Blood pressure measuring device and blood pressure measuring system

Abstract

To provide a technique capable of optimizing the frequency of calibrating a blood pressure value calculation algorithm according to a user when estimating the blood pressure of a human body using a feature amount related to estimation of a blood pressure value.SOLUTION: Provided is a blood pressure measuring device that is characterized in having: a feature amount acquisition unit for acquiring one or more feature amounts related to estimating the blood pressure value of a human body; a blood pressure value calculating unit for calculating the estimated blood pressure value on the basis of the feature amount; a measured blood pressure value acquiring unit for acquiring the measured blood pressure value; a calibration assessing unit for assessing whether the feature amount acquired by the feature amount acquiring unit deviates from a prescribed reference value, and when assessed that there is a deviation, determining that the measured blood pressure value is to be acquired; and a calibration processing unit for calibrating an algorithm by which the blood pressure value calculating unit calculates the estimated blood pressure value, wherein the calibration processing unit alters the reference value on the basis of the measured blood pressure value acquired by the determination made by the calibration assessing unit and the estimated blood pressure value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a blood pressure measuring device and a blood pressure measuring system.

Background Art

[0002] Conventionally, as a method for measuring the blood pressure of a human body, a technique is known in which a blood pressure estimated value is calculated based on a feature value that can be obtained non-invasively, and the blood pressure is measured using the estimated value. Specifically, for example, it is known that there is a correlation between the Pulse Transit Time (PTT), which is the time required for a pulse wave to propagate between two points on an artery, and blood pressure. Based on such a correlation, a device for non-invasive continuous blood pressure measurement has been proposed (for example, Patent Document 1). [[ID=十三]]

[0003] Patent Document 1 discloses a blood pressure measuring device that measures blood pressure by providing an electrode as an ECG (ElectroCardioGraphic) sensor and a pulse wave sensor such as a PPG (PhotoPlethysmoGraphic) sensor on a belt portion that is wrapped around a measurement site of a user, and calculating the PTT based on the time difference between the waveform feature points of the electrocardiogram and the waveform feature points of the pulse wave signal. In this way, with a configuration in which both the electrode and the pulse wave sensor are provided on the belt portion, the electrode and the pulse wave sensor can be attached to the user by wrapping the belt portion around the user. Therefore, according to the technique described in Patent Document 1, it is possible to provide a blood pressure measuring device that is easy to wear by the user and can greatly reduce the burden on the user in performing non-invasive continuous blood pressure measurement on a daily basis.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when blood pressure measurement (estimation) is performed based on the correlation with non-invasively obtainable features, as in the technology described in Patent Document 1, the correlation differs for each user and for each blood pressure measurement situation. Therefore, it is necessary to measure accurate blood pressure values ​​at appropriate timings and frequencies and calibrate the blood pressure estimation algorithm based on these values. Patent Document 1 also describes determining whether the conditions for recommending the measurement of the user's blood pressure for calibration have been met, and if the conditions are met, outputting information instructing blood pressure measurement.

[0006] As mentioned above, when obtaining accurate blood pressure values ​​for calibration, methods such as the oscillometric method or the Korotkoff method can be considered. However, the compression of the measurement site by the cuff is uncomfortable for most users. Therefore, when blood pressure is measured continuously, frequent calibration measurements become a burden for the user. On the other hand, when performing blood pressure measurement (estimation) based on feature quantities, in order to calculate reliable and highly accurate measured values ​​(estimates), it is necessary to perform calibration as appropriate according to various usage conditions such as the user's exercise level, ambient temperature, and nutritional status during continuous measurement. In other words, when calibrating a blood pressure calculation algorithm according to the user, it is desirable that calibration be performed at a frequency necessary to accurately estimate blood pressure values, while minimizing the burden on the user.

[0007] However, in actual use environments, users intentionally experiment with various measurement conditions (exercise intensity, ambient temperature, nutritional status, etc.) to actually measure blood pressure under diverse conditions and perform calibration. This is difficult to achieve. Furthermore, if the blood pressure calculation algorithm is uniformly calibrated based on predetermined feature thresholds, as in conventional technologies, the frequency of calibration will remain the same even if the accuracy of blood pressure estimation is low (or conversely, if it is sufficiently accurate). Therefore, it is not possible to reduce the number of calibrations to prevent unnecessary blood pressure measurements, or increase the number of calibrations to calculate estimated blood pressure values ​​with greater accuracy, depending on the individual characteristics of the user and measurement conditions. In other words, there was a problem in that calibration could not be performed at an appropriate frequency.

[0008] In view of the above circumstances, the present invention aims to provide a technology that can optimize the frequency of calibration of the blood pressure calculation algorithm according to the user when estimating human blood pressure using features related to blood pressure estimation. [Means for solving the problem]

[0009] A feature acquisition unit that acquires one or more feature quantities related to the estimation of human blood pressure values, A blood pressure value calculation unit calculates an estimated blood pressure value based on the aforementioned feature quantities, A blood pressure value acquisition unit that acquires actual blood pressure values ​​measured by a method different from that calculated by the blood pressure value calculation unit, A calibration determination unit determines whether the feature obtained by the feature acquisition unit deviates from a predetermined reference value, and if it determines that it deviates, it decides to acquire the measured blood pressure value. The system includes a calibration processing unit that calibrates the algorithm for calculating the estimated blood pressure value by the blood pressure value calculation unit using the measured blood pressure value, The blood pressure measuring device is characterized in that the calibration processing unit modifies the reference value based on the measured blood pressure value obtained by the determination of the calibration determination unit and the estimated blood pressure value calculated using the characteristic quantity that deviates from the reference value.

[0010] The features referred to here include waveform-related data such as the height at inflection points, the slope between inflection points, and the area of ​​a specific point in the waveform, obtained from the electrocardiogram (ECG) and pulse wave waveform, respectively, as well as PTT and pulse wave conduction time (PAT). This includes, but is not limited to, biometric information such as features calculated based on multiple waveform data (e.g., Arrival Time) and other heart rate-related data. For example, it also includes information related to the patient's personal attributes such as height, age, weight, and medication history, as well as environmental information such as season and temperature. Furthermore, "calculating an estimated blood pressure value based on features" does not only mean calculating a single estimate from a specific feature, but also includes calculating an estimated blood pressure value by combining multiple features.

[0011] In this way, if the reference value for determining whether calibration is necessary is changed based on the measured blood pressure value and the estimated blood pressure value, it becomes possible to improve the accuracy of blood pressure estimation by repeatedly calibrating the blood pressure calculation algorithm according to the differences in the individual characteristics of the user, and to optimize the frequency of calibration of the blood pressure calculation algorithm.

[0012] Furthermore, if the difference between the measured blood pressure value obtained by the determination of the calibration determination unit and the estimated blood pressure value calculated using the feature quantity that deviates from the reference value is less than or equal to a predetermined threshold, the calibration processing unit may change the reference value to a value that decreases the frequency with which it is determined that the measured blood pressure value is obtained. Alternatively, if the difference between the measured blood pressure value obtained by the determination of the calibration determination unit and the estimated blood pressure value calculated using the feature quantity that deviates from the reference value exceeds a predetermined threshold, the calibration processing unit may change the reference value to a value that increases the frequency with which it is determined that the measured blood pressure value is obtained.

[0013] When calibration blood pressure measurements are performed, the larger the difference between the estimated blood pressure value and the actual blood pressure value, the less appropriate the previous blood pressure estimation algorithm was. Therefore, as described above, if the difference between the estimated blood pressure value and the actual blood pressure value is large, the reference value of the feature should be changed so that the frequency of calibration increases (for example, if it is set as an upper threshold, that value should be decreased). On the other hand, if the difference between the estimated blood pressure value and the actual blood pressure value is small and the accuracy of blood pressure estimation is sufficient, the frequency of calibration should be changed so that it decreases (for example, if it is set as an upper threshold, that value should be increased) to reduce the burden on the user. In this way, it becomes possible to easily optimize the number of calibration processes without performing complex processing.

[0014] Furthermore, the blood pressure measuring device may also have an output means, and when the calibration determination unit decides to acquire the actual blood pressure value, it may output information from the output means indicating that the actual blood pressure value should be acquired. The output means referred to here may be, for example, a liquid crystal display, but it may also be other display means such as an LED light, or output means other than a display means such as a speaker or a vibration mechanism. With such a configuration, the user can easily recognize that it is necessary to acquire the actual blood pressure value.

[0015] Furthermore, the blood pressure measuring device may further include a blood pressure measuring means for measuring the actual blood pressure value, and the actual blood pressure value acquisition unit may acquire the actual blood pressure value by measuring the actual blood pressure value using the blood pressure measuring means when the calibration determination unit decides to acquire the actual blood pressure value. In this way, by further including a blood pressure measuring means, it becomes possible to easily acquire the actual blood pressure value by measuring the blood pressure value when it becomes necessary to acquire the actual blood pressure value. This reduces the burden of measuring blood pressure using other equipment for actual measurement, and the burden of data input.

[0016] Further, the blood pressure measuring device may further include blood pressure measuring means for measuring the actually measured blood pressure value and operation input means, and when the actually measured blood pressure value acquisition unit receives an input instructing measurement of the actually measured blood pressure value via the operation input unit, it measures the actually measured blood pressure value by the blood pressure measuring means to obtain the actually measured blood pressure value.

[0017] According to this, since the actual measurement of the blood pressure value by the blood pressure measuring means is performed by the operation of the user, the user can perform blood pressure measurement after sufficiently preparing for the actual measurement of the blood pressure value. That is, it is possible to prevent the measurement of the actually measured blood pressure value from being executed at an unexpected timing or an inconvenient timing for the user.

