Sphygmomanometer and blood pressure measuring method

Abstract

A sphygmomanometer (100) is provided with a blood pressure measurement unit (220) that measures the blood pressure of a user on the basis of a pulse wave signal during pressurization in which a cuff pressure indicating the internal pressure of a cuff (20) attached to a site to be measured of the user is pressurized. The blood pressure measurement unit (220) slows the pressurization speed during a predetermined period of the pressurization process than during other periods other than the predetermined period of the pressurization process. The predetermined period is set on the basis of the timing at which the amplitude of the pulse wave signal is maximum during the pressurization or the timing at which the cuff pressure is the average blood pressure of the user during the pressurization. The sphygmomanometer (100) is further provided with a determination unit (230) that determines the arrhythmia of the user on the basis of the pulse wave signal during the pressurization process.

Description

Technical Field

[0001] The present disclosure relates to a sphygmomanometer and a blood pressure measuring method. Background Art

[0002] In the past, there is a known technology for detecting atrial fibrillation using a signal obtained during blood pressure measurement. For example, the sphygmomanometer of Patent Document 1 (Japanese Patent Publication No. 2020-192322) determines atrial fibrillation by using the interval time data of the pulse signal of the measurement data in the pressurization phase and the interval time data of the pulse signal of the measurement data in the decompression phase.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-192322 Summary of the invention

[0006] Problems to be solved by the invention

[0007] As a method for determining arrhythmia using a sphygmomanometer based on the oscillometric method, there is known a method for determining arrhythmia such as atrial fibrillation by using a pattern of pulse wave intervals obtained during the process of increasing or decreasing the pressure of the cuff. For example, the rising point or maximum point of the pulse wave signal of each beat is detected as a feature point, and the interval between the current beat and the previous beat is calculated as the pulse wave interval. In order to correctly calculate the pulse wave interval, the amplitude of the acquired pulse wave signal is preferably large. Therefore, in order to improve the accuracy of arrhythmia determination based on the pattern of pulse wave intervals, it is preferred to obtain many pulse wave signals with large amplitudes.

[0008] An object of one aspect of the present disclosure is to provide a sphygmomanometer and a blood pressure measurement method that can accurately determine arrhythmia by acquiring many pulse wave signals with large amplitudes during blood pressure measurement.

[0009] Technical Solution

[0010] In one example of the present disclosure, a sphygmomanometer includes a blood pressure measuring unit that measures the user's blood pressure based on a pulse wave signal during a pressurization process in which the cuff pressure is increased, wherein the cuff pressure represents the internal pressure of the cuff worn on the measured part of the user. The blood pressure measuring unit makes the pressurization speed during a specified period of the pressurization process slower than the pressurization speed during other periods of the pressurization process except the specified period. The specified period is set based on the timing when the amplitude of the pulse wave signal during the pressurization process becomes maximum or the timing when the cuff pressure during the pressurization process becomes the average blood pressure of the user. The sphygmomanometer also includes a determination unit that determines the user's arrhythmia based on the pulse wave signal during the pressurization process.

[0011] According to the above configuration, when measuring blood pressure using the pressurization measurement method, a large number of pulse wave signals with large amplitudes can be obtained, thereby making it possible to determine arrhythmia with high accuracy.

[0012] In another example of the present disclosure, the blood pressure measurement unit sets a period from a timing when the amplitude of the pulse wave signal becomes maximum during the pressurization to a lapse of a predetermined time as the predetermined period.

[0013] According to the above configuration, a pulse wave signal with a large amplitude can be efficiently acquired during blood pressure measurement using the pressurization measurement method.

[0014] In another example of the present disclosure, the sphygmomanometer further includes a storage unit that stores association information obtained by associating the cuff pressure obtained in the user's past blood pressure measurement with the pulse wave signal. The blood pressure measurement unit extracts the cuff pressure at the timing when the amplitude of the pulse wave signal during the pressurization process during the user's past blood pressure measurement becomes maximum based on the association information, and sets the period from the timing when the cuff pressure during the pressurization process during the user's current blood pressure measurement reaches the extracted cuff pressure to the time after the prescribed time has passed as the prescribed period.

[0015] According to the above configuration, when measuring blood pressure using the pressurization measurement method, a pulse wave signal with a large amplitude can be efficiently acquired based on the user's past measurement results.

[0016] In another example of the present disclosure, the sphygmomanometer further includes a storage unit that stores the systolic blood pressure and diastolic blood pressure of the user obtained in the past blood pressure measurement of the user. The blood pressure measurement unit calculates the average blood pressure based on the systolic blood pressure and the diastolic blood pressure, and sets the period from the timing when the cuff pressure in the pressurization process during the current blood pressure measurement of the user reaches the average blood pressure to the time after the prescribed time has passed as the prescribed period.

[0017] According to the above configuration, when measuring blood pressure using the pressurization measurement method, a pulse wave signal with a large amplitude can be efficiently acquired based on the user's past measurement results.

[0018] In another example of the present disclosure, the blood pressure measurement unit sets the inflation speed to zero during a predetermined period.

[0019] According to the above configuration, more pulse wave signals with larger amplitudes can be acquired during blood pressure measurement using the pressurization measurement method.

[0020] In another example of the present disclosure, a sphygmomanometer includes a blood pressure measuring unit that measures the user's blood pressure based on a pulse wave signal during a decompression process in which the cuff pressure is reduced after a pressurization process in which the cuff pressure is increased to a pressure greater than a prescribed pressure, wherein the cuff pressure represents the internal pressure of the cuff worn on the measured part of the user. The blood pressure measuring unit makes the decompression speed during a prescribed period of the decompression process slower than the decompression speed during other periods of the decompression process except the prescribed period. The prescribed period is set based on the timing when the amplitude of the pulse wave signal during the decompression process becomes maximum or the timing when the cuff pressure during the decompression process becomes the average blood pressure of the user. The sphygmomanometer also includes a determination unit that determines the user's arrhythmia based on the pulse wave signal during the decompression process.

[0021] According to the above configuration, when measuring blood pressure using the reduced pressure measurement method, arrhythmia can be determined with high accuracy by acquiring a large number of pulse wave signals with a large amplitude.

[0022] In another example of the present disclosure, the blood pressure measurement unit sets a period from a timing when the amplitude of the pulse wave signal becomes maximum during the decompression to a lapse of a predetermined time as the predetermined period.

[0023] According to the above configuration, a pulse wave signal with a large amplitude can be efficiently acquired during blood pressure measurement using the reduced pressure measurement method.

[0024] In another example of the present disclosure, the sphygmomanometer further includes a storage unit that stores association information obtained by associating the cuff pressure obtained in the user's past blood pressure measurement with the pulse wave signal. The blood pressure measurement unit extracts the cuff pressure at the timing when the amplitude of the pulse wave signal in the decompression process during the user's past blood pressure measurement becomes the maximum based on the association information, and sets the period from the timing when the cuff pressure in the decompression process during the user's current blood pressure measurement reaches the extracted cuff pressure to the time after the prescribed time has passed as the prescribed period.

[0025] According to the above configuration, when measuring blood pressure using the reduced pressure measurement method, a pulse wave signal with a large amplitude can be efficiently acquired based on the user's past measurement results.

[0026] In another example of the present disclosure, the sphygmomanometer further includes a storage unit that stores the systolic blood pressure and diastolic blood pressure of the user obtained in the past blood pressure measurement of the user. The blood pressure measurement unit calculates the average blood pressure based on the systolic blood pressure and the diastolic blood pressure, and sets the period from the timing when the cuff pressure in the decompression process during the current blood pressure measurement of the user reaches the average blood pressure to the time after the prescribed time has passed as the prescribed period.

[0027] According to the above configuration, when measuring blood pressure using the reduced pressure measurement method, a pulse wave signal with a large amplitude can be efficiently acquired based on the user's past measurement results.

[0028] In another example of the present disclosure, the blood pressure measurement unit estimates the user's systolic blood pressure and diastolic blood pressure during the pressurization process, estimates the average blood pressure based on the estimated systolic blood pressure and diastolic blood pressure, and sets the period from the timing when the cuff pressure during the decompression process reaches the average blood pressure to the lapse of a specified time as the specified period.

[0029] According to the above configuration, a pulse wave signal with a large amplitude can be efficiently acquired during blood pressure measurement using the reduced pressure measurement method.

[0030] In another example of the present disclosure, the blood pressure measurement unit determines the cuff pressure at the timing when the amplitude of the pulse wave signal becomes maximum during the pressurization process, and sets the period from the timing when the cuff pressure during the decompression process reaches the determined cuff pressure to the elapse of a predetermined time as the predetermined period.

[0031] According to the above configuration, a pulse wave signal with a large amplitude can be efficiently acquired during blood pressure measurement using the reduced pressure measurement method.

[0032] In another example of the present disclosure, the blood pressure measurement unit sets the decompression rate in a predetermined period to zero.

[0033] According to the above configuration, more pulse wave signals with a larger amplitude can be acquired during blood pressure measurement using the reduced pressure measurement method.

