Biological signal measuring device, method and program

Abstract

To measure biological information without omission in the event of a change in the condition of a subject while suppressing power consumption.SOLUTION: A biological signal related to pulsations of the heart of a subject is acquired from a biological sensor. A feature amount is detected from the acquired biological signal, and on the basis of the detected feature amount and first threshold information set beforehand, an abnormal change in the feature amount is determined. An operation mode of the biological sensor is set to a continuous operation mode when an abnormal change in the feature amount is determined while the operation mode of the biological sensor is set to an intermittent operation mode in other periods.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] One aspect of the present invention relates to a biosignal measuring device, a method, and a program for measuring, for example, a human biosignal. [Background technology]

[0002] One example of a biological signal is the pulse wave. The pulse wave is a periodic waveform signal that is generated when the aorta vibrates in response to the beating of the heart. The propagation speed of the pulse wave flowing through the artery (PWV) is correlated with the volume elasticity of the blood vessel, and the volume elasticity increases as the blood pressure increases. Therefore, by determining the propagation speed of the pulse wave, it is possible to estimate the blood pressure and the progress of arteriosclerosis. The pulse wave propagation speed can be determined, for example, by measuring the pulse transit time (PTT), which is the time it takes for a pulse wave to propagate between two different points on an artery.

[0003] Incidentally, a known technique for measuring the pulse wave transit time (PTT) is to calculate the pulse wave transit time based on the output of an electrocardiogram (ECG) sensor attached to a person's torso and the output of a photoelectric sensor using a photoelectric volume pulse wave measuring method (Plethysmography (PPG)) attached to the ear when measuring blood pressure, as described in Patent Document 1. Another known measurement technique is to calculate the pulse wave transit time based on the pulse waves measured by PPG sensors placed at two different points on an artery when measuring blood pressure, as described in Patent Document 2, for example.

[0004] However, PPG sensors used to measure pulse wave transit time generally use light emitting diodes (LEDs) as light emitting elements, and consume more power than other biosensors such as ECG sensors. For this reason, for example, if you try to measure blood pressure continuously while sleeping (for example, for 8 hours) using a blood pressure monitor that uses a PPG sensor, there is a risk that the battery capacity will be insufficient and measurement will not be possible throughout the measurement period.

[0005] Therefore, the present inventors have proposed reducing power consumption by causing the light emitting element of the PPG sensor to emit light intermittently. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5984088 [Patent Document 2] Japanese Patent Application Publication No. 7-327940 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when the light emitting element of the PPG sensor is operated to emit light intermittently, the pulse wave is not detected during the period when the light emission is not performed, and as a result, there may be a gap in the measurement data of the blood pressure value. For this reason, for example, if the blood pressure of the person being measured changes abnormally for some reason while sleeping, even if a medical professional or the like tries to examine the situation of this abnormal change in detail later, the examination work may be hindered due to the gap in the measurement data of the blood pressure value.

[0008] This invention has been made in light of the above-mentioned circumstances, and one aspect of the invention is to provide a technology that can reduce power consumption while also being able to measure vital information without omission when the condition of the person being measured changes. [Means for solving the problem]

[0009] According to one aspect of the present invention, a biosignal measuring device or a biosignal measuring method includes acquiring a biosignal related to the heartbeat of a subject from a biosensor, and calculating a heart rate from the acquired biosignal. Regarding the pulsation Detecting a feature amount, and Amount of change per unit time The first threshold value is set in advance. To More defined threshold and when the amount of change is reduced below the threshold, it is determined that a first change has occurred in the feature amount. The biosensor is configured to set the operation mode of the biosensor to a continuous operation mode when it is determined that the first change has occurred in the feature amount, and to set the operation mode of the biosensor to an intermittent operation mode during the period until it is determined that the first change has occurred. Furthermore, when the period during which the operation mode of the biosensor is set to the continuous operation mode exceeds a preset time, the operation mode of the biosensor is restored to the intermittent operation mode. Effect of the Invention

[0010] According to one aspect of the present invention, when the change in the characteristic amount detected from the biosignal is within the normal range, the biosensor operates in an intermittent operation mode, so that the power consumption of the biosensor is suppressed and the continuous use period of the device can be extended. On the other hand, when the change in the characteristic amount detected from the biosignal is determined to be abnormal, the operation mode of the biosensor is set to a continuous operation mode. Therefore, when the characteristic amount of the biosignal shows an abnormal change, the biosignal can be measured without loss, and thus the biosignal can be examined with high accuracy.

[0011] That is, according to one aspect of the present invention, it is possible to provide a technique that can reduce power consumption during normal operation, while enabling measurement of a biological signal without loss during an abnormal operation. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing an example of the overall configuration of a blood pressure measuring device which is a first embodiment of a biological signal measuring device according to the present invention. [Diagram 2]FIG. 2 is a diagram showing an example of the configuration of the front side of the attachment unit of the blood pressure measurement device shown in FIG. [Diagram 3] FIG. 3 is a diagram showing an example of the configuration of the back side of the attachment unit of the blood pressure measurement device shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view showing an example of a state in which the attachment unit of the blood pressure measuring device shown in FIG. 1 is attached to the upper arm of a subject. [Diagram 5] FIG. 5 is a block diagram showing an example of a hardware configuration of the blood pressure measurement device shown in FIG. [Figure 6] FIG. 6 is a block diagram showing an example of a software configuration of the blood pressure measurement device shown in FIG. [Figure 7] FIG. 7 is a flowchart showing the processing procedure and processing contents of the blood pressure measurement unit of the blood pressure measurement device shown in FIG. [Figure 8] FIG. 8 is a flowchart showing the procedure and contents of the biological abnormality determination and handling process in the flowchart shown in FIG. [Figure 9] FIG. 9 is a waveform diagram for explaining a first operation example of the blood pressure measuring device according to the first embodiment of the present invention. [Figure 10] FIG. 10 is a waveform diagram for explaining a second operation example of the blood pressure measuring device according to the first embodiment of the present invention. [Figure 11] FIG. 11 is a block diagram showing an example of a software configuration of a blood pressure measurement device according to the second embodiment of the present invention. [Figure 12] FIG. 12 is a flowchart showing the processing procedure and processing contents of the blood pressure measurement unit of the blood pressure measurement device shown in FIG. [Figure 13] FIG. 13 is a flowchart showing the procedure and contents of the biological abnormality determination and handling process in the flowchart shown in FIG. [Figure 14] FIG. 14 is a waveform diagram for explaining an operation example of the blood pressure measuring device according to the second embodiment of the present invention. [Figure 15]FIG. 15 is a block diagram showing an example of a software configuration of a blood pressure measurement device according to the third embodiment of the present invention. [Figure 16] FIG. 16 is a flowchart showing the processing procedure and processing contents of the blood pressure measurement unit of the blood pressure measurement device shown in FIG. [Figure 17] FIG. 17 is a flowchart showing the procedure and contents of the biological abnormality determination and handling process in the flowchart shown in FIG. [Figure 18] FIG. 18 is a waveform diagram for explaining an operation example of the blood pressure measuring device according to the third embodiment of the present invention. [Figure 19] FIG. 19 is a diagram showing an example of types of pulse wave feature amounts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to one aspect of the present invention will now be described with reference to the drawings. However, the embodiment described below is merely an example of the present invention in all respects.

