CN106037693B

CN106037693B - Sphygmomanometer

Info

Publication number: CN106037693B
Application number: CN201610177595.7A
Authority: CN
Inventors: 栗尾胜; 筑田克美
Original assignee: Terumo Corp
Current assignee: Terumo Corp
Priority date: 2015-04-09
Filing date: 2016-03-25
Publication date: 2020-07-07
Anticipated expiration: 2036-03-25
Also published as: JP2016198276A; TW201639522A; CN106037693A; TWI674087B; JP6487756B2

Abstract

The invention provides a sphygmomanometer which can easily judge the time when the operation of a balloon should be stopped. A sphygmomanometer (1) is provided with: a balloon (40) for delivering air to the internal space (12) of the cuff (10); a display unit (360); a pressure sensor (320) that detects the pressure of the internal space (12); a valve (330) for depressurizing the interior space (12); and a control unit (350) that calculates the pressure in the internal space (12) on the basis of the output from the pressure sensor (320) and displays the calculated pressure on a display unit (360). The control unit (350) controls the display of the display unit (350) in such a manner that: while the pressure of the internal space (12) is increased by the operation of the balloon (40), a characteristic point in the pressure fluctuation of the internal space (12) is detected, and the continuous display of the pressure of the characteristic point is started based on the detection of the characteristic point.

Description

Sphygmomanometer

Technical Field

The present invention relates to a sphygmomanometer having a balloon.

Background

Some blood pressure monitors are configured to measure the blood pressure while compressing the arm portion or the like at a sufficient pressure by inflating the cuff by delivering air to the cuff using a balloon. By repeating the operation of increasing and decreasing the force of grasping the balloon to deliver air to the internal space of the cuff, the pressure in the internal space can be increased. The pressure in the internal space of the cuff is correlated with the force with which the cuff presses the arm portion and the like. The pressure in the internal space of the cuff can be expressed more easily as the pressure of the cuff in general, but in this specification, as an accurate expression, an expression such as the pressure in the internal space of the cuff is used.

When the balloon is gripped, air is supplied to the cuff, and when the force for gripping the balloon is weakened, air is sucked into the balloon from the outside. In the course of operating the balloon to increase the pressure in the internal space of the cuff by such an operation, the pressure is gradually increased while repeating an increase and a small decrease.

Patent document 1 describes a sphygmomanometer in which a straight line connecting a pressure rise point and a next pressure rise point is obtained, and when a detected pressure Pn of a pressure sensor exceeds a pressure Pcn given by the straight line, Pcn is displayed, and when the detected pressure Pn does not exceed the pressure Pcn, Pn is displayed.

Patent document 1: japanese patent laid-open publication No. 2002-360524

In the sphygmomanometer disclosed in patent document 1, since the pressure to be displayed is determined based on a straight line defined by the two closest pressure rise points, if the speed at which the balloon (rubber ball) is operated changes in the middle, the difference between the displayed pressure and the actual pressure may increase. For example, if the speed of operating the balloon suddenly slows, then Pn may not exceed Pcn and Pn may be displayed directly. When Pn is displayed directly, the displayed pressure repeatedly rises and falls. A user such as a doctor or a nurse needs to raise the pressure in the internal space of the cuff to a pressure slightly higher than the assumed maximum blood pressure value of the subject, but it is difficult to accurately determine when to stop the balloon inflation operation because the displayed pressure repeatedly rises and falls.

Disclosure of Invention

The purpose of the present invention is to provide a sphygmomanometer in which the timing at which the operation of a balloon should be stopped can be easily determined.

One aspect of the present invention relates to a sphygmomanometer including a balloon for delivering air to an internal space of a cuff, a display unit, a pressure sensor for detecting a pressure in the internal space, and a valve for reducing the pressure in the internal space, the sphygmomanometer including a control unit for calculating the pressure in the internal space based on an output from the pressure sensor and displaying the calculated pressure in the internal space on the display unit, wherein the control unit controls display on the display unit as follows: while the pressure in the internal space is being increased by the operation of the balloon, a characteristic point in the pressure fluctuation in the internal space is detected, and the continuous display of the pressure at the characteristic point is started based on the detection of the characteristic point.

According to the present invention, a sphygmomanometer is provided that facilitates determination of a timing at which an operation of a balloon should be stopped.

Drawings

Fig. 1 is a diagram showing a configuration of a blood pressure monitor according to an embodiment of the present invention.

