JP2936816B2 - Electronic sphygmomanometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillometric sphygmomanometer.

[0002]

2. Description of the Related Art In an oscillometric sphygmomanometer, for example, the cuff pressure is changed over time (see FIG. 9A), and the amplitude of a pulse wave superimposed on this cuff pressure is changed (see FIG. There is one that calculates the blood pressure from b)). (B) of FIG.
This figure shows a change in pulse wave amplitude in the process of reducing the cuff pressure of such a sphygmomanometer, and point P is a maximum amplitude point (A _MAX
). Point D is a point having an amplitude of 0.7 A _MAX with respect to the maximum amplitude point, and point S is a point having an amplitude of 0.5 A _MAX with respect to the maximum amplitude point. Then, for example, FIG. 9A corresponding to points S and D
From these points, the systolic blood pressure (systolic blood pressure) and the diastolic blood pressure (diastolic blood pressure) were determined.

In an oscillometric sphygmomanometer, for example,
Since the blood pressure value is determined as described above, it is necessary to pressurize the blood so that the point S in FIG. 9B can be detected. However, since the systolic blood pressure (systolic blood pressure) cannot be predicted before the measurement, the pressure is increased. It is difficult to set the target value (the point at which the pressurization of the cuff pressure is stopped) to an appropriate value, and it is particularly difficult for a hypertensive subject with severe blood pressure fluctuation. If the target pressurization value is set to an unnecessarily high value, the subject may be distressed.

Therefore, conventionally, in the process of applying the cuff pressure, a cuff pressure signal is captured, and a temporal transition (pulse wave envelope) of the amplitude of the pulse wave superimposed on the cuff pressure signal is obtained. The systolic pressure was simply estimated. For example, to identify the point with an amplitude of 0.5A _MAX the maximum amplitude value A _MAX, was estimated systolic pressure with the cuff pressure at the point with an amplitude of 0.5A _MAX. And the pressurization target value was automatically set based on the estimated systolic pressure.

[0005]

However, in the above-described sphygmomanometer, only the pulse wave signal of a normal level exceeding a predetermined threshold value is set as an object for calculating the amplitude of the pulse wave signal.
Envelopes needed to estimate systolic pressure may not be complete. That is, when the cuff pressure pressurization speed is faster than the pulse wave extraction timing, and conversely, when the pulse wave cycle is longer (the pulse rate is smaller) than the cuff pressure pressurization speed, the pulse pressure (systolic blood pressure and Diastolic blood pressure difference) is small and the amplitude decreases sharply around the peak of the pulse wave amplitude,
In addition, when the pulse wave amplitude is small as a whole, a necessary envelope cannot be formed unless a minute pulse wave amplitude portion is included, and therefore, the systolic pressure may not be estimated.

As a solution to such a problem, the threshold value can be set extremely low. However, if the threshold value is set too low, the systolic pressure can be sufficiently estimated from a pulse signal of a normal level. Until it is possible, noise superimposed on the pulse wave signal will be picked up, which is not appropriate. SUMMARY OF THE INVENTION The present invention focuses on the above problem, and when an envelope of a pulse wave amplitude cannot be sufficiently specified by a normal pulse wave signal, an envelope is specified using the amplitude of a minute pulse wave signal. Accordingly, an object of the present invention is to provide a sphygmomanometer that estimates a systolic pressure and automatically sets a pressurization target value of the cuff pressure.

[0007]

To achieve the above object, a sphygmomanometer according to the present invention detects a cuff for compressing a living artery, a pressurizing means for pressurizing the cuff, and a pressure in the cuff. A pressure sensor, pulse wave extracting means for extracting a pulse wave signal superimposed on the cuff pressure signal from the cuff pressure signal detected by the pressure sensor, and a pulse wave signal extracted by the pulse wave extracting means exceeding a predetermined value width. In the case of vibration, a break point detecting means for detecting a break point of a pulse wave which is a rising point of one beat of vibration, and a pulse wave amplitude calculating means for calculating an amplitude value of a pulse wave in a section delimited by the break point And a systolic pressure estimating means for estimating the systolic pressure in the process of applying the cuff pressure based on the temporal transition of the pulse wave amplitude calculated by the pulse wave amplitude calculating means; Set the pressurization target value based on the cuff A pressure stop means for stopping the operation of the pressurizing means when the pressure reaches the pressurization target value, a pressure reducing means for gradually reducing the cuff pressure after the pressurization is stopped, and the pulse wave amplitude calculation in the process of reducing the cuff pressure. A blood pressure monitor for determining a blood pressure value based on a calculation result of the means, a return check for detecting the end of one pulse wave oscillation for a pulse wave vibrating beyond a predetermined value width. Output means and a section from the return point to the break point,
A minute amplitude calculating means for sequentially extracting a signal that oscillates minutely to obtain an amplitude value thereof, and calculating the minute amplitude calculating means when the breakpoint cannot be detected even if a predetermined time has elapsed from the return point. A minute amplitude supplying means for supplying an amplitude value to the systolic pressure estimating means.