[0018] Further, the present invention can also be regarded as a blood pressure measurement system having the following configuration. That is, feature quantity acquisition means for acquiring one or more feature quantities related to the estimation of the blood pressure value of the human body, blood pressure value calculation means for calculating an estimated blood pressure value based on the feature quantity, actually measured blood pressure value acquisition means for acquiring an actually measured blood pressure value measured by a method different from the calculation by the blood pressure value calculation means, calibration determination means for determining whether or not the feature quantity acquired by the feature quantity acquisition unit deviates from a predetermined reference value, and when it is determined that there is a deviation, determining to acquire the actually measured blood pressure value, calibration processing means for calibrating the algorithm for calculating the estimated blood pressure value by the blood pressure value calculation unit using the actually measured blood pressure value, and having, the calibration processing means changes the reference value based on the actually measured blood pressure value acquired by the determination of the calibration determination unit and the estimated blood pressure value calculated using the feature quantity that has deviated from the reference value, which is a blood pressure measurement system characterized by this.

[0019] With such a configuration, each means can be configured without being integrated, and as an entire system, it is possible to provide a function for solving problems. Therefore, it is possible to reduce the burden on the user in a flexible way, such as narrowing down the functions of the devices owned and used by the user.

[0020] Also, the blood pressure measurement system may include a measuring device having at least one or more sensors for detecting at least the feature amount, and an information processing device having at least the calibration processing means.

[0021] With such a configuration, the configuration processing means for performing complex arithmetic processing can be a separate dedicated information processing terminal, and by communicating with a server or the like installed at a location remote from the measuring device used by the user, it is possible to construct a cloud system capable of calibrating the algorithms of the measuring devices of individual users.

[0022] Also, the measuring device may further include blood pressure measurement means for measuring the actually measured blood pressure value. Further, the measuring device may be a wearable device that can be constantly worn on the human body. The present invention is suitable for performing non-invasive continuous blood pressure measurement daily using a system having such a configuration.

[0023] In addition, each of the above configurations and processes can be combined with each other to constitute the present invention as long as no technical contradiction occurs.

Effects of the Invention

[0024] According to the present invention, it is possible to provide a technology capable of optimizing the frequency of calibrating a blood pressure value calculation algorithm according to a user when estimating the blood pressure of a human body using a feature amount related to the estimation of the blood pressure value.

Brief Description of the Drawings

[0025] [Figure 1]Figure 1 is a schematic diagram showing a blood pressure measuring device according to Embodiment 1 of the present invention. [Figure 2] Figure 2 is a first diagram illustrating the external appearance of a blood pressure measuring device according to Embodiment 1. [Figure 3] Figure 3 is a second diagram illustrating the external appearance of the blood pressure measuring device according to Embodiment 1. [Figure 4] Figure 4 is a diagram illustrating a cross-section of a blood pressure measuring device according to Embodiment 1. [Figure 5] Figure 5 is a block diagram illustrating the hardware configuration of the control system of the blood pressure measuring device according to Embodiment 1. [Figure 6] Figure 6 is a block diagram illustrating the software configuration of a blood pressure measuring device according to Embodiment 1. [Figure 7] Figure 7 is a flowchart showing an example of the processing flow by the blood pressure measuring device according to Embodiment 1. [Figure 8] Figure 8 is a schematic diagram showing a blood pressure measurement system according to Embodiment 2 of the present invention. [Figure 9] Figure 9 is a block diagram illustrating the schematic functional configuration of each element of the blood pressure measurement system according to Embodiment 2. [Figure 10] Figure 10 is a schematic diagram showing a blood pressure measurement system according to Embodiment 3 of the present invention. [Figure 11] Figure 11 is a block diagram illustrating the schematic functional configuration of each element of the blood pressure measurement system according to Embodiment 3. [Modes for carrying out the invention]

[0026] <Embodiment 1> Specific embodiments of the present invention will be described below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, etc., of the components described in the following embodiments are not included. This limitation is not intended to limit the scope of this invention to those examples only.

[0027] (overview) Figure 1 is a schematic diagram illustrating a blood pressure measuring device 10 according to one embodiment. The blood pressure measuring device 10 is a wearable device that is attached to the user's upper arm, which is the site to be measured. The blood pressure measuring device 10 generally comprises a belt portion 120, a first blood pressure measurement unit 130, a second blood pressure measurement unit 140, a calibration determination unit 150, an instruction unit 160, and a calibration processing unit 170.

[0028] The belt portion 120 comprises a belt 121 and a main body 122. The belt 121 refers to a band-shaped member that wraps around the upper arm and may also be called by other names such as a band or cuff. The belt 121 has an inner surface and an outer surface. The inner surface is the surface that contacts the user's upper arm when the user is wearing the blood pressure measuring device 10 (hereinafter simply referred to as "wearing state"), and the outer surface is the surface opposite the inner surface.

[0029] The main body 122 is attached to the belt 121. The main body 122, along with the operation unit 1221 and the display unit 1222, houses components such as the control unit 1501 (shown in Figure 5), which will be described later. The operation unit 1221 is an input device that allows the user to input instructions for the blood pressure measuring device 10. In the example in Figure 1, the operation unit 1221 includes a plurality of push buttons. The display unit 1222 is a display device that displays information such as messages prompting the user to perform blood pressure measurement and blood pressure measurement results. As the display device, for example, a liquid crystal display (LCD) or an OLED (Organic Light Emitting Diode) display can be used. A touchscreen that serves as both a display device and an input device may also be used. The main body 122 may be provided with a sound-producing element such as a speaker or a piezoelectric sounder. The main body 122 may also be provided with a microphone so that the user can input instructions by voice.

[0030] The first blood pressure measurement unit 130 non-invasively measures the user's pulse wave time (PTT) and calculates a blood pressure value based on the measured pulse wave time (PTT). Hereinafter, the blood pressure value calculated based on the pulse wave time in this manner will also be referred to as the estimated blood pressure value. The first blood pressure measurement unit 130 can perform continuous blood pressure measurement to obtain a blood pressure value for each heartbeat.

[0031] The second blood pressure measurement unit 140 measures blood pressure using a different method than the first blood pressure measurement unit 130. Specifically, the second blood pressure measurement unit 140 measures blood pressure at a specific timing, for example, in response to user operation, using methods such as the oscillometric method or the Korotkoff method. The second blood pressure measurement unit 140 cannot perform continuous blood pressure measurement, but it can measure blood pressure more accurately than the first blood pressure measurement unit 130. Hereinafter, the blood pressure value measured by the second blood pressure measurement unit 140 will also be referred to as the actual blood pressure value.

[0032] The first blood pressure measurement unit 130 is equipped with the following functional modules: an electrocardiogram acquisition unit 131, a pulse wave signal acquisition unit 132, a pulse wave propagation time calculation unit 133, and a blood pressure value calculation unit 134.

[0033] The electrocardiogram acquisition unit 131 is equipped with multiple electrodes and uses these electrodes to acquire the user's electrocardiogram (ECG). The electrocardiogram represents the electrical activity of the heart. The electrodes are provided on the belt portion 120. For example, the electrodes are arranged on the inner surface of the belt 121 so that when worn, the electrodes are in contact with the skin of the user's upper arm.

[0034] The pulse wave signal acquisition unit 132 is equipped with a pulse wave sensor and uses the pulse wave sensor to acquire a pulse wave signal representing the user's pulse wave. The pulse wave sensor is provided on the belt portion 120. For example, the pulse wave sensor is positioned on the inner circumference of the belt 121, so that when worn, the pulse wave sensor can detect the user's pulse wave. It is designed to be in contact with the skin of the upper arm. However, some types of pulse wave sensors, such as the pulse wave sensor based on the Radio Law described later, do not need to be in contact with the skin of the user's upper arm when worn.

[0035] The pulse wave propagation time calculation unit 133 calculates the pulse wave propagation time based on the time difference between the waveform feature points of the electrocardiogram acquired by the electrocardiogram acquisition unit 131 and the waveform feature points of the pulse wave signal acquired by the pulse wave signal acquisition unit 132. For example, the pulse wave propagation time calculation unit 133 calculates the time difference between the waveform feature points of the electrocardiogram and the waveform feature points of the pulse wave signal and outputs the calculated time difference as the pulse wave propagation time. In this embodiment, the pulse wave propagation time corresponds to the time required for the pulse wave to propagate through the artery from the heart to the upper arm (specifically, the position where the pulse wave sensor is placed).

[0036] The blood pressure calculation unit 134 calculates the blood pressure value based on the pulse wave propagation time calculated by the pulse wave propagation time calculation unit 133 and the blood pressure calculation formula. The blood pressure calculation formula is a relational expression that represents the correlation between pulse wave propagation time and blood pressure. An example of the blood pressure calculation formula is shown below. SBP = A1 / PTT 2 +A2···(1) Here, SBP represents systolic blood pressure, PTT represents pulse wave time, and A1 and A2 are parameters.

[0037] The pulse wave propagation time calculation unit 133 can calculate the pulse wave propagation time for each heartbeat, and therefore, the blood pressure value calculation unit 134 can calculate the blood pressure value for each heartbeat.

[0038] The calibration determination unit 150 monitors a predetermined feature (for example, PTT in this embodiment) acquired by the first blood pressure measurement unit 130 and determines whether the feature has deviated from a predetermined reference value (for example, upper and lower threshold limits). If it determines that the feature has deviated from the predetermined reference value, it decides to acquire the user's actual blood pressure value.

[0039] When the calibration determination unit 150 decides to acquire actual blood pressure values, the instruction unit 160 outputs information instructing the second blood pressure measurement unit 140 to perform blood pressure measurement. For example, the instruction unit 160 outputs a notification sound (e.g., a melody) through a sound-producing device and displays the message "Please perform blood pressure measurement" on the display unit 1222. When the user presses a predetermined button in response to the instruction from the instruction unit 160, the second blood pressure measurement unit 140 performs blood pressure measurement. Blood pressure measurement by the second blood pressure measurement unit 140 will be described later.