[0014] [First embodiment] (Configuration example) (1) Overall configuration of the device Fig. 1 is a diagram showing the overall configuration of a blood pressure measuring device which is a first embodiment of a biological signal measuring device according to the present invention, and Fig. 5 and Fig. 6 are block diagrams showing the hardware and software configurations, respectively, of the blood pressure measuring device shown in Fig. 1.

[0015] The blood pressure measurement device according to the first embodiment is composed of a wearing unit 10 and a blood pressure measurement unit 20 connected to the wearing unit 10. Note that, although Fig. 1 illustrates a case in which the wearing unit 10 and the blood pressure measurement unit 20 are configured as separate bodies, the blood pressure measurement unit 20 may be provided integrally with the wearing unit 10, so that the blood pressure measurement device functions as a so-called wearable device.

[0016] (2) Mounting unit 10 The wearing unit 10 is worn on the upper arm 1 of a person to be measured, as shown in Fig. 1. Fig. 2 shows an example of the configuration of the front side of the wearing unit 10, and Fig. 3 shows an example of the configuration of the back side of the wearing unit 10.

[0017] The wearing unit 10 has a belt part 11 made of, for example, flexible resin or fiber, and a wearing unit circuit part 12 is disposed on the surface side of the belt part 11. The wearing unit circuit part 12 includes an operation part 13, a display part 14, an ECG detection part 32 of an electrocardiographic (ECG) sensor 30 described later, and a pulse drive part 42 of a pulse wave sensor 40.

[0018] The operation unit 13 is, for example, a push button switch, and is used to input instructions to start / end blood pressure measurement, and instructions to display or transmit measured blood pressure data, etc. The display unit 14 uses, for example, liquid crystal or organic EL (Electro Luminescence) as a display device, and is used to display measured blood pressure data, etc. The operation unit 13 and the display unit 14 can also be configured as a tablet-type device in which a touch panel sheet is placed on the display screen of the display unit.

[0019] On the other hand, on the back side of the belt part 11, as shown in Fig. 3, an electrode group 31 of the ECG sensor 30 is arranged in the longitudinal direction of the belt part 11. The electrode group 31 is made up of a plurality of electrodes 311-316 (six in this example) arranged at equal intervals, and detects ECG signals by contacting the skin of the person being measured. The arrangement position of the electrode group 31 in the width direction of the belt part 11 is set to be close to the shoulder of the person being measured, as shown in Fig. 3. This is to enable the ECG sensor 30 to detect ECG signals as close as possible to the heart of the person being measured.

[0020] As illustrated in FIG. 5, the ECG detection unit 32 of the ECG sensor 30 includes a switch circuit 321, a subtraction circuit 322, and an AFE (Analog Front End) 323. The switch circuit 321 selects two of the six electrodes 311 to 316 and connects them to the subtraction circuit 322 in response to a switching control signal output from the control unit 21 of the blood pressure measurement unit 20 described later. The subtraction circuit 322 is, for example, an instrumentation amplifier, and outputs a potential difference between signals output from the two electrodes selected by the switch circuit 321. The AFE 323 includes, for example, a low-pass filter (LPF), an amplifier, and an analog / digital converter. The potential difference signal output from the subtraction circuit 322 is subjected to removal of unnecessary noise components by the LPF, amplified by the amplifier, and then converted into a digital signal by the analog / digital converter, and the converted digital signal is output to the blood pressure measurement unit 20 as an ECG signal.

[0021] A photoelectric sensor 41 of the pulse wave sensor 40 is disposed on the back side of the belt portion 11, approximately at the center in the longitudinal and width directions of the belt portion 11. The photoelectric sensor 41 includes an LED (Light Emitting Diode) 411 as a light emitting element and a PD (Photo Diode) 412 as a light receiving element. The light generated by the LED 411 is irradiated onto the skin surface of the upper arm 1, and the irradiated light is reflected by the skin surface and received by the PD 412. An electrical signal according to the intensity of the received light is output to the pulse driver 42.

[0022] The pulse driver 42 of the pulse wave sensor 40 has an electric current and voltage detection circuit 421. The electric current and voltage detection circuit 421 drives the LED 411 to emit light intermittently or continuously in response to an emission control signal output from the control unit 21 of the blood pressure measurement unit 20. The intermittent emission control operation will be described in detail later. In addition, the electric current and voltage detection circuit 421 removes noise components from the electrical signal output from the PD 412, amplifies the signal to a predetermined level, converts the signal into a digital signal, and outputs a pulse wave signal consisting of the converted digital signal to the blood pressure measurement unit 20.

[0023] Although not shown, a loop surface member and a hook surface member constituting a hook-and-loop fastener are attached to the front and back sides of the belt portion 11, respectively. By using the hook-and-loop fastener, the fitting unit 10 is fixed in a state in which the belt portion 11 is wrapped around the upper arm 1 of the person to be measured in the circumferential direction. Fig. 4 is a cross-sectional view showing an example of the fitting unit 10 being fitted to the upper arm 1.

[0024] (3) Blood pressure measuring unit The blood pressure measurement unit 20 includes a control unit 21 having a hardware processor such as a central processing unit (CPU), and a program storage unit 22, a data storage unit 23, and a communication unit 24 are connected to the control unit 21. The blood pressure measurement unit 20 also includes a power supply circuit 25 built therein.

[0025] The communication unit 24 is used to transmit, for example, measured blood pressure data to an information terminal (not shown) under the control of the control unit 21. As a communication interface, an interface that adopts a low-power data communication standard such as Bluetooth (registered trademark) is used. As an information terminal, for example, a smartphone or a personal computer is used.

[0026] The power supply circuit 25 generates a required power supply voltage Vcc based on the output of the battery 251, and supplies the generated power supply voltage Vcc to each section in the blood pressure measurement unit 20 and the attachment unit circuit section 12 of the attachment unit 10.

[0027] The program storage unit 22 is configured, for example, by combining a non-volatile memory such as an HDD (Hard Disk Drive) or SSD (Solid State Drive) as a storage medium that can be written to and read at any time, and a non-volatile memory such as a ROM (Read Only Memory), and stores, in addition to middleware such as an OS (Operating System), programs necessary for executing various control processes according to one embodiment of the present invention.

[0028] The data storage unit 23 is configured, for example, by combining a non-volatile memory such as an HDD or SSD, which can be written to and read from at any time, as a storage medium, with a volatile memory such as a RAM (Random Access Memory), and is provided with an ECG signal storage unit 231, a pulse wave signal storage unit 232, a PTT data storage unit 233, and a blood pressure data storage unit 234 as main storage areas for implementing the first embodiment of the present invention.

[0029] The ECG signal storage unit 231 is used to store the ECG signal output from the ECG sensor 30 in chronological order. The pulse wave signal storage unit 232 is used to store the pulse wave signal output from the pulse wave sensor 40 in chronological order. The PTT data storage unit 233 is used to store the PTT calculated by the control unit 21, which will be described later. The blood pressure data storage unit 234 is used to store blood pressure data estimated by the control unit 21, which will be described later.

[0030] The control unit 21 includes, as processing functions for carrying out the first embodiment of the present invention, an ECG signal acquisition unit 211, an R-wave peak detection unit 212, a pulse wave signal acquisition unit 213, a pulse wave feature amount detection unit 214, a pulse wave transit time calculation unit 215, a blood pressure estimation unit 216, a biological abnormality determination unit 217, a light emission control unit 218, and a blood pressure data / alarm output unit 219. All of these processing units 211 to 219 are realized by causing a hardware processor of the control unit 21 to execute a program stored in the program storage unit 22.