[0034] In another example of the present disclosure, a blood pressure measurement method includes the following steps: measuring the user's blood pressure based on a pulse wave signal during a pressurization process in which the cuff pressure is pressurized, wherein the cuff pressure represents the internal pressure of the cuff worn on the measured part of the user. The step of measuring includes making the pressurization speed during a specified period of the pressurization process slower than the pressurization speed during other periods of the pressurization process except the specified period. The specified period is set based on the timing when the amplitude of the pulse wave signal during the pressurization process becomes the maximum or the timing when the cuff pressure during the pressurization process becomes the average blood pressure of the user. The blood pressure measurement method also includes the following steps: determining the user's arrhythmia based on the pulse wave signal during the pressurization process.

[0035] According to the above configuration, when measuring blood pressure using the pressurization measurement method, a large number of pulse wave signals with large amplitudes can be obtained, thereby making it possible to determine arrhythmia with high accuracy.

[0036] In another example of the present disclosure, a blood pressure measurement method includes the following steps: measuring the user's blood pressure based on a pulse wave signal during a decompression process in which the cuff pressure is reduced after a pressurization process in which the cuff pressure is increased to a pressure greater than a specified pressure, wherein the cuff pressure represents the internal pressure of the cuff worn on the measured part of the user. The step of measuring includes making the decompression speed during a specified period of the decompression process slower than the decompression speed during other periods of the decompression process except the specified period. The specified period is set based on the timing when the amplitude of the pulse wave signal during the decompression process becomes the maximum or the timing when the cuff pressure during the decompression process becomes the average blood pressure of the user. The blood pressure measurement method also includes: determining the user's arrhythmia based on the pulse wave signal during the decompression process.

[0037] According to the above configuration, when measuring blood pressure using the reduced pressure measurement method, arrhythmia can be determined with high accuracy by acquiring a large number of pulse wave signals with a large amplitude.

[0038] Effects of the Invention

[0039] According to the present disclosure, arrhythmia can be determined with high accuracy by acquiring many pulse wave signals with large amplitudes during blood pressure measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a diagram showing a blood pressure monitor according to this embodiment.

[0041] Figure 2 This is a block diagram showing an example of the hardware configuration of a blood pressure monitor.

[0042] Figure 3 This is a block diagram showing the functional configuration of a sphygmomanometer.

[0043] Figure 4 This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement in the general mode (pressure measurement method).

[0044] Figure 5 This is a flowchart showing an example of the blood pressure measurement process in the general mode (pressure measurement method).

[0045] Figure 6 This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement in the general mode (decompression measurement method).

[0046] Figure 7 This is a flowchart showing the blood pressure measurement process in the general mode (decompression measurement method).

[0047] Figure 8 This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement in the arrhythmia determination mode (pressurization measurement method).

[0048] Fig. 9 This is a flowchart showing the blood pressure measurement process (pressurization measurement method) in the arrhythmia determination mode.

[0049] Fig.10 This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement in the arrhythmia determination mode (decompression measurement method).

[0050] Fig.11 This is a flowchart showing the blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode.

[0051] Fig.12 This is a flowchart showing a first modification of the blood pressure measurement process (pressurization measurement method) in the arrhythmia determination mode.

[0052] Fig.13 This is a flowchart showing a first modification of the blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode.

[0053] Fig.14 This is a flowchart showing a second modification of the blood pressure measurement process (pressurization measurement method) in the arrhythmia determination mode.

[0054] Fig.15 This is a flowchart showing a second modification of the blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode.

[0055] Fig.16 This is a flowchart showing a third modification of the blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode.

[0056] Fig.17 This is a flowchart showing a fourth modification of the blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode.

[0057] Fig.18 This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement (pressurization measurement method) in the arrhythmia determination mode according to another embodiment.

[0058] Fig.19 This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement in the arrhythmia determination mode (decompression measurement method) according to another embodiment.

[0059] Fig. 20 This is a flowchart showing a blood pressure measurement process (pressurization measurement method) in an arrhythmia determination mode according to another embodiment.

[0060] Fig.21This is a flowchart showing a blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode according to another embodiment. DETAILED DESCRIPTION

[0061] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same components are marked with the same reference numerals. Their names and functions are also the same. Therefore, they will not be described in detail again.

[0062] [Application Examples]

[0063] Reference Figure 1 , an application example of the present invention is described. Figure 1 It is a diagram showing a sphygmomanometer 100 according to this embodiment.

[0064] Reference Figure 1 The sphygmomanometer 100 is an upper arm sphygmomanometer that measures blood pressure by compressing the measured part of the user (i.e., the subject) with a cuff. The sphygmomanometer 100 performs blood pressure measurement based on the oscillometric method. The sphygmomanometer 100 has a main body and a cuff (armband) as main components. It should be noted that the sphygmomanometer 100 can also be a wrist sphygmomanometer in which the main body and the cuff (armband) are integrated. Figure 1 Describe the processing content.

[0065] exist Figure 1 In the embodiment, it is assumed that a user measures his / her own blood pressure using the sphygmomanometer 100. The sphygmomanometer 100 measures the user's blood pressure by a pressurization measurement method of measuring the blood pressure during the pressurization of the cuff pressure, wherein the cuff pressure represents the internal pressure of the cuff attached to the user's measured part (e.g., arm).

[0066] The sphygmomanometer 100 starts to pressurize the cuff (corresponding to Figure 1 (1)). The cuff pressure increase speed is set to speed Va.

[0067] The sphygmomanometer 100 monitors the amplitude of the pulse wave signal (pulse wave amplitude) (corresponding to Figure 1 (2)). The pulse wave amplitude gradually increases as the cuff pressure increases, and gradually decreases after reaching the maximum value. In this way, it is known that the pulse wave amplitude changes in a mountain shape during the pressurization process.

[0068] Then, the sphygmomanometer 100 changes the pressure increase speed (corresponding to Figure 1(3)). For example, when the sphygmomanometer 100 determines that the pulse wave amplitude has reached the maximum, it changes the pressurization speed to a speed Vb that is slower than the speed Va. The sphygmomanometer 100 continues to pressurize the cuff pressure at the speed Vb until a certain time has passed since the determination time point. After the certain time has passed, the sphygmomanometer 100 returns the pressurization speed to the speed Va and continues to pressurize the cuff pressure.

[0069] The change process of the pressurization speed is a process for obtaining a sufficient number of pulse wave signals so as to detect arrhythmia (e.g., atrial fibrillation) with high accuracy during blood pressure measurement. Typically, the sphygmomanometer 100 determines the presence or absence of arrhythmia based on the interval (pulse wave interval) of the pulse wave signals obtained during blood pressure measurement. Therefore, in order to perform this determination with high accuracy, it is preferable to obtain more pulse wave signals with a large amplitude. Therefore, the sphygmomanometer 100 obtains many pulse wave signals with a large amplitude by slowing down the pressurization speed during the period in which a large pulse wave amplitude can be obtained.

[0070] Then, the sphygmomanometer 100 calculates the user's blood pressure value based on the pulse wave signal obtained during the pressurization process, and determines whether arrhythmia occurs (corresponding to Figure 1 In this case, the sphygmomanometer 100 displays the user's blood pressure value and the result of the arrhythmia determination on the display.

[0071] According to the above application example, during the pressurization process, the cuff pressure is increased at a slower pressurization speed during the period when the pulse wave amplitude is large, and the cuff pressure is increased at a normal pressurization speed during other periods. As a result, more pulse wave signals with large amplitudes can be efficiently acquired, and as a result, arrhythmia can be determined with high accuracy.

[0072] In addition, it is known that the cuff pressure at which the pulse wave amplitude becomes maximum is near the user's average blood pressure. Therefore, it can be said that the period during which the cuff pressure reaches the average blood pressure is a period during which the pulse wave amplitude is large. Therefore, it is also possible that the sphygmomanometer 100 changes the pressurization speed to a speed Vb that is slower than the speed Va when it is determined that the cuff pressure has become the user's average blood pressure. In this case, the pressurization speed is slowed down during the period during which the cuff pressure reaches the average blood pressure, so that many pulse wave signals with large amplitudes can be obtained.

[0073] [Configuration example]

[0074] <Hardware Configuration>

[0075] Figure 2 1 is a block diagram showing an example of the hardware configuration of the sphygmomanometer 100. Figure 2The sphygmomanometer 100 includes a main body 10 and a cuff 20 as main components. A fluid bag 22 is contained in the cuff 20. The main body 10 includes a processor 110, an air system component 30 for blood pressure measurement, an A / D conversion circuit 310, a pump drive circuit 320, a valve drive circuit 330, a display 50, a memory 51, an operation unit 52, a communication interface 53, and a power supply unit 54.

[0076] The processor 110 is a calculation processing unit such as a CPU (Central Processing Unit) or an MPU (MultiProcessing Unit). The processor 110 implements various processes (steps) of the sphygmomanometer 100 described later by reading and executing a program stored in the memory 51. For example, the processor 110 controls the driving pump 32 and the valve 33 according to an operation signal from the operation unit 52. In addition, the processor 110 calculates the blood pressure value using an algorithm for calculating the blood pressure based on the oscillometric method, and displays the blood pressure value on the display 50.

[0077] The memory 51 is implemented by a RAM (Random Access Memory), a ROM (Read-Only Memory), a flash memory, etc. The memory 51 stores: a program for controlling the sphygmomanometer 100, data for controlling the sphygmomanometer 100, setting data for setting various functions of the sphygmomanometer 100, and data of measurement results of blood pressure values, pulse counts, pulse wave intervals, etc. The memory 51 is also used as a working memory when executing a program, etc.

