Sphygmomanometer

Abstract

To enable both blood pressure measurement and atrial fibrillation determination while reducing a burden on a user.SOLUTION: A sphygmomanometer 20 measures blood pressure of a user on the basis of a pulse wave signal superposed on a cuff pressure signal detected in the process of pressurizing or depressurizing cuff pressure indicating inner pressure of a cuff worn on a measurement part of the user. The sphygmomanometer 20 includes a storage part for acquiring pulse wave feature information indicating a feature amount of a pulse wave from the pulse wave signal superposed on the cuff pressure signal detected in the blood pressure measurement for each blood pressure measurement, and storing the acquired pulse wave feature information for each blood pressure measurement, a number-of-pulse-waves determination part for determining the number of pulse waves having the feature amount indicated by the pulse wave feature information on the pulse wave feature information for each blood pressure measurement, and an atrial fibrillation determination part for determining atrial fibrillation in the pulse waves on the basis of the pulse wave feature information in the storage part when the sum total of the number of pulse waves for each blood pressure measurement reaches a predetermined number.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a blood pressure monitor, and more particularly to a blood pressure monitor having a function of determining atrial fibrillation. [Background technology]

[0002] Early detection of atrial fibrillation, which can cause heart disease, is desirable. Conventionally, a technology has been proposed that estimates atrial fibrillation from pulse wave information acquired by a home electronic blood pressure monitor. Specifically, in one measurement opportunity using an electronic blood pressure monitor, blood pressure measurements are performed consecutively, for example, multiple times, and a pulse wave interval, which is the interval between pulse wave signals acquired in each blood pressure measurement, is acquired, and atrial fibrillation is detected based on the pulse wave interval.

[0003] For example, US Patent Application Publication No. 2016 / 0228017 (Patent Document 1) discloses a blood pressure measuring device that can indicate the presence or absence of atrial fibrillation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2016 / 0228017 Summary of the Invention [Problem to be solved by the invention]

[0005] In the device disclosed in Patent Document 1, in order to determine the presence or absence of atrial fibrillation, blood pressure must be measured three times in succession at one measurement opportunity. Measuring blood pressure three times in succession at each measurement opportunity in this way is burdensome for the user, as it takes a long time to measure and the measurement site is compressed by the cuff, making the user feel restricted.

[0006] The present disclosure provides a blood pressure monitor that enables both blood pressure measurement and atrial fibrillation determination while reducing the burden on the user. [Means for solving the problem]

[0007] A blood pressure monitor according to the present disclosure includes a cuff pressure adjustment unit which increases or decreases a cuff pressure indicating the internal pressure of a cuff attached to a measurement site of a user, a cuff pressure detection unit which detects a cuff pressure signal indicating the cuff pressure, a blood pressure measurement unit which measures the user's blood pressure based on a pulse wave signal superimposed on the cuff pressure signal detected in the process of increasing or decreasing the cuff pressure, an information acquisition unit which acquires, for each blood pressure measurement, pulse wave feature information which indicates a feature amount of the pulse wave from the pulse wave signal superimposed on the cuff pressure signal detected in the blood pressure measurement, a storage unit which stores the acquired pulse wave feature information for each blood pressure measurement, a pulse number determination unit which determines, for the pulse wave feature information for each blood pressure measurement, the number of pulse waves having the feature amount represented by the pulse wave feature information, and an atrial fibrillation determination unit which determines atrial fibrillation in the pulse wave based on the pulse wave feature information in the storage unit when the total number of pulse waves for each blood pressure measurement reaches a predetermined number.

[0008] According to the above disclosure, atrial fibrillation is determined from the pulse wave based on the pulse wave characteristic information stored in the storage unit when the total number of pulse waves per blood pressure measurement reaches a predetermined number. This eliminates the need to perform multiple blood pressure measurements to determine atrial fibrillation during one blood pressure measurement. As a result, it is possible to achieve both blood pressure measurement and atrial fibrillation determination while reducing the burden on the user, such as the user being repeatedly pressed on the measurement site during blood pressure measurement and the length of time required for blood pressure measurement.

[0009] The pulse rate determination unit in the above-mentioned blood pressure monitor determines the number of pulse waves for each blood pressure measurement by excluding, from the pulse wave characteristic information for each blood pressure measurement, pulse wave characteristic information corresponding to a blood pressure measurement for which the elapsed time since the blood pressure measurement was performed is equal to or greater than a threshold value.

[0010] According to the above-described blood pressure monitor, it is possible to exclude old past pulse wave characteristic information from the pulse wave characteristic information used to determine atrial fibrillation.

[0011] In the above-described blood pressure meter, the characteristic amount of the pulse wave represented by the pulse wave characteristic information includes the interval between pulse waves indicated by the pulse wave signal superimposed on the cuff pressure signal detected during blood pressure measurement.

[0012] According to the above-described blood pressure monitor, the pulse wave interval can be included in the feature amount of the pulse wave used to determine atrial fibrillation.

[0013] In the above-mentioned blood pressure monitor, the pulse wave interval includes the time interval between the maximum amplitudes of adjacent pulse waves.