Fig. 2 is a diagram illustrating the pressure in the internal space of the cuff when the blood pressure of the subject is measured by the sphygmomanometer.

Fig. 3 is a diagram exemplarily illustrating detection of a valley pressure and update of a display in the first embodiment of the present invention.

Fig. 4 is a diagram illustrating a method of detecting a valley pressure in the first embodiment of the present invention.

Fig. 5 is a diagram illustrating an operation of the sphygmomanometer according to the first embodiment of the present invention.

Fig. 6 is a view exemplarily showing a process including detection and display of inflection point pressure in the second embodiment of the present invention.

Fig. 7 is a diagram illustrating a method of detecting a peak in the second embodiment of the present invention.

Fig. 8 is a diagram illustrating a method of detecting a first inflection point after a peak in the second embodiment of the present invention.

Fig. 9 is a diagram illustrating an operation of the sphygmomanometer according to the second embodiment of the present invention.

Detailed Description

The present invention will be described below with reference to the accompanying drawings by way of exemplary embodiments thereof.

Fig. 1 shows a configuration of a blood pressure monitor 1 according to an embodiment of the present invention. The sphygmomanometer 1 includes a main body 30 having a flow passage 310 communicating with the internal space 12 of the cuff 10 via a hose 20, and an air supply bulb 40 connected to the main body 30 so as to be able to supply air to the internal space 12 of the cuff 10 via the hose 20 and the flow passage 310. The sphygmomanometer 1 further includes a pressure sensor 320, a valve 330, an operation unit 340, a control unit 350, a display unit 360, and a buzzer 370. The pressure sensor 320 is connected to the flow path 310 so as to be able to detect the pressure in the internal space 12 of the cuff 10. The valve 330 is connected to the flow path 310 so as to be able to reduce the pressure in the internal space 12 of the cuff 10. The operation unit 340 includes, for example, switches and buttons for turning on and off the power supply and setting the mode. The display unit 360 displays, for example, the state of the sphygmomanometer 1, the pressure in the internal space 12 of the cuff 10, the measured blood pressure, and the like. The buzzer 370 is used for reporting an error or the like.

The control unit 350 calculates the pressure in the internal space 12 of the cuff 10 based on the output from the pressure sensor 320, and displays the calculated pressure on the display unit 360. Here, the control section 350 controls the display of the control display section 360 in such a manner that: while the pressure in the internal space 12 of the cuff 10 is increased by the operation of the balloon 40, a characteristic point in the pressure fluctuation in the internal space 12 of the cuff 10 is detected, and the continuous display of the pressure at the characteristic point is started based on the detection of the characteristic point.

In the first embodiment of the present invention, the characteristic point is a valley in the pressure change in the internal space 12 of the cuff 10. In the second embodiment of the present invention, the characteristic point is the first inflection point after the peak in the pressure fluctuation in the internal space 12 of the cuff 10.

First, a first embodiment of the present invention will be explained below. In the first embodiment, the control section 350 controls the display of the display section 360 in such a manner that: while the pressure in the internal space 12 of the cuff 10 is increased by the operation of the balloon 40, the pressure at the valley (hereinafter referred to as "valley pressure") in the pressure change in the internal space 12 of the cuff 10 is detected as the pressure at the characteristic point, and the continuous display of the valley pressure is started based on the detection of the valley pressure. In the first embodiment of the present invention, the control unit 350 updates the display of the display unit 360 so that, for example, the latest valley pressure (that is, the newly detected valley pressure) is displayed each time the valley pressure is detected.

Fig. 2 exemplarily shows the pressure of the internal space 12 of the cuff 10 when the blood pressure of the subject is measured by the sphygmomanometer 1. In fig. 2, the horizontal axis represents time, and the vertical axis represents the pressure in the internal space 12 of the cuff 10 detected by the pressure sensor 320. The power switch of the operation unit 340 is operated to turn on the power supply, and thereafter, the balloon 40 is operated (repetition of the gripping operation and the release operation) to increase the pressure in the internal space 12 of the cuff 10, and at time t10 when it is determined that the pressure exceeds the predetermined value TH, the processing of detecting and displaying the valley pressure is started. This process continues to time t11 at which it is determined that the operation of the balloon 40 is stopped. In other words, the processing of detection and display of the valley pressure is performed during the period TP from the time t10 to the time t 11. If a decision is made that the operation of the balloon 40 is stopped, the measurement of the blood pressure (typically, the detection of the maximum blood pressure value and the minimum blood pressure value) is started. The blood pressure is measured, for example, based on a change in pressure detected by the pressure sensor 320.