[0031] The ECG signal acquisition unit 211 performs a process of acquiring an ECG signal output from the ECG detection unit 32 of the ECG sensor 30, and temporarily storing the acquired ECG signal in chronological order in the ECG signal storage unit 231. The R-wave peak detection unit 212 reads the ECG signal from the ECG signal storage unit 231, and performs a process of detecting, for example, an R-wave peak RP, which is one of the feature quantities of the ECG signal, from the ECG signal.

[0032] Pulse wave signal acquirer 213 takes in the pulse wave signal output from pulse driver 42 of pulse wave sensor 40, and performs processing to temporarily store the pulse wave signal in chronological order in pulse wave signal storage unit 232. Pulse wave feature detector 214 reads the pulse wave signal from pulse wave signal storage unit 232, and performs processing to detect one of the feature values ​​of the pulse wave signal, for example, the pulse wave rise point PS, from the pulse wave signal.

[0033] The pulse wave transit time calculation unit 215 calculates the pulse wave transit time (PTT) based on the time difference between the R wave peak RP detected by the R wave peak detection unit 212 and the pulse wave rising edge PS detected by the pulse wave feature amount detection unit 214. Then, a process of storing the calculated PTT value in the PTT data storage unit 233 is performed.

[0034] The blood pressure estimation unit 216 performs a process of estimating the blood pressure value corresponding to the PTT value stored in the PTT data storage unit 233, for example, by using a conversion table indicating the relationship between the PTT and blood pressure value stored in advance in the data storage unit 23, or by using a conversion formula.

[0035] The biological abnormality determination unit 217 reads the PTT data from the PTT data storage unit 233, and monitors the decrease and increase of the PTT value in a unit period. If the PTT value decreases by a preset threshold value or more in a unit period, it determines that an abnormality has occurred in the PTT value. Furthermore, if the PTT value increases by a preset threshold value or more in a unit period after determining that an abnormality has occurred, the biological abnormality determination unit 217 determines that the PTT value has returned to the normal range. Then, it performs a process of notifying the light emission control unit 218 and the blood pressure data / alarm output unit 219 of each of the above determination results.

[0036] The light emission control unit 218 controls the light emission control mode of the pulse wave sensor 40 based on the determination result of the PTT value change notified from the biological abnormality determination unit 217. For example, a mode (continuous light emission drive mode) is set in which the LED 411 of the pulse wave sensor 40 emits light continuously for a preset fixed period from the timing of determining the occurrence of an abnormality, or for the period from the timing of determining the occurrence of an abnormality to the timing of determining recovery from the abnormality. On the other hand, a mode (intermittent light emission drive mode) is set in which the LED 411 of the pulse wave sensor 40 emits light intermittently according to a preset duty ratio for other periods.

[0037] When the blood pressure data alarm output unit 219 is notified of the abnormality determination result from the biological abnormality determination unit 217, it monitors the duration of the abnormality, and when the duration exceeds a preset period, it generates an alarm from a sounder or speaker (not shown).

[0038] When a request to display blood pressure data is input by the operation unit 13, the blood pressure data / alarm output unit 219 reads blood pressure data from the blood pressure data storage unit 234 and performs processing to display the blood pressure data on the display unit 14. When a request to transmit blood pressure data is input by the operation unit 13, the blood pressure data / alarm output unit 219 reads blood pressure data from the blood pressure data storage unit 234 and performs processing to transmit the blood pressure data from the communication unit 24 to an information terminal that is set in advance as a transmission destination.

[0039] (1) Measurement of blood pressure using PTT Next, the operation of the blood pressure measuring device configured as above will be described, taking as an example a case where a person to be measured measures his / her own blood pressure fluctuation while sleeping, for example.

[0040] FIG. 7 is a flowchart showing the processing procedure and processing contents by the control unit 21 of the blood pressure measurement unit 20. The subject first wraps the belt portion 11 of the wearing unit 10 around his / her upper arm 1 and fastens it with a hook-and-loop fastener with the back side of the belt in contact with the skin surface of the upper arm 1. Then, in this state, the subject operates the operation portion 13 provided on the wearing unit 10 to input a measurement start request. This measurement start request also serves as a power-on signal.

[0041] The blood pressure measurement unit 20 monitors input of a measurement start request in step S10. When the measurement start request is input from the wearing unit 10 in this state, the power supply circuit 25 operates under the control of the control unit 21 and starts supplying the power supply voltage Vcc to each part in the device. As a result, the blood pressure measurement unit 20 and the wearing unit 10 enter an operating state.

[0042] When the blood pressure measurement unit 20 is in an operating state, first in step S11, the blood pressure measurement unit 20 sets the intermittent light emission drive mode under the control of the light emission control unit 218. Then, in this intermittent light emission drive mode, the light emission control unit 218 generates an intermittent light emission control signal and supplies it to the pulse drive unit 42 of the pulse wave sensor 40. As a result, the LED 411 is driven to emit light intermittently by the pulse drive unit 42, whereby the pulse wave sensor 40 intermittently outputs a pulse wave signal.

[0043] In the intermittent light emission drive mode, the intermittent light emission pattern is set, for example, so that only the period corresponding to one cardiac cycle per several cardiac cycles is the light emission period, and the remaining period is the off period. The ratio of the light emission period to the off period of the intermittent light emission pattern, that is, the duty ratio, is set to, for example, 25%, but this value can be set arbitrarily according to the power consumption reduction target.

[0044] In this state, in step S12, blood pressure measurement unit 20 acquires an ECG signal output from ECG sensor 30 by ECG signal acquisition unit 211, and stores the ECG signal in chronological order in ECG signal storage unit 231. In addition, in step S13, blood pressure measurement unit 20 acquires a pulse wave signal output from pulse wave sensor 40 by pulse wave signal acquisition unit 213, and stores the pulse wave signal in chronological order in pulse wave signal storage unit 232.

[0045] Then, in step S14, the blood pressure measurement unit 20 reads the ECG signal from the ECG signal storage unit 231 using the R wave peak detection unit 212 and detects the R wave peak RP, which is one of the feature quantities of the ECG signal, and also reads the pulse wave signal from the pulse wave signal storage unit 232 using the pulse wave feature detection unit 214 and detects the pulse wave rise PS, which is one of the feature quantities of the ECG signal.

[0046] Next, in step S15, the blood pressure measurement unit 20 calculates the time difference between the detection timing of the R wave peak RP and the detection timing of the pulse wave rise PS detected in one cardiac cycle using the pulse wave transit time calculation unit 215, and stores the calculated time difference in the PTT data memory unit 233 in the data memory unit 23 as the pulse wave transit time (PTT) value in the one cardiac cycle.

[0047] Next, in step S16, the blood pressure measurement unit 20 reads the PTT value from the PTT data storage unit 233 under the control of the blood pressure estimation unit 216 every time the PTT value of one heartbeat cycle is calculated. Then, by using a previously prepared PTT-blood pressure value conversion table or conversion formula, the blood pressure value corresponding to the PTT value is estimated, and the estimated blood pressure value is linked to the identification information of the heartbeat and stored in the blood pressure data storage unit 234. As a result, the blood pressure value of one heartbeat of the subject is stored in the blood pressure data storage unit 234.

[0048] (2) Display or transmit blood pressure data While executing the above-mentioned series of processes for blood pressure measurement, the blood pressure measurement unit 20 monitors, in step S17, input of a request to display / send blood pressure data via the blood pressure data / alarm output unit 219. Then, for example, when the subject operates the operation unit 13 for a request to display / send, under the control of the blood pressure data / alarm output unit 219, in step S18, blood pressure data is read from the blood pressure data storage unit 234 and displayed on the display unit 14 or transmitted from the communication unit 24 to an information terminal (not shown) such as a smartphone owned by the subject.