[0014] According to the above-mentioned blood pressure monitor, the time interval of the maximum amplitude can be included as the pulse wave interval.

[0015] In the above-described blood pressure monitor, the pulse rate determination unit determines the number of pulse waves for each blood pressure measurement by excluding pulse wave characteristic information corresponding to a pulse wave whose amplitude, having a characteristic amount represented by the pulse wave characteristic information for each blood pressure measurement, is equal to or less than a threshold value.

[0016] According to the above-described blood pressure monitor, it is possible to exclude pulse wave characteristic information corresponding to a pulse wave whose amplitude is equal to or smaller than a threshold value from the pulse wave characteristic information used to determine atrial fibrillation.

[0017] In the above-described blood pressure monitor, the pulse rate determination unit further determines whether or not the total number of pulse wave numbers corresponding to the pulse wave characteristic information for each blood pressure measurement in the storage unit has reached a predetermined number.

[0018] According to the above-described blood pressure monitor, when the pulse rate determination unit determines that the total number of pulse wave numbers corresponding to the pulse wave characteristic information for each blood pressure measurement in the storage unit has reached a predetermined number, it is possible to determine atrial fibrillation in the pulse wave based on the pulse wave characteristic information stored in the storage unit. Effect of the Invention

[0019] The present disclosure makes it possible to measure blood pressure and determine atrial fibrillation while reducing the burden on the user. [Brief description of the drawings]

[0020] [Figure 1]1 is a diagram showing an example of a network configuration to which a blood pressure measurement system according to an embodiment of the present invention is applied; [Diagram 2] FIG. 2 is a block diagram showing an example of a hardware configuration of a sphygmomanometer 20 according to the present embodiment. [Diagram 3] FIG. 2 is a diagram showing an example of a functional configuration of a sphygmomanometer 20 according to the present embodiment. [Figure 4] 5 is a flowchart showing an example of processing relating to measurement by the sphygmomanometer 20 according to the present embodiment. [Diagram 5] 5 is a flowchart showing an example of the blood pressure measurement process of FIG. 4. [Figure 6] 3A to 3C are diagrams showing examples of information displayed on a display 31 according to the present embodiment. [Figure 7] 3A to 3C are diagrams showing examples of information displayed on a display 31 according to the present embodiment. [Figure 8] 5A to 5C are diagrams showing an example of a plurality of pulse waves used for AF determination in the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[0022] <Application Examples> An application example of the blood pressure monitor according to the present embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram showing an example of a functional configuration of blood pressure monitor 20 according to the present embodiment. Hereinafter, atrial fibrillation will be referred to as AF.

[0023] The blood pressure monitor 20 according to the present embodiment is configured to measure blood pressure by increasing or decreasing the cuff pressure, which indicates the internal pressure of a cuff (air bag) wrapped around a measurement site of a user, for example, an arm. Note that the measurement site is not limited to the upper arm.

[0024] 3, the sphygmomanometer 20 includes, as main functional components, a blood pressure measurement unit 220, an AF determination unit 230, an output control unit 240 that controls the output of information, and a storage control unit 250 that controls reading and writing of information from and to the storage unit 36. Each of these units is realized, for example, by the processor 30 of the sphygmomanometer 20 reading a program stored in a storage 35 described later, and expanding and executing the read program in a memory 33 described later. Note that some or all of these units may be configured to be realized by a hardware circuit including an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array), etc.

[0025] The storage unit 36 ​​is configured to include a storage 35 described later or a memory 33 described later. The storage unit 36 ​​includes a working memory area 361 mainly configured of a volatile storage medium, and an information memory area. This information memory area stores information including interval information 362, blood pressure measurement information 363 indicating information on measured blood pressure, and AF determination information 364 indicating the AF determination result. The interval information 362 indicates the interval of a pulse wave, which is an example of a feature of a pulse wave detected in time series from a measurement site during blood pressure measurement.

[0026] The blood pressure measurement unit 220 controls the cuff pressure in accordance with an instruction given by a user's operation on the blood pressure measurement unit that measures the user's blood pressure and the sphygmomanometer based on a pulse wave signal superimposed on a cuff pressure signal indicating the cuff pressure detected by the pressure sensor 22. Specifically, the blood pressure measurement unit 220 drives the pump 23 via the pump drive circuit 26 and controls the drive of the valve 24 via the valve drive circuit 27. The valve 24 is opened and closed to discharge or seal air in the fluid bag to control the cuff pressure.

[0027] The blood pressure measurement unit 220 receives the cuff pressure signal detected by the pressure sensor 22 and extracts a pulse wave signal representing the pulse wave at the measurement site superimposed on the cuff pressure signal. That is, the blood pressure measurement unit 220 detects a time-series pulse wave, which is a pressure component superimposed on the cuff pressure signal in synchronization with the pulsation of the user's heart, from the cuff pressure signal. The pulse wave signal, which is an analog signal measured by the pressure sensor 22, is converted into pulse wave information of a digital signal. The interval calculation unit 221 included in the blood pressure measurement unit 220 calculates the interval between adjacent pulse waves in the time-series pulse wave constituting the pulse wave information. For each pair of two adjacent pulse waves in the time-series pulse wave, the interval calculation unit 221 generates interval information 362 indicating the interval between adjacent pulse waves constituting the pair in association with the pair. The interval information 362 is stored in the memory unit 36 ​​by the storage control unit 250. In this embodiment, the interval between pulse waves indicates, for example, the time from the time when the maximum peak of the amplitude of the pulse wave signal is detected to the time when the next peak of the amplitude of the pulse wave signal is detected.