The detection of the valley pressure and the update of the display during the period TP will be described with reference to fig. 3. In fig. 3, the horizontal axis represents time, and the vertical axis represents the pressure in the internal space 12 of the cuff 10 detected by the pressure sensor 320 (more specifically, the pressure calculated by the control unit 350 based on the output of the pressure sensor 320). In fig. 3, the pressure in the interior space 12 is shown as a curve, but the pressure is typically a discrete value. The control unit 350 samples the output (signal) from the pressure sensor 320 at predetermined sampling intervals, and calculates the pressure in the internal space 12 of the cuff 10 based on the sampled output. To give a more specific example, the control unit 350 obtains the pressure corresponding to the output of the sampling by multiplying the output by a conversion coefficient, or by referring to a look-up table, for example.

The numerical value of the pressure in the internal space 12 of the cuff 10 thus obtained indicates the pressure fluctuation. The control unit 350 updates the display of the display unit 360 so as to detect the valley pressure in the pressure change as the pressure of the feature point and display the latest valley pressure (that is, the newly detected valley pressure) each time the valley pressure is detected. That is, when the valley pressure is detected, the pressure displayed on the display unit 360 is updated so that the valley pressure is displayed, and the display of the pressure is maintained until the valley pressure is detected next time.

In fig. 4, the horizontal axis represents time, and the vertical axis represents the pressure in the internal space 12 of the cuff 10 detected by the pressure sensor 320 (more specifically, the pressure determined by the control unit 350 through calculation based on the output of the pressure sensor 320), ○ in fig. 4 represents the pressure determined by sampling the output of the pressure sensor 320, and the curve is a graph for convenience of illustration.

In the example shown in fig. 4, the control unit 350 detects that a decrease in the pressure in the internal space 12 of the cuff 10 has occurred, based on the determination that the difference Pc-Pp between the latest pressure Pc and the previous pressure Pp has been lower than the threshold TH1 (negative value) twice in succession. In the example shown in fig. 4, at time t1, it is detected that a decrease in the pressure in the internal space 12 of the cuff 10 has occurred. After time t1, the pressure is written every time the pressure is obtained based on the output of the pressure sensor 320 in the ring buffer capable of holding the pressure five times.

Then, the control unit 350 detects that the pressure in the internal space 12 of the cuff 10 has increased, based on the determination that the difference Pc-Pp between the latest pressure Pc and the previous pressure Pp is higher than the threshold TH2 (positive value) three consecutive times. In the example shown in fig. 4, the difference Pc-Pp is first higher than the threshold TH2 at time t 2. Then, by the time t3, the difference Pc-Pp is continuously higher than the threshold TH2 three times. In other words, at time t3, it is detected that a rise in pressure of the internal space 12 of the cuff 10 has occurred. In response to this, the control unit 350 determines the lowest value of the five pressures held in the ring buffer as the valley pressure Pb, and updates the display of the display unit 360 so that the valley pressure Pb is displayed on the display unit 360. The above-described determination reference and the number of stages of the ring buffer can be changed as appropriate, and the method of detecting the valley pressure can be changed as appropriate.

Next, the operation of the sphygmomanometer 1 according to the first embodiment of the present invention will be described with reference to fig. 5. In step S501, the power switch of the operation unit 340 is operated to turn on the power supply, and the sphygmomanometer 1 is started. Next, in step S502, the control unit 350 causes the display unit 360 to display an initial pressure value (for example, 0 mmHg). Next, in step S503, the control unit 350 starts displaying the pressure in the internal space 12 of the cuff 10 in real time. In other words, every time the control unit 350 obtains the pressure in the internal space 12 of the cuff 10 based on the output of the pressure sensor 320, the display of the display unit 360 that displays the pressure is updated.

Thereafter, the balloon 40 is operated (repetition of the gripping operation and the release operation) to raise the pressure in the internal space 12 of the cuff 10. In step S504, the control unit 350 monitors the increase in pressure in the internal space 12 of the cuff 10, and detects that the air supply balloon 40 has been operated, based on the determination that the pressure exceeds the reference value.

Correspondingly, in step S505, the control unit 350 closes the valve 330. Thereafter, in step S506, it is waited for that the pressure of the internal space 12 of the cuff 10 is greater than the predetermined value TH, and if the pressure of the internal space 12 of the cuff 10 is greater than the predetermined value TH, the process proceeds to step S507, and the real-time display of the pressure is stopped.