[0040] The calibration processing unit 170 calibrates the blood pressure calculation formula (1) based on the actual blood pressure values ​​measured by the second blood pressure measurement unit 140. Since the correlation between pulse wave propagation time and blood pressure expressed by the blood pressure calculation formula differs for each individual user, it is necessary to calibrate the blood pressure calculation formula for each user. The calibration of the blood pressure calculation formula (specifically, the determination of parameters A1 and A2) is performed based on the actual blood pressure values ​​obtained by the second blood pressure measurement unit 140. Details regarding the calibration of the blood pressure calculation formula will be described later.

[0041] As described above, in the blood pressure measurement device 10, multiple electrodes used to acquire an electrocardiogram and a pulse wave sensor used to acquire a pulse wave signal are both provided on the belt portion 120. This makes it possible to attach the electrodes and pulse wave sensor to the user simply by wrapping the belt portion 120 around the upper arm. Therefore, it is easy for the user to attach the device, and the user's reluctance to wear the blood pressure measurement device 10 can be reduced.

[0042] Furthermore, the time difference between the waveform feature points of the electrocardiogram and the waveform feature points of the pulse wave signal in the upper arm is calculated as the pulse wave propagation time. The pulse wave propagation time obtained by the blood pressure measuring device 10 is a larger value compared to when the pulse wave propagation time is measured between two points in the upper arm. In other words, a longer pulse wave propagation distance is ensured. Therefore, the waveform feature points of the electrocardiogram and the waveform feature points of the pulse wave signal The impact of errors in calculating the time difference between points on the pulse wave propagation time is reduced, allowing for accurate measurement of the pulse wave propagation time. As a result, the reliability of blood pressure values ​​obtained by blood pressure measurement based on pulse wave propagation time is improved.

[0043] (Example configuration) The blood pressure measuring device 10 will be described in more detail below. An example of the configuration of the blood pressure measuring device 10 according to this embodiment will be described with reference to Figures 2 to 6. Figures 2 and 3 are plan views illustrating the external appearance of the blood pressure measuring device 10. Specifically, Figure 2 shows the blood pressure measuring device 10 viewed from the outer circumferential surface 1211 side of the belt 121 when the belt 121 is unfolded, and Figure 3 shows the blood pressure measuring device 10 viewed from the inner circumferential surface 1212 side of the belt 121 when the belt 121 is unfolded. Figure 4 shows a cross-section of the blood pressure measuring device 10 in the worn state.

[0044] The belt 121 includes an attachment member that allows the belt 121 to be attached to and detached from the upper arm. In the example shown in Figures 2 and 3, the attachment member is a hook fastener having a loop surface 1213 with multiple loops and a hook surface 1214 with multiple hooks. The loop surface 1213 is located on the outer circumferential surface 1211 of the belt 121 and is positioned at the longitudinal end 1215A of the belt 121. The longitudinal direction corresponds to the circumferential direction of the upper arm when worn. The hook surface 1214 is located on the inner circumferential surface 1212 of the belt 121 and is positioned at the longitudinal end 1215B of the belt 121. The end 1215B faces the end 1215A in the longitudinal direction of the belt 121. When the loop surface 1213 and the hook surface 1214 are pressed together, the loop surface 1213 and the hook surface 1214 are joined. Furthermore, by pulling the loop surface 1213 and the hook surface 1214 apart from each other, the loop surface 1213 and the hook surface 1214 can be separated.

[0045] As shown in Figure 3, an electrode group 1311 for measuring an electrocardiogram is arranged on the inner circumferential surface 1212 of the belt 121. In the example in Figure 3, the electrode group 1311 has six electrodes 1312 aligned at regular intervals along the longitudinal direction of the belt 121. The spacing between the electrodes 1312 is set, for example, to one-quarter of the upper arm circumference of the hypothetical thinnest user. In this arrangement, as shown in Figure 4, for the hypothetical thinnest user, when worn, four of the six electrodes 1312 are in contact with the upper arm UA and are equally spaced on the circumference of the upper arm, while the remaining two electrodes 1312 are in contact with the outer circumferential surface of the belt 121. In Figure 4, the humerus UAB and brachial artery UAA are shown. For the hypothetical thickest user, when worn, all six electrodes 1312 are in contact with the upper arm UA.

[0046] Note that the number of electrodes 1312 is not limited to six, but may be 2 to 5 or 7 or more. If two or three electrodes 1312 are in contact with the upper arm, the electrocardiogram may not be measured properly depending on how the device is attached. If the electrocardiogram cannot be measured properly, it is necessary to display a message on the display unit 1222 or otherwise ask the user to readjust the blood pressure measuring device 10. To avoid a situation where the electrocardiogram cannot be measured, it is desirable that at least four electrodes 1312 are in contact with the upper arm when the device is attached.

[0047] The closer the electrode 1312 is positioned to the heart when worn, the larger the signal representing the electrical activity of the heart obtained using the electrode 1312 becomes, i.e., the higher the signal-to-noise ratio (S / N ratio). Preferably, as shown in Figure 3, the electrode 1312 is positioned in the central portion 1217A of the belt 121. The central portion 1217A is the part that is positioned centrally (towards the shoulder) of the centerline 1216 when worn. More preferably, the electrode 1312 is positioned in the central end 1218A of the belt 121. The central end 1218A is the end that is positioned centrally when worn, and the width of the central end 1218A is, for example, one-third of the total width of the belt 121.

[0048] The inner circumferential surface 1212 of the belt 121 is further equipped with a sensor section 1322 of a pulse wave sensor 1321 for measuring pulse waves. In the example shown in Figure 3, the sensor section 1322 includes a pair of electrodes 1323A and 1323D for energizing the upper arm, and a pair of electrodes 1323B and 1323C for detecting voltage. The electrodes 1323A, 1323B, 1323C, and 1323D are arranged in this order in the width direction of the belt 121. The width direction of the belt 121 is aligned with the brachial artery (UAA) when worn.

[0049] Furthermore, the further the sensor unit 1322 is located from the heart when worn, the longer the pulse wave propagation distance becomes, and the larger the measured pulse wave propagation time. As a result, the error that occurs when calculating the time difference between the waveform feature points of the electrocardiogram and the waveform feature points of the pulse wave signal becomes relatively smaller with respect to the pulse wave propagation time, allowing for accurate measurement of the pulse wave propagation time. Preferably, the sensor unit 1322 is located in the peripheral portion 1217B of the belt 121. The peripheral portion 1217B is the part located distal (elbow side) to the center line 1216 when worn. More preferably, the sensor unit 1322 is located in the peripheral end 1218C of the belt 121. The peripheral end 1218C is the end located distally when worn, and the width of the peripheral end 1218C is, for example, one-third of the total width of the belt 121. The portion 1218B between the central end 1218A and the peripheral end 1218C is referred to as the intermediate portion.

[0050] As shown in Figure 4, the belt 121 includes an inner fabric 1210A, an outer fabric 1210B, and a pressure cuff 1401 provided between the inner fabric 1210A and the outer fabric 1210B. The pressure cuff 1401 is a long, strip-like body in the longitudinal direction of the belt 121 so as to be able to surround the upper arm. For example, the pressure cuff 1401 is constructed as a fluid bag by placing two stretchable polyurethane sheets opposite each other in the thickness direction and welding their peripheries together. The electrode group 1311 and the sensor part 1322 are provided on the inner fabric 1210A so as to be positioned between the pressure cuff 1401 and the upper arm UA when worn.

[0051] Figure 5 illustrates an example of the hardware configuration of the control system of the blood pressure measuring device 10 according to this embodiment. In the example in Figure 5, the main unit 122 is equipped with, in addition to the operation unit 1221 and display unit 1222 described above, a control unit 1501, a memory unit 1505, a battery 1506, a switch circuit 1313, a subtraction circuit 1314, an analog front end (AFE) 1315, a pressure sensor 1402, a pump 1403, a valve 1404, an oscillation circuit 1405, and a pump drive circuit 1406. The pulse wave sensor 1321 is equipped with, in addition to the sensor unit 1322 described above, an energization and voltage detection circuit 1324. In this example, the energization and voltage detection circuit 1324 is mounted on the belt 121.

[0052] The control unit 1501 includes a CPU (Central Processing Unit) 1502, RAM (Random Access Memory) 1503, ROM (Read Only Memory) 1504, etc., and controls each component according to information processing. The storage unit 1505 is an auxiliary storage device such as a hard disk drive (HDD) or semiconductor memory (e.g., flash memory), and non-volatilely stores programs executed by the control unit 1501 (e.g., pulse wave propagation time measurement program and blood pressure measurement program), setting data necessary for executing the programs, blood pressure measurement results, etc. The storage medium provided by the storage unit 1505 is a medium that stores information such as programs recorded on it by electrical, magnetic, optical, mechanical, or chemical action so that computers and other devices, machines, etc., can read the information such as programs recorded on it. Note that part or all of the program may be stored in the ROM 1504.

[0053] The battery 1506 supplies power to components such as the control unit 1501. The battery 1506 is, for example, a rechargeable battery.

[0054] Each electrode 1312 in the electrode group 1311 is connected to an input terminal of a switch circuit 1313. The two output terminals of the switch circuit 1313 are each connected to two input terminals of a subtraction circuit 1314. The switch circuit 1313 receives a switch signal from the control unit 1501 and connects the two electrodes 1312 specified by the switch signal to the subtraction circuit 1314. The subtraction circuit 1314 subtracts the potential input from one input terminal from the potential input from the other input terminal. The subtraction circuit 1314 outputs a potential difference signal representing the potential difference between the two connected electrodes 1312 to the AFE 1315. The subtraction circuit 1314 is, for example, an instrumentation amplifier. The AFE 1315 includes, for example, a low-pass filter (LPF), an amplifier, and an analog-to-digital converter. The potential difference signal is filtered by the LPF, amplified by the amplifier, and converted to a digital signal by the analog-to-digital converter. The potential difference signal, converted into a digital signal, is supplied to the control unit 1501. The control unit 1501 acquires the potential difference signal output from the AFE1315 in time series as an electrocardiogram.