[0049] The blood pressure measurement unit 20 monitors the input of a measurement end request in step S19 while executing the above-mentioned blood pressure measurement process. In this state, for example, if the person to be measured performs an operation to request the end of measurement using the operation unit 13, the blood pressure measurement unit 20 ends the blood pressure measurement process and stops the supply of the power supply voltage Vcc from the power supply circuit 25 to each unit. Note that the blood pressure data stored in the blood pressure data storage unit 234 is retained even after the power supply is terminated.

[0050] (3) Identifying and Treating Biological Abnormalities Meanwhile, while the blood pressure measurement unit 20 is performing a series of controls for blood pressure measurement according to the above (1) and a control for displaying or transmitting blood pressure data according to (2), it determines a biological abnormality of the subject in step S20 under the control of the biological abnormality determination section 217, and executes corresponding processing as follows.

[0051] FIG. 8 is a flowchart showing an example of the procedure and contents of the biological abnormality determination process and the corresponding process. First, in step S21, the biological abnormality determination unit 217 reads the PTT value of a past preset unit time (for example, 5 to 6 cardiac cycles) from the PTT data storage unit 233, and calculates the amount of change ΔPTT1 in the read PTT value. Then, in step S22, the calculated amount of change ΔPTT1 in the PTT value is compared with a preset first threshold value, and it is determined whether the amount of change ΔPTT1 has decreased below the first threshold value.

[0052] In this state, for example, suppose that the PTT value changes due to the onset of sleep apnea syndrome, and the amount of change per unit time, ΔPTT1, falls below the first threshold. In response, biological abnormality determination unit 217 determines that an abnormal decrease has occurred in the PTT value, and in step S25 changes the operation mode of pulse wave sensor 40 to continuous light emission drive mode and notifies light emission control unit 218 of this mode. As a result, a continuous light emission control signal is output from light emission control unit 218 to pulse drive unit 42 of pulse wave sensor 40, and thereafter LED 411 of photoelectric sensor 41 performs a continuous light emission operation. As a result, pulse wave sensor 40 continuously detects pulse wave signals, and the continuously detected pulse wave signals are sequentially stored in pulse wave signal storage unit 232 of blood pressure measurement unit 20.

[0053] When the continuous light emission drive mode is set, the biological abnormality determination unit 217 measures the length of the period (abnormal period) during which the PTT value continues to decrease in step S26, and determines in step S27 whether the length of the abnormal period exceeds a preset threshold value Ta. When the length of the abnormal period exceeds the threshold value Ta, an instruction to generate an alarm is given to the blood pressure data / alarm output unit 219 in step S28. As a result, under the control of the blood pressure data / alarm output unit 219, an alarm sound is generated from, for example, a sounder or speaker (not shown) to notify the subject. As described above, if an alarm is generated when the abnormal period exceeds the threshold value Ta, it is possible to prevent an alarm from being generated when a temporary PTT change unrelated to a biological abnormality occurs.

[0054] The alarm may be generated immediately when a sudden decrease in PTT is detected in step S22, and the alarm may be generated by lighting or blinking of a light-emitting element, displaying a warning message on the display unit 14, vibrating, or the like, other than by sound. Furthermore, the alarm may be transmitted to a terminal owned by a family member or a medical professional, thereby notifying the family member or medical professional.

[0055] In a state where the continuous light-emitting operation mode is set, in step S23, the biological abnormality determination unit 217 compares the amount of change ΔPTT2 of the PTT value per unit time calculated in step S21 with a second threshold value set in advance, and determines whether or not the amount of change ΔPTT2 of the PTT value per unit time has increased above the second threshold value. If the result of this determination is that the amount of change ΔPTT2 of the PTT value per unit time does not meet the second threshold value, the biological abnormality determination unit 217 checks the currently set light-emitting operation mode in step S24 and maintains the continuous light-emitting drive mode. Then, steps S26 to S28 are subsequently performed to measure the length of the abnormal period and to control the generation of an alarm according to the length.

[0056] On the other hand, suppose that the subject's biological condition recovers from an apneic state to a normal breathing state, and the amount of change in the PTT value per unit time ΔPTT2 increases by more than the second threshold value. In this case, in step S29, the biological abnormality determination unit 217 resets the value of the abnormal period being timed in step S26, and then returns to step S11 shown in Fig. 7. Then, in step S11, the light emission operation mode of the pulse wave sensor 40 is changed from the continuous light emission drive mode to the intermittent light emission drive mode.

[0057] As a result, an intermittent light emission control signal is output from the light emission control unit 218 of the blood pressure measurement unit 20 to the pulse driver 42 of the pulse wave sensor 40, and the light emission operation mode of the LED 411 of the pulse wave sensor 40 returns to the intermittent light emission operation. Therefore, the pulse wave sensor 40 returns to a state in which it operates with low power consumption.

[0058] (Typical operation example) Next, a description will be given of a representative operation example in the first embodiment. Note that the operation example is not limited to the following example, and various other operation examples are also possible.

[0059] (1) First operation example FIG. 9 is a signal waveform diagram for explaining the first operation example. The blood pressure measurement unit 20 normally drives the pulse wave sensor 40 to emit light intermittently and performs blood pressure measurement operation by the PTT method. During this blood pressure measurement operation, the amount of change ΔPTT1 in the PTT value per unit time is monitored.

[0060] In this state ,time Assume that at time t1, the change amount ΔPTT1 of the PTT per unit time has decreased by more than the first threshold value. In this case, the blood pressure measurement unit 20 determines that an abnormal change in the PTT value due to, for example, the onset of sleep apnea syndrome has been detected, and changes the light emission operation mode of the LED 411 of the pulse wave sensor 40 from the intermittent light emission drive mode to the continuous light emission drive mode. As a result, the LED 411 of the pulse wave sensor 40 continuously emits light and continuously detects the pulse wave signal. Therefore, thereafter, the blood pressure measurement unit 20 becomes able to measure the blood pressure value for each heartbeat based on the continuously detected pulse wave signal without any loss.

[0061] In addition, in the state where the continuous light emission drive mode is set, the blood pressure measurement unit 20 monitors the change amount ΔPTT2 of the PTT value per unit time. Then, for example, at time t2, when the change amount ΔPTT2 of the PTT value per unit time increases beyond the second threshold, the blood pressure measurement unit 20 determines that the PTT value has returned to the normal range, and changes the light emission operation mode of the LED 411 of the pulse wave sensor 40 from the continuous light emission drive mode to the intermittent light emission drive mode.

[0062] As a result, LED 411 of pulse wave sensor 40 emits light intermittently, thus reducing power consumption by pulse wave sensor 40 and extending the life of battery 251. This makes it possible to measure blood pressure for a long period of time without using a large-capacity battery.

[0063] (2) Second operation example FIG. 10 is a signal waveform diagram for explaining the second operation example. The blood pressure measurement unit 20 measures the duration of the continuous light-emitting drive mode while it is set. The continuous light-emitting drive mode is maintained until the duration of the continuous light-emitting drive mode exceeds a threshold value Ta. On the other hand, when the duration of the continuous light-emitting drive mode exceeds the threshold value Ta, the blood pressure measurement unit 20 restores the light-emitting operation mode of the pulse wave sensor 40 to the intermittent light-emitting drive mode. The threshold value Ta is set to a time longer than the onset time of general sleep apnea syndrome by a predetermined length, for example, depending on the length of the onset time of the syndrome.