[0028] The interval calculation unit 221 is one embodiment of an "information acquisition unit" that acquires a feature amount of a pulse wave. In Fig. 1, the interval calculation unit 221 is shown as a function included in the blood pressure measurement unit 220, but it may be provided as a function independent of the blood pressure measurement unit 220. Note that, although the feature amount is the interval of the pulse wave, it is not limited to the interval.

[0029] The blood pressure measurement unit 220 calculates blood pressure measurement information 363 representing the user's blood pressure based on the pulse wave signal. The blood pressure measurement information 363 is stored in the storage unit 36 ​​and is also output to the output control unit 240 as a measurement result. Specifically, in blood pressure measurement, the cuff pressure is increased to a predetermined pressure, and based on the pulse wave signal detected during the subsequent depressurization process, the blood pressure measurement unit 220 measures the user's blood pressure according to the oscillometric method, outputs the measurement result to the output control unit 240, and stores the blood pressure measurement information 363 including the measurement result in the storage unit 36 ​​via the storage control unit 250. Typically, the blood pressure measurement information 363 calculated by the blood pressure measurement unit 220 includes a systolic blood pressure, a diastolic blood pressure, and a pulse rate.

[0030] In the AF determination process performed by the AF determination unit 230, the pulse number determination unit 232 analyzes the interval information 362 stored in the storage unit 36, and determines whether or not the number of pulse waves corresponding to the interval information 362 has reached a predetermined number based on the analysis result. In response to the pulse number determination unit 232 determining that the number of pulse waves corresponding to the interval information 362 has reached a predetermined number, the AF determination unit 230 performs a predetermined process based on the interval information 362 corresponding to the predetermined number of pulse waves in the storage unit 36 ​​to determine whether or not AF exists in the pulse wave. The above-mentioned predetermined process is a process for detecting AF, and determines whether or not AF exists using, for example, a pattern of pulse wave intervals. In the pulse wave signal, a peak (maximum point) of the amplitude for each beat is detected, and the time interval between the peaks of the current beat and the beat one beat before is calculated as the pulse wave interval. Note that the interval used for the determination is not limited to the interval between the peaks, and may be the interval between the rising points of adjacent pulse waves.

[0031] The result of the above-mentioned AF determination process is output to the output control unit 240, and AF determination information 364 indicating the result of the determination is stored in the storage unit .

[0032] The output control unit 240 generates display data for displaying the blood pressure values ​​and the AF judgment results based on the measurement results from the blood pressure measurement unit 220 and the judgment results from the AF judgment unit 230, and outputs the generated display data to the display control circuit 31A. The display control circuit 31A drives the display 31 based on such display data, thereby causing the display 31 to display information on the blood pressure values ​​and the AF judgment.

[0033] In the AF determination process, the selection unit 231 included in the AF determination unit 230 selects a set of pulse waves that allows AF determination to be performed with high accuracy. Specifically, for each of a plurality of sets of pulse waves indicated by the interval information 362 stored in the storage unit 36, the selection unit 231 deletes from the interval information 362 a set of pulse rates corresponding to a blood pressure measurement in which the elapsed time from the time when the pulse wave was measured (blood pressure measurement date and time) is equal to or greater than a threshold value.

[0034] Furthermore, in the AF determination process, the selection unit 231 compares the peak value of the amplitude of the pulse wave signal with a threshold value for each of a plurality of pairs of pulse waves indicated by the interval information 362 stored in the memory unit 36. Based on the comparison result, the selection unit 231 detects a pair of pulse waves having an amplitude corresponding to a peak value less than the threshold value, and deletes the detected pair from the interval information 362.

[0035] The pulse rate determination section 232 and the AF determination section 230 process the interval information 362 after the selection section 231 has selectively deleted such sets of pulse waves. As a result, information on pulse waves from old measurement dates and times or pulse waves with insufficient amplitude is excluded from the pulse wave information used for AF determination. This prevents such information from acting as noise, and improves the accuracy of AF determination. Note that the method of selecting pulse waves to be deleted may be either selection based on the time elapsed since measurement or selection based on the amplitude of the pulse wave signal, or both.

[0036] According to the blood pressure monitor 20 described above, AF is judged based on the interval information 362 corresponding to the predetermined number of pulse waves stored in the memory unit 36 ​​when the total number of pulse waves acquired for each blood pressure measurement reaches a predetermined number. In this way, the trigger for AF judgment is the total number of pulse waves acquired by the measurement reaching a predetermined number, not the number of blood pressure measurements. Therefore, unlike Patent Document 1, it is not necessary to always perform three consecutive blood pressure measurements for AF judgment, which reduces the burden on the user.