[0055] The current and voltage detection circuit 1324 flows a high-frequency constant current between electrodes 1323A and 1323D. For example, the current frequency is 50 kHz and the current value is 1 mA. With current flowing between electrodes 1323A and 1323D, the current and voltage detection circuit 1324 detects the voltage between electrodes 1323B and 1323C and generates a detection signal. The detection signal represents the change in electrical impedance due to the pulse wave propagating through the artery opposite electrodes 1323B and 1323C. The current and voltage detection circuit 1324 performs signal processing on the detection signal, including rectification, amplification, filtering, and analog-to-digital conversion, and provides the detection signal to the control unit 1501. The control unit 1501 acquires the detection signal output from the current and voltage detection circuit 1324 in time series as a pulse wave signal.

[0056] The pressure sensor 1402 is connected to the pressure cuff 1401 via piping, and the pump 1403 and valve 1404 are also connected to the pressure cuff 1401 via piping. These pipes may be a single common pipe or separate pipes. The pump 1403 is, for example, a piezoelectric pump, and supplies air as a fluid to the pressure cuff 1401 through the piping to increase the pressure inside the pressure cuff 1401. The valve 1404 is mounted on the pump 1403 and is configured to open and close according to the operating state (on / off) of the pump 1403. Specifically, when the pump 1403 is turned on, the valve 1404 is closed, and when the pump 1403 is turned off, the valve 1404 is open. When the valve 1404 is open, the pressure cuff 1401 communicates with the atmosphere, and the air inside the pressure cuff 1401 is discharged into the atmosphere. Valve 1404 also functions as a check valve, preventing air from flowing back. The pump drive circuit 1406 drives the pump 1403 based on the control signal received from the control unit 1501.

[0057] The pressure sensor 1402 detects the pressure inside the compression cuff 1401 (also called cuff pressure) and generates an electrical signal representing the cuff pressure. The cuff pressure is, for example, a pressure relative to atmospheric pressure. The pressure sensor 1402 is, for example, a piezoresistive pressure sensor. The oscillation circuit 1405 oscillates based on the electrical signal from the pressure sensor 1402 and outputs a frequency signal having a frequency corresponding to the electrical signal to the control unit 1501. In this example, the output of the pressure sensor 1402 is used to control the pressure in the compression cuff 1401 and to calculate blood pressure values ​​(including systolic and diastolic blood pressure) by the oscillometric method.

[0058] The compression cuff 1401 may be used to adjust the contact between the electrode 1312 or the sensor portion 1322 of the pulse wave sensor 1321 and the upper arm (UA). For example, when performing blood pressure measurement based on pulse wave propagation time, the compression cuff 1401 is kept to contain a certain amount of air. This ensures that the electrode 1312 and the sensor portion 1322 of the pulse wave sensor 1321 make reliable contact with the upper arm (UA).

[0059] In the example shown in Figures 2 to 5, there is an electrode group 1311, a switch circuit 1313, and a subtraction circuit 1 314 and AFE1315 correspond to the electrocardiogram acquisition unit 131 of the first blood pressure measurement unit 130 shown in Figure 1, and the pulse wave sensor 1321 (electrode 1323 and energization and voltage detection circuit 1324) corresponds to the pulse wave signal acquisition unit 132 of the first blood pressure measurement unit 130. In addition, the pressure cuff 1401, pressure sensor 1402, pump 1403, valve 1404, oscillation circuit 1405, and pump drive circuit 1406 correspond to the second blood pressure measurement unit 140.

[0060] Regarding the specific hardware configuration of the blood pressure measuring device 10, components can be omitted, replaced, and added as appropriate depending on the embodiment. For example, the control unit 1501 may include multiple processors. The blood pressure measuring device 10 may also include a communication unit 1507 for communicating with an external device such as the user's mobile terminal (e.g., a smartphone). The communication unit 1507 includes a wired communication module and / or a wireless communication module. As a wireless communication method, for example, Bluetooth®, BLE (Bluetooth Low Energy), etc. can be used.

[0061] Figure 6 illustrates an example of the software configuration of the blood pressure measuring device 10 according to this embodiment. In the example shown in Figure 6, the blood pressure measuring device 10 includes an electrocardiogram measurement control unit 1601, an electrocardiogram storage unit 1602, a pulse wave measurement control unit 1603, a pulse wave signal storage unit 1604, a pulse wave propagation time calculation unit 133, a blood pressure value calculation unit 134, a blood pressure calculation formula storage unit 1605, an estimated blood pressure value storage unit 1606, a calibration determination unit 150, an instruction unit 160, a blood pressure measurement control unit 1608, an actual blood pressure value storage unit 1609, a display control unit 1607, an instruction input unit 1610, a calibration processing unit 170, and a calibration determination criterion value storage unit 1611. The electrocardiogram measurement control unit 1601, pulse wave measurement control unit 1603, pulse wave propagation time calculation unit 133, blood pressure value calculation unit 134, calibration determination unit 150, instruction unit 160, blood pressure measurement control unit 1608, display control unit 1607, instruction input unit 1610, and calibration processing unit 170 perform the following processes when the control unit 1501 of the blood pressure measuring device 10 executes a program stored in the memory unit 1505. When the control unit 1501 executes a program, the control unit 1501 loads the program into the RAM 1503. Then, the control unit 1501 has the CPU 1502 interpret and execute the program loaded into the RAM 1503 and control each component. The electrocardiogram storage unit 1602, pulse wave signal storage unit 1604, blood pressure calculation formula storage unit 1605, estimated blood pressure value storage unit 1606, measured blood pressure value storage unit 1609, and calibration judgment criterion value storage unit 1611 are all implemented by the storage unit 1505.

[0062] The electrocardiogram measurement control unit 1601 controls the switch circuit 1313 to acquire an electrocardiogram. Specifically, the electrocardiogram measurement control unit 1601 generates a switch signal to select two of the six electrodes 1312 and provides this switch signal to the switch circuit 1313. The electrocardiogram measurement control unit 1601 acquires the potential difference signal obtained using the two selected electrodes 1312 and stores the time-series data of the acquired potential difference signal as an electrocardiogram in the electrocardiogram storage unit 1602.

[0063] When the user attaches the blood pressure measuring device 10 to their upper arm, the electrocardiogram measurement control unit 1601 determines the optimal electrode pair for acquiring an electrocardiogram. For example, the electrocardiogram measurement control unit 1601 acquires an electrocardiogram for each of the electrode pairs and determines the electrode pair that provides the electrocardiogram with the largest R wave amplitude as the optimal electrode pair. Subsequently, the electrocardiogram measurement control unit 1601 measures the electrocardiogram using the optimal electrode pair.

[0064] The pulse wave measurement control unit 1603 controls the energization and voltage detection circuit 1324 to acquire a pulse wave signal. Specifically, the pulse wave measurement control unit 1603 instructs the energization and voltage detection circuit 1324 to flow current between electrodes 1323A and D, and acquires a detection signal indicating the voltage between electrodes 1323B and 1323C detected while current is flowing between electrodes 1323A and D. The pulse wave measurement control unit 1603 stores the time-series data of the detection signal as a pulse wave signal in the pulse wave signal storage unit 1604.

[0065] The pulse wave propagation time calculation unit 133 reads the electrocardiogram from the electrocardiogram storage unit 1602 and the pulse wave signal from the pulse wave signal storage unit 1604, and calculates the pulse wave propagation time based on the time difference between the waveform feature points of the electrocardiogram and the waveform feature points of the pulse wave signal. For example, the pulse wave propagation time calculation unit 133 detects the time (time) of the peak point corresponding to the R wave from the electrocardiogram, detects the time (time) of the rising point from the pulse wave signal, and calculates the pulse wave propagation time as the difference between the rising point time and the peak point time.

[0066] The pulse wave propagation time calculation unit 133 may also correct the above time difference based on the preejection period (PEP) and output the corrected time difference as the pulse wave propagation time. For example, assuming that the preejection period is constant, the pulse wave propagation time calculation unit 133 may calculate the pulse wave propagation time by subtracting a predetermined value from the above time difference.

[0067] The peak point corresponding to the R wave is an example of a waveform feature point in an electrocardiogram (ECG). The waveform feature point in an ECG may also be the peak point corresponding to the Q wave or the peak point corresponding to the S wave. Since the R wave appears as a more distinct peak compared to the Q wave or S wave, the time of the R wave peak can be more accurately determined. For this reason, the R wave peak is preferably used as the waveform feature point in an ECG. The rising edge is another example of a waveform feature point in a pulse wave signal. The waveform feature point in a pulse wave signal may also be a peak point. Because pulse wave signals change slowly over time, errors are likely to occur when determining the time of waveform feature points in a pulse wave signal.

[0068] Referring to Figure 6, the blood pressure value calculation unit 134 calculates an estimated blood pressure value based on the pulse wave propagation time calculated by the pulse wave propagation time calculation unit 133 and the blood pressure calculation formula. The blood pressure value calculation unit 134 uses the algorithm for blood pressure value calculation (specifically, for example, formula (1) above) stored in the blood pressure calculation formula storage unit 1605 as the blood pressure calculation formula. The blood pressure value calculation unit 134 stores the calculated blood pressure value in the estimated blood pressure value storage unit 1606, associating it with time information.

[0069] Note that the blood pressure calculation formula is not limited to formula (1) above. The blood pressure calculation formula may also be, for example, the following formula. SBP = B1 / PTT 2 +B2 / PTT+B3×PTT+B4···(2) Here, B1, B2, B3, and B4 are parameters.