[0064] According to this second operation example, the blood pressure measurement unit 20 can return the light emission operation mode of the pulse wave sensor 40 to the intermittent light emission drive mode by a simple process that omits the process of monitoring the recovery of the PTT value. The threshold value can be set to any length depending on the period during which the abnormality of the PTT value continues, and may be set to infinity in some cases. In this case, the power consumption of the battery 251 cannot be suppressed, but it is possible to continuously measure the blood pressure over the entire period after the onset as long as the capacity of the battery 251 lasts.

[0065] [Second embodiment] (Configuration example) Fig. 11 is a block diagram showing the software configuration of a blood pressure measurement device according to the second embodiment of the present invention. In Fig. 11, the same parts as those in Fig. 6 are given the same reference numerals and detailed explanations are omitted.

[0066] The control unit 21 of the blood pressure measurement unit 20 includes an R-wave peak / HR detection unit 222 instead of the R-wave peak detection unit 212 shown in Fig. 6. The R-wave peak / HR detection unit 222 detects an R-wave peak and one heartbeat period (Heart Rate: HR) as feature values ​​from the ECG signal.

[0067] Further, the data storage unit 23 is provided with an HR data storage unit 235 instead of the PTT data storage unit 233 shown in Fig. 6. This HR data storage unit 235 is used to store the cycle of one heartbeat (HR) detected by the ECG sensor 30 in chronological order.

[0068] The biological abnormality determination unit 227 reads the HR data from the HR data storage unit 235, and monitors the increase and decrease of the HR value in a unit period. Then, when the amount of change in the HR value per unit time, ΔHR, increases by a predetermined first threshold value or more, it determines that an abnormality has occurred in the HR value. Furthermore, when the amount of change in the HR value per unit time, ΔHR, decreases by a predetermined second threshold value or more after determining that the abnormality has occurred, the biological abnormality determination unit 227 determines that the HR value has returned to the normal range. Then, it performs a process of notifying the light emission control unit 218 and the blood pressure data / alarm output unit 219 of each of the above determination results.

[0069] Light emission control section 218 controls the light emission control mode of pulse wave sensor 40 based on the determination result of the amount of change ΔHR in HR value per unit time notified by biological abnormality determination section 227. For example, a mode (continuous light emission drive mode) is set in which the LED 411 of pulse wave sensor 40 emits light continuously for a preset fixed period from the time when an abnormal increase in HR value is detected or for the period until a recovery of the HR value is detected. On the other hand, a mode (intermittent light emission drive mode) is set in which the LED 411 of pulse wave sensor 40 emits light intermittently according to a preset duty ratio for other periods.

[0070] When the blood pressure data alarm output unit 219 is notified of the result of the determination of an abnormal increase in the amount of change in HR value per unit time, ΔHR, from the biological abnormality determination unit 227, the blood pressure data alarm output unit 219 monitors the duration of the abnormality in the HR value, and when the duration of the abnormality exceeds a preset period Ta, generates an alarm from a sounder or speaker (not shown).

[0071] (Example of operation) Next, the operation of the blood pressure measuring device configured as above will be described. Note that in this example, the case where the subject measures his / her own blood pressure fluctuation while sleeping will also be described as an example. 12 and 13 are flowcharts showing the processing procedure and processing contents by the control unit 21 of the blood pressure measurement unit 20. In Fig. 12 and Fig. 13, steps having the same processing contents as those in Fig. 7 and Fig. 8 are denoted by the same reference numerals and will be described.

[0072] When the blood pressure measurement operation is started, the blood pressure measurement unit 20 first sets the intermittent light emission drive mode in step S11 under the control of the light emission control unit 218. Then, under this intermittent light emission drive mode, the light emission control unit 218 generates an intermittent light emission control signal and supplies it to the pulse drive unit 42 of the pulse wave sensor 40. As a result, the LED 411 is driven to emit light intermittently by the pulse drive unit 42, whereby the pulse wave sensor 40 intermittently outputs a pulse wave signal.

[0073] In the intermittent light emission drive mode, the intermittent light emission pattern is set, for example, so that only the period corresponding to one cardiac cycle per multiple cardiac cycles is the light emission period, and the remaining period is the off period, as in the first embodiment. The ratio of the light emission period to the off period of the intermittent light emission pattern, that is, the duty ratio, is set to, for example, 25%, but this value can be set arbitrarily according to the power consumption reduction target.

[0074] In this state, in step S12, blood pressure measurement unit 20 acquires an ECG signal output from ECG sensor 30 by ECG signal acquisition unit 211, and stores the ECG signal in chronological order in ECG signal storage unit 231. In addition, in step S13, blood pressure measurement unit 20 acquires a pulse wave signal output from pulse wave sensor 40 by pulse wave signal acquisition unit 213, and stores the pulse wave signal in chronological order in pulse wave signal storage unit 232.

[0075] Next, in step S141, the blood pressure measurement unit 20 reads the ECG signal from the ECG signal storage unit 231 using the R-wave peak / HR detection unit 222, and detects the R-wave peak RP and the heartbeat period (HR), which are its feature quantities.The detected heartbeat period (HR) is then stored in the HR data storage unit 235. At the same time, the pulse wave feature quantity detection unit 214 reads the pulse wave signal from the pulse wave signal storage unit 232, and detects the pulse wave rise PS, which is one of the feature quantities.

[0076] Next, in step S15, the blood pressure measurement unit 20 calculates the time difference between the detection timing of the R wave peak RP and the detection timing of the pulse wave rising edge PS detected in one cardiac cycle by the pulse wave transit time calculation unit 215, and sets the calculated time difference as the pulse wave transit time (PTT) in one cardiac cycle. Then, in step S16, under the control of the blood pressure estimation unit 216, the blood pressure measurement unit 20 estimates a blood pressure value corresponding to the calculated PTT value by using, for example, a previously prepared PTT-blood pressure value conversion table or conversion formula, and stores the estimated blood pressure value in the blood pressure data storage unit 234. As a result, the blood pressure value in one cardiac cycle of the subject is stored in the blood pressure data storage unit 234.

[0077] Meanwhile, while executing the series of processes for measuring blood pressure, the blood pressure measurement unit 20 determines whether or not there is a biological abnormality in the subject in step S201 under the control of the biological abnormality determining section 227, and also executes a corresponding process as described below.

[0078] That is, first in step S211, the biological abnormality determination unit 227 reads the HR values ​​for a past unit time (for example, 5 to 6 cardiac cycles) from the HR data storage unit 235, and calculates the amount of change ΔHR1 in the read HR value during the unit time. Then, in step S221, it compares the calculated amount of change ΔHR1 in the HR value per unit time with a preset first threshold value to determine whether the amount of change ΔHR1 has increased to or above the first threshold value.

[0079] In this state, suppose that the amount of change in HR value per unit time, ΔHR1, increases to or exceeds the first threshold value due to the onset of sleep apnea syndrome. In this case, biological abnormality determination unit 227 determines that the heart rate has increased abnormally, and in step S25 changes the operation mode of pulse wave sensor 40 to continuous light emission drive mode and notifies light emission control unit 218 of this mode. As a result, a continuous light emission control signal is output from light emission control unit 218 to pulse drive unit 42 of pulse wave sensor 40, and thereafter LED 411 of photoelectric sensor 41 performs a continuous light emission operation. As a result, pulse wave sensor 40 continuously detects pulse wave signals, and the continuously detected pulse wave signals are sequentially stored in pulse wave signal storage unit 232 of blood pressure measurement unit 20.