[0037] <Network configuration> FIG. 1 is a diagram showing an example of a network configuration to which a blood pressure monitor 20 according to the present embodiment is applied. With reference to FIG. 1, a network system 1 includes a blood pressure monitor 20, a server 40, and portable information processing terminals 10A and 10B such as smartphones, which are connectable to a network. The blood pressure monitor 20 communicates with the terminal 10A via the network 10. The terminals 10A and 10B communicate with the server 40 via a network 15. Information measured by the blood pressure monitor 20 may be transferred to the server 40 and stored in a database 42. The networks 10 and 15 include various communication networks such as Wi-Fi (registered trademark), a mobile communication network, and the Internet.

[0038] The blood pressure monitor 20 may include different types of blood pressure monitors 20A, 20B, and 20C. The blood pressure monitor 20 is a stationary upper arm blood pressure monitor in which the main body and the cuff 21 are separate. The blood pressure monitor 20B is a wristwatch-type blood pressure monitor in which the main body and the cuff are integrated. The blood pressure monitor 20C is configured with the cuff and the main body integrated, and is worn, for example, on the upper arm. In the following, for convenience of explanation, the blood pressure monitors 20A, 20B, and 20C may be collectively referred to as "blood pressure monitor 20". Any type of blood pressure monitor is configured to be able to perform the blood pressure measurement and AF determination described above. In this embodiment, the blood pressure monitor 20 is described by taking the blood pressure monitor 20A as an example of the blood pressure monitor 20.

[0039] The terminals 10A and 10B are, for example, smartphones having a touch panel constituting a display. The terminal 10A receives measurement information from the sphygmomanometer 20, displays the received measurement information on the display, and transfers the received measurement information to the server 40 to store it in the database 42. The terminal 10B communicates with the server 40, receives measurement information searched from the database 42, and displays it on the display. Even if the sphygmomanometer 20 is a stationary type, the user can obtain information measured by the sphygmomanometer 20 by using the terminals 10A and 10B that the user carries.

[0040] In this embodiment, the functions of FIG. 3 are implemented in the sphygmomanometer 20, but the implementation method is not limited thereto. For example, the blood pressure measurement system may be configured by cooperation between a plurality of devices, such as the sphygmomanometer 20, the server 40, and the terminals 10A and 10B. When such a plurality of devices cooperate with each other, the process for realizing the functions of the blood pressure measurement system can be realized by distributed processing among such a plurality of devices. As the distributed processing, for example, among the functions of the sphygmomanometer 20 in FIG. 3, the AF determination unit 230 may be implemented in the terminal 10A or the server 40. In addition, the storage unit 36 ​​may be configured in the database 42 of the server 40 or the terminals 10A and 10B. The distribution method is not limited thereto.

[0041] <Hardware configuration> FIG. 2 is a block diagram showing an example of a hardware configuration of the blood pressure monitor 20 according to the present embodiment. Referring to FIG. 2, the blood pressure monitor 20 includes, as main components, a main body and a cuff 21. The cuff 21 contains an air fluid bag. The main body includes a processor 30, an air system component constituting a "cuff pressure adjustment unit" for blood pressure measurement, an A / D conversion circuit 25, a pump drive circuit 26, a valve drive circuit 27, a display 31 to which a display control circuit 31A is connected, a storage unit 36, an operation unit 32 to receive a user operation on the blood pressure monitor 20, a communication interface 28 to communicably connect the blood pressure monitor 20 to a network, a reader / writer 29 to which a non-volatile storage medium such as a memory card 29A is detachably attached, and a power source 34.

[0042] The processor 30 constitutes an arithmetic processing circuit such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The processor 30 realizes the processing of the sphygmomanometer 20 by reading and executing a program from the storage unit 36. For example, the processor 30 controls the driving of the pump 23 and the valve 24 in response to an operation signal from the operation unit 32. The processor 30 also calculates a blood pressure value using an algorithm for calculating blood pressure by the oscillometric method, and displays the calculated blood pressure value on the display 31.

[0043] The storage unit 36 ​​includes a non-volatile storage medium such as a hard disk drive (HDD) 35, and a memory 33. The memory 33 includes a volatile or non-volatile storage medium. The memory 33 includes, for example, a random access memory (RAM), a read-only memory (ROM), a flash memory, and the like. The storage unit 36 ​​stores a program for controlling the sphygmomanometer 20, data used for controlling the sphygmomanometer 20, setting data for setting various functions of the sphygmomanometer 20, and information on the measurement results of blood pressure values. The memory 33 is also used as a work memory or the like for the processor 30 to expand and execute a program read from the storage unit 36.

[0044] The air system component increases or decreases the cuff pressure indicating the internal pressure of the cuff 21 attached to the measurement site of the user. Specifically, the air system component includes a pressure sensor 22 for detecting the cuff pressure, which is the pressure inside the fluid bag, and a pump 23 and a valve 24 as an inflation / deflation mechanism for inflating and deflating the fluid bag so that air can be supplied to or discharged from the fluid bag contained in the cuff 21 through an air pipe.