[0008]

The breakpoint detecting means detects a rising point (breakpoint) of a normal-level pulse wave signal vibrating beyond a predetermined value width. On the other hand, the return point detecting means detects a point (return point) at which the vibration of the pulse wave at the normal level ends. Then, the minute amplitude calculating means calculates the amplitude value of the minute signal in the section of the break point from the return point. Note that this small signal is
When the breakpoints can be detected one after another, it is considered to be noise.However, the pulse wave amplitude decreases as the cuff pressure increases. It is considered as a pulse wave.

On the other hand, the pulse wave amplitude calculating means calculates the amplitude value of the normal level pulse wave signal oscillating in the section between the previous break point and the present break point at the timing when the break point detecting means detects the break point. calculate. Then, the systolic pressure estimation means, based on the temporal transition (envelope) of the pulse wave amplitude,
For example the cuff pressure corresponding to the point having the pulse wave amplitude of 0.5A _MAX the maximum pulse wave amplitude A _MAX estimating the systolic pressure.

However, there is a case where the envelope of the pulse wave amplitude cannot be sufficiently specified only by the pulse wave signal of the normal level. In such a case, the minute amplitude supplying means and the systolic pressure estimating means operate as follows. That is, the minute amplitude supply means, when the break point detection means cannot detect the break point even after a predetermined time has elapsed from the return point, calculates the amplitude value calculated by the minute amplitude calculation means to the systolic pressure. Supply to estimation means. That is, since a breakpoint cannot be detected even after a predetermined time has elapsed from the return point, it is determined that the pulse wave amplitude has shifted from the normal level to the minute level, and the pulse wave amplitude at the minute level is determined by the systolic pressure estimation means. To supply. Then, the systolic pressure estimating means specifies the pulse wave envelope including the amplitude value of the micro pulse wave and estimates the systolic pressure.

Here, the amplitude of the minute pulse wave signal means the maximum value of the pulse wave signal or the difference between the maximum value and the minimum value of the pulse wave signal. Further, as the cuff pressure corresponding to the amplitude value of the micropulse wave signal, the cuff pressure at which point in the pressurization process is adopted is not particularly limited, but, for example, the micropulse wave has a maximum value in the microvibration section. Adopt the cuff pressure at the time.

[0012]

1 is a block diagram of an electronic sphygmomanometer according to an embodiment of the present invention. This electronic sphygmomanometer includes a cuff 1 for compressing a living artery, a pump 2 for pressurizing the cuff 1, and a cuff 1
Quick exhaust valve 3 for rapidly exhausting the pressure (air pressure), a slow exhaust valve 4 for gradually exhausting the air of the cuff 1, a pressure sensor 5 for detecting the pressure of the cuff 1, and a low-pass filter 6
A / D for converting the output of the pressure sensor 5 into a digital value
A converter 7, an MPU 8 that takes in signals from the A / D converter 7 and performs various processes described later, and a display 9 that displays a measured blood pressure value are provided. The low-pass filter 6 removes pressure noise of the pressurizing pump 2 mixed in the cuff pressure signal when extracting a pulse wave during pressurization.

FIGS. 2 and 3 are general flowcharts showing the overall operation of the electronic sphygmomanometer shown in FIG. still,
Pulse wave extraction processing (ST4), pulse wave amplitude calculation processing (ST
8) The target pressurization value setting process (ST14) and the blood pressure measurement process (ST17) are portions that perform the following processes, respectively. Pulse wave extraction process (ST4): This is a process of extracting a pulse wave signal superimposed on the cuff pressure data from the cuff pressure data. Pulse Wave Amplitude Calculation Process (ST8): This is a process for calculating the pulse wave amplitude value by recognizing the starting point and the ending point of the pulse wave of the normal level exceeding the threshold width for each beat. Target pressurization setting process (ST14): This is a process of adding an appropriate value to the estimated systolic pressure (systolic blood pressure value) to obtain a target pressurization value. Blood pressure measurement process (ST17): This is a process of calculating a systolic blood pressure value (systolic pressure) and a diastolic blood pressure value (diastolic pressure) from the envelope of the pulse wave amplitude in the process of reducing the cuff pressure.