[0080] When the continuous light emission drive mode is set, the biological abnormality determination unit 227 measures the length of the period during which the abnormality in the HR value occurs (abnormality duration) in step S26, and determines whether the abnormality duration exceeds a preset threshold value Ta in step S27. When the abnormality duration exceeds the threshold value Ta, an alarm generation instruction is given to the blood pressure data / alarm output unit 219 at that point in time in step S28. As a result, an alarm sound is generated from, for example, a sounder or speaker (not shown) under the control of the blood pressure data / alarm output unit 219 to notify the subject. By generating an alarm when the abnormality duration exceeds the threshold value Ta in this way, it is possible to prevent an alarm from being generated when a temporary HR change unrelated to a biological abnormality occurs.

[0081] The above alarm is issued in step S22. 1 The alarm may be generated immediately when a sudden increase in HR value is detected in the monitor 11, and the alarm may be generated by using a voice message, light emission, vibration, or a warning message displayed on the display unit 14, in addition to a sound. Furthermore, the alarm may be transmitted to a terminal owned by a family member or a medical professional, thereby notifying the family member or the medical professional.

[0082] In addition, in a state in which the continuous light emission operation mode is set, the biological abnormality determination unit 227 compares the change amount ΔHR2 of the HR value per unit time calculated in step S211 with a second threshold value set in advance, and if the change amount ΔHR2 of the HR value per unit time is equal to or smaller than the second threshold value, high and low If the result of this determination is that the amount of change ΔHR2 (amount of decrease) in the HR value per unit time does not satisfy the second threshold, the biological abnormality determination unit 227 checks the currently set light emission operation mode in step S24 and maintains the continuous light emission drive mode. Then, steps S26 to S28 are continued to count the length of the abnormal period and control the generation of an alarm according to that length.

[0083] On the other hand, suppose that the subject's condition returns from an apneic state to a normal breathing state, causing the amount of change in HR value per unit time, ΔHR2, to drop by equal to or more than the second threshold. In this case, the biological abnormality determination unit 227 determines that the HR value has returned to the normal range, and in step S29, resets the abnormality duration time being measured in step S26, and then returns to step S11 shown in Fig. 12. Then, in step S11, the light emission operation mode of the pulse wave sensor 40 is changed from the continuous light emission drive mode to the intermittent light emission drive mode.

[0084] As a result, the light emission drive signal output from the light emission control unit 218 of the blood pressure measurement unit 20 to the pulse drive unit 42 of the pulse wave sensor 40 becomes an intermittent light emission control signal, and the LED 411 of the pulse wave sensor 40 returns to the intermittent light emission operation. Therefore, the pulse wave sensor 40 returns to a state in which it operates with low power consumption.

[0085] (Typical operation example) Next, a description will be given of a representative operation example in the second embodiment. Note that the operation example is not limited to the following example, and various other operation examples are also possible.

[0086] FIG. 14 is a signal waveform diagram for explaining a representative operation example. The blood pressure measurement unit 20 normally drives the pulse wave sensor 40 to emit light intermittently and performs blood pressure measurement operation by the PTT method. During this blood pressure measurement operation, the amount of change ΔHR1 in the HR value per unit time is monitored.

[0087] In this state, assume that the change in HR value per unit time, ΔHR1, increases by more than the first threshold value at time t1. The blood pressure measurement unit 20 then determines that the heart rate per unit time has abnormally decreased due to, for example, the onset of sleep apnea syndrome, and changes the light emission operation mode of the LED 411 of the pulse wave sensor 40 from the intermittent light emission drive mode to the continuous light emission drive mode. As a result, the LED 411 of the pulse wave sensor 40 emits light continuously to continuously detect the pulse wave signal. Therefore, the blood pressure measurement unit 20 can thereafter measure the blood pressure value for each heartbeat based on the continuously detected pulse wave signal without any loss.

[0088] Furthermore, with the continuous light emission drive mode set, the blood pressure measurement unit 20 monitors the amount of change ΔHR2 in the HR value per unit time. Then, for example, at time t2, when the amount of change ΔHR2 in the HR value per unit time decreases by more than the second threshold, that is, when the heart rate per unit time returns to the normal range, the light emission operation mode of the LED 411 of the pulse wave sensor 40 is changed from the continuous light emission drive mode to the intermittent light emission drive mode. As a result, the LED 411 of the pulse wave sensor 40 switches to the intermittent light emission drive mode. Create Therefore, power consumption by pulse wave sensor 40 is reduced and the life of battery 251 is extended, making it possible to measure blood pressure for a long period of time without using a large-capacity battery.

[0089] [Third embodiment] (Configuration example) Fig. 15 is a block diagram showing the software configuration of a blood pressure measurement device according to the third embodiment of the present invention. In Fig. 15, the same parts as those in Fig. 6 are given the same reference numerals and detailed explanations are omitted.

[0090] A pulse wave feature quantity detector 224 provided in the control unit 21 of the blood pressure measurement unit 20 detects the pulse wave rise time PS and the pulse wave amplitude PA as feature quantities from the pulse wave signal stored in the pulse wave signal storage unit 232.

[0091] Furthermore, data storage unit 23 is provided with a pulse wave amplitude data storage unit 236 instead of PTT data storage unit 233 shown in Fig. 6. This pulse wave amplitude data storage unit 236 is used to store the pulse wave amplitude PA detected by pulse wave feature amount detection unit 224 in chronological order.

[0092] The biological abnormality determination unit 237 reads the pulse wave amplitude data from the pulse wave amplitude data storage unit 236, and monitors the amount of change ΔPA in the pulse wave amplitude PA per unit time. If the amount of change ΔPA in the pulse wave amplitude PA per unit time decreases by a predetermined first threshold or more, the biological abnormality determination unit 237 determines that an abnormality has occurred in the pulse wave amplitude PA. If the amount of change ΔPA in the pulse wave amplitude PA per unit time increases by a predetermined second threshold or more after determining that an abnormality has occurred, the biological abnormality determination unit 237 determines that the pulse wave amplitude PA has returned to the normal range. Then, the biological abnormality determination unit 237 performs a process of notifying the light emission control unit 218 and the blood pressure data / alarm output unit 219 of each of the above determination results.

[0093] Light emission control unit 218 controls the light emission control mode of pulse wave sensor 40 based on the result of the determination of the amount of change ΔPA per unit time in pulse wave amplitude PA notified by biological abnormality determination unit 237. For example, a mode (continuous light emission drive mode) is set in which LED 411 of pulse wave sensor 40 emits light continuously for a preset fixed period from the time when an abnormal decrease in pulse wave amplitude PA is detected, or for the period until recovery of pulse wave amplitude PA is detected. On the other hand, a mode (intermittent light emission drive mode) is set in which LED 411 of pulse wave sensor 40 emits light intermittently according to a preset duty ratio for other periods.

[0094] When the blood pressure data alarm output unit 219 is notified of the result of the determination of an abnormal decrease in the change amount ΔPA per unit time of the pulse wave amplitude PA from the biological abnormality determination unit 237, the blood pressure data alarm output unit 219 monitors the duration of the abnormality in the pulse wave amplitude PA, and when the duration of the abnormality exceeds a preset period Ta, generates an alarm from a sounder or speaker (not shown).