Steps S508 to S510 thereafter are processing in the period TP in fig. 2. In step S508, as described by way of example with reference to fig. 3 and 4, the control unit 350 detects the valley pressure, and when the valley pressure is detected, the process proceeds to step S509. In step S509, the control unit 350 causes the display unit 360 to display the detected valley pressure as the pressure in the internal space 12 of the cuff 10. Next, in step S510, the control unit 350 determines whether or not the operation (pressurization) of the balloon 40 is stopped, and if it is determined that the operation of the balloon 40 is stopped, the routine proceeds to step S511, otherwise, the routine returns to step S508. In other words, the detection of the trough pressure continues until it is determined that the operation of the air feed balloon 40 is stopped. The operation of stopping the balloon 40 can be determined based on the change in the pressure in the internal space 12 of the cuff 10, and for example, it can be determined that the operation of the balloon 40 is stopped when the valley pressure is not detected for a predetermined period.

In steps S508 to S510, as described above, the display of the display unit 360 is updated so that the valley pressure is displayed every time the valley pressure is detected, and the display is maintained until the next valley pressure is detected, so that the pressure lower than the actual pressure is displayed on the display unit 360. Therefore, the user such as a doctor or a nurse can easily determine the timing at which the balloon-feeding operation should be stopped. Thereby, the operation for pressurization is prevented from being stopped in a state where the pressure is insufficient.

In step S511, the control unit 350 restarts displaying the pressure in the internal space 12 of the cuff 10 in real time. In other words, the control unit 350 updates the display of the display unit 360 that displays the pressure each time the pressure in the internal space 12 of the cuff 10 is determined based on the output of the pressure sensor 320.

Next, in step S512, the valve 330 is opened to start the decompression of the internal space 12 of the cuff 10. Thereafter, in step S513, the blood pressure is measured, in step S514, the internal space 12 of the cuff 10 is sufficiently exhausted, and in step S515, the blood pressure measured in step S513 is displayed on the display unit 360.

Next, a second embodiment of the present invention will be explained. Here, differences from the first embodiment will be mainly described. Matters not mentioned as the second embodiment may be in accordance with the first embodiment. In the second embodiment, the control section 350 controls the display of the display section 360 in such a manner that: while the pressure in the internal space 12 of the cuff 10 is increased by the operation of the balloon 40, the pressure at the first inflection point (hereinafter referred to as "inflection point pressure") following the peak in the pressure fluctuation in the internal space 12 of the cuff 10 is detected as the pressure at the characteristic point, and the continuous display of the inflection point pressure is started based on the detection of the inflection point pressure. In the second embodiment of the present invention, the control unit 350 starts the continuous display of the inflection point pressure in the display unit 360 every time, for example, an inflection point is detected, and displays the pressure in the internal space 12 of the cuff 10 on the display unit 360 in real time, in accordance with the fact that the pressure in the internal space 12 of the cuff 10 is lower than the inflection point pressure and then higher than the inflection point pressure.

In the second embodiment of the present invention, processing including detection and display of the inflection point pressure is executed during the period TP shown in fig. 2. If it is determined that the operation of the air supply balloon 40 is stopped, the measurement of the blood pressure (typically, the detection of the maximum blood pressure value and the minimum blood pressure value) is started. The blood pressure is measured, for example, based on a change in pressure detected by the pressure sensor 320.

Processing including detection and display of the inflection point pressure in the period TP will be described with reference to fig. 6. In fig. 6, the horizontal axis represents time, and the vertical axis represents the pressure in the internal space 12 of the cuff 10 detected by the pressure sensor 320 (more specifically, the pressure calculated by the control unit 350 based on the output of the pressure sensor 320). In fig. 6, the pressure in the inner space 12 is shown as a curve, but the pressure is typically a discrete value. The control unit 350 samples the output (signal) from the pressure sensor 320 at predetermined sampling intervals, and calculates the pressure in the internal space 12 of the cuff 10 based on the sampled output. To give a more specific example, the control unit 350 obtains the pressure corresponding to the output of the sampling by multiplying the output by a conversion coefficient, or by referring to a look-up table, for example.