[0078] The air system assembly 30 supplies air to the fluid bag 22 contained in the cuff 20 or discharges air from the fluid bag 22 contained in the cuff 20 through the gas piping. The air system assembly 30 includes: a pressure sensor 31 for detecting the pressure in the fluid bag 22; and a pump 32 and a valve 33 as an expansion and contraction mechanism for expanding and contracting the fluid bag 22.

[0079] The pressure sensor 31 detects the pressure (cuff pressure) in the fluid bag 22, and outputs a signal (cuff pressure signal) corresponding to the detected pressure to the A / D conversion circuit 310. The pressure sensor 31 is, for example, a piezoresistive pressure sensor, and is connected to the pump 32, the valve 33, and the fluid bag 22 contained in the cuff 20 via a gas pipe. The pump 32 supplies air as a fluid to the fluid bag 22 through the gas pipe to increase the cuff pressure. The valve 33 is opened / closed to control the cuff pressure by discharging the air in the fluid bag 22 through the gas pipe or sealing the air into the fluid bag 22.

[0080] The A / D conversion circuit 310 converts the output value of the pressure sensor 31 (e.g., a voltage value corresponding to the change in resistance caused by the piezoresistive effect) from an analog signal to a digital signal and outputs it to the processor 110. The processor 110 obtains a signal indicating the cuff pressure based on the output value of the A / D conversion circuit 310. The pump drive circuit 320 controls the drive of the pump 32 based on the control signal given by the processor 110. The valve drive circuit 330 controls the opening / closing of the valve 33 based on the control signal given by the processor 110.

[0081] The processor 110 performs blood pressure measurement by a pressurization measurement method or a decompression measurement method, wherein the pressurization measurement method measures the user's blood pressure based on a pulse wave signal during a pressurization process in which the cuff pressure is pressurized, and the decompression measurement method measures the user's blood pressure based on a pulse wave signal during a decompression process in which the cuff pressure is decompressed after the cuff pressure is pressurized to a pressure greater than a specified pressure (for example, the "estimated systolic blood pressure" described later).

[0082] For example, when measuring based on the decompression measurement method, the following actions are roughly performed. The cuff is pre-wrap around the user's measured part (wrist, arm, etc.), and during the measurement, the pump 32 and valve 33 are controlled to increase the cuff pressure to a level higher than the estimated systolic blood pressure, and then the cuff pressure is gradually reduced. During this decompression process, the cuff pressure is detected by the pressure sensor 31, and the change in arterial volume occurring in the artery of the measured part is taken out as a pulse wave signal. Based on the change in the amplitude of the pulse wave signal (mainly rising and falling) accompanying the change in the cuff pressure at this time, the highest blood pressure (systolic blood pressure) and the lowest blood pressure (diastolic blood pressure) are calculated.

[0083] The operation unit 52 inputs an operation signal corresponding to the user's instruction to the processor. The operation unit 52 includes a measurement switch 52A for accepting a blood pressure measurement instruction from the user and a mode selection switch 52B for selecting a measurement mode.

[0084] When the measurement switch 52A is pressed, the measurement site is temporarily compressed by the cuff 20, and the blood pressure measurement is performed by the oscillometric method. When the measurement switch 52A is pressed again during the blood pressure measurement, the blood pressure measurement is stopped.

[0085] In addition, when the mode selection switch 52B is pressed, the measurement mode is switched. For example, when the current measurement mode is set to the general measurement mode (hereinafter also referred to as the "general mode"), when the mode selection switch 52B is pressed, the measurement mode is switched to the arrhythmia determination mode.

[0086] The display 50 displays various information including blood pressure measurement results based on a control signal from the processor 110. The communication interface 53 exchanges various information with an external device. The power supply unit 54 supplies power to the processor 110 and various hardware.

[0087] <Functional Configuration>

[0088] Figure 3 is a block diagram showing the functional configuration of the sphygmomanometer 100. Figure 3 The sphygmomanometer 100 includes a mode setting unit 210, a blood pressure measuring unit 220, a determination unit 230, and an output control unit 240 as main functional components. These functions are implemented, for example, by causing the processor 110 of the sphygmomanometer 100 to execute a program stored in the memory 51. It should be noted that some or all of these functions may also be implemented by hardware. The sphygmomanometer 100 also includes a storage unit 250. The storage unit 250 is implemented by the memory 51.

[0089] The mode setting unit 210 sets one of an arrhythmia determination mode in which the user determines whether or not there is an arrhythmia and a general mode in which the arrhythmia determination is not performed. Typically, the mode setting unit 210 sets one of the arrhythmia determination mode and the general mode in accordance with a mode selection instruction given by the user via the operation unit 52 (e.g., the mode selection switch 52B).

[0090] It should be noted that the mode setting unit 210 may also be configured to automatically set any mode according to a predetermined schedule. For example, when blood pressure measurement is started in time period H of a day (for example, blood pressure measurement is started by pressing the measurement switch 52A), the arrhythmia determination mode is automatically set. On the other hand, when blood pressure measurement is performed in a time period other than time period H of a day, the general mode is automatically set.

[0091] The blood pressure measuring unit 220 controls the cuff pressure in accordance with a measurement start instruction given by the user via the operation unit 52 (e.g., the measurement switch 52A). Specifically, the blood pressure measuring unit 220 controls the pump 32 to be driven via the pump driving circuit 320 and the valve 33 to be driven via the valve driving circuit 330. The valve 33 is opened / closed to control the cuff pressure in a manner such that air in the fluid bag 22 is discharged or sealed.

[0092] The blood pressure measuring unit 220 receives the cuff pressure signal detected by the pressure sensor 31, and extracts a pulse wave signal representing the pulse wave of the measured part superimposed on the cuff pressure signal. That is, the blood pressure measuring unit 220 detects the pressure component, i.e., the pulse wave, superimposed on the cuff pressure signal in synchronization with the heart beat of the user from the cuff pressure signal.

[0093] The blood pressure measuring unit 220 calculates the user's blood pressure information based on the cuff pressure signal and the pulse wave signal superimposed on the cuff pressure signal. Specifically, the blood pressure measuring unit 220 measures the user's blood pressure by a pressurization measurement method or a decompression measurement method according to the oscillometric method. Typically, the blood pressure measuring unit 220 calculates systolic blood pressure, diastolic blood pressure, pulse rate, pulse pressure, etc. The storage unit 250 stores information obtained during blood pressure measurement (for example, cuff pressure, pulse wave signal, systolic blood pressure, diastolic blood pressure, pulse rate, pulse pressure, etc.).

[0094] Here, it is assumed that the measurement mode is set to the general mode by the mode setting unit 210. In this case, when the blood pressure measurement is performed by the pressurization measurement method, the blood pressure measurement unit 220 makes the pressurization speed during the pressurization process constant. In addition, when the blood pressure measurement is performed by the decompression measurement method, the blood pressure measurement unit 220 makes the decompression speed during the decompression process constant.

[0095] It is assumed that the measurement mode is set to the arrhythmia determination mode by the mode setting unit 210. First, a case where the blood pressure measurement unit 220 performs blood pressure measurement by the pressurization measurement method will be described.

[0096] When the blood pressure measurement is performed by the pressurization measurement method, the blood pressure measurement unit 220 makes the pressurization speed in the pressurization process period Tb slower than the pressurization speed in other periods Ta except the period Tb in the pressurization process. The period Tb is set based on the timing when the amplitude of the pulse wave signal becomes maximum during the pressurization process or the timing when the cuff pressure during the pressurization process reaches the average blood pressure of the user.

[0097] In one aspect, the blood pressure measurement unit 220 sets the period from the timing when the amplitude of the pulse wave signal becomes maximum during the pressurization to the elapse of a predetermined time as the period Tb.

[0098] On the other hand, the blood pressure measuring unit 220 sets the period Tb based on the association information stored in the storage unit 250. Specifically, the storage unit 250 stores association information obtained by associating the cuff pressure and the pulse wave signal obtained when the user's blood pressure was measured in the past. For example, the association information includes information indicating the correspondence between the cuff pressure and the pulse wave signal during the pressurization process or the decompression process when measuring the user's blood pressure.

[0099] The blood pressure measuring unit 220 extracts the cuff pressure at the timing when the amplitude of the pulse wave signal during the pressurization process of the user's past blood pressure measurement becomes the maximum based on the associated information. The blood pressure measuring unit 220 sets the period from the timing when the cuff pressure during the pressurization process of the user's current blood pressure measurement reaches the extracted cuff pressure to the time after the predetermined time has passed as the period Tb.

[0100] On the other hand, the blood pressure measuring unit 220 sets the period Tb based on the average blood pressure of the user. Specifically, the storage unit 250 stores the systolic blood pressure and diastolic blood pressure of the user obtained during the user's past blood pressure measurement. The blood pressure measuring unit 220 calculates the average blood pressure based on the systolic blood pressure and diastolic blood pressure stored in the storage unit 250. For example, the blood pressure measuring unit 220 calculates the average blood pressure based on the relationship "average blood pressure = diastolic blood pressure + (systolic blood pressure - diastolic blood pressure) ÷ 3". The blood pressure measuring unit 220 sets the period from the timing when the cuff pressure in the pressurization process during the user's current blood pressure measurement reaches the average blood pressure to the time after a specified time has passed as the period Tb.