[0095] (Example of operation) Next, the operation of the blood pressure measuring device configured as above will be described. Note that in this example, the case where the subject measures his / her own blood pressure fluctuation while sleeping will also be described as an example. 16 and 17 are flowcharts showing the processing procedure and processing contents by the control unit 21 of the blood pressure measurement unit 20. In Fig. 16 and Fig. 17, steps having the same processing contents as those in Fig. 7 and Fig. 8 are denoted by the same reference numerals and will be described.

[0096] When the blood pressure measurement operation is started, the blood pressure measurement unit 20 first sets the intermittent light emission drive mode in step S11 under the control of the light emission control unit 218. Then, under this intermittent light emission drive mode, the light emission control unit 218 generates an intermittent light emission control signal and supplies it to the pulse drive unit 42 of the pulse wave sensor 40. As a result, the LED 411 is driven to emit light intermittently by the pulse drive unit 42, whereby the pulse wave sensor 40 intermittently outputs a pulse wave signal.

[0097] In the intermittent light emission drive mode, the intermittent light emission pattern is set, for example, so that only the period corresponding to one cardiac cycle per multiple cardiac cycles is the light emission period, and the remaining period is the off period, as in the first and second embodiments. The ratio of the light emission period to the off period of the intermittent light emission pattern, that is, the duty ratio, is set to, for example, 25%, but this value can be set arbitrarily according to the power consumption reduction target.

[0098] In this state, in step S12, blood pressure measurement unit 20 acquires an ECG signal output from ECG sensor 30 by ECG signal acquisition unit 211, and stores the ECG signal in chronological order in ECG signal storage unit 231. In addition, in step S13, blood pressure measurement unit 20 acquires a pulse wave signal output from pulse wave sensor 40 by pulse wave signal acquisition unit 213, and stores the pulse wave signal in chronological order in pulse wave signal storage unit 232.

[0099] Next, in step S142, blood pressure measurement unit 20 reads the ECG signal from ECG signal storage unit 231 using R wave peak detection unit 212 and detects the R wave peak RP, which is its characteristic amount. At the same time, pulse wave characteristic amount detection unit 224 reads the pulse wave signal from pulse wave signal storage unit 232 and detects the R wave peak RP, which is its characteristic amount. By quantity A certain pulse wave rising edge PS and pulse wave amplitude PA are detected. The detected values ​​of pulse wave amplitude PA are then stored in pulse wave amplitude data storage unit 236 in chronological order.

[0100] Next, in step S15, the blood pressure measurement unit 20 calculates the time difference between the detection timing of the R wave peak RP and the detection timing of the pulse wave rising edge PS detected in one cardiac cycle by the pulse wave transit time calculation unit 215, and sets the calculated time difference as the pulse wave transit time (PTT) in one cardiac cycle. Then, in step S16, under the control of the blood pressure estimation unit 216, the blood pressure measurement unit 20 estimates a blood pressure value corresponding to the calculated PTT value by using, for example, a previously prepared PTT-blood pressure value conversion table or conversion formula, and stores the estimated blood pressure value in the blood pressure data storage unit 234. As a result, the blood pressure value in one cardiac cycle of the subject is stored in the blood pressure data storage unit 234.

[0101] Meanwhile, while executing the series of processes for measuring blood pressure, the blood pressure measurement unit 20 determines whether or not there is a biological abnormality in the subject in step S202 under the control of the biological abnormality determining section 237, and also executes a corresponding process as described below.

[0102] That is, first, in step S212, biological abnormality determination unit 237 reads pulse wave amplitude PA for a past unit time (for example, 5 to 6 cardiac cycles) from pulse wave amplitude data storage unit 236, and calculates a change amount ΔPA1 in the read pulse wave amplitude PA during the unit time. Then, in step S222, the calculated change amount ΔPA1 per unit time in the pulse wave amplitude PA is compared with a preset first threshold value, and it is determined whether the change amount ΔPA1 has decreased to or above the first threshold value.

[0103] In this state, suppose that the amount of change ΔPA1 per unit time in pulse wave amplitude PA decreases by equal to or more than the first threshold value due to the occurrence of some biological abnormality. In response, biological abnormality determination unit 237 changes the operation mode of pulse wave sensor 40 to the continuous light emission drive mode in step S25 and notifies light emission control unit 218 of this mode. As a result, a continuous light emission control signal is output from light emission control unit 218 to pulse drive unit 42 of pulse wave sensor 40, and thereafter LED 411 of photoelectric sensor 41 performs a continuous light emission operation. As a result, pulse wave sensor 40 continuously detects a pulse wave signal, and the continuously detected pulse wave signals are sequentially stored in pulse wave signal storage unit 232 of blood pressure measurement unit 20.

[0104] When the continuous light emission drive mode is set, the biological abnormality determination unit 237 measures the length of the period during which the abnormality of the pulse wave amplitude PA occurs (abnormality duration) in step S26, and determines in step S27 whether the abnormality duration exceeds a preset threshold value Ta. When the abnormality duration exceeds the threshold value Ta, an alarm generation instruction is given to the blood pressure data / alarm output unit 219 in step S28. As a result, under the control of the blood pressure data / alarm output unit 219, an alarm sound is generated from, for example, a sounder or speaker (not shown) to notify the subject. By generating an alarm when the abnormality duration exceeds the threshold value Ta in this way, it is possible to prevent an alarm from being generated when a temporary change in PA occurs that is unrelated to a biological abnormality.

[0105] The above alarm is issued in step S22. 2The alarm may be generated promptly when a sudden increase in pulse wave amplitude PA is detected in the monitor 11, and the alarm may be generated by using a voice message, light emission, vibration, or a warning message displayed on the display unit 14, in addition to a sound. Furthermore, the alarm may be transmitted to a terminal owned by a family member or a medical professional, thereby notifying the family member or the medical professional.

[0106] Furthermore, in a state where the continuous light-emitting operation mode is set, in step S232, biological abnormality determination unit 237 compares the change amount ΔPA2 per unit time of pulse wave amplitude PA calculated in step S212 with a second threshold value set in advance, and determines whether or not the change amount ΔPA2 per unit time of pulse wave amplitude PA has increased by more than the second threshold value. If the result of this determination is that the change amount ΔPA2 (increase amount) per unit time of pulse wave amplitude PA does not meet the second threshold value, biological abnormality determination unit 237 checks the currently set light-emitting operation mode in step S24 and maintains the continuous light-emitting drive mode. Then, steps S26 to S28 are subsequently performed to measure the length of the abnormal period and to control the generation of an alarm according to that length.

[0107] On the other hand, suppose that the subject's biological condition returns to a normal state, causing the change ΔPA2 per unit time in the pulse wave amplitude PA to increase by more than the second threshold. In this case, biological abnormality determination unit 237 determines that the pulse wave amplitude PA has returned to the normal range, and in step S29 resets the value of the abnormality duration being measured in step S26 above, and then returns to step S11 shown in Fig. 12. Then, in step S11, the light emission operation mode of pulse wave sensor 40 is changed from the continuous light emission drive mode to the intermittent light emission drive mode.

[0108] As a result, the light emission drive signal output from the light emission control unit 218 of the blood pressure measurement unit 20 to the pulse drive unit 42 of the pulse wave sensor 40 becomes an intermittent light emission control signal, and the LED 411 of the pulse wave sensor 40 returns to the intermittent light emission operation. Therefore, the pulse wave sensor 40 returns to a state in which it operates with low power consumption.

[0109] (Typical operation example) Next, a description will be given of a representative operation example in the third embodiment. Note that the operation example is not limited to the following example, and various other operation examples are also possible.