[0070] The calibration determination unit 150 determines whether the conditions for recommending the measurement of the user's blood pressure have been met, based on predetermined feature quantities related to blood pressure estimation, such as the pulse wave propagation time calculated by the pulse wave propagation time calculation unit 133, and predetermined reference values ​​for said feature quantities stored in the calibration determination reference value storage unit 1611. Even if the blood pressure calculation formula has been calibrated at the start of use of the device, the accuracy of the calculated estimated blood pressure value may be low if the feature quantities related to the calculation of the estimated blood pressure value deviate from predetermined reference values ​​(upper and lower threshold limits). In such cases, it is desirable to perform an accurate blood pressure measurement using the second blood pressure measurement unit 140 and compare it with the actual blood pressure value to confirm the accuracy of the estimated blood pressure value, and if the accuracy is low (i.e., the difference between the actual blood pressure value and the estimated blood pressure value is large), it is desirable to calibrate the blood pressure calculation formula.

[0071] As another example, the calibration determination unit 150 may determine whether the rate of change in blood pressure exceeds a threshold as a predetermined feature quantity. The rate of change in blood pressure is, for example, the amount of change in blood pressure value per unit time. Specifically, the calibration determination unit 150 determines whether the difference obtained by subtracting the blood pressure value from the latest blood pressure value from the blood pressure value from the unit time ago exceeds a threshold. The latest systolic blood pressure value is SBP0, the systolic blood pressure value from the unit time ago is SBP1, and the threshold is V th Therefore, the calibration determination unit 150 determines that SBP0 - SBP1 > V th It determines whether the given condition is met. The unit time is, for example, 30 seconds, and the threshold is, for example, 20 [mmHg]. The value of the latest pulse wave propagation time is used to determine PT If T0 is the pulse wave propagation time value from a unit time ago, then the above conditional equation can be rearranged using equation (1) to get A1(1 / PTT0 2 -1 / PTT1 2 )>V th This is the result.

[0072] In other words, the calibration determination unit 150 may use the pulse wave propagation time itself, or it may use the blood pressure value calculated based on the pulse wave propagation time. Alternatively, the calibration determination unit 150 may determine whether the difference between the latest blood pressure value and the blood pressure value from a predetermined number of heartbeats ago (e.g., 30 beats ago) exceeds a threshold. In another example, the calibration determination unit 150 determines whether the latest systolic blood pressure value exceeds a threshold (e.g., 150 [mmHg]). This threshold may be fixed or variable. For example, the higher the user's average blood pressure, the higher the threshold value may be set.

[0073] When the calibration determination unit 150 decides to acquire the actual blood pressure value, the instruction unit 160 outputs information instructing the second blood pressure measurement unit 140 to perform blood pressure measurement. For example, the instruction unit 160 gives an instruction signal to the display control unit 1607 to display a message prompting the user to perform blood pressure measurement on the display unit 1222. Furthermore, the instruction unit 160 outputs a control signal to control the drive circuit that drives the sound-producing element in order to generate a notification sound. The instruction unit 160 may also transmit an instruction signal to the user's mobile terminal via the communication unit 1507, thereby prompting the user to perform blood pressure measurement through the mobile terminal.

[0074] The instruction input unit 1610 receives instructions from the user using the operation unit 1221. For example, when an operation is made to instruct the execution of blood pressure measurement, the instruction input unit 1610 gives a blood pressure measurement start instruction to the blood pressure measurement control unit 1608. The instruction input unit 1610 and the operation unit 1221 correspond to the operation input unit according to the present invention.

[0075] The blood pressure measurement control unit 1608 controls the pump drive circuit 1406 to perform blood pressure measurement. When the blood pressure measurement control unit 1608 receives an instruction to start blood pressure measurement from the instruction input unit 1610, it drives the pump 1403 via the pump drive circuit 1406. This starts the supply of air to the compression cuff 1401. The compression cuff 1401 inflates, thereby compressing the user's upper arm. The blood pressure measurement control unit 1608 monitors the cuff pressure using the pressure sensor 1402. During the pressurization process of supplying air to the compression cuff 1401, the blood pressure measurement control unit 1608 calculates the blood pressure value using the oscillometric method based on the pressure signal output from the pressure sensor 1402. The blood pressure value includes, but is not limited to, systolic blood pressure (SBP) and diastolic blood pressure (DBP). The blood pressure measurement control unit 1608 stores the calculated blood pressure value in the measured blood pressure value storage unit 1609, associating it with time information. The blood pressure measurement control unit 1608 can calculate the pulse rate simultaneously with the blood pressure value. Once the blood pressure measurement control unit 1608 has finished calculating the blood pressure value, it stops the pump 1403 via the pump drive circuit 1406. As a result, air is exhausted from the pressure cuff 1401 through the valve 1404.

[0076] The display control unit 1607 controls the display unit 1222. For example, the display control unit 1607 receives an instruction signal from the instruction unit 160 and displays the message contained in the instruction signal on the display unit 1222. Also, after the blood pressure measurement control unit 1608 has completed blood pressure measurement, the display control unit 1607 displays the blood pressure measurement result on the display unit 1222.

[0077] The calibration processing unit 170 calibrates the blood pressure calculation formula based on the estimated blood pressure value obtained by the blood pressure value calculation unit 134 and the measured blood pressure value obtained by the blood pressure measurement control unit 1608. In addition, the calibration of the blood pressure calculation formula by the calibration processing unit 170 may be performed as an initial setting, for example, when the user puts on the blood pressure measurement device 10. The correlation between pulse wave propagation time and blood pressure value differs from person to person. Furthermore, the correlation changes depending on how the blood pressure measurement device 10 is attached to the user's upper arm. For example, even for the same user, the correlation changes when the blood pressure measurement device 10 is positioned closer to the shoulder compared to when it is positioned closer to the elbow. To reflect such changes in the correlation, the blood pressure calculation formula Calibration is performed.

[0078] The calibration processing unit 170 also modifies the reference values ​​stored in the calibration judgment reference value storage unit 1611. Specifically, for example, it calculates the difference between the estimated blood pressure value when the calibration judgment unit 150 decides to acquire the actual blood pressure value and the actual blood pressure value. If the difference is large, it modifies the reference value so that the frequency of calibration increases; if the difference is small, it modifies the reference value so that the frequency of calibration decreases.

[0079] In this embodiment, an example is described in which all functions of the blood pressure measuring device 10 are implemented by a general-purpose processor. However, some or all of the functions may be implemented by one or more dedicated processors.

[0080] (Example of operation) Next, an example of the operation of the blood pressure measuring device 10 according to this embodiment will be described with reference to Figure 7. Figure 7 is a flowchart showing an example of the processing flow performed by the blood pressure measuring device 10. First, when a user uses the blood pressure measuring device 10 for the first time, the initial calibration of the blood pressure calculation formula is performed (S101). In this process, the control unit 1501 operates as a calibration processing unit 170. If the number of parameters included in the blood pressure calculation formula is N, then at least N sets of pulse wave propagation time measurements and blood pressure measurements are required. The blood pressure calculation formula (1) above has two parameters A1 and A2. In this case, for example, the control unit 1501 acquires a set of pulse wave propagation time measurements and blood pressure measurements when the user is at rest, and then has the user exercise, and acquires a set of pulse wave propagation time measurements and blood pressure measurements after the exercise. As a result, two sets of pulse wave propagation time measurements and blood pressure measurements are acquired. The control unit 1501 determines parameters A1 and A2 based on the two acquired sets of pulse wave propagation time measurements and blood pressure measurements.

[0081] Following this, a reference value is set for determining whether or not to acquire actual blood pressure values ​​(S102). The reference value at this time may be calculated according to the determined parameters A1 and A2, or a general-purpose reference value may be set. The reference value set here is stored in the calibration judgment reference value storage unit 1611.

[0082] After the initial calibration is completed, blood pressure measurement (estimation) based on pulse wave propagation time becomes possible, and continuous, non-invasive blood pressure measurement is performed by repeating the following loop process L1 until predetermined termination conditions are met.

[0083] In loop processing L1, the following processes are repeatedly executed. First, the control unit 1501 continuously calculates the pulse wave propagation time to calculate the estimated blood pressure value (S103). Furthermore, it calculates the estimated blood pressure value based on the calculated pulse wave propagation time and the blood pressure calculation formula stored in the blood pressure calculation formula storage unit (S104). Next, it performs a process to determine whether the calculated pulse wave propagation time deviates from the reference value stored in the calibration judgment reference value storage unit 1611 (S105). The reference value may be, for example, an upper threshold or a lower threshold for pulse wave propagation time. It may also be an upper or lower threshold that defines a predetermined numerical range. That is, in step S105, if the reference value is an upper threshold, it is determined whether it exceeds the reference value, and if the reference value is a lower threshold If the value is a threshold, it is determined whether it is below the standard value. If the standard value is an upper or lower threshold, it is determined whether it falls within a predetermined numerical range between those thresholds.

[0084] If it is determined in step S105 that the value does not deviate from the reference value, the process returns to step S103 and the subsequent processes are repeated. On the other hand, if it is determined in step S105 that the value deviates from the reference value, the process proceeds to step S106, where it is decided that the actual blood pressure value measured by the second blood pressure measurement unit 140 should be obtained for the calibration of the blood pressure calculation formula. In the process of step S105, the control unit 1501 functions as a calibration determination unit 150.

[0085] In step S106, the control unit 1501 performs control to output information instructing the second blood pressure measurement unit 140 to perform blood pressure measurement. In step S106, the control unit 1501 operates as an instruction unit 160. Then, upon receiving a command from the user to start blood pressure measurement via the operation unit 1221, the process of acquiring the actual blood pressure value by the second blood pressure measurement unit 140 is performed (S107). In step S107, the control unit 1501 operates as a blood pressure measurement control unit 1608.