[0101] It should be noted that the blood pressure measurement unit 220 may set the inflation speed in the inflation period Tb to zero. That is, the blood pressure measurement unit 220 may maintain the cuff pressure constant by stopping the inflation of the cuff pressure in the inflation period Tb.

[0102] Next, a case where the arrhythmia determination mode is set and the blood pressure measurement unit 220 performs blood pressure measurement by the decompression measurement method is described. In this case, the blood pressure measurement unit 220 makes the decompression speed in the period Tg of the decompression process slower than the decompression speed in the other periods Tf of the decompression process except the period Tg. The period Tg is set based on the timing when the amplitude of the pulse wave signal becomes the maximum during the decompression process or the timing when the cuff pressure becomes the average blood pressure of the user during the decompression process.

[0103] In one aspect, the blood pressure measurement unit 220 sets the period from the timing when the amplitude of the pulse wave signal becomes maximum during the decompression process to the elapse of a predetermined time as the period Tg.

[0104] On the other hand, the blood pressure measurement unit 220 extracts the cuff pressure at the timing when the amplitude of the pulse wave signal in the decompression process during the user's past blood pressure measurement becomes maximum based on the related information stored in the storage unit 250. The blood pressure measurement unit 220 sets the period from the timing when the cuff pressure in the decompression process during the current blood pressure measurement of the user reaches the extracted cuff pressure to the elapse of a predetermined time as the period Tg.

[0105] On the other hand, the blood pressure measuring unit 220 sets the period Tg based on the average blood pressure of the user. Specifically, the blood pressure measuring unit 220 calculates the average blood pressure based on the systolic blood pressure and the diastolic blood pressure stored in the storage unit 250. The blood pressure measuring unit 220 sets the period from the timing when the cuff pressure in the decompression process during the current blood pressure measurement of the user reaches the average blood pressure to the time after a predetermined time has passed as the period Tg.

[0106] On the other hand, the blood pressure measuring unit 220 estimates the systolic blood pressure and diastolic blood pressure of the user during the pressurization process of the decompression measurement method, and estimates the average blood pressure (i.e., calculates the estimated average blood pressure) based on the estimated systolic blood pressure (hereinafter, also referred to as "estimated systolic blood pressure") and diastolic blood pressure (hereinafter, also referred to as "estimated diastolic blood pressure"). The estimation of the systolic blood pressure and the diastolic blood pressure is performed by a well-known method. For example, the blood pressure measuring unit 220 estimates the systolic blood pressure and the diastolic blood pressure based on the pulse wave envelope that represents the pattern of the amplitude change of the pulse wave signal that changes during the process of pressurizing the cuff pressure. The blood pressure measuring unit 220 calculates the estimated average blood pressure based on the relationship "estimated average blood pressure = estimated diastolic blood pressure + (estimated systolic blood pressure - estimated diastolic blood pressure) ÷ 3". The blood pressure measuring unit 220 sets the period from the timing when the cuff pressure reaches the estimated average blood pressure during the decompression process to the time after the predetermined time has passed as the period Tg.

[0107] On the other hand, the blood pressure measuring unit 220 determines the cuff pressure at the timing when the amplitude of the pulse wave signal becomes maximum during the pressurization process of the decompression measurement method. The blood pressure measuring unit 220 sets the period from the timing when the cuff pressure during the decompression process reaches the determined cuff pressure to the elapse of a predetermined time as the period Tg.

[0108] It should be noted that the blood pressure measurement unit 220 may set the decompression rate in the period Tg of the decompression process to zero. That is, the blood pressure measurement unit 220 may maintain the cuff pressure constant by stopping the decompression of the cuff pressure in the period Tg.

[0109] When the arrhythmia determination mode is set, the determination unit 230 performs arrhythmia determination. When the blood pressure measurement unit 220 performs blood pressure measurement by a pressurization measurement method, the determination unit 230 determines whether arrhythmia occurs in the user based on the pulse wave signal during the pressurization process. When the blood pressure measurement unit 220 performs blood pressure measurement by a decompression measurement method, the determination unit 230 determines whether arrhythmia occurs in the user based on the pulse wave signal during the decompression process. Regarding the determination method of arrhythmia, a well-known method is used. For example, the determination unit 230 determines whether arrhythmia occurs based on the generation interval of multiple pulse waves obtained from the pulse wave signal (i.e., the pulse wave interval).

[0110] The output control unit 240 displays the measurement results of the blood pressure measurement unit 220 and the determination results of the determination unit 230 on the display 50. It should be noted that the output control unit 240 can send the measurement results and determination results to an external device via the communication interface 53, or can be configured to output sound via a speaker (not shown).

[0111] <Processing in normal mode>

[0112] Figure 4 This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement in the normal mode (pressure measurement method). Figure 4 , the sphygmomanometer 100 starts the pressurization process and pressurizes the cuff at a constant speed (e.g., speed Va). During the pressurization process, the pulse wave amplitude gradually increases as the cuff pressure increases, and gradually decreases after reaching the maximum point. When the blood pressure measurement is completed, the sphygmomanometer 100 stops the pump 32 to end the pressurization process, and opens the valve 33. As a result, the cuff pressure decreases sharply.

[0113] Figure 5 This is a flowchart showing an example of the blood pressure measurement process in the general mode (pressure measurement method).

[0114] Reference Figure 5 The processor 110 of the sphygmomanometer 100 initializes the pressure sensor 31 (step S12). Specifically, the processor 110 initializes the processing storage area, and performs 0 mmHg adjustment of the pressure sensor 31 (setting the atmospheric pressure to 0 mmHg) while the pump 32 is disconnected (stopped) and the valve 33 is opened.

[0115] Next, the processor 110 closes the valve 33 via the valve drive circuit 330 (step S14), drives the pump 32 via the pump drive circuit 320, and starts pressurizing the cuff 20 (fluid bag 22) (step S16). At this time, the processor 110 controls the pressurization speed of the cuff pressure, which is the pressure in the fluid bag 22, based on the output of the pressure sensor 31 while supplying air from the pump 32 to the fluid bag 22. Thus, the pressurization process starts. The processor 110 controls the pressurization speed to a constant speed (for example, speed Va).

[0116] Next, the processor 110 extracts a pulse wave signal from the cuff pressure signal detected by the pressure sensor 31, attempts to calculate the systolic blood pressure and the diastolic blood pressure based on the pulse wave signal, and determines whether the blood pressure calculation is complete (step S18).

[0117] If the blood pressure calculation cannot be completed due to insufficient data (No in step S18), the processor 110 repeats the processing of steps S16 and S18 unless the cuff pressure reaches a preset upper limit pressure (e.g., 300 mmHg). If the blood pressure calculation is completed (Yes in step S18), the processor 110 performs the following control: stop the pump 32 (step S20), open the valve 33 (step S22), and exhaust the air in the cuff 20. The processor 110 displays the blood pressure value measured by the blood pressure measurement on the display 50 (step S24).

[0118] Figure 6This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement in the normal mode (decompression measurement method). Figure 6 , the sphygmomanometer 100 starts the pressurization process and increases the cuff pressure until the cuff pressure reaches a predetermined pressure (eg, estimated systolic blood pressure). At this time, the pulse wave amplitude increases as the cuff pressure increases, and then decreases.

[0119] When the cuff pressure reaches the specified pressure, the sphygmomanometer 100 changes from the pressurization process to the decompression process to reduce the cuff pressure. During the decompression process, the pulse wave amplitude gradually increases as the cuff pressure decreases, and gradually decreases after reaching the maximum point. When the blood pressure measurement is completed, the sphygmomanometer 100 ends the decompression process and fully opens the valve 33.

[0120] Figure 7 This is a flowchart showing the blood pressure measurement process in the general mode (decompression measurement method).

[0121] Reference Figure 7 The processing of steps S32 to S36 is respectively Figure 5 The processing of steps S12 to S16 is the same, so the detailed description thereof will not be repeated.

[0122] The processor 110 calculates the estimated systolic blood pressure, the estimated diastolic blood pressure and the pulse rate based on the pulse wave signal obtained during the pressurization process (step S38). Next, the processor 110 determines whether the cuff pressure reaches or exceeds the threshold value Th (step S40). Typically, the threshold value Th is set to a value that is a fixed value (e.g., 40 mmHg) higher than the estimated systolic blood pressure.

[0123] When the cuff pressure is less than the threshold value Th (No in step S40), the processor 110 returns to step S36. When the cuff pressure is greater than the threshold value Th (Yes in step S40), the processor 110 stops the pump 32 (step S42). The processor 110 calculates the decompression speed (for example, speed Vf) based on the estimated pulse pressure and the pulse rate, which are the difference between the estimated systolic blood pressure and the estimated diastolic blood pressure (step S44). Typically, the processor 110 sets the decompression speed so that the pulse rate generated between the estimated pulse pressures is greater than or equal to a predetermined pulse rate.

[0124] The processor 110 controls the valve 33 to gradually open at a speed Vf (step S46 ). Thus, the process changes from the pressurization process to the depressurization process, and the cuff pressure is gradually reduced.