The operation of the electronic sphygmomanometer shown in FIG. 1 will be described below with reference to the flowcharts of FIGS. When the operation is started by a start switch or the like, the MPU 8 drives the pump 2 to start pressurization (step ST (hereinafter abbreviated as ST) 1), and a counter t ₀ for data such as cuff pressure.
Is initially set to 1 (ST2). Next, MPU 8 executes A /
The cuff pressure data P (t ₀ ) is read from the D converter 7 (S
T3) The process proceeds to the above-described pulse wave extraction processing, and the cuff pressure data P
(T ₀₎ from extracting the pulse wave signal P _W (t ₀₎ (ST
4). This pulse wave signal extraction processing is realized, for example, as processing of a high-pass filter using cuff pressure data P (t ₀ ) as an input value. Turning now to the pulse wave separator processing (ST5), it examines the current time point t ₀ is the breakpoint of the pulse wave, that is, whether or not a time when the pulse wave is to do exactly rise. And then, for one beat of the pulse wave having an amplitude of normal level, in preparation for obtaining the pulse wave amplitude, the updating of the value of the maximum value D _MAX0 and the minimum value D _MIN0 (ST6).

Subsequently, in ST7, based on the processing result in ST5, it is determined whether or not the current time point t ₀ is a pulse wave separation point (a point at which the next pulse wave is about to rise) (ST7). ). If it is a pulse wave breakpoint, the current time point t ₀
Is the end point of the current normal pulse wave and the start point of the next normal pulse wave, the amplitude calculation process for the normal-level pulse wave shown in FIG. 5 is performed (ST8). I will check again,
This amplitude calculation process (ST8) is a process for obtaining the amplitude of the pulse wave vibration when the pulse wave has a normal level amplitude exceeding a predetermined threshold value.

[0016] Hereinafter, concretely describing amplitude calculating processing (ST8) with reference to FIG. 5, right now t _0, so is the end point of the pulse wave vibration, first, to update the pulse wave number i (ST
8 _-1 ). Then, to obtain an amplitude value of the pulse wave of the maximum value of the pulse wave which are obtained in ST6 D _MAX0 and current than the minimum value D _MIN0 (i _{th) AMP (i) (ST8 -2} ). Next, this time (i
It is necessary to specify the cuff pressure P _C (i) corresponding to the pulse wave of (th), but the end point (separation point) of the pulse wave oscillation is shown in the array T.
, The elapsed time from the start of pressurization is stored, so that the cuff pressure P corresponding to the current (i-th) pulse wave vibration
_C a (i), the previous, that is i-1 th time T of the end point of the pulse wave oscillating (i-1) based on identifying as P [T (i-1)] (ST8 _-3) . Since the processing for the current (i-th) normal pulse wave is completed by the above processing, D _MAX and D _MIN are initialized to 0 in preparation for the calculation of the amplitude value of the next pulse wave vibration. Then, the process proceeds to ST12 in FIG.

After the calculation of the amplitude (ST8) for the current (i-th) normal level pulse wave, the systolic blood pressure (systolic pressure) is estimated (ST12). This process (FIG. 8)
And when the reference), the estimated systolic pressure ESP is calculated simply there is a case where the maximum value A _MAX of the pulse wave amplitude AMP (i) is updated (the details will be described later), systolic pressure is still estimated If not, the process returns to ST3 to repeat the processing of ST3 to ST12 (ST13). Conversely, when the systolic pressure ESP has been estimated, the processing moves to the processing shown in FIG. In addition,
In the estimation process of the systolic blood pressure (systolic pressure) in ST12, the amplitude value AMP (i) of the pulse wave and the like are necessary (see FIG. 8), but this amplitude value AMP (i) is the normal level obtained in ST8. In addition to the amplitude value of the pulse wave, the amplitude value of the pulse wave at a minute level obtained in the process of ST11 described later is also included.

Next, returning to the process of ST7 shown in FIG.
A case where the current time point t ₀ is not a break point will be described. If the current time point t ₀ is not a break point, it is determined whether the current time point t ₀ is a return point (ST9). Here, the return point is a point at which the pulse wave signal has passed through the positive and negative peaks of the pulse wave and the pulse wave signal has almost returned to the baseline level.How to detect this point is described below. It will be described later (see FIG. 6).