[0086] When an actual blood pressure value is obtained, the control unit 1501 calibrates the blood pressure calculation formula stored in the blood pressure calculation formula storage unit 1605 based on this value (S108), and also performs a process to determine whether the difference between the estimated blood pressure value and the actual blood pressure value is greater than or equal to a predetermined threshold (S109).

[0087] If the difference is greater than or equal to a threshold, the reference value stored in the calibration judgment reference value storage unit 1611 is changed so that the frequency with which the instruction unit 160 instructs to acquire the actual blood pressure value increases (S110). Specifically, if the reference value is the upper and lower limit threshold of pulse wave propagation time, the upper limit threshold is decreased and the lower limit threshold is increased, that is, the numerical range determined by the upper and lower limit thresholds is narrowed. In this way, the calculated pulse wave propagation time is more likely to deviate from the upper and lower limit thresholds than before the reference value was changed, and as a result, the frequency with which the instruction unit 160 instructs to acquire the actual blood pressure value increases.

[0088] On the other hand, if it is determined in step S108 that the difference is less than the threshold, the reference value is changed so that the frequency with which the indicator unit 160 instructs to acquire the actual blood pressure value decreases (S111). Specifically, contrary to the case in step S110 above, if the reference value is the upper and lower threshold limits for pulse wave propagation time, the upper threshold limit is increased and the lower threshold limit is decreased, that is, the numerical range determined by the upper and lower threshold limits is expanded. In this way, the calculated pulse wave propagation time is less likely to deviate from the upper and lower threshold limits than before the reference value was changed, and as a result, the frequency with which the indicator unit 160 instructs to acquire the actual blood pressure value decreases.

[0089] When the processing in step S110 or step S111 is executed, the series of loop processing L1 ends, and the process returns to the starting point of loop processing L1 (i.e., step S103) and a new loop processing L1 is executed. During the processing from step S108 to step S111, the control unit 1501 functions as the calibration processing unit 170.

[0090] Note that the processing procedure shown in Figure 7 is an example, and the processing order or the content of each process can be changed as appropriate. For example, in the above processing procedure, step S108 is used to calibrate the blood pressure calculation formula, and then step S109 is used to determine whether the difference between the measured blood pressure value and the estimated blood pressure value is greater than or equal to a predetermined threshold. However, this order can be reversed, and the process of determining whether the difference between the measured blood pressure value and the estimated blood pressure value is greater than or equal to a predetermined threshold can be performed first. Furthermore, if the difference is less than the predetermined threshold, the calibration of the blood pressure calculation formula can be omitted.

[0091] Furthermore, in the above processing procedure, if the difference is greater than or equal to a predetermined threshold in step S109, the reference value is changed to increase the calibration frequency, and otherwise, the reference value is changed to decrease the calibration frequency. However, the threshold may be set as an upper and lower limit. That is, if the difference is greater than or equal to the upper threshold, the reference value may be changed to increase the calibration frequency, if the difference is less than or equal to the lower threshold, the reference value may be changed to decrease the calibration frequency, and if the difference does not deviate from the upper or lower threshold, the reference value may not be changed.

[0092] (effect) As described above, in the blood pressure measuring device 10 according to this embodiment, the electrode group 1311 and pulse wave sensor Both the electrode group 1311 and the pulse wave sensor 1321 are mounted on the belt 121. Therefore, by simply wrapping the belt 121 around the upper arm, both the electrode group 1311 and the pulse wave sensor 1321 are attached to the user. Thus, the user can easily put on the blood pressure measuring device 10. Since the user only needs to wear one device, the user's reluctance to wear the blood pressure measuring device 10 is reduced.

[0093] Furthermore, since the blood pressure measuring device 10 is attached to the upper arm, blood pressure is measured at approximately the same height as the heart. This eliminates the need to perform height correction on the acquired blood pressure measurement results. In addition, if the blood pressure measuring device 10 is an upper arm type, it can be hidden by the sleeve of clothing, making it less noticeable that the blood pressure measuring device 10 is being worn.

[0094] Furthermore, since the pulse wave propagation time is calculated based on the electrocardiogram and the pulse wave signal obtained for the upper arm, the pulse wave propagation time can be obtained over a long distance from the heart to the upper arm. This improves robustness against errors that occur when calculating the time difference between the waveform feature points of the electrocardiogram and the waveform feature points of the pulse wave signal. In addition, the electrode group 1311 is placed on the central part 1217A of the belt 121, and the sensor part 1322 of the pulse wave sensor 1321 is placed on the peripheral part 1217B of the belt 121. This arrangement ensures a longer pulse wave propagation distance and allows for the acquisition of an electrocardiogram with a high signal-to-noise ratio. This further improves robustness. As a result, it becomes possible to accurately measure the pulse wave propagation time, and the reliability of the blood pressure value calculated based on the pulse wave propagation time is improved.

[0095] Furthermore, in this embodiment, blood pressure measurement based on pulse wave propagation time and blood pressure measurement using the oscillometric method can be performed with a single device, making it highly convenient for the user. In addition, since the second blood pressure measurement unit 140 is integrated with the first blood pressure measurement unit 130, and the blood pressure calculation formula is calibrated based on the actual blood pressure value obtained by the second blood pressure measurement unit 140, the blood pressure measurement device 10 can be calibrated on its own. This makes it easy to calibrate the blood pressure calculation formula.

[0096] Then, based on the results of continuous blood pressure measurement by the first blood pressure measurement unit 130, it is determined whether or not the user's actual blood pressure value should be acquired (i.e., whether or not the algorithm for calculating blood pressure needs to be calibrated). If the conditions are met, the user is notified that blood pressure measurement should be performed by the second blood pressure measurement unit 140. This allows the user to perform accurate blood pressure measurement in situations where blood pressure measurement is recommended.

[0097] Furthermore, by changing the reference value of a predetermined feature that serves as the criterion for determining whether or not to acquire actual blood pressure values, according to the difference between the actual blood pressure value and the estimated blood pressure value (i.e., the accuracy of the estimated blood pressure value), the frequency of acquiring actual blood pressure values ​​can be optimized. This allows for repeated calibration of the blood pressure calculation algorithm to improve the accuracy of blood pressure estimation according to the user, and provides a technology that can optimize the frequency of calibration of the blood pressure calculation algorithm.

[0098] (modified version) In the embodiments described above, the pulse wave sensor employs an impedance method to detect changes in impedance associated with changes in arterial volume. However, the pulse wave sensor may employ other measurement methods such as the photoelectric method, piezoelectric method, or radio wave method. In embodiments employing the photoelectric method, the pulse wave sensor comprises a light-emitting element that irradiates light toward the artery passing through the measurement site, and a photodetector that detects the reflected or transmitted light, thereby detecting changes in light intensity associated with changes in arterial volume. In embodiments employing the piezoelectric method, the pulse wave sensor comprises a piezoelectric element provided on a belt so as to be in contact with the measurement site, thereby detecting changes in pressure associated with changes in arterial volume. In embodiments employing the radio wave method, a transmitting element transmits radio waves toward the artery passing through the measurement site, and a receiving element receives the reflected waves of the radio waves. It comprises a receiving element and detects the phase difference between the transmitted wave and the reflected wave due to changes in arterial volume.

[0099] The blood pressure measuring device 10 may further include a pressure cuff for adjusting the contact state between the sensor portion 1322 of the pulse wave sensor 1321 and the upper arm, a pump for supplying air to the pressure cuff, a pump drive circuit for driving the pump, and a pressure sensor for detecting the pressure inside the pressure cuff. The pressure cuff is provided at the distal end 1218C of the belt 121. In this case, the pressure cuff 1401 is provided, for example, at the middle portion 1218B of the belt 121.

[0100] The part involved in measuring pulse wave propagation time may be implemented as a standalone device. In one embodiment, a pulse wave propagation time measuring device is provided, comprising a belt section 120, an electrocardiogram acquisition section 131, a pulse wave signal acquisition section 132, and a pulse wave propagation time calculation section 133. This pulse wave propagation time measuring device may further include a calibration determination section 150 and an indicator section 160. The pulse wave propagation time measuring device may further include a pressure cuff, a pump, and a pump drive circuit for pressing the electrode 1312 and the pulse wave sensor 1321 against the upper arm.

[0101] The blood pressure measuring device 10 does not necessarily have to include a second blood pressure measuring unit 140. In embodiments in which the blood pressure measuring device 10 does not include a second blood pressure measuring unit 140, it is necessary to input blood pressure values ​​obtained by measuring with another blood pressure monitor into the blood pressure measuring device 10 in order to calibrate the blood pressure calculation formula.

[0102] <Embodiment 2> In the above embodiment 1, the present invention was applied as a blood pressure measuring device, and all functions, including the memory unit, blood pressure value calculation unit, and display unit, were integrated into a single device. However, the present invention can also be applied as a blood pressure measuring system in which some of these components and functions are separated. Figures 8 and 9 show examples of such blood pressure measuring systems.

[0103] Figure 8 shows a schematic of the blood pressure measurement system 2 according to this embodiment. As shown in Figure 8, the blood pressure measurement system 2 includes a sensor device 21 that is attached to the user's upper arm and an information processing terminal 22 that processes the biological information acquired by the sensor device 21. The sensor device 21 is a wearable device equipped with multiple electrodes (electrocardiogram sensors) and a pulse wave sensor (not shown), and is used by being fixed to the user's upper arm by a fixing means such as a belt. The information processing terminal 22 can be any device that can communicate with the sensor device 21, but for example, as shown in Figure 8, a smartphone can be used as the information processing terminal 22.