[0125] During the decompression process, the processor 110 extracts the pulse wave signal from the cuff pressure signal detected by the pressure sensor 31, attempts to calculate the systolic blood pressure and the diastolic blood pressure based on the pulse wave signal, and determines whether the blood pressure calculation is completed (step S48). If the blood pressure calculation is not completed (no in step S48), the processor 110 repeatedly performs the processing of steps S46 and S48. If the blood pressure calculation is completed (yes in step S48), the processor 110 performs the following control: fully open the valve 33 (step S50) to quickly discharge the air in the cuff 20. The processor 110 displays the blood pressure value measured by the blood pressure measurement on the display 50 (step S52).

[0126] <Processing in Arrhythmia Detection Mode>

[0127] Figure 8 This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement in the arrhythmia determination mode (pressure measurement method). Figure 8 , the sphygmomanometer 100 starts the pressurization process and pressurizes the cuff pressure at a constant pressurization speed (eg, speed Va). During the pressurization process, the pulse wave amplitude gradually increases as the cuff pressure increases and reaches a maximum point.

[0128] When the sphygmomanometer 100 determines that the pulse wave amplitude has reached the maximum, it changes the pressurization speed from speed Va to speed Vb (wherein speed Vb is slower than speed Va). The speed change period during which the cuff pressure is pressurized at speed Vb is a period from the time point of the determination to a predetermined time. The speed change period corresponds to the above-mentioned period Tb, and the other periods during the pressurization process except the speed change period correspond to the above-mentioned period Ta.

[0129] When the period Tb ends, the sphygmomanometer 100 returns the inflation speed from speed Vb to speed Va to continue the inflation of the cuff. When the blood pressure measurement is completed, the pump 32 is stopped to end the inflation process, and the valve 33 is opened. As a result, the cuff pressure is rapidly reduced.

[0130] Fig. 9 This is a flowchart showing the blood pressure measurement process (pressurization measurement method) in the arrhythmia determination mode.

[0131] Reference Fig. 9 The processing of steps S102 to S106 is respectively Figure 5 The processing of steps S12 to S16 is the same, so the detailed description thereof will not be repeated. It should be noted that in step S106, it is assumed that the processor 110 increases the cuff pressure at a speed Va (eg, 5.5 mmHg / s). Thus, the pressurization process starts.

[0132] Processor 110 determines whether the pulse wave amplitude has reached the maximum value during the pressurization process (step S108). For example, the change rate of the pulse wave amplitude when the pulse wave amplitude increases is positive, and the change rate of the pulse wave amplitude when the pulse wave amplitude decreases is negative. In this case, processor 110 determines that the pulse wave amplitude has reached the maximum value at the timing when the change rate of the pulse wave amplitude changes from positive to negative.

[0133] When the pulse wave amplitude is not at its maximum (No in step S108), the processor 110 continues the cuff pressure at the speed Va by executing step S106. When the pulse wave amplitude is at its maximum (Yes in step S108), the processor 110 changes the pressure increase speed from the speed Va to the speed Vb (e.g., 3 mmHg / s) (step S110).

[0134] The processor 110 determines whether a predetermined time has passed since the pressure increase speed was changed to speed Vb (step S112). If the predetermined time has not passed (No in step S112), the processor 110 repeats the process of step S112. If the predetermined time has passed (Yes in step S112), the processor 110 returns the pressure increase speed from speed Vb to speed Va (step S114).

[0135] The processor 110 attempts to calculate the systolic blood pressure and the diastolic blood pressure based on the pulse wave signal during the pressurization process, and determines whether the blood pressure calculation is completed (step S116). If the blood pressure calculation cannot be completed due to insufficient data (no in step S116), the processor 110 repeatedly performs the process of step S116 unless the cuff pressure reaches a preset upper limit pressure (for example, 300 mmHg). That is, the processor 110 continues to pressurize the cuff pressure at a speed Va and attempts to calculate the blood pressure.

[0136] When the blood pressure calculation is completed (Yes in step S116), the processor 110 performs arrhythmia determination processing (step S118). Specifically, the processor 110 determines whether the user has arrhythmia based on the pulse wave interval obtained from the pulse wave signal during the pressurization process. Next, the processor 110 performs the processing of steps S120 to S124. The processing of steps S120 to S124 is respectively the same as Figure 5 The processing of steps S20 to S24 is the same, so the detailed description thereof will not be repeated. It should be noted that in step S124, the processor 110 displays the determination result of arrhythmia on the display 50 together with the blood pressure value.

[0137] exist Fig. 9In the example of , the speed change period (ie, period Tb) during which the cuff pressure is increased at speed Vb is the period from the timing when the pulse wave amplitude becomes maximum to the elapse of a predetermined time.

[0138] It should be noted that the timing for changing the pressurization speed from speed Va to speed Vb (i.e., the start timing of period Tb) may be set to a timing before the timing when the pulse wave amplitude becomes maximum. In this case, the start timing of period Tb may be set to a timing just before the change rate of the pulse wave amplitude changes from positive to negative (e.g., the timing when the positive change rate is less than a threshold value).

[0139] Alternatively, the start timing of period Tb may be set to a timing later than the timing when the pulse wave amplitude becomes maximum. In this case, the start timing of period Tb may be set to a time after a predetermined time (for example, 1 second) has passed since the timing when the pulse wave amplitude is determined to be maximum.

[0140] Fig.10 This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement in the arrhythmia determination mode (decompression measurement method). Fig.10 , the sphygmomanometer 100 starts the pressurization process and pressurizes the cuff pressure at a constant pressurization speed. When the cuff pressure reaches the specified pressure, the sphygmomanometer 100 changes from the pressurization process to the decompression process and decompresses the cuff pressure at a speed Vf. During the decompression process, the pulse wave amplitude gradually increases as the cuff pressure decreases and reaches the maximum point.

[0141] When the sphygmomanometer 100 determines that the pulse wave amplitude has reached the maximum, it changes the decompression speed from speed Vf to speed Vg (wherein speed Vg is sufficiently slower than speed Vf). The speed change period during which the cuff pressure is reduced at speed Vf is a period from the determination time point until a predetermined time has passed. The speed change period corresponds to the above-mentioned period Tg, and the other periods in the decompression process except the speed change period correspond to the above-mentioned period Tf.

[0142] When the period Tg ends, the sphygmomanometer 100 returns the decompression speed from the speed Vg to the speed Vf, and continues the decompression of the cuff. When the blood pressure measurement is completed, the sphygmomanometer 100 ends the decompression process and fully opens the valve 33 .

[0143] Fig.11 This is a flowchart showing the blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode.

[0144] Reference Fig.11 The processing of steps S132 to S146 is respectively Figure 7The processes of steps S32 to S46 are the same, so the detailed description thereof will not be repeated. It should be noted that in step S146, the processor 110 reduces the cuff pressure at a speed Vf, thereby starting the decompression process.

[0145] The processor 110 determines whether the pulse wave amplitude has reached the maximum value during the decompression process (step S148). If the pulse wave amplitude has not reached the maximum value (No in step S148), the processor 110 continues the decompression of the cuff pressure at the speed Vf by executing step S146. If the pulse wave amplitude has reached the maximum value (Yes in step S148), the processor 110 changes the decompression speed from the speed Vf to the speed Vg (for example, 4 mmHg / s) (step S150). The speed Vg is a speed sufficiently slower than the speed Vf.

[0146] The processor 110 determines whether a predetermined time has passed since the decompression speed was changed to speed Vg (step S152). If the predetermined time has not passed (No in step S152), the processor 110 repeats the process of step S152. If the predetermined time has passed (Yes in step S152), the processor 110 restores the decompression speed from speed Vg to speed Vf (step S154).

[0147] The processor 110 attempts to calculate the systolic blood pressure and the diastolic blood pressure based on the pulse wave signal during the decompression process, and determines whether the blood pressure calculation is completed (step S156). If the blood pressure calculation cannot be completed (no in step S156), the processor 110 performs the processing of step S156. That is, the processor 110 continues to reduce the cuff pressure at the speed Vf and attempts to calculate the blood pressure.

[0148] When the blood pressure calculation is completed (Yes in step S156), the processor 110 executes arrhythmia determination processing (step S158). Next, the processor 110 fully opens the valve 33 (step S160) and displays the arrhythmia determination result together with the blood pressure value on the display 50 (step S162).

[0149] exist Fig.11 In the example, the speed change period (i.e., period Tg) for reducing the cuff pressure at speed Vg is the period from the timing when the pulse wave amplitude becomes maximum to the time after a predetermined time has passed. It should be noted that the timing for changing the decompression speed from speed Vf to speed Vg (i.e., the start timing of period Tg) may also be set to the timing before or after the timing when the pulse wave amplitude becomes maximum.

[0150] <Modification>

[0151] Fig.12This is a flowchart showing a first modification of the blood pressure measurement process (pressurization measurement method) in the arrhythmia determination mode.

[0152] Reference Fig.12 , each process of steps S102 to S106, S110 to S124 and Fig. 9 The corresponding processing is the same, so the detailed description will not be repeated.

[0153] After processing in step S106, the processor 110 determines whether the cuff pressure being pressurized has reached the cuff pressure corresponding to the maximum value of the pulse wave amplitude during the user's past blood pressure measurement (step S180). Specifically, the processor 110 reads out the associated information representing the relationship between the cuff pressure and the pulse wave amplitude during the past blood pressure measurement (for example, the last measurement) from the memory 51. Based on the associated information, the processor 110 extracts the cuff pressure at the time when the pulse wave amplitude during the pressurization process during the last measurement became the maximum (i.e., the maximum pulse wave amplitude was obtained). The processor 110 determines whether the cuff pressure during the pressurization process during the current blood pressure measurement (i.e., the cuff pressure during the current pressurization) has reached the extracted cuff pressure.