[0045] The pressure sensor 22 detects the pressure (cuff pressure) in the fluid bag and outputs a signal (cuff pressure signal) corresponding to the detected pressure to the A / D conversion circuit 25. The pressure sensor 22 is, for example, a piezo-resistance pressure sensor, and is fluidly connected to the pump 23, the valve 24, and the fluid bag contained in the cuff 21 via air piping. The pump 23 supplies air as a fluid to the fluid bag through the air piping to increase the cuff pressure. The valve 24 is opened and closed to control the cuff pressure by discharging air from the fluid bag through the air piping or by sealing air in the fluid bag.

[0046] The A / D conversion circuit 25 converts the output value (e.g., electrical resistance) of the pressure sensor 22 from an analog signal to a digital signal and outputs it to the processor 30. In this example, the processor 30 acts as an oscillation circuit that oscillates at a frequency according to the change in electrical resistance from the pressure sensor 22 due to the piezo-resistance effect, and obtains a signal representing the cuff pressure according to the oscillation frequency. The pump drive circuit 26 controls the drive of the pump 23 based on a control signal provided by the processor 30. The valve drive circuit 27 controls the opening and closing of the valve 24 based on a control signal provided by the processor 30.

[0047] When blood pressure is measured according to the oscillometric method, the following operation is generally performed. Specifically, the cuff 21 is wrapped around the measurement site (wrist, arm, etc.) of the user (subject) in advance, and during measurement, the pump 23 and the valve 24 are controlled to pressurize the cuff 21. In this pressurization process, when the cuff pressure is pressurized to a predetermined pressure Cp, the pump 23 is stopped and the valve 24 is controlled to gradually open. This reduces the cuff pressure. In such a depressurization process, the change in arterial volume occurring in the artery at the measurement site is extracted as a pulse wave signal superimposed on the cuff pressure signal. The systolic blood pressure and the diastolic blood pressure are calculated based on the change in amplitude of the pulse wave signal (mainly the rise and fall) accompanying the change in cuff pressure in the depressurization process. Note that such blood pressure measurement is not limited to the case where it is performed in the depressurization process, and may be performed using the pulse wave signal superimposed on the cuff pressure signal detected in the pressurization process.

[0048] The operation unit 32 receives an operation performed by the user on the sphygmomanometer 20, and outputs an operation signal indicating the received user operation to the processor 30. The processor 30 outputs a command based on the operation signal to each unit. The operation unit 32 includes a measurement switch 32A that is operated to instruct the start of blood pressure measurement. The operation unit 32 may include other types of switches or buttons.

[0049] When the measurement switch 32A is operated, the processor 30 controls the air system components so that the measurement site is compressed by the cuff 21, and calculates the blood pressure value according to the oscillometric method. When the measurement switch 32A is operated again during such blood pressure measurement, the processor 30 stops the blood pressure measurement.

[0050] Reader / writer 29 reads out a program or data from memory card 29A that is attached. Processor 30 stores the read out program or data in storage unit 36. Reader / writer 29 also writes information such as measurement results that is read out from storage unit 36 ​​by processor 30 to the attached memory card 29A.

[0051] The display 31 displays various information including blood pressure measurement results and AF determination information based on display data from the display control circuit 31A. The communication interface 28 includes, for example, a NIC (Network Interface Card) and controls the exchange of information between the sphygmomanometer 20 and other devices (terminals 10A, 10B and server 40). The power supply 34 supplies power to the processor 30 and each piece of hardware.

[0052] <Flowchart and display examples> 4 is a flowchart showing an example of a process relating to measurement by the blood pressure monitor 20 according to the present embodiment. At the start of this process, the cuff 21 of the blood pressure monitor 20 is attached (wrapped) around the measurement site of the user.

[0053] 4, the processor 30 of the sphygmomanometer 20 receives an operation signal based on a user operation of the measurement switch 32A from the operation unit 32 (step S1). In response to the operation signal, the processor 30 starts a blood pressure measurement process (step S2). In this blood pressure measurement process, interval information 362 is stored in the storage unit 36. The blood pressure measurement process will be described in detail later.

[0054] Processor 30 detects the number of pulse waves corresponding to interval information 362 stored in memory 36, and determines whether the number of detected pulse waves reaches a predetermined number (step S4). If processor 30 determines that the number of pulse waves reaches the predetermined number (YES in step S4), it performs the AF determination process described above (step S5). In the AF determination process of step S5, processor 30 extracts interval information corresponding to the predetermined number of pulse waves from interval information 362 in memory 36, and determines the presence or absence of AF in the pulse wave based on the extracted interval information.

[0055] The processor 30 outputs display data for displaying the result of the AF determination in step S5 on the display 31 to the display control circuit 31A (step S6).

[0056] On the other hand, if processor 30 does not determine that the number of pulse waves has reached the predetermined number (NO in step S4), the AF determination in step S5 and the process of displaying the determination result (steps S5 and S6) are not performed, and the process ends.

[0057] Fig. 5 is a flowchart showing an example of the blood pressure measurement process of Fig. 4. In Fig. 5, the processor 30 turns off (stops) the pump 23 and initializes the pressure sensor 22 with the valve 24 open (step S21). In initializing the pressure sensor 22, the current output value of the pressure sensor 22 is set as a value equivalent to the atmospheric pressure. In step S21, the processor 30 initializes the working memory area 361 of the storage unit 36.