[0104] Figure 9 is a block diagram showing the functional configuration of the sensor device 21 and information processing terminal 22 of the blood pressure measurement system 2. The sensor device 21 has functional units including an electrode unit 211, a pulse wave sensor unit 212, a control unit 210, a storage unit 213, an operation unit 214, a power supply unit 215, and a communication unit 216. The control unit 210 also includes an electrocardiogram acquisition unit 201 and a pulse wave signal acquisition unit 202 as its functional modules.

[0105] The pulse wave sensor unit 212 and pulse wave signal acquisition unit 202 in the sensor device 21 can employ, for example, a photoelectric method. Specifically, it includes a light-emitting element that irradiates light toward the artery passing through the measurement site, and a photodetector that detects the reflected or transmitted light, thereby detecting changes in light intensity accompanying changes in arterial volume (neither of which are shown). Furthermore, the electrode unit 211 and electrocardiogram acquisition unit 201 can have the same configuration as the blood pressure measuring device 10 of Embodiment 1, so a detailed explanation is omitted.

[0106] Furthermore, the memory unit 213 only has main memory such as RAM or ROM, and its storage capacity is limited. The operation unit 214 also has a limited configuration, such as a power switch, and is simply constructed. The power supply unit 215 can be, for example, a rechargeable secondary battery. The signal unit 216 includes a wired communication module and / or a wireless communication module. The connection terminals for wired communication may also serve as the charging terminals for the power supply unit 215.

[0107] Thus, the sensor device 21 in this embodiment has a configuration that has only very limited functions for acquiring biological information for calculating estimated blood pressure values. For this reason, the electrocardiogram signals and pulse wave signals measured by each sensor unit are transmitted in real time to the information processing terminal 22 via the communication unit 216.

[0108] The information processing terminal 22 comprises the following functional units: a control unit 220, a display unit 225, an operation unit 226, a communication unit 227, and a storage unit 228. The control unit 220 also includes functional modules: a blood pressure value calculation unit 221, a calibration determination unit 222, an actual blood pressure value acquisition unit 223, and a calibration processing unit 224.

[0109] The information processing terminal 22 communicates with the sensor device 22 via the communication unit 227 and receives the user's electrocardiogram signal and pulse wave signal measured by the sensor device 21. The communication standard is not particularly limited, but communication can be performed using wireless communication standards such as Bluetooth®, Wi-Fi®, and infrared communication. The hardware configuration of the information processing terminal 22 is the same as that of a smartphone, for example, the touch panel display serves as both the display unit 225 and the operation unit 226.

[0110] The biological information received from the sensor device 21 via the communication unit 227 is stored in the storage unit 228, and various processes, such as the calculation of estimated blood pressure values, are performed based on the stored information. The storage unit 228, like the storage unit 1505 of the blood pressure measuring device 10 in Embodiment 1, stores not only electrocardiogram and pulse wave signals, but also information such as the algorithm for calculating blood pressure values, the criteria for determining whether calibration is necessary, estimated blood pressure values, and actual blood pressure values.

[0111] The blood pressure value calculation unit 221, the calibration determination unit 222, and the calibration processing unit 224 are functional modules that perform the following processes, similar to the blood pressure measuring device 10 of Embodiment 1: calculation of estimated blood pressure values, determination of whether or not to perform algorithmic calibration using measured blood pressure values, algorithmic calibration processing for blood pressure calculation, and modification of the reference value for determining whether or not calibration is necessary. Since these processes are the same as in Embodiment 1, a further explanation is omitted here.

[0112] The actual blood pressure value acquisition unit 223 executes a process to acquire the actual blood pressure value when the calibration determination unit 222 determines that calibration of the blood pressure calculation algorithm using the actual blood pressure value is necessary. In this embodiment, the user is notified to input the actual blood pressure value, for example, via the display unit 225 or a speaker (not shown). The user measures the actual blood pressure value using another device (not shown) capable of accurate blood pressure measurement, such as the oscillometric method, and inputs the blood pressure value into the information processing terminal 22 by operating the operation unit 226. That is, the actual blood pressure value acquisition unit 223 acquires the actual blood pressure value via the operation unit 226. The acquired actual blood pressure value is stored in the storage unit 228.

[0113] In this embodiment, the blood pressure measurement system 2 uses a sensor device 21 to sense biological information (e.g., electrocardiogram and pulse wave signals) for continuous estimated blood pressure calculation, while the actual blood pressure calculation process, calibration necessity determination process, and algorithm calibration process are performed by an information processing terminal 22. This configuration simplifies the structure of the wearable device and further reduces the burden on the user when wearing the device. Furthermore, since it is possible to utilize existing information processing terminals such as smartphones, the cost for users to introduce the system can be reduced.

[0114] <Embodiment 3> In the above embodiment, an example was described in which blood pressure is measured daily and continuously using a dedicated wearable blood pressure measurement device. However, the present invention can be implemented without using such a dedicated blood pressure measurement device. Figures 10 and 11 show examples of blood pressure measurement systems in such cases.

[0115] Figure 10 shows a schematic of the blood pressure measurement system 3 according to this embodiment. As shown in Figure 10, the blood pressure measurement system 3 is configured such that a body composition analyzer 31, a blood pressure measuring device 32, and a server 33 are connected via a communication network N. The communication network N is, for example, a WAN (Wide Area Network), which is a global public communication network such as the Internet. Communication networks (N) and other communication networks may be used. Furthermore, communication network N may include telephone communication networks such as mobile phones, and wireless communication networks such as Wi-Fi (registered trademark).

[0116] The body composition analyzer 31 generally consists of a main body 31A and a handle 31B. Although not shown in the diagram, it also includes communication means for communication, sensors (e.g., strain gauges, electrodes, speed sensors, etc.) for acquiring various biological information such as weight, body fat percentage, electrocardiogram, pulse wave signal, and ballistocardiogram (BCG), as well as an output unit such as a liquid crystal display, an input unit such as operation buttons, and a power supply unit.

[0117] The blood pressure measuring device 32 is a general household blood pressure measuring device having a main body 32A and a cuff 32B, and is equipped with various elements for oscillometric blood pressure measurement such as a pressure sensor, a pressure cuff, and a pump, as well as an output unit such as a liquid crystal display and an input unit such as operation buttons.

[0118] Server 33 is composed of a typical server computer and is equipped with a processor such as a CPU, main memory such as RAM and ROM, and auxiliary storage devices such as EPROM, HDD, and removable media.

[0119] Figure 11 is a block diagram showing the functional configuration of the blood pressure measurement system 3. The body composition analyzer includes an electrocardiogram acquisition unit 311, a pulse wave signal acquisition unit 312, a pulse wave propagation time calculation unit 313, a blood pressure value calculation unit 314, a calibration determination unit 315, a memory unit 316, and a communication unit 317.

[0120] The electrocardiogram acquisition unit 311 acquires the user's electrocardiogram via electrodes placed on the upper surface of the main body 31A and the handle portion 31B of the body composition analyzer 31. The pulse wave signal acquisition unit 312 acquires the user's pulse wave signal (peripheral pulse wave) via a pulse wave sensor placed on the handle portion 31B. The pulse wave sensor may be an impedance type or a photoelectric type. The acquired electrocardiogram and pulse wave signal are stored in the storage unit 316. In addition to this biological information, the storage unit 316 also stores a blood pressure calculation algorithm, a judgment criterion value for determining whether calibration is necessary, etc., similar to the blood pressure measuring device 10 of Embodiment 1.

[0121] The pulse wave propagation time calculation unit 313 reads the electrocardiogram and pulse wave signals from the memory unit 316 and calculates the pulse wave propagation time based on the time difference between the waveform feature points of the electrocardiogram and the waveform feature points of the pulse wave signal. The blood pressure value calculation unit 314 calculates the blood pressure value based on the calculated pulse wave propagation time and the blood pressure calculation algorithm stored in the memory unit 316. The calibration determination unit 315 determines whether or not the blood pressure calculation algorithm should be calibrated based on the calculated pulse wave propagation time and a predetermined reference value stored in the memory unit 316. Since each of these processes is the same as in the case of the blood pressure measuring device 10 of Embodiment 1, a detailed explanation is omitted here.

[0122] If the calibration determination unit 315 determines that the blood pressure calculation algorithm needs calibration, it notifies the user of this fact via a display unit (not shown) or the like, and transmits the estimated blood pressure value at the time of the calibration determination to the server 33 via the communication unit 317 and network N. ru.

[0123] The blood pressure measuring device 32 includes a blood pressure measurement unit 321 and a communication unit 322 as functional units. The blood pressure measurement unit 321 is a functional unit that performs accurate blood pressure measurement by means such as the oscillometric method, and can have a configuration similar to the second blood pressure measurement unit 140 in the blood pressure measuring device 10 of form 1, so its description is omitted here. The actual blood pressure value measured by the blood pressure measurement unit 321 is transmitted to the server 33 via the communication unit 322 and the network N.

[0124] Server 33 comprises a calibration processing unit 331, a storage unit 332, and a communication unit 333. Information transmitted from the body composition analyzer 31 and the blood pressure measuring device 32 and received by the communication unit 333 (such as estimated blood pressure values ​​and actual blood pressure values) is stored in the storage unit 332. Based on the estimated blood pressure values ​​and actual blood pressure values ​​stored in the storage unit 332, the calibration processing unit 331 performs processing for calibrating the blood pressure calculation algorithm of the body composition analyzer 31. Specifically, it calculates more appropriate parameter values ​​based on the estimated blood pressure values ​​and actual blood pressure values, and transmits the newly calculated parameter data to the body composition analyzer 31 via the communication unit 333 and the network N. The blood pressure calculation algorithm stored in the storage unit 316 of the body composition analyzer 31 is then updated to a new algorithm using the new parameters, thereby calibrating the blood pressure calculation algorithm.