[0154] If the cuff pressure during pressurization has not reached the extracted cuff pressure (No in step S180), the processor 110 executes step S106. If the cuff pressure during pressurization has reached the extracted cuff pressure (Yes in step S180), the processor 110 changes the pressurization speed from speed Va to speed Vb (e.g., 3 mmHg / s) (step S110).

[0155] exist Fig.12 In the example of , the speed change period (i.e., period Tb) of increasing the cuff pressure at speed Vb is the period from the time point when the cuff pressure in the current measurement is judged to reach the extracted cuff pressure to the time after the prescribed time has passed. It should be noted that in the above step S180, the processor 110 may also extract the timing cuff pressure that obtains a pulse wave amplitude that is smaller than the maximum pulse wave amplitude in the pressurization process in the previous measurement by a prescribed value (or larger than a prescribed value) based on the associated information. The prescribed value is set to a smaller value.

[0156] Fig.13 This is a flowchart showing a first modification of the blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode.

[0157] Reference Fig.13 , each process of steps S132 to S146, S150 to S162 and Fig.11 The corresponding processing is the same, so the detailed description will not be repeated.

[0158] After processing in step S146, the processor 110 determines whether the cuff pressure being decompressed has reached the cuff pressure corresponding to the maximum value of the pulse wave amplitude during the user's past blood pressure measurement (step S190). Specifically, the processor 110 reads out the associated information representing the relationship between the cuff pressure and the pulse wave amplitude during the past blood pressure measurement (for example, the last measurement) from the memory 51. Based on the associated information, the processor 110 extracts the cuff pressure at the time when the pulse wave amplitude during the decompression process during the last measurement became the maximum (that is, the maximum pulse wave amplitude was obtained). The processor 110 determines whether the cuff pressure during the decompression process during the current blood pressure measurement (that is, the cuff pressure during the current decompression) has reached the extracted cuff pressure.

[0159] If the cuff pressure during decompression has not reached the extracted cuff pressure (No in step S190), the processor 110 executes step S146. If the cuff pressure during decompression has reached the extracted cuff pressure (Yes in step S190), the processor 110 changes the decompression speed from speed Vf to speed Vg (e.g., 4 mmHg / s) (step S150).

[0160] exist Fig.13 In the example, the speed change period (i.e., period Tg) during which the cuff pressure is reduced at a speed Vg is a period from the time when the cuff pressure in the current measurement is determined to reach the extracted cuff pressure to the time after a predetermined time has passed. In addition, in the above step S190, the processor 110 may also extract the timing cuff pressure that obtains a pulse wave amplitude that is smaller than the maximum pulse wave amplitude in the decompression process in the previous measurement by a predetermined value (or larger than a predetermined value) based on the associated information. The predetermined value is assumed to be a smaller value.

[0161] <Modification 2>

[0162] Fig.14 This is a flowchart showing a second modification of the blood pressure measurement process (pressurization measurement method) in the arrhythmia determination mode.

[0163] Reference Fig.14 , each process of steps S102, S104, S106, S110 to S124 and Fig. 9 The corresponding processing is the same, so the detailed description will not be repeated.

[0164] After the processing of step S102, the processor 110 calculates the average blood pressure based on the past blood pressure measurement values ​​(step S200). Specifically, the processor 110 reads the systolic blood pressure and diastolic blood pressure measured in the past blood pressure measurement (for example, the last measurement) from the memory 51, and calculates the average blood pressure based on the systolic blood pressure and diastolic blood pressure.

[0165] In addition, the processor 110 starts increasing the cuff pressure by driving the pump 32 (step S106), and determines whether the cuff pressure reaches the average blood pressure calculated in step S200 (step S210). If the cuff pressure does not reach the average blood pressure (no in step S210), the processor 110 executes step S106. If the cuff pressure reaches the average blood pressure (yes in step S210), the processor 110 changes the pressure increase speed from speed Va to speed Vb (for example, 3 mmHg / s) (step S110).

[0166] exist Fig.14 In the example of , the speed change period (i.e., period Tb) during which the cuff pressure is increased at a speed Vb is the period from the time when the cuff pressure is determined to reach the average blood pressure to the time after a predetermined time has passed. It should be noted that in the above step S210, the processor 110 may also determine whether the cuff pressure reaches a blood pressure that is a predetermined pressure less than the average blood pressure (or a predetermined pressure greater than the predetermined pressure). The predetermined pressure is assumed to be a smaller value.

[0167] Fig.15 This is a flowchart showing a second modification of the blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode.

[0168] Reference Fig.15 , each process of steps S132, S134~S146, S150~S162 and Fig.11 The corresponding processing is the same, so the detailed description will not be repeated.

[0169] After the process of step S132, the processor 110 calculates the average blood pressure based on the past blood pressure measurement values ​​(step S220).

[0170] Furthermore, after the processing of step S146, the processor 110 determines whether the cuff pressure during decompression reaches the average blood pressure calculated in step S220 (step S230). If the cuff pressure does not reach the average blood pressure (no in step S230), the processor 110 executes step S146. If the cuff pressure reaches the average blood pressure (yes in step S230), the processor 110 changes the decompression speed from speed Vf to speed Vg (for example, 4 mmHg / s) (step S150).

[0171] exist Fig.15In the example, the speed change period (i.e., period Tg) during which the cuff pressure is reduced at a speed Vg is the period from the time when the cuff pressure is determined to have reached the average blood pressure to the time after a predetermined time has passed. It should be noted that in the above step S210, the processor 110 may also determine whether the cuff pressure has reached a blood pressure that is less than a predetermined pressure (or greater than a predetermined pressure) than the average blood pressure. The predetermined pressure is set to a smaller value.

[0172] <Variation 3>

[0173] Fig.16 This is a flowchart showing a third modification of the blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode.

[0174] Reference Fig.16 , each process of steps S132 to S144, S146, S150 to S162 and Fig.11 The corresponding processing is the same, so the detailed description will not be repeated.

[0175] After the process of step S144, the processor 110 estimates the average blood pressure based on the estimated systolic blood pressure and the estimated diastolic blood pressure calculated in step S138 (step S240). Specifically, the processor 110 calculates the estimated average blood pressure based on the estimated systolic blood pressure and the estimated diastolic blood pressure.

[0176] After the process of step S146, the processor 110 determines whether the cuff pressure during decompression reaches the estimated average blood pressure calculated in step S240 (step S250). If the cuff pressure does not reach the estimated average blood pressure (no in step S250), the processor 110 executes step S146. If the cuff pressure reaches the estimated average blood pressure (yes in step S250), the processor 110 changes the decompression speed from speed Vf to speed Vg (for example, 4 mmHg / s) (step S150).

[0177] exist Fig.16 In the example, the speed change period (i.e., period Tg) for reducing the cuff pressure at speed Vg is the period from the time when the cuff pressure is determined to reach the estimated average blood pressure to the time after the prescribed time has passed. It should be noted that in the above step S250, the processor 110 may also determine whether the cuff pressure reaches a blood pressure that is less than a prescribed pressure (or greater than a prescribed pressure) than the estimated average blood pressure. The prescribed pressure is assumed to be a smaller value.

[0178] <Variation 4>

[0179] Fig.17 This is a flowchart showing a fourth modification of the blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode.

[0180] Reference Fig.17 , each process of steps S132 to S136, S138 to S146, S150 to S162 and Fig.11 The corresponding processing is the same, so the detailed description will not be repeated.

[0181] After the processing of step S136, the processor 110 determines whether the pulse wave amplitude has reached the maximum during the pressurization process (step S270). If the pulse wave amplitude has not reached the maximum (No in step S270), the processor 110 continues the pressurization of the cuff pressure by executing the processing of step S136. If the pulse wave amplitude has reached the maximum (Yes in step S270), the processor 110 determines the cuff pressure corresponding to the maximum pulse wave amplitude (i.e., the cuff pressure at the timing when the pulse wave amplitude reaches the maximum) (step S280), and executes the processing of step S138.

[0182] After the processing of step S146, the processor 110 determines whether the cuff pressure during decompression reaches the cuff pressure determined in step S280 (hereinafter, also referred to as "determined cuff pressure") (step S290). If the cuff pressure does not reach the determined cuff pressure (No in step S290), the processor 110 executes step S146. If the cuff pressure reaches the determined cuff pressure (Yes in step S290), the processor 110 changes the decompression speed from speed Vf to speed Vg (for example, 4 mmHg / s) (step S150).

[0183] exist Fig.17 In the example of , the speed change period (i.e., period Tg) for reducing the cuff pressure at speed Vg is the period from the time when the cuff pressure is determined to have reached the determined cuff pressure to the time after the prescribed time has passed. It should be noted that in the above step S290, the processor 110 may also determine whether the cuff pressure has reached a pressure that is less than a prescribed pressure (or greater than a prescribed pressure) than the determined cuff pressure. The prescribed pressure is assumed to be a smaller value.