[0058] The processor 30 closes the valve 24 via the valve drive circuit 27 (step S22). Next, the processor 30 turns on (starts) the pump 23 via the pump drive circuit 26 and starts pressurizing the cuff 21 (fluid bag) at a predetermined pressurization speed (step S23).

[0059] The processor 30 compares the cuff pressure indicated by the cuff pressure signal detected by the pressure sensor 22 with a predetermined pressure Cp, and determines whether the cuff pressure has reached the predetermined pressure Cp based on the result of the comparison (step S24). If it is determined that the cuff pressure has not reached the predetermined pressure Cp (NO in step S24), the process returns to step S23, and the cuff 21 is inflated at a predetermined inflation speed.

[0060] When it is determined that the cuff pressure has reached the predetermined pressure Cp (YES in step S24), the processor 30 turns off (stops) the pump 23 via the pump drive circuit 26 (step S25). After that, the processor 30 gradually opens the valve 24 via the valve drive circuit 27 so that the cuff pressure indicated by the cuff pressure signal detected by the pressure sensor 22 is reduced at a predetermined reduction speed (step S26).

[0061] During the decompression process in which the pressure is reduced at this predetermined speed, the processor 30 extracts a pulse wave signal from the cuff pressure signal detected by the pressure sensor 22, and tries to calculate the maximum blood pressure (systolic blood pressure) and minimum blood pressure (diastolic blood pressure) based on the extracted pulse wave signal, and judges whether the blood pressure calculation is completed or not (step S28). The processor 30 stores the pulse wave signal detected during the decompression process in the working memory area 361. If the processor 30 judges based on the pulse wave signal stored in the working memory area 361 that the blood pressure calculation cannot be completed yet because the pulse wave signal is not sufficiently obtained (NO in step S28), the processor 30 returns to step S26. If the processor 30 judges that the blood pressure calculation is completed (YES in step S28), the processor 30 sets the valve 24 to be fully open via the valve drive circuit 27 so that the air in the cuff 21 is rapidly exhausted (step S29). The processor 30 displays the blood pressure value (measurement result) measured in step S27 on the display 31 (step S30). Moreover, blood pressure measurement information 363 indicating the blood pressure value (measurement result) is stored in the storage unit .

[0062] The processor 30 calculates the interval between the pulses for each set of a plurality of pulses indicated by the pulse wave signal stored in the working memory area 361 (step S31), and stores the interval information 362 indicating the calculated interval for each set in the storage unit 36 (step S32).

[0063] As described above, in this embodiment, for each blood pressure measurement, interval information 362 is acquired for a plurality of pulse waves corresponding to the pulse wave signal used for calculating the blood pressure. As a result, the interval information 362 acquired for each blood pressure measurement is stored in the storage unit 36 in association with the measurement date and time of the corresponding blood pressure measurement.

[0064] FIG. 6 and FIG. 7 are diagrams showing examples of information display on the display 31 according to this embodiment. FIG. 6 shows a display example when it is determined that there is AF in a case where the AF determination process (step S5) is performed after the blood pressure measurement (step S2). In FIG. 6, the results of the blood pressure measurement (systolic blood pressure SYS, diastolic blood pressure DIA, pulse rate PLS) and a message 311 indicating that it is determined that there is AF are displayed.

[0065] On the other hand, FIG. 7 shows a display example in a case where the AF determination process (step S5) is not performed after the blood pressure measurement (step S2), or in a case where the AF determination process (step S5) is performed after the blood pressure measurement (step S2) and it is determined that "there is no AF". In FIG. 7, only the results of the blood pressure measurement (systolic blood pressure SYS, diastolic blood pressure DIA, pulse rate PLS) are displayed, and the determination result of AF is not displayed. In a case where the AF determination process (step S5) is performed after the blood pressure measurement (step S2) and it is determined that "there is no AF", a message "there is no AF" may be displayed on the screen of FIG. 7.

[0066] <Example of AF determination> FIG. 8 is a diagram showing an example of a plurality of pulse waves used for AF determination according to this embodiment. In this embodiment, the interval information 362 of the pulse waves acquired in each of a plurality of blood pressure measurements is integrated, and AF determination is performed based on the integrated interval information 362.