[0110] FIG. 18 is a signal waveform diagram for explaining a representative operation example. The blood pressure measurement unit 20 normally drives the pulse wave sensor 40 to emit light intermittently and performs blood pressure measurement operation by the PTT method. During this blood pressure measurement operation, the amount of change ΔPA1 per unit time of the pulse wave amplitude PA is monitored.

[0111] In this state, assume that at time t1, the change amount ΔPA1 per unit time of the pulse wave amplitude PA increases by more than the first threshold value. In this case, the blood pressure measurement unit 20 determines that a biological abnormality has occurred in the subject, and changes the light emission operation mode of the LED 411 of the pulse wave sensor 40 from the intermittent light emission drive mode to the continuous light emission drive mode. As a result, the LED 411 of the pulse wave sensor 40 emits light continuously and detects the pulse wave signal continuously. Therefore, the blood pressure measurement unit 20 can thereafter measure the blood pressure value for each heartbeat based on the continuously detected pulse wave signal without any loss.

[0112] Furthermore, with the continuous light emission drive mode set, the blood pressure measurement unit 20 monitors the amount of change ΔPA2 per unit time in the pulse wave amplitude PA. Then, for example, at time t2, when the amount of change ΔPA2 per unit time in the pulse wave amplitude PA increases by more than the second threshold, that is, when the pulse wave amplitude PA returns to the normal range, the light emission operation mode of the LED 411 of the pulse wave sensor 40 is returned from the continuous light emission drive mode to the intermittent light emission drive mode. As a result, the LED 411 of the pulse wave sensor 40 switches to the intermittent light emission drive mode. Create Therefore, power consumption by pulse wave sensor 40 is reduced and the life of battery 251 is extended, making it possible to measure blood pressure for a long period of time without using a large-capacity battery.

[0113] [Other embodiments] In the third embodiment, the pulse wave amplitude PA is detected as a pulse wave feature for detecting biological abnormalities. However, the following features may be detected as the pulse wave feature. FIG. 19 is a diagram showing examples of pulse wave waveforms B1, B2, and B3 and examples of the types of the pulse wave feature. The types of the pulse wave feature are exemplified in JP2018-517528A.

[0114] That is, the pulse wave features include the period T1 from the rising edge of the pulse wave to the first peak P1, the period T2 from the rising edge of the pulse wave to the second peak P2, the reciprocal 1 / T1 of the period T1 to the first peak P1, the reciprocal 1 / T2 of the period T2 to the second peak P2, the period (T2-T1) from the first peak P1 to the second peak P2, the period Tr to reflection, the ejection period ED, the ratio of the amplitude PP (SP-DP) of the second peak P2 to T2, (P2-DP) / (P1-DP), (P1-DP) / (P2-DP), etc.

[0115] In addition to ECG signals and pulse wave signals, the type of biosignal related to heartbeat may be the impedance of the skin, which changes in response to the vibration of blood vessels. In addition, the configuration of the biosignal measuring device, the processing procedure and processing contents, the configuration of the light emission control pattern of the light emitting element of the pulse wave sensor, etc. may be modified in various ways without departing from the spirit and scope of the present invention.

[0116] Although each embodiment of the present invention has been described in detail above, the above description is merely an example of the present invention in every respect, and it goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. In other words, in implementing the present invention, specific configurations corresponding to each embodiment may be appropriately adopted.

[0117] In addition, various inventions can be constructed by appropriately combining the multiple components disclosed in each of the above embodiments. For example, some components may be deleted from all the components shown in each embodiment. Furthermore, components across different embodiments may be appropriately combined. [Explanation of symbols]

[0118] 1. Upper arm 2…Bone part 3…Arteries 10...Installation unit 11…Belt section 12...Mounting unit circuit section 13...Operation unit 14...Display section 20...Blood pressure measuring unit 21...Control unit 22...Program memory section 23...Data storage unit 24…Communications Department 25…Power circuit 211...ECG signal acquisition section 212…R wave peak detector 213...Pulse wave signal acquisition unit 214, 224...Pulse wave feature detection unit 215...Pulse wave propagation time calculation unit 216…Blood pressure estimation section 217, 227, 237…Biological abnormality detection section 218...Light emission control unit 219…Blood pressure data / alarm output unit 222…R wave peak / HR detector 231...ECG signal storage section 232...Pulse wave signal storage unit 233…PTT data storage unit 234...Blood pressure data storage unit 235…HR data storage unit 236...Pulse wave amplitude data storage unit 251…Battery 30…ECG sensor 31...electrode group 32…ECG detector 321...Switch circuit 322…Subtraction circuit 323…AFE 40...Pulse wave sensor 41...Photoelectric sensor 411...LED 412…PD 42...Pulse drive unit 421...Electrical current and voltage detection circuit

Claims

1. an acquisition unit that acquires a biosignal related to the heartbeat of the subject from a biosensor; A detection unit that detects a feature amount related to the pulsation from the acquired biological signal; a first determination unit that compares an amount of change per unit time of the detected feature amount with a threshold defined by preset first threshold information, and determines that a first change has occurred in the feature amount when the amount of change has decreased below the threshold defined by the first threshold information; a control unit that sets an operation mode of the biosensor to a continuous operation mode when it is determined by the first determination unit that the first change has occurred in the feature amount, and sets the operation mode of the biosensor to an intermittent operation mode during a period until it is determined that the first change has occurred; Equipped with the control unit restores the operation mode of the biosensor to the intermittent operation mode when a period during which the operation mode of the biosensor is set to the continuous operation mode exceeds a preset time. Biosignal measuring device.

2. a second determination unit that compares the amount of change per unit time of the detected feature amount with a threshold defined by preset second threshold information, and determines that a second change has occurred in the feature amount when the amount of change has increased above the threshold defined by the second threshold information, The control unit changes the operation mode of the biosensor to the intermittent operation mode when the second determination unit determines that the second change has occurred in a state in which the operation mode of the biosensor is set to the continuous operation mode. The biological signal measuring device according to claim 1 .

3. The biological signal measuring device according to claim 1 , wherein the detection unit detects, as the feature of the biological signal, any one of a propagation speed of a pulse wave in a blood vessel, a heart rate per unit time of the heart, and a feature of the pulse wave.

4. The biological signal measuring device of claim 1, further comprising an alarm control unit that generates and outputs alarm information for notifying the subject of the first change in the feature when the first judgment unit judges that the first change has occurred in the feature.

5. A biosignal measuring method in which a biosignal measuring device executes a process for measuring a biosignal of a subject, comprising: a step of acquiring a biosignal associated with the heartbeat of a subject from a biosensor by the biosignal measuring device; a step of detecting a feature amount related to the pulsation from the acquired biological signal by the biological signal measuring device; a step of the biological signal measuring device comparing a change amount per unit time of the detected characteristic amount with a threshold defined by preset first threshold information, and determining that a first change has occurred in the characteristic amount when the change amount is smaller than the threshold; a step of setting the operation mode of the biosensor to a continuous operation mode when it is determined that the first change has occurred in the feature amount, and setting the operation mode of the biosensor to an intermittent operation mode during a period until it is determined that the first change has occurred, by the biosignal measuring device; Equipped with the setting step includes, when a period during which the operation mode of the biosensor is set to the continuous operation mode exceeds a preset time, restoring the operation mode of the biosensor to the intermittent operation mode. Biosignal measurement methods.

6. A program that causes a processor provided in the biosignal measuring device to execute processing of each part of the biosignal measuring device described in any one of claims 1 to 4.

Images