[0184] <Other Implementation Methods>

[0185] (1) In the above embodiment, the configuration in which the pressurization speed is slowed down during the period Tb and the depressurization speed is slowed down during the period Tg is described, but the present invention is not limited to this configuration. For example, the pressurization of the cuff pressure may be stopped during the period Tb (ie, the pressurization speed is zero), and the depressurization of the cuff pressure may be stopped during the period Tg (ie, the depressurization speed is zero).

[0186] Fig.18 This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement (pressurization measurement method) in the arrhythmia determination mode according to another embodiment. Fig.18 During the period Tb, the cuff pressure is stopped and maintained. The speed Vb, which is the pressure increase speed during the period Tb, is zero.

[0187] Fig.19 This is a diagram showing the correspondence between the pulse wave signal and the cuff pressure during blood pressure measurement (decompression measurement method) in the arrhythmia determination mode according to another embodiment. Fig.19 During the period Tg, the cuff pressure is stopped from being depressurized and the cuff pressure is maintained. The speed Vg, which is the depressurization speed during the period Tg, is zero.

[0188] Fig. 20 This is a flowchart showing a blood pressure measurement process (pressurization measurement method) in an arrhythmia determination mode according to another embodiment. Fig. 20 The flowchart is equivalent to Fig. 9 The flowchart is obtained by replacing steps S110 and S114 with steps S300 and S310 respectively.

[0189] Reference Fig. 20 , each process of steps S102 to S108, S112, S116 to S124 and Fig. 9 The corresponding processing is the same, so the detailed description will not be repeated.

[0190] When the pulse wave amplitude reaches the maximum value (YES in step S108), processor 110 stops pump 32 (step S300). Thus, the cuff pressure is stopped and the cuff pressure is maintained.

[0191] The processor 110 determines whether a predetermined time has passed since the pump 32 was stopped (maintenance of the cuff pressure was started) (step S112). If the predetermined time has not passed (No in step S112), the processor 110 executes step S112. If the predetermined time has passed (Yes in step S112), the processor 110 drives the pump 32 to start pressurizing the cuff 20 at the speed Va (step S310), and executes step S116.

[0192] It should be noted that, similarly, it can also be constructed as Fig.12 , Fig.14 Steps S110 and S114 are replaced by steps S300 and S310 respectively.

[0193] Fig.21 This is a flowchart showing a blood pressure measurement process (decompression measurement method) in the arrhythmia determination mode according to another embodiment. Fig.21 The flowchart is equivalent to Fig.11 The flowchart is obtained by replacing steps S150 and S154 with steps S320 and S330 respectively.

[0194] Reference Fig.21 , each process of steps S132 to S148, S152, S156 to S162 and Fig.11 The corresponding processing is the same, so the detailed description will not be repeated.

[0195] When the pulse wave amplitude becomes maximum (yes in step S148), the processor 110 closes the valve 33 (step S320). As a result, the cuff pressure is stopped from being reduced and the cuff pressure is maintained. The processor 110 determines whether a predetermined time has passed since the valve 33 was closed (the cuff pressure maintenance started) (step S152). If the predetermined time has not passed (no in step S152), the processor 110 executes step S152. If the predetermined time has passed (yes in step S152), the processor 110 controls the valve 33 to gradually open at a speed Vf (step S330), and executes step S156.

[0196] In addition, similarly, it can also be configured to Fig.13 , Fig.15 , Fig.16 , Fig.17 Steps S150 and S154 are replaced by steps S320 and S330 respectively.

[0197] (2) In the above embodiment, a program for enabling a computer to function to execute the control described in the above flowchart can also be provided. Such a program can be recorded on a non-temporary computer-readable recording medium such as a floppy disk, a CD-ROM (Compact Disc Read Only Memory), a secondary storage device, a main storage device, and a memory card attached to the computer, and provided as a program product. Alternatively, the program can be provided by recording on a recording medium such as a hard disk built into the computer. In addition, the program can also be provided by downloading via a network.

[0198] (3) The configuration illustrated as an example in the above embodiment is an example of the configuration of the present invention, and can be combined with other known technologies, and can also be configured to omit a part and make changes within the scope of the main purpose of the present invention. In addition, in the above embodiment, the processing and configuration described in other embodiments can also be appropriately adopted for implementation.

[0199] [Note]

[0200] As described above, the present embodiment includes the following disclosures.

[0201] [Composition 1]

[0202] A sphygmomanometer (100) comprises: a blood pressure measuring unit (220) for measuring a user's blood pressure based on a pulse wave signal during a pressurization process in which a cuff pressure is increased, wherein the cuff pressure represents the internal pressure of a cuff (20) worn on a measured part of the user, the blood pressure measuring unit (220) making the pressurization speed during a specified period of the pressurization process slower than the pressurization speed during other periods of the pressurization process except the specified period, and setting the specified period based on a timing when the amplitude of the pulse wave signal during the pressurization process becomes maximum or a timing when the cuff pressure during the pressurization process becomes the average blood pressure of the user, the sphygmomanometer (100) further comprising a determination unit (230) for determining whether the user has arrhythmia based on the pulse wave signal during the pressurization process.

[0203] [Composition 2]

[0204] According to the sphygmomanometer (100) of configuration 1, the blood pressure measurement unit (220) sets a period from a timing when the amplitude of the pulse wave signal becomes maximum during the pressurization to a lapse of a predetermined time as the predetermined period.

[0205] [Composition 3]

[0206] According to the sphygmomanometer (100) described in configuration 1, the sphygmomanometer (100) further includes a storage unit (250), the storage unit (250) storing association information obtained by associating the cuff pressure obtained during the user's past blood pressure measurement with the pulse wave signal, and the blood pressure measurement unit (220) performing the following processing: extracting the cuff pressure at the timing when the amplitude of the pulse wave signal during the pressurization process becomes maximum during the user's past blood pressure measurement based on the association information, and setting the period from the timing when the cuff pressure during the pressurization process during the user's current blood pressure measurement reaches the extracted cuff pressure to the lapse of a specified time as the specified period.

[0207] [Composition 4]

[0208] According to the sphygmomanometer (100) described in configuration 1, the sphygmomanometer (100) further includes a storage unit (250), the storage unit (250) stores the systolic blood pressure and diastolic blood pressure of the user obtained in the past blood pressure measurement of the user, and the blood pressure measurement unit (220) performs the following processing: calculating the average blood pressure based on the systolic blood pressure and the diastolic blood pressure, and setting the period from the timing when the cuff pressure in the pressurization process during the current blood pressure measurement of the user reaches the average blood pressure to the lapse of a specified time as the specified period.

[0209] [Composition 5]

[0210] The blood pressure meter (100) according to any one of Configurations 1 to 4, wherein the blood pressure measurement unit (220) sets the inflation speed in the predetermined period to zero.

[0211] [Composition 6]

[0212] A sphygmomanometer (100) comprises a blood pressure measuring unit (220), wherein the blood pressure measuring unit (220) measures the blood pressure of a user based on a pulse wave signal during a decompression process in which the cuff pressure is reduced after a pressurization process in which the cuff pressure is increased to a pressure greater than a specified pressure, wherein the cuff pressure represents the internal pressure of a cuff (20) worn on a measured part of the user, the blood pressure measuring unit (220) makes the decompression speed during a specified period of the decompression process slower than the decompression speed during other periods of the decompression process except the specified period, and sets the specified period based on the timing when the amplitude of the pulse wave signal during the decompression process becomes maximum or the timing when the cuff pressure during the decompression process becomes the average blood pressure of the user, and the sphygmomanometer (100) further comprises a determination unit (230), wherein the determination unit (230) determines whether the user has arrhythmia based on the pulse wave signal during the decompression process.

[0213] [Composition 7]

[0214] According to the sphygmomanometer (100) according to configuration 6, the blood pressure measurement unit (220) sets a period from a timing when the amplitude of the pulse wave signal becomes maximum during the decompression process to a lapse of a predetermined time as the predetermined period.

[0215] [Composition 8]

[0216] According to the sphygmomanometer (100) described in configuration 6, the sphygmomanometer (100) further includes a storage unit (250), the storage unit (250) storing association information obtained by associating the cuff pressure obtained in the past blood pressure measurement of the user with the pulse wave signal, and the blood pressure measurement unit (220) performing the following processing: based on the association information, extracting the cuff pressure at the timing when the amplitude of the pulse wave signal in the decompression process becomes maximum in the past blood pressure measurement of the user, and setting the period from the timing when the cuff pressure in the decompression process in the current blood pressure measurement of the user reaches the extracted cuff pressure to the lapse of a specified time as the specified period.

[0217] [Composition 9]

[0218] According to the sphygmomanometer (100) described in configuration 6, the sphygmomanometer (100) further includes a storage unit (250), the storage unit (250) stores the systolic blood pressure and diastolic blood pressure of the user obtained in the past blood pressure measurement of the user, and the blood pressure measurement unit (220) performs the following processing: calculating the average blood pressure based on the systolic blood pressure and the diastolic blood pressure, and setting the period from the timing when the cuff pressure in the decompression process during the current blood pressure measurement of the user reaches the average blood pressure to the lapse of a specified time as the specified period.

[0219] [Composition 10]

[0220] According to the sphygmomanometer (100) described in configuration 6, the blood pressure measuring unit (220) performs the following processing: estimating the user's systolic blood pressure and diastolic blood pressure during the pressurization process, estimating the average blood pressure based on the estimated systolic blood pressure and diastolic blood pressure, and setting the period from the timing when the cuff pressure during the decompression process reaches the average blood pressure to the lapse of a specified time as the specified period.