[0067] In FIG. 8, when blood pressure measurements are performed three times in a day, in the morning (7:00), afternoon (13:00), and evening (23:00), pulse wave interval information 362 is acquired in each blood pressure measurement and stored in the storage unit 36. In this case, interval information 362 corresponding to each blood pressure measurement is stored in the storage unit 36 ​​in each of the morning and afternoon blood pressure measurements. When blood pressure is measured in the afternoon, in step S4 in FIG. 4, the pulse rate determination unit 232 determines that the number of pulse waves corresponding to the interval information 362 stored in the storage unit 36 ​​does not reach M required for AF determination (NO in step S4 in FIG. 4), and AF determination processing is not performed. In the subsequent evening blood pressure measurement, interval information 362 corresponding to the blood pressure measurement is stored in the storage unit 36. When the evening blood pressure measurement is performed, in step S4 of FIG. 4, the pulse number determination unit 232 determines that the number of pulse waves corresponding to the interval information 362 stored in the memory unit 36 ​​reaches M necessary for AF determination (YES in step S4 of FIG. 4). That is, the pulse number determination unit 232 counts the number of pulse waves corresponding to the interval information 362 in the memory unit 36, that is, the total number of pulse waves obtained by integrating the pulse waves acquired in the morning, afternoon, and evening blood pressure measurements, as (total number=N1+N2+N3), and determines that the condition (total number≧M) is satisfied (YES in step S4 of FIG. 4). Thus, in FIG. 8, when the evening blood pressure measurement is performed (step S2 of FIG. 4), the AF determination unit 230 integrates the interval information 362 corresponding to the pulse waves (M pulse waves) acquired in each of the morning, afternoon, and evening blood pressure measurements stored in the memory unit 36, and performs AF determination (step S5 of FIG. 4) based on such integrated information. The above-mentioned M pulse waves include a plurality of pulse waves acquired in one or more blood pressure measurements (step S2 in FIG. 4). More specifically, the M pulse waves include a plurality of pulse waves acquired in one or more blood pressure measurements (step S2 in FIG. 4) performed after the previous AF determination process was performed.

[0068] <Advantages of the embodiment> AF is a disease that causes severe heart disease and treatment must be started early. However, since many cases are asymptomatic, the start of treatment is delayed without the patient realizing that they have AF. For this reason, it is desirable to routinely screen for the presence or absence of AF. Such screening is performed based on an electrocardiogram test at a medical institution, and opportunities to detect AF are limited. In contrast, the home blood pressure monitor 20 according to this embodiment can provide many opportunities to detect AF by taking advantage of the opportunity for the user to measure blood pressure and using the pulse wave acquired by the blood pressure measurement to screen (determine) AF. Some AF patients do not always have AF symptoms, but may have symptoms due to environmental factors such as drinking alcohol, stress, and lack of sleep. Therefore, a mechanism that provides many opportunities for AF detection, as in this embodiment, can provide support information for effectively determining the start of treatment in such cases.

[0069] Moreover, the blood pressure monitor 20 according to this embodiment is configured to perform the AF determination process when it is determined that the total number of pulse waves corresponding to the interval information 362 has reached a predetermined number. This configuration eliminates the need to measure three times in succession every time blood pressure is measured, as in Patent Document 1. As a result, according to this embodiment, the time required for measurement is not lengthened, and the measurement site is not burdened by being repeatedly compressed with a predetermined pressure Cp equal to or higher than the systolic blood pressure.

[0070] Furthermore, in this embodiment, even though three consecutive blood pressure measurements are not required, unlike Patent Document 1, the selection unit 231 removes information about old measurement dates and times or pulse waves with insufficient amplitude from the interval information 362 used for AF determination, thereby preventing such information from affecting the determination as noise, and improving the accuracy of the determination.

[0071] Furthermore, in this embodiment, only pulse wave interval information 362 is stored in the memory unit 36 ​​for AF determination, rather than the pulse wave information itself, so that the memory capacity for storing information necessary for determination can be saved.

[0072] <Other embodiments> (1) In the above-described embodiment, a program is provided that causes a computer such as the processor 30 of the sphygmomanometer 20 to execute the processes described in the above-described flowchart. Such a program can be provided as a program product by being recorded on a non-transitory computer-readable recording medium such as a flexible disk, a CD-ROM (Compact Disk Read Only Memory), a secondary storage device, a main storage device, or a memory card 29A that is attached to the computer. Alternatively, such a program can be provided by being recorded on a recording medium such as the HDD 35 built into the computer. In addition, the program can be provided to such a computer by downloading it from a distribution server (not shown) via the networks 10 and 15.

[0073] (2) The configurations exemplified as the above-mentioned embodiments are merely examples of the configurations of the present invention, and may be combined with other known technologies, or may be modified, such as by omitting some parts, without departing from the scope of the present invention. In addition, the above-mentioned embodiments may be implemented by appropriately adopting the processes and configurations described in other embodiments.

[0074] [Note] As described above, the present embodiment includes the following disclosure.

[0075] (Configuration 1) a cuff pressure adjusting unit (23, 24) for increasing or decreasing a cuff pressure indicating an internal pressure of a cuff attached to a measurement site of a user; a cuff pressure detection unit (22) for detecting a cuff pressure signal indicative of the cuff pressure; a blood pressure measuring unit (220) that measures the blood pressure of the user based on a pulse wave signal superimposed on a cuff pressure signal detected during the process of increasing or decreasing the cuff pressure; an information acquiring unit (221) that acquires, for each blood pressure measurement, pulse wave feature information that represents a feature amount of a pulse wave from the pulse wave signal superimposed on the cuff pressure signal detected in the blood pressure measurement; a storage unit (36) for storing the acquired pulse wave characteristic information for each blood pressure measurement; a pulse number determination unit (232) that determines the number of pulse waves having a feature amount represented by the pulse wave feature information for each blood pressure measurement; and an atrial fibrillation determination unit (230) that determines atrial fibrillation in the pulse wave based on the pulse wave characteristic information in the storage unit when the total number of the pulse waves for each blood pressure measurement reaches a predetermined number.

