse wave value V. forming means 8a;
In addition to smoothing the noise by area calculation,
The absolute value of the arterial pulse wave value ■ becomes larger, the peak value of the arterial pulse wave is taken as the arterial pulse wave value V, and blood pressure judgment errors due to whisker-like noise are reduced compared to the case where the peak value of the arterial pulse wave is set to the arterial pulse wave value V, and the A/D converter 7
Even if the peak value is not sampled due to low resolution, erroneous blood pressure judgments will not be made.Furthermore, the area value V as the arterial pulse wave value VS/T
Since the value VS'/T, which is obtained by dividing s by the area calculation period T, is used, it is possible to avoid problems such as ischemia, non-linearity of the arterial wall during blood flow, non-constant pumping speed, and external effects when the body is moved during measurement. Even if the pulse waveform is distorted by noise or the like and the area calculation period is extended, the arterial pulse wave value V is not affected by the distortion of the pulse waveform, and blood pressure judgment errors due to the distortion of the pulse waveform occur. This reduces blood pressure, making it possible to more accurately determine blood pressure.

[Effects of the Invention] As described above, the present invention includes a cuff that is attached to the main part of a subject to ischemize blood flow, a pressurizing means that increases the pressure inside the cuff, and a wandering means that gradually decreases the pressure inside the cuff. a pressure sensor that converts the pressure inside the cuff into an electrical signal, an A/D converter that samples the pressure sensor output and converts it into a digital value, and a pressure value gradually output from the A/D connozator during the evacuation period. Arterial pulse wave extraction means for digitally extracting an arterial pulse wave value from the pressure value and cuff pressure extraction means for extracting a pressure value from which arterial pulses and waves have been removed by digital calculation. and storage means for storing arterial pulse wave values and cuff pressure values corresponding to the pulse waves extracted by the pressure information separation means, and appropriately reading out the pressure values stored in the storage means and performing comparison calculations. best,
It consists of a blood pressure determiner stage that determines the diastolic blood pressure value and a display means that displays both determined blood pressure values. Since the force is not used, there is no discomfort when wearing the force 7, and it is easy to wear the force 7. Moreover, since the arterial pulse wave value is extracted by digital calculation, the analog composition is It has the effect of being simple and easy to downsize and reduce cost, and also calculates the area value of the pulse wave by using the value of the pulse wave rise starting point of the pressure value output from the A/D converter as an offset value. Since the arterial pulse wave extraction means is configured to take the value obtained by dividing the area value by the area calculation period as the arterial pulse wave value, the whisker-like outer part is smaller than when the peak value is taken as the arterial pulse wave value. The effect is that erroneous measurements are not performed due to the influence of noise, and blood pressure measurement errors can be reduced even if the resolution of the A/D converter is low and the peak value is not sampled. Furthermore, even if the pulse waveform is distorted due to external noise and the area calculation period is extended, the effect of the distortion of the pulse waveform does not appear on the arterial pulse wave value, and the distortion of the pulse waveform does not occur. This has the effect of reducing blood pressure judgment errors caused by blood pressure and enabling more accurate blood pressure measurements.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a schematic configuration diagram of an embodiment of the present invention, Fig. 2 is a block circuit diagram of the main parts of the same as above, Fig. 3 is a block circuit diagram of the main parts of the same as above, and Fig. 4 is a block diagram of the main parts of the same as above. 5 to 10 are explanatory diagrams of the operation of the same as above, FIGS. 11 and 12 are explanatory diagrams of the operation of another embodiment, and FIG. 13 is a schematic configuration diagram of the conventional example. 1 is the upper arm, 2 is the cuff, '3 is the pressurizing means, 4 is the depressurizing means,
5 is a pressure sensor, 7 is an A/D humbater, 8a is an arterial pulse wave extraction means, 8b is a cuff pressure extraction means, 9 is a pressure information separation means, 10 is a storage means, 13 is a blood pressure determination means, and 16 is a display means. be. Agent Patent Attorney Ishi 1) Chief 7 Figure 9 Figure 6 Figure 7 Figure 8 TBase Tpeak Pressure value Figure 9 Pressure value Figure 10 Pressure 4LfPeak Figure 11 Pressure value Figure 12 Vs VS/T Hiro l. Special opening 863-238847 (10) Figure 13

Claims (1)

[Claims] (1) A cuff that is attached to the main part of the person to be measured, a pressurizing means to increase the pressure inside the cuff, an exhaust means to gradually lower the pressure inside the cuff, and an electric signal to control the pressure inside the cuff. an A/D converter that samples the pressure sensor output and converts it into a digital value, and an arterial pulse wave value that is extracted by digital calculation from the pressure value that is gradually output from the A/D converter during the exhaust period. Arterial pulse wave extraction means; pressure information separation means equipped with cuff pressure extraction means for digitally extracting cuff pressure values from which arterial pulse waves have been removed from the pressure values; a storage means for storing corresponding arterial pulse wave values and cuff pressure values; a blood pressure determination means for determining systolic and diastolic blood pressure values by suitably reading out the values stored in the storage means and performing comparison calculations; In an electronic blood pressure monitor comprising display means for displaying a blood pressure value, the area value of the pulse wave is calculated using the value of the pulse wave rise starting point of the pressure value output from the A/D converter as an offset value, and the area value is calculated as the area value. An electronic blood pressure monitor characterized in that an arterial pulse wave extraction means is formed so that the value divided by the calculation period is the arterial pulse wave value.