[0221] [Composition 11]

[0222] According to the sphygmomanometer (100) described in configuration 6, the blood pressure measuring unit (220) performs the following processing: determining the timing cuff pressure at which the amplitude of the pulse wave signal becomes maximum during the pressurization process, and setting the period from the timing when the cuff pressure during the decompression process reaches the determined cuff pressure to the lapse of a specified time as the specified period.

[0223] [Composition 12]

[0224] The sphygmomanometer (100) according to any one of Configurations 6 to 11, wherein the blood pressure measurement unit (220) sets the decompression rate in the predetermined period to zero.

[0225] [Composition 13]

[0226] A blood pressure measurement method comprises the following steps: measuring a user's blood pressure based on a pulse wave signal during a pressurization process in which a cuff pressure is increased, wherein the cuff pressure represents the internal pressure of a cuff (20) worn on a measured part of the user, the measuring step comprising making the pressurization speed during a specified period of the pressurization process slower than the pressurization speed during other periods of the pressurization process except the specified period, setting the specified period based on the timing when the amplitude of the pulse wave signal during the pressurization process becomes maximum or the timing when the cuff pressure during the pressurization process becomes the average blood pressure of the user, the blood pressure measurement method further comprises the following steps: determining the user's arrhythmia based on the pulse wave signal during the pressurization process.

[0227] [Composition 14]

[0228] A blood pressure measurement method comprises the following steps: measuring the blood pressure of a user based on a pulse wave signal during a decompression process of reducing the cuff pressure after a pressurization process of increasing the cuff pressure to a pressure greater than a specified pressure, wherein the cuff pressure represents the internal pressure of a cuff (20) worn on a measured part of the user, the measuring step comprising making the decompression speed during a specified period of the decompression process slower than the decompression speed during other periods of the decompression process except the specified period, setting the specified period based on the timing when the amplitude of the pulse wave signal during the decompression process becomes maximum or the timing when the cuff pressure during the decompression process becomes the average blood pressure of the user, the blood pressure measurement method further comprising the following steps: determining the user's arrhythmia based on the pulse wave signal during the decompression process.

[0229] The embodiments disclosed this time should be considered as illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

[0230] Description of Reference Numerals

[0231] 10: Main body; 20: Cuff; 22: Fluid bag; 30: Air system component; 31: Pressure sensor; 32: Pump; 33: Valve; 50: Display; 51: Memory; 52: Operation unit; 52A: Measurement switch; 52B: Mode selection switch; 53: Communication interface; 54: Power supply unit; 100: Sphygmomanometer; 110: Processor; 210: Mode setting unit; 220: Blood pressure measurement unit; 230: Determination unit; 240: Output control unit; 250: Storage unit; 310: A / D conversion circuit; 320: Pump drive circuit; 330: Valve drive circuit.

Claims

1. A sphygmomanometer, comprising: The blood pressure measuring unit measures the user's blood pressure based on the pulse wave signal during the process of increasing the cuff pressure. The cuff pressure indicates the internal pressure of the cuff worn on the measured part of the user. The blood pressure measurement unit makes the inflation speed during a predetermined period of the inflation process slower than the inflation speed during other periods of the inflation process other than the predetermined period. The predetermined period is set based on a timing when the amplitude of the pulse wave signal becomes maximum during the pressurization or a timing when the cuff pressure becomes the average blood pressure of the user during the pressurization, The sphygmomanometer further includes a determination unit configured to determine arrhythmia of the user based on a pulse wave signal during the pressurization.

2. The sphygmomanometer according to claim 1, wherein: The blood pressure measurement unit sets a period from a timing when the amplitude of the pulse wave signal becomes maximum during the pressurization to a lapse of a predetermined time as the predetermined period.

3. The sphygmomanometer according to claim 1, wherein: The sphygmomanometer further includes a storage unit that stores correlation information obtained by correlating the cuff pressure and the pulse wave signal obtained in past blood pressure measurements of the user. The blood pressure measurement unit performs the following processing: extracting the cuff pressure at a timing when the amplitude of the pulse wave signal during the pressurization process becomes maximum when the user's blood pressure was measured in the past based on the associated information; The predetermined period is set as a period from the timing when the cuff pressure in the pressurization process during the current blood pressure measurement of the user reaches the extracted cuff pressure to a lapse of a predetermined time.

4. The sphygmomanometer according to claim 1, wherein: The sphygmomanometer further includes a storage unit that stores the systolic blood pressure and diastolic blood pressure of the user obtained in past blood pressure measurements of the user. The blood pressure measurement unit performs the following processing: calculating the average blood pressure based on the systolic blood pressure and the diastolic blood pressure, The predetermined period is set as the period from the timing when the cuff pressure in the pressurization process during the current blood pressure measurement of the user reaches the average blood pressure to the elapse of a predetermined time.

5. The sphygmomanometer according to any one of claims 1 to 4, wherein The blood pressure measurement unit sets the inflation speed to zero during the predetermined period.

6. A sphygmomanometer, comprising: The blood pressure measuring unit measures the blood pressure of the user based on a pulse wave signal in a decompression process of decompressing the cuff pressure after a pressurization process of pressurizing the cuff pressure to a pressure greater than a predetermined pressure, wherein: The cuff pressure indicates the internal pressure of the cuff worn on the measured part of the user. The blood pressure measurement unit makes the decompression speed in a predetermined period of the decompression process slower than the decompression speed in other periods of the decompression process except the predetermined period, The predetermined period is set based on a timing when the amplitude of the pulse wave signal during the decompression becomes maximum or a timing when the cuff pressure during the decompression becomes the average blood pressure of the user, The sphygmomanometer further includes a determination unit configured to determine whether the user has arrhythmia based on a pulse wave signal during the decompression process.

7. The sphygmomanometer according to claim 6, wherein: The blood pressure measurement unit sets a period from a timing when the amplitude of the pulse wave signal becomes maximum during the decompression to a lapse of a predetermined time as the predetermined period.

8. The sphygmomanometer according to claim 6, wherein: The sphygmomanometer further includes a storage unit that stores correlation information obtained by correlating the cuff pressure and the pulse wave signal obtained in past blood pressure measurements of the user. The blood pressure measurement unit performs the following processing: extracting the cuff pressure at a timing when the amplitude of the pulse wave signal during the decompression process becomes maximum when the user's blood pressure is measured in the past based on the associated information; The predetermined period is set as the period from the timing when the cuff pressure in the decompression process during the current blood pressure measurement of the user reaches the extracted cuff pressure to the elapse of a predetermined time.

9. The sphygmomanometer according to claim 6, wherein: The sphygmomanometer further includes a storage unit that stores the systolic blood pressure and diastolic blood pressure of the user obtained in past blood pressure measurements of the user. The blood pressure measurement unit performs the following processing: calculating the average blood pressure based on the systolic blood pressure and the diastolic blood pressure, The predetermined period is set as the period from the timing when the cuff pressure in the decompression process during the current blood pressure measurement of the user reaches the average blood pressure to the elapse of a predetermined time.

10. The sphygmomanometer according to claim 6, wherein: The blood pressure measurement unit performs the following processing: During the pressurization process, the systolic blood pressure and the diastolic blood pressure of the user are estimated, and the average blood pressure is estimated based on the estimated systolic blood pressure and the diastolic blood pressure. The predetermined period is set as a period from the timing when the cuff pressure in the decompression process reaches the average blood pressure to the elapse of a predetermined time.

11. The sphygmomanometer according to claim 6, wherein: The blood pressure measurement unit performs the following processing: determining the cuff pressure at the timing when the amplitude of the pulse wave signal becomes maximum during the pressurization process, The predetermined period is set as a period from when the cuff pressure in the decompression process reaches the determined cuff pressure to when a predetermined time has passed.

12. The sphygmomanometer according to any one of claims 6 to 11, wherein The blood pressure measurement unit sets the decompression rate in the predetermined period to zero.

13. A method for measuring blood pressure, comprising the following steps: The blood pressure of the user is measured based on a pulse wave signal during a pressurization process of increasing the cuff pressure, wherein the cuff pressure indicates the internal pressure of the cuff worn on the measured part of the user, The step of measuring includes making the pressurization speed in a predetermined period of the pressurization process slower than the pressurization speed in other periods of the pressurization process except the predetermined period, The predetermined period is set based on a timing when the amplitude of the pulse wave signal becomes maximum during the pressurization or a timing when the cuff pressure becomes the average blood pressure of the user during the pressurization, The blood pressure measurement method further includes the step of determining arrhythmia of the user based on a pulse wave signal during the pressurization process.

14. A method for measuring blood pressure, comprising the following steps: The blood pressure of the user is measured based on a pulse wave signal in a decompression process of decompressing the cuff pressure after the cuff pressure is increased to a pressure greater than a predetermined pressure, wherein the cuff pressure indicates the internal pressure of the cuff worn on the measured part of the user, The step of measuring includes making the decompression rate in a predetermined period of the decompression process slower than the decompression rate in other periods of the decompression process except the predetermined period, The predetermined period is set based on a timing when the amplitude of the pulse wave signal during the decompression becomes maximum or a timing when the cuff pressure during the decompression becomes the average blood pressure of the user, The blood pressure measurement method further includes the step of determining arrhythmia of the user based on a pulse wave signal during the decompression process.

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