If the current time t ₀ is a return point, window processing is initialized (ST10, see FIG. 4). Specifically, a variable t for calculating the time lapse starting from the return point
_1, initially set to the variable D _MAX, all D _MIN 0 for obtaining the maximum value and the minimum value of the minute vibration in the vibration region of the weak signal (section from the return point to the breakpoint) (ST10 shown in FIG. 4 _-1 , ST10 _-2 ).

If the current time t ₀ is not the return point, a window-based amplitude calculation process is performed (ST11).
In this process, the maximum value D _MAX and the minimum value D _MIN of the micro vibration are calculated while calculating the lapse of time from the return point, and the amplitude of the micro signal is obtained 1.5 seconds after the return point. (See FIG. 7), which will be described later in detail. As outlined above in ST9 to ST11, from the return point of the pulse wave vibration (the point where the pulse wave signal has almost returned to the baseline level) to the break point of the pulse wave vibration (the start point of the next pulse wave vibration) Also, the amplitude value AMP of the minute vibration in that section
(I), and the corresponding cuff pressure value P _C (i) is obtained.
If necessary, these values are used in systolic blood pressure (systolic pressure) estimation processing ST12. In other words, even when the amplitude of the normal level pulse wave (pulse wave oscillating beyond the threshold) cannot be used to draw the required envelope because the cuff pressure is applied at a high speed, the normal level pulse wave cannot be drawn. The required envelope can be drawn using the amplitude of the minute vibration of the pulse wave within a 1.5 second section after the last vibration.

Turning now to FIG. 3, systolic blood pressure (systolic pressure)
The processing after the estimation is completed will be described. When the systolic pressure is estimated, the processing after ST14 shown in FIG. 3 is performed. That is, the MPU 8 calculates a pressurization target value based on the estimated systolic pressure (ST14), and continues pressurization until the pressurization target value is reached (ST15). The target pressure value is, for example, a value obtained by adding 30 mmHg to the estimated systolic pressure in consideration of the estimation error of the systolic pressure and the pressure drop from immediately after the stop of the pressurization to the start of the pulse wave amplitude measurement. Is set to When the cuff pressure reaches the pressurization target value, pressurization is stopped (ST16).

Thereafter, the normal blood pressure measurement processing is performed.
That is, the low-speed exhaust valve 4 is operated to shift to the process of reducing the cuff pressure. The systolic blood pressure and the diastolic blood pressure are calculated from the envelope of the pulse wave amplitude in this depressurizing process, and the blood pressure values are displayed on the display 9. Then, all the processing ends. FIG. 6 is a flowchart showing a method of detecting the return point (see ST9 of FIG. 2). Pulse wave signal P extracted from cuff pressure signal P (t ₀ )
First, it is determined whether the value of _W (t ₀ ) is negative (ST9 ₋₁ ). If the pulse wave signal P _W (t ₀ ) is not negative, it is determined that the current time point t ₀ is not a return point. If the reverse pulse wave signal P _W (t ₀₎ is negative, then the level of the pulse wave signal P _W (t ₀₎ is compared magnitude with a threshold value TH (negative value) (ST9 _-2 ). And the pulse wave signal P
_If the level of _W (t ₀ ) is lower than the level of the threshold value TH (negative value), it is determined that the current time point t ₀ is not a return point.

If the current time t₀Pulse wave signal P
_W(T₀) Is greater than or equal to the threshold TH
For example, the previous pulse wave signal P_W(T₀-1) level
The threshold value TH is compared in magnitude (ST9)._-3). And 1
Time t before₀-1 is also the current time t ₀, Together
No.P_WIs higher than the threshold value TH, it returns now
After the point, and therefore the current time t₀Is the return point
Is determined to be.

The above processing (ST9)_-1~ ST9_-3Amended)
After all, the process ends with ST9 _-FourTo move to
Is the pulse wave signal P_WIs a negative level (ST9_-1),Previous
Times t₀-1 was lower than the threshold TH,
(ST9_-3), For the first time, a level higher than the threshold value TH
(ST9_-2) Is a condition. And this
In such a case, the current time t₀But the pulse wave that has just ended
The time t of the negative peak_DIPHow long from
It is determined whether the time has elapsed (ST9)._-Four). And now
Time t₀Is the negative peak time t of the pulse wave_DIPFrom for example
If within 0.3 seconds, t now₀Is determined as a return point
(ST9_-Four).