The numerical value of the pressure in the internal space 12 of the cuff 10 thus obtained indicates the pressure fluctuation. The control section 350 controls the display of the display section 360 in such a manner that: the first inflection point pressure after the peak in the pressure fluctuation is detected as the pressure of the characteristic point, and the continuous display of the inflection point pressure is started according to the detection of the inflection point pressure. For example, the control unit 350 starts the continuous display of the inflection point pressure by the display unit 360 every time the inflection point is detected, and displays the pressure in the internal space 12 of the cuff 10 on the display unit 360 in real time according to a case where the pressure in the internal space 12 of the cuff 10 is lower than the inflection point pressure and then higher than the inflection point pressure. In the second embodiment, for example, the control unit 350 is configured to detect a peak of pressure variation in the internal space 12 of the cuff 10, and detect a first inflection point following the peak using the peak as a trigger.

The method of detecting a peak is described by way of example with reference to fig. 7. In fig. 7, the horizontal axis represents time, and the vertical axis represents the pressure in the internal space 12 of the cuff 10 detected by the pressure sensor 320 (more specifically, the pressure calculated by the control unit 350 based on the output of the pressure sensor 320). The diamonds in fig. 7 indicate pressures obtained by sampling the output of the pressure sensor 320 and based on the sampled outputs, and the curves are for convenience of illustration.

In the example shown in fig. 7, the control unit 350 detects a pressure increase in the internal space 12 of the cuff 10 based on the determination that the difference Pc-Pp between the latest pressure Pc and the previous pressure Pp is higher than the threshold TH3 (positive value) twice in succession. In the example shown in fig. 7, at time t11, the difference Pc-Pp rises above the threshold TH3 (positive value) twice in succession. Then, the difference Pc-Pp is also continuously higher than the threshold TH3 (positive value) twice, and the rise in pressure in the internal space 12 of the cuff 10 continues.

Then, the control unit 350 detects a pressure drop in the internal space 12 of the cuff 10 at time t13 based on the determination that the difference Pc-Pp falls below the threshold TH4 (negative value) twice in succession. Then, it is determined that a peak of the pressure fluctuation exists at the time of two previous samplings, that is, at the time t 12. This enables detection of a peak in the pressure variation of the inner space 12 of the cuff 10.

A method of detecting the first inflection point after the peak is exemplarily described with reference to fig. 8. In fig. 8, the horizontal axis represents time, and the vertical axis represents the pressure in the internal space 12 of the cuff 10 detected by the pressure sensor 320 (more specifically, the pressure calculated by the control unit 350 based on the output of the pressure sensor 320). The diamonds in fig. 8 represent pressures obtained by sampling the output of the pressure sensor 320 and based on the sampled pressures, and the triangles in fig. 8 represent second order differentials of the pressures.

After the detection of the peak, the control unit 350 calculates the second derivative of the pressure in the internal space 12 of the cuff 10. Then, the control unit 350 detects the inflection point as a criterion of determination, in a case where the second derivative of the pressure in the internal space 12 of the cuff 10 is continuously higher than the threshold TH5 (positive value) twice. The inflection point pressure is the pressure of the interior space 12 of the cuff 10 at the inflection point.

Next, the operation of the sphygmomanometer 1 according to the second embodiment of the present invention will be described with reference to fig. 9. In step S601, the power switch of the operation unit 340 is operated to turn on the power supply, and the sphygmomanometer 1 is started. Next, in step S602, the control unit 350 causes the display unit 360 to display an initial pressure value (for example, 0 mmHg). Next, in step S603, the control unit 350 starts real-time display of the pressure in the internal space 12 of the cuff 10. In other words, every time the control unit 350 obtains the pressure in the internal space 12 of the cuff 10 based on the output of the pressure sensor 320, the display of the display unit 360 that displays the pressure is updated.

Thereafter, the balloon 40 is operated (repetition of the gripping operation and the release operation) to raise the pressure in the internal space 12 of the cuff 10. In step S604, the control unit 350 monitors the increase in pressure in the internal space 12 of the cuff 10, and detects that the air supply balloon 40 has been operated, based on the determination that the pressure exceeds the reference value.

Accordingly, in step S605, the control unit 350 closes the valve 330. Thereafter, in step S606, the pressure of the internal space 12 of the cuff 10 is waited for to be greater than the predetermined value TH, and if the pressure of the internal space 12 of the cuff 10 is greater than the predetermined value TH, the routine proceeds to step S607.

Steps S607 to S611 thereafter are processing in the period TP in fig. 2. In step S607, as described by way of example with reference to fig. 7 and 8, the control unit 350 detects the first inflection point after the peak, and when the first inflection point after the peak is detected, the process proceeds to step S608 to stop the real-time display of the pressure.