[0125] Furthermore, the calibration processing unit 331 also performs the process of changing the reference value used in the judgment process performed by the calibration judgment unit 315, similar to embodiments 1 and 2. In this case as well, similar to the calibration of the algorithm, the server 33 calculates a new reference value, transmits the calculated new reference value to the body composition analyzer 31, and stores the new reference value in the storage unit 316, thereby changing the reference value.

[0126] As described above, in the blood pressure measurement system 3 of this embodiment, the acquisition of biological information for calculating estimated blood pressure values ​​is performed using a general-purpose body composition analyzer 31, rather than using a dedicated device. Furthermore, the calibration processing unit 331 is not located in the body composition analyzer 31, but is executed on the server 33. This eliminates the need for complex calculation processing for algorithm calibration to be performed on the measuring instrument side, allowing blood pressure values ​​to be measured (estimated) using a general-purpose body composition analyzer, and the algorithm to be calibrated as needed. In other words, it becomes possible to maintain a high accuracy of estimated blood pressure values ​​even when using a general-purpose body composition analyzer. In this embodiment, the body composition analyzer 31 was configured to include a handle 31B, but it is also possible to use a body composition analyzer without a handle 31B.

[0127] <Other> The embodiments described above are merely illustrative examples of the present invention, and the present invention is not limited to the specific forms described above. The present invention can be modified and combined in various ways within the scope of its technical concept. For example, in each of the above examples, the feature quantity used to determine whether calibration of the blood pressure calculation algorithm is necessary was pulse wave propagation time, but the determination of whether calibration of the algorithm is necessary may be made based on other feature quantities. For example, in Embodiment 3, it is possible to obtain information such as weight, BMI, electrocardiogram, and pulse wave velocity (PWV) from various sensors provided by the body composition analyzer 31, and these feature quantities can also be used for blood pressure estimation. That is, these feature quantities can also be used to determine whether calibration of the algorithm is necessary. In addition, the height at the inflection point of the pulse wave or electrocardiogram shape, the slope between two inflection points, the area between the two inflection points, and the ratio thereof may also be used as feature quantities for determining whether calibration of the algorithm is necessary. Furthermore, information related to heart rate (e.g., difference from the previous beat, difference from the average beat), personal user attribute information (height, age, medication history, etc.), information related to the conditions at the time of measurement (user activity level, posture, etc.), and environmental information (season, external temperature, etc.) may also be used as features.

[0128] Furthermore, in Embodiment 1 described above, an example was explained in which both the upper and lower threshold values ​​are changed when the reference value is an upper and lower threshold for pulse wave propagation time. However, the modification of the reference value is not limited to this, and various patterns can be set. For example, the reference value can be set to either an upper threshold or a lower threshold. When a lower threshold is used, increasing the reference value can increase the frequency of calibration, and decreasing the reference value can decrease the frequency of calibration. Also, when the reference value is an upper and lower threshold, either only the upper threshold or only the lower threshold may be changed. Even in such cases, the width of the numerical range in which the feature should fit can be changed, and the frequency of calibration can be changed accordingly.

[0129] Furthermore, the devices used to measure biometric information are not limited to those exemplified in the embodiments described above; for example, they may be devices such as so-called smartwatches. Also, the measurement site is not limited to the upper arm or wrist; measuring devices that are attached to other parts of the body, such as the thigh or ankle, may also be used. [Explanation of Symbols]

[0130] 10… Blood pressure measuring device, 120...Belt section, 121...Belt, 122...Main body, 130...First blood pressure measurement unit, 131...Electrocardiogram acquisition unit, 132...Pulse wave signal acquisition unit, 133...Pulse wave propagation time calculation unit, 134...Blood pressure value calculation unit, 140...Second blood pressure measurement unit, 150...Calibration and judgment unit, 160...Indicator unit, 1210A...Inner fabric, 1210B...Outer fabric, 1213...Loop side, 1214...Hook side, 1221...Operating section, 1222...Display section 1311…Electrode group, 1312…Electrode, 1313…Switch circuit, 1314…Subtraction circuit, 1315…Analog front end, 1321…Pulse wave sensor, 1322…Sensor unit, 1323A~1323D…Electrode, 1324…Energy and voltage detection circuit, 1401...Pressure cuff, 1402...Pressure sensor, 1403...Pump, 1404...Valve, 1405...Oscillation circuit, 1406...Pump drive circuit, 1501...Control unit, 1502...CPU, 1503...RAM, 1504...ROM 1505...Memory unit, 1506...Battery, 1507...Communication unit, 1601...ECG measurement control unit, 1602...ECG memory unit, 1603...Pulse wave measurement control unit, 1604...Pulse wave signal memory unit, 1605...Blood pressure calculation formula memory unit, 1606...Estimated blood pressure value memory unit, 1607...Display control unit, 1608...Blood pressure measurement control unit, 1609...Measured blood pressure value memory unit, 1610...Instruction input unit, 1611...Calibration judgment criterion value memory unit UA...Upper arm, UAA...Brachial artery, UAB...Humerus 2, 3… Blood pressure measurement system 21...Sensor device, 22 Information processing terminal 31...Body composition analyzer, 31A...Main unit, 31B...Handle unit 32... Blood pressure measuring device, 32A... Main unit, 32B... Cuff 33... Server N... Network

Claims

1. a feature acquisition unit for acquiring one or more feature values ​​related to an estimation of a blood pressure value of a human body; a blood pressure value calculation unit for calculating an estimated blood pressure value based on the feature amount; an actual blood pressure value acquiring unit that acquires an actual blood pressure value measured by a method different from that calculated by the blood pressure value calculating unit; a calibration determination unit that determines whether the feature acquired by the feature acquisition unit deviates from a predetermined reference value, and when it is determined that the feature deviates, determines to acquire the actual blood pressure value; and a calibration processing unit that calibrates a calculation algorithm of the estimated blood pressure value by the blood pressure value calculation unit using the actual blood pressure value, the calibration processing unit changes the reference value based on the actual blood pressure value acquired by the determination of the calibration determination unit and the estimated blood pressure value calculated using the feature amount deviating from the reference value. A blood pressure measuring device comprising:

2. When a difference between the actual blood pressure value acquired by the determination of the calibration determination unit and the estimated blood pressure value calculated using the feature amount deviating from the reference value is equal to or smaller than a predetermined threshold, the calibration processing unit changes the reference value to a value that reduces the frequency with which the actual blood pressure value is determined to be acquired.

2. The blood pressure measuring device according to claim 1 .

3. The calibration processing unit includes: If the reference value is an upper threshold value for the feature amount, the reference value is increased; If the reference value is a lower threshold value for the feature amount, the value of the reference value is decreased; In the case where the reference value is an upper or lower threshold value that defines a numerical range for the feature amount, the upper threshold value is increased and / or the lower threshold value is decreased.

3. The blood pressure measuring device according to claim 2.

4. When a difference between the actual blood pressure value acquired by the determination of the calibration determination unit and the estimated blood pressure value calculated using the feature amount deviating from the reference value exceeds a predetermined threshold, the calibration processing unit changes the reference value to a value that increases the frequency with which the actual blood pressure value is determined to be acquired.

2. The blood pressure measuring device according to claim 1 .

5. The calibration processing unit includes: If the reference value is an upper threshold value for the feature amount, the value of the reference value is decreased; If the reference value is a lower threshold value for the feature amount, the value of the reference value is increased; When the reference value is an upper or lower threshold value that defines a numerical range for the feature amount, the upper threshold value is decreased and / or the lower threshold value is increased.

5. The blood pressure measuring device according to claim 4.

6. The device further includes an output means, When the calibration determination unit determines that the actual blood pressure value should be acquired, the output unit outputs information indicating that the actual blood pressure value should be acquired.

6. The blood pressure measuring device according to claim 1, wherein the blood pressure measuring device is a blood pressure measuring device.

7. The blood pressure measuring device further includes a blood pressure measuring means for measuring the actual blood pressure value. When the calibration determination unit determines to acquire the actual blood pressure value, the actual blood pressure value acquisition unit acquires the actual blood pressure value by measuring the actual blood pressure value using the blood pressure measurement means.

7. The blood pressure measuring device according to claim 1, wherein the blood pressure measuring device is a blood pressure measuring device.

8. The blood pressure measuring device further includes a blood pressure measuring means for measuring the actual blood pressure value and an operation input means, the actual blood pressure value acquisition unit, when receiving an input instructing measurement of the actual blood pressure value via the operation input means, acquires the actual blood pressure value by measuring the actual blood pressure value using the blood pressure measurement means; 7. The blood pressure measuring device according to claim 1, wherein the blood pressure measuring device is a blood pressure measuring device.

9. A feature acquisition means for acquiring one or more feature values ​​related to the estimation of a blood pressure value of a human body; a blood pressure value calculation means for calculating an estimated blood pressure value based on the feature amount; an actual blood pressure value acquiring means for acquiring an actual blood pressure value measured by a method different from that calculated by the blood pressure value calculating means; a calibration determination means for determining whether the feature acquired by the feature acquisition means deviates from a predetermined reference value, and, if it is determined that the feature deviates, determining to acquire the actual blood pressure value; a calibration processing means for calibrating a calculation algorithm of the estimated blood pressure value by the blood pressure value calculation means using the actual blood pressure value, the calibration processing means changes the reference value based on the actual blood pressure value acquired by the determination of the calibration determination means and the estimated blood pressure value calculated using the feature amount deviating from the reference value. A blood pressure measuring system comprising:

10. The blood pressure measurement system comprises: A measuring device including one or more sensors for detecting at least the feature amount, and an information processing device including at least the calibration processing means.

10. The blood pressure measurement system according to claim 9.

11. The measuring device further includes a blood pressure measuring means for measuring the actual blood pressure value.

11. The blood pressure measurement system according to claim 10.

12. The measuring device is a wearable device that can be permanently attached to the human body.

12. A blood pressure measurement system according to claim 10 or 11.

Images