FIG. 7 shows a window-based amplitude calculation process (FIG. 2).
21 is a flowchart showing ST11) of FIG.
Here, the window-based amplitude calculation processing means calculating the maximum value D _MAX and the minimum value D _MIN of the micro-vibration while calculating the time lapse t ₁ from the return point, and when 1.5 seconds have passed from the return point. Is a process for obtaining the amplitude and the like of the minute signal. This will be described below with reference to FIG.

[0026] First, the value of the return 0 cleared counter t ₁ at point 1 is added to (ST10 see _-1 in FIG. 4) to update the value (ST11 _-1). Then, the value of the pulse wave signal P _W (t ₁ ) at the current time point t ₁ is compared with the value of the variable D _MAX for obtaining the maximum value (ST11 _-2 ). And if P _W (t
₁ ) If ≧ D _MAX , the value of the variable D _MAX for obtaining the maximum value is updated (ST11 _-3 ), and the cuff pressure P at this time t ₁ is updated.
(T ₁ ) is stored in the variable P _MAX (ST11 _-4 ).

[0027] Subsequently, the present time t ₁ of the pulse wave signal P _W (t
Value of ₁₎ is compared to the value of the variable D _MIN for obtaining the minimum value (ST11 _-5). And if P _W (t ₁ ) ≦ D
If _MIN, the value of the variable D _MIN for obtaining the minimum value is updated (ST11 _-6). Next, it is determined whether, for example, 1.5 seconds have elapsed from the current time point t ₁ from the return point (ST1).
_1-7 ). If the current time point t ₁ is within 1.5 seconds from the return point, the process of ST11 is finished without doing anything, and the process proceeds to the process of ST12 in FIG. Conversely, if the current time point t ₁ has elapsed 1.5 seconds return point, to end the process of extracting the amplitude of the fine vibration at this time, it updates the value of the pulse wave number i (ST1 _-8 ), The maximum value D _MAX for micro vibration
And the minimum value D _MIN to obtain the pulse wave amplitude AMP (i) (S
T11 _-9). Then, P as the cuff pressure corresponding to the cuff pressure value P _MAX that has been stored at ST11 _-4 pulse wave number i
And stored in _{C (i) (ST11 -10)} .

The above operation completes the window-based amplitude calculation process (ST11).
P (i) and the cuff pressure P _C (i) are sufficient when the pulse wave amplitude and the cuff pressure by the normal amplitude calculation (ST8 in FIG. 2) are sufficient and the pulse wave envelope cannot be specified (for example, the pulse in ST8). When it is not possible to specify the time point at which the amplitude becomes 0.5 A _MAX or less by the wave amplitude alone), it is used in the systolic blood pressure estimation processing (ST12).

In this embodiment, the difference between the maximum value D _MAX and the minimum value D _MIN is used as the amplitude of the minute vibration. However, the present invention is not limited to this. For example, the maximum value of the pulse wave signal is used. Is also good. Further, in this embodiment, the cuff pressure P _C which corresponds to the pulse wave number i (i), the level of fine vibration using the cuff pressure at which the highest value (see ST11 _-4), limited to No need to be done.

FIG. 8 shows a systolic blood pressure estimation process (ST1 in FIG. 2).
It is a flowchart which shows 2) in more detail. In FIG. 8, AMP (i) is a normal amplitude calculation (ST8).
Alternatively, the pulse wave amplitude for the normal level pulse wave or the minute level pulse wave extracted in the window amplitude calculation (ST11) is shown. Each cuff pressure P _C (i) is also for each pulse wave amplitude AMP (i), it is calculated in the usual amplitude calculating (ST8) or the amplitude calculated by the window (ST11) (ST8 in Fig. 5 _-3, Figure see ST11 _-9 of 7). still,
i is a pulse wave number indicating the order of the extracted pulse waves, and a pulse wave number i and a variable A for obtaining the maximum value of the pulse wave amplitude.
_MAX is initially set to 0. Hereinafter, the contents of the systolic blood pressure (systolic pressure) estimation processing will be described with reference to FIG.