Next, in step 609, the control unit 350 determines whether or not the pressure in the internal space 12 of the cuff 10 is higher than the inflection point pressure immediately before the pressure, and if the pressure in the internal space 12 of the cuff 10 is higher than the inflection point pressure immediately before the pressure, the flow proceeds to step S610, and the real-time display of the pressure is resumed.

Next, in step S611, the control unit 350 determines whether or not the operation (pressurization) of the balloon 40 is stopped, and if it is determined that the operation of the balloon 40 is stopped, the routine proceeds to step S612, otherwise, the routine returns to step S607. The operation of stopping the balloon 40 can be determined based on the change in the pressure in the internal space 12 of the cuff 10, and for example, it can be determined that the operation of the balloon 40 is stopped when the peak is not detected for a predetermined period.

In steps S607 to S611, as described above, the control unit 350 starts the continuous display of the inflection point pressure by the display unit 360 every time the inflection point is detected, and displays the pressure in the internal space 12 of the cuff 10 on the display unit 360 in real time in accordance with the fact that the pressure in the internal space 12 of the cuff 10 is lower than the inflection point pressure and then higher than the inflection point pressure. Therefore, the user such as a doctor or a nurse can easily determine the timing at which the balloon-feeding operation should be stopped. Thereby, the operation for pressurization is prevented from being stopped in a state where the pressure is insufficient.

Next, in step S613, the valve 330 is opened to start the decompression of the internal space 12 of the cuff 10. Thereafter, in step S614, the blood pressure is measured, in step S615, the internal space 12 of the cuff 10 is sufficiently exhausted, and in step S616, the blood pressure measured in step S614 is displayed on the display unit 360.

Description of reference numerals:

10: a cuff, 12: inner space, 20: hose, 30: main body, 40: balloon delivery, 310: a flow path.

Claims

1. A sphygmomanometer comprising: a balloon for sending air to an internal space of a cuff, a display unit, a pressure sensor for detecting a pressure in the internal space, and a valve for reducing the pressure in the internal space, wherein the sphygmomanometer is characterized in that,

the sphygmomanometer is provided with a control unit which calculates the pressure in the internal space based on the output from the pressure sensor and displays the pressure on the display unit,

the control section controls display of the display section in such a manner that: while the pressure in the internal space is being increased by the operation of the balloon, a trough in the pressure change in the internal space is detected, and the continuous display of the pressure in the trough is started in response to the detection of the trough.

2. The sphygmomanometer according to claim 1,

the control unit updates the display of the display unit so that the latest pressure of the trough is displayed each time the pressure of the trough is detected.

3. A sphygmomanometer according to claim 1 or 2,

the control unit starts the detection of the pressure at the trough if the pressure in the internal space is larger than a predetermined value, and stops the detection of the pressure at the trough if it is determined that the operation of the balloon pump is stopped.

4. The sphygmomanometer according to claim 1,

the control unit has a ring buffer for holding the pressure in the internal space, and sets the lowest value of the pressures held in the ring buffer as the valley pressure in response to detection of a rise in the pressure in the internal space after detection of a fall in the pressure in the internal space.

5. The sphygmomanometer according to claim 1,

the control unit causes the display unit to display the pressure in the internal space in real time until the pressure in the internal space becomes higher than a predetermined value.

6. The sphygmomanometer according to claim 1,

the control unit displays the pressure in the internal space on the display unit in real time after determining that the operation of the balloon has stopped.

7. A sphygmomanometer comprising: a balloon for sending air to an internal space of a cuff, a display unit, a pressure sensor for detecting a pressure in the internal space, and a valve for reducing the pressure in the internal space, wherein the sphygmomanometer is characterized in that,

the control section controls display of the display section in such a manner that: while the pressure in the internal space is being increased by the operation of the balloon, a first inflection point following a peak in the pressure fluctuation in the internal space is detected, and the continuous display of the pressure at the inflection point is started based on the detection of the inflection point.

8. A sphygmomanometer according to claim 7,

the control unit starts continuous display of the pressure of the inflection point by the display unit every time the inflection point is detected, and displays the pressure of the internal space on the display unit in real time according to a case where the pressure of the internal space is higher than the pressure of the inflection point after being lower than the pressure of the inflection point.

9. A sphygmomanometer according to claim 7,

10. A sphygmomanometer according to claim 7,