[0076] (Configuration 2) The pulse rate determination unit (232) The blood pressure monitor (20) according to configuration 1, wherein the number of pulse waves for each blood pressure measurement is determined by excluding, from the pulse wave characteristic information for each blood pressure measurement, pulse wave characteristic information corresponding to a blood pressure measurement in which an elapsed time from when the blood pressure measurement was performed is equal to or greater than a threshold value.

[0077] (Configuration 3) 3. The blood pressure monitor (20) according to configuration 1 or 2, wherein the characteristic amount of the pulse wave represented by the pulse wave characteristic information includes an interval of the pulse wave represented by the pulse wave signal superimposed on the cuff pressure signal detected during the blood pressure measurement.

[0078] (Configuration 4) 4. The blood pressure monitor (20) of configuration 3, wherein the pulse wave interval includes a time interval between maximum amplitudes of adjacent pulse waves.

[0079] (Configuration 5) The pulse rate determination unit The blood pressure monitor (20) according to any one of configurations 1 to 4, wherein the number of pulse waves for each blood pressure measurement is determined by excluding pulse wave characteristic information corresponding to a pulse wave having a characteristic amount represented by the pulse wave characteristic information for each blood pressure measurement, the amplitude of which is equal to or less than a threshold value.

[0080] (Configuration 6) The pulse rate determination unit further The blood pressure monitor (20) according to any one of configurations 1 to 5, further comprising: determining whether or not a total number of pulse wave counts corresponding to the pulse wave characteristic information for each blood pressure measurement in the storage unit has reached the predetermined number. [Explanation of symbols]

[0081] 1 network system, 10, 15 network, 10A, 10B terminal, 20, 20A, 20B, 20C blood pressure monitor, 21 cuff, 22 pressure sensor, 23 pump, 24 valve, 25 A / D conversion circuit, 26 pump drive circuit, 27 valve drive circuit, 28 communication interface, 29 reader / writer, 29A memory card, 30 processor, 31 display, 31A display control circuit, 32 operation unit, 32A measurement switch, 33 memory, 34 power supply, 35 storage, 36 memory unit, 40 server, 42 database, 220 blood pressure measurement unit, 221 interval calculation unit, 230 AF determination unit, 231 selection unit, 232 pulse rate determination unit, 240 output control unit, 250 storage control unit, 311 message, 361 working memory area, 362 interval information, 363 Blood pressure measurement information, 364 judgment information, Cp specified pressure.

Claims

1. a cuff pressure adjusting unit that increases or decreases the cuff pressure that indicates the internal pressure of the cuff attached to the measurement site of the user; a cuff pressure detection unit that detects a cuff pressure signal indicating the cuff pressure; a blood pressure measurement unit that measures the blood pressure of the user based on a pulse wave signal superimposed on a cuff pressure signal detected during the process of increasing or decreasing the cuff pressure; an information acquiring unit that acquires, for each blood pressure measurement, pulse wave feature information representing a feature amount of a pulse wave from the pulse wave signal superimposed on the cuff pressure signal detected in the blood pressure measurement; a storage unit for storing the acquired pulse wave characteristic information for each blood pressure measurement; a pulse rate determination unit that determines the number of pulse waves having a feature value represented by the pulse wave feature information for each blood pressure measurement; a total number determination unit that determines whether the total number of pulse waves obtained by integrating pulse waves for each blood pressure measurement has reached a predetermined number; an atrial fibrillation determination unit that determines atrial fibrillation in the pulse wave based on the pulse wave characteristic information corresponding to the integrated pulse wave in the storage unit each time it is determined that the total number has reached a predetermined number, The total number determination unit determines whether the total number of pulse waves obtained by integrating pulse waves determined by the pulse rate determination unit for one or more blood pressure measurements since the previous atrial fibrillation determination has reached the predetermined number.

2. The pulse rate determination unit 2. The blood pressure monitor according to claim 1, wherein the number of pulse waves for each blood pressure measurement is determined by excluding, from the pulse wave characteristic information for each blood pressure measurement, pulse wave characteristic information corresponding to a blood pressure measurement for which an elapsed time since the blood pressure measurement was performed is equal to or greater than a threshold value.

3. 3. The blood pressure monitor according to claim 1, wherein the pulse wave characteristic information indicates a pulse wave characteristic amount including an interval between pulse waves indicated by the pulse wave signal superimposed on the cuff pressure signal detected during the blood pressure measurement.

4. The blood pressure monitor according to claim 3 , wherein the pulse wave interval includes a time interval between maximum amplitudes of adjacent pulse waves.

5. The pulse rate determination unit 5. The sphygmomanometer according to claim 4, wherein the number of pulse waves for each blood pressure measurement is determined by excluding pulse wave characteristic information corresponding to pulse waves having a characteristic amount represented by the pulse wave characteristic information for each blood pressure measurement, the amplitude of which is equal to or less than a threshold value.

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