[0031] First, comparing the pulse wave amplitude AMP (i) is the pulse wave amplitude maximum value A _MAX (ST21). Where AMP
(I) If ≧ A _MAX, it is determined that the envelope of the pulse wave is in the ascending process and has not yet reached the maximum point, and the value of AMP (i) is substituted for A _MAX (ST22). Ends. Conversely, when AMP (i) <A _MAX , it is determined that the envelope of the pulse wave amplitude is in the process of decreasing after passing through the maximum point, and the pulse wave amplitude AMP (i) is used to determine the systolic pressure. (ST23). In this embodiment, the threshold value for determining the systolic pressure is set to, for example, 0.5 A _MAX , and if AMP (i) ≦ 0.5 A _MAX , the process proceeds to the next processing to estimate the systolic pressure estimated value ESP. Is calculated (ST24). Conversely, if AMP (i)> 0.5 A _MAX , the process ends without determining the estimated systolic pressure. Since the cuff pressure changes greatly in the pressurized section and the cuff pressure interval between pulse waves is wide, the cuff pressure at the time when the pulse wave amplitude decreases below the threshold value is directly used as the estimated value of the systolic pressure. Then the accuracy is poor. Further, there is a case where the envelope is specified by the pulse wave amplitude of the minute level because the pulse wave amplitude of the normal level cannot be extracted. Therefore,
In the present embodiment, the estimated value ESP of the systolic pressure is calculated using the following linear interpolation formula.

[0032]

(Equation 1)

In the equation (1), TH _S is a threshold value for determining the systolic pressure.

[0034]

As described above, in the electronic sphygmomanometer according to the present invention, a pulse wave signal that oscillates minutely even if a normal level pulse wave signal cannot be captured during the cuff pressure application process. Capture and estimate systolic blood pressure. Therefore, even when the pulse wave amplitude of the normal level cannot be extracted in the pressurization process, the pressurization target value can be automatically set.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of an electronic sphygmomanometer according to one embodiment of the present invention.

FIG. 2 is a part of a flowchart for explaining the overall operation of the electronic sphygmomanometer of FIG. 1;

FIG. 3 is a remaining part of the flowchart for explaining the overall operation of the electronic sphygmomanometer of FIG. 1;

FIG. 4 is a flowchart for explaining a window initialization operation of the electronic sphygmomanometer of FIG. 1;

FIG. 5 is a flowchart for explaining a normal amplitude calculation process of the electronic sphygmomanometer of FIG. 1;

FIG. 6 is a flowchart illustrating a process of calculating a return point of the electronic sphygmomanometer of FIG. 1;

FIG. 7 is a flowchart for explaining amplitude calculation processing by a window of the electronic sphygmomanometer of FIG. 1;

FIG. 8 is a flowchart for explaining a systolic blood pressure estimation process of the electronic sphygmomanometer of FIG. 1;

FIG. 9 is a diagram for explaining a blood pressure determination method in the oscillometric electronic sphygmomanometer.

[Description of Signs] 1 Cuff 2 Pump 3 Quick exhaust valve 4 Slow exhaust valve 5 Pressure sensor 8 MPU

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) A61B 5/00-5/03

Claims (1)

(57) [Claims] 1. A cuff for compressing a living artery, a pressurizing means for pressurizing the cuff, a pressure sensor for detecting a pressure in the cuff, and a cuff pressure signal detected by the pressure sensor superimposed on the cuff pressure signal. Pulse wave extracting means for extracting a pulse wave signal
When the pulse wave signal extracted by the pulse wave extracting means vibrates beyond a predetermined value width, a break point detecting means for detecting a break point of a pulse wave which is a rising point of one beat of vibration, and a break point separated by the break point Pulse wave amplitude calculating means for calculating an amplitude value of a pulse wave in a section to be taken, and a systolic pressure in a cuff pressure increasing process based on a temporal transition of a pulse wave amplitude calculated by the pulse wave amplitude calculating means. Pressure estimating means for estimating, and pressurization stopping means for setting the pressurization target value based on the estimated systolic pressure, and stopping the operation of the pressurization means when the cuff pressure reaches the pressurization target value. An electronic sphygmomanometer comprising pressure reducing means for gradually reducing the cuff pressure after pressurization is stopped, and blood pressure determining means for determining a blood pressure value based on the calculation result of the pulse wave amplitude calculating means in the process of reducing the cuff pressure. , Pulse wave oscillating beyond the specified width A return point detecting means for detecting the end of the pulse wave of one beat, and a minute signal for sequentially extracting a minutely oscillating signal and obtaining an amplitude value in a section from the return point to the break point. Amplitude calculating means, and a minute amplitude supplying means for supplying the amplitude value calculated by the minute amplitude calculating means to the systolic pressure estimating means when the break point cannot be detected even if a predetermined time has elapsed from the return point. An electronic sphygmomanometer characterized by comprising: