JPWO2015115114A1 - Blood pressure measurement system and pulse wave sensor - Google Patents

Abstract

The blood pressure measurement system of the present invention reduces the sense of incongruity in daily life and enables continuous blood pressure measurement with low power consumption. Pulse wave detection means for detecting the voltage of power in time series, and processing means for calculating blood pressure based on the voltage, the pulse wave detection means, the permanent magnet for generating the lines of magnetic force, And an electrode for detection.

Description

  The present invention relates to a pulse wave sensor that can be always worn on a daily basis, and a blood pressure measurement system that wears the pulse wave sensor and continuously measures blood pressure.

  As a method for measuring blood pressure non-invasively, a method of wrapping a bag-like belt called a cuff mainly around the upper arm and applying pressure to an artery from the outside of the body (hereinafter referred to as a cuff method) has become widespread. The cuff method includes a Korotrov method using Korotrov sound, an oscillometric method using pulse wave vibration, and a capacitance compensation method. However, in the cuff method, since the cuff is attached to an arm or a fingertip to perform pressurization or decompression, the apparatus cannot be reduced in size, and a sense of incongruity during measurement is great. For this reason, there is a problem that it is not suitable for measuring blood pressure constantly while living daily life. Further, the Korotrov method and the oscillometric method, which are widely used among the cuff methods, have a problem that only representative blood pressure indexes such as the maximum blood pressure, the minimum blood pressure, and the average blood pressure can be measured intermittently.

  The tonometry method is known as a non-invasive method for obtaining a continuous blood pressure waveform. Examples of applying this method are disclosed in Patent Document 1 and Patent Document 2. However, this method has a problem that the sense of discomfort is still great because the pressure sensor must be pressed against the artery with a certain pressure. In addition, both the cuff method and the tonometry method are easily affected by disturbances caused by body movements. Therefore, this method is also not suitable for continuous blood pressure measurement in daily life.

  Non-patent document 1 proposes a method for measuring a pulse wave propagation delay shown in FIG. 12 as a method for measuring blood pressure continuously to some extent with little discomfort. The subject 100 is equipped with pulse wave sensors 101A and 101B. Pulse wave sensors 101A and 101B are attached to places where the arrival times of pulse waves are different, for example, wrists and ankles, and measure pulse waves at the respective places. Or you may make it use the electrocardiogram sensor 102 attached to the chest and one pulse wave sensor, for example, one of the pulse wave sensors 101A or 101B.

  FIG. 13 shows an example of an electrocardiogram (Electrocardiogram, ECG) measured by the electrocardiographic sensor 102 and an example of a pulse wave signal (Photoplethysmography, PPG) measured by the pulse wave sensor 101A or 101B. t is time. Non-Patent Document 1 discloses a method for obtaining a time difference T between ECG peak time and PPG rise time and calculating blood pressure (Blood pressure, P) based on the time difference T. As the time difference T, a pulse wave arrival time difference between the two pulse wave sensors 101A and 101B may be used.

  At this time, as an electrocardiographic sensor, a sensor that is compact and can be measured without a sense of incongruity at the time of wearing has already been developed. On the other hand, as a pulse wave sensor, a photoelectric pulse wave sensor disclosed in Patent Document 3 has been developed.

  FIG. 14 is a diagram for explaining the principle of this photoelectric pulse wave sensor. The photoelectric pulse wave sensor emits infrared irradiation light 40 toward the artery 20 in the body from the light source 30 attached to the skin surface 16, and receives the reflected light 41 reflected by the blood 23 in the artery 20 as a light receiver 31. And measuring the change in the intensity of the reflected light 41. The pulse wave can be measured by utilizing the fact that the intensity of the reflected light 41 changes according to the pulse wave. Since this photoelectric pulse wave sensor is relatively small, there is an advantage that there is little uncomfortable feeling at the time of wearing. Further, since the pulse wave propagation delay is used, it is only necessary to know the time of the pulse wave peak or rise, and there is an advantage that it is not affected by a slight fluctuation in the wave height.

JP 2002-272690 A JP-T-2006-526487 JP 2008-302260 A

Sawa Puke, Takuji Suzuki, Kanako Nakayama, Hirokazu Tanaka, Shigenobu Minami. “Blood pressure estimation from pulse wave velocity measured on the chest”, 35th Annual International Conference of the IEEE EMBS Osaka, Japan. 6107-6110, 3-7 July, 2013.

  However, the blood pressure measurement method based on the pulse wave propagation delay time using the photoelectric pulse wave sensor disclosed in Patent Document 3 has the following problems. That is, since the photoelectric pulse wave sensor uses a light source such as an LED (Light Emitting Diode), power consumption is large, and there is a problem that the battery needs to be frequently replaced and charged. Moreover, since only one blood pressure value can be obtained for each heartbeat, there is a problem that a continuous blood pressure waveform cannot be obtained.

  The present invention has been made in view of the above problems, and an object of the present invention is to realize continuous blood pressure measurement with reduced power consumption and low power consumption.

  A blood pressure measurement system according to the present invention includes: a pulse wave detection unit that detects in time series a voltage of an electromotive force generated by a blood flow of a subject crossing a magnetic field line; and a processing unit that calculates a blood pressure based on the voltage. The pulse wave detection means includes a permanent magnet that generates the lines of magnetic force, and an electrode that detects the voltage.

  The pulse wave sensor according to the present invention includes a permanent magnet that generates a line of magnetic force, and an electrode that detects a voltage of an electromotive force generated by a blood flow across the line of magnetic force.

  ADVANTAGE OF THE INVENTION According to this invention, the discomfort in everyday life can be reduced, and a continuous blood pressure measurement can be performed with low power consumption.

1 is a block diagram illustrating a configuration of a blood pressure measurement system according to a first embodiment of the present invention. It is a block diagram which shows the structure of the blood pressure measurement system of the 2nd Embodiment of this invention. It is a perspective view which shows the example which equips a subject with the pulse-wave detection means of the 2nd Embodiment of this invention. It is a figure which shows the cross-section of the pulse-wave detection means of the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the circuit part of the pulse-wave detection means of the 2nd Embodiment of this invention. It is a figure which shows the structure seen from the sensor part of the pulse-wave detection means of the 2nd Embodiment of this invention. It is a graph which shows the blood flow velocity V (t) by the blood pressure measurement system of the 2nd Embodiment of this invention. It is a graph which shows the blood pressure P (t) by the blood pressure measurement system of the 2nd Embodiment of this invention. It is a flowchart of the blood-pressure calculation by the blood-pressure measurement system of the 2nd Embodiment of this invention. It is a figure which shows the cross-section of the pulse-wave detection means of the 3rd Embodiment of this invention. It is a figure which shows the structure seen from the lower side of the sensor part of the pulse-wave detection means of the 3rd Embodiment of this invention. It is a flowchart of the blood-pressure calculation by the blood-pressure measurement system of the 4th Embodiment of this invention. It is a figure which shows the sensor mounting example for demonstrating the method to measure a pulse wave propagation delay. It is a graph which shows the example of the electrocardiogram signal (ECG) measured by the electrocardiogram sensor, and the pulse wave signal (PPG) measured by the pulse wave sensor. It is a figure explaining the principle of a photoelectric pulse wave sensor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the preferred embodiments described below are technically preferable for carrying out the present invention, but the scope of the invention is not limited to the following.
(First embodiment)
FIG. 1 is a diagram showing a configuration of a blood pressure measurement system according to a first embodiment of the present invention. The blood pressure measurement system 1 includes: a pulse wave detection unit 2 that detects in time series a voltage of an electromotive force generated by a blood flow of a subject crossing a magnetic field line; and a processing unit 3 that calculates a blood pressure based on the voltage. Prepare. Further, the pulse wave detecting means 2 includes a permanent magnet that generates the magnetic lines of force, and an electrode that detects the voltage.

According to the present embodiment, it is possible to perform continuous blood pressure measurement with reduced discomfort in daily life and low power consumption.
(Second Embodiment)
FIG. 2 is a diagram showing a configuration of a blood pressure measurement system according to the second embodiment of the present invention. The blood pressure measurement system 1 includes a pulse wave detection unit 2 that is a pulse wave sensor, and a processing unit 3 that calculates blood pressure based on the pulse wave.

  The pulse wave detection means 2 includes a sensor unit 4 that detects a pulse wave by detecting, in time series, a voltage generated by the blood flow of the subject crossing the magnetic field lines. Furthermore, a circuit unit 5 that uses the voltage detected by the sensor unit 4 as time-series digital data and a communication unit 6 that transmits the digital data obtained by the circuit unit 5 to the processing means 3 are provided. The transmission can be performed wirelessly.

  The processing unit 3 includes a communication unit 9 that receives the digital data transmitted from the communication unit 6 of the pulse wave detection unit 2. Furthermore, in order to perform calibration when calculating blood pressure from the digital data, a storage unit 7 that stores a blood pressure value of a subject obtained by another method in advance, and an input unit that inputs the blood pressure value and the like 10. Furthermore, a calculation unit 8 that calculates a continuous blood pressure waveform that is time-series data of blood pressure based on the digital data and the blood pressure value, and a display unit 11 that displays the calculation result are provided.

  For example, a server device can be used as the processing unit 3. The calculation unit 8 can be realized by a calculation function of a central processing unit (CPU) of the server device. Further, the storage unit 7 by a storage function such as a memory of the server device, the communication unit 9 by a communication function such as wireless communication, the input unit 10 by an input function such as a keyboard, the display unit 11 by a display function such as a display, Each can be realized.

  The processing means 3 can also use a portable terminal such as a smartphone. By using the processing means 3 as a portable terminal, blood pressure can be continuously measured even when the subject moves.

  FIG. 3 is a perspective view showing an example in which the pulse wave detecting means 2 which is a pulse wave sensor of the present embodiment is attached to a subject. The pulse wave detecting means 2 is attached by a method such as sticking on the skin surface of the arm 12 of the subject. An artery passes under the pulse wave detection means 2, and blood flows in the blood flow direction 25, that is, in the direction from the heart to the hand 13.

  4 is a cross-sectional view taken along the cross section 14 of the body of the pulse wave detecting means 2 in FIG. The pulse wave detecting means 2 includes a sensor unit 4 having a permanent magnet 50, an electrode 61 and an electrode 62 disposed on the skin surface 16, a circuit unit 5 connected to the electrode 61 and the electrode 62 by a wiring 71 and a wiring 72, A communication unit 6 is included.

  In the sensor unit 4, the permanent magnet 50 generates lines of magnetic force 55 when, for example, the lower surface facing the skin surface 16 is an N pole and the upper surface is an S pole. The artery 20 passes under the permanent magnet 50, and in this case, the blood 23 flows from the back of the page toward the front. Since the blood 23 is an electric conductor, an electromotive force known as Fleming's law is generated in the blood 23 by flowing across the magnetic field lines 55. For this reason, a voltage is generated between the left and right blood vessel walls 21 and the blood vessel wall 22 of the artery 20. This voltage can be detected by the electrode 61 and the electrode 62. Since this voltage is proportional to the blood flow velocity V, time series data corresponding to the blood flow velocity can be obtained by measuring this voltage in time series.

  The voltage obtained by the sensor unit 4 is processed by the circuit unit 5. FIG. 5 is a diagram illustrating a configuration of the circuit unit 5. The circuit unit 5 includes an amplifying unit 17 for amplifying the voltage, a filter unit 18 for removing noise from the voltage, and analog-to-digital conversion (abbreviated as Analog-to-Digital Converter, ADC) of the voltage for time series digital. And an ADC unit 19 for data d (t) (t is time). The voltage converted into time-series digital data by the circuit unit 5 is transmitted from the communication unit 6 to the communication unit 9 of the processing means 3.

  6 is a view of the sensor unit 4 as viewed from the lower side of FIG. A line of magnetic force 55 emerging from the north pole of the permanent magnet 50 penetrates the blood 23 in the artery 20 toward the front of the page. A voltage is generated in a direction perpendicular to the direction of the lines of magnetic force 55 and the blood flow direction 25, and is detected by the electrodes 61 and 62. The detected voltage is converted into digital data d (t) by the circuit unit 5 and sent to the calculation unit 8 via the communication unit 6 and the communication unit 9.

  Below, the process in the calculation part 8 is demonstrated.

First, since the blood flow velocity V (t) is proportional to the digital data d (t), V (t) = u × d (t) (equation 1) using the proportionality constant u.
It can be expressed as. The blood pressure P (t) can be obtained from the digital data d (t) by using Equation 1 and a relational expression between the blood flow velocity V (t) and the blood pressure P (t).

As a relational expression between the blood flow velocity V (t) and the blood pressure P (t), the following Expression 2 is a preferable example because it is simple and easy to handle.
V (t) = C × dP (t) / dt + P (t) / r (Formula 2)
This is an ordinary differential equation for blood pressure P (t), and a continuous blood pressure waveform can be obtained by solving this. C is called vascular compliance and r is called vascular resistance. For example, as shown in FIG. 7A, the continuous blood pressure waveform P (t) of FIG. 7B is obtained by solving Equation 2 using V (t) obtained from the digital data d (t).

  Actually, the digital data d (t) is data at discrete sampling times, and the blood pressure P (t) obtained from this is also time-series data at discrete sampling times. However, if there is a sufficient number of samples in one heartbeat, a continuous waveform as shown in FIGS. 7A and 7B can be approximated with sufficient accuracy. Solving differential equations numerically requires high computing power and a lot of power consumption. For this reason, it is desirable that the processing means 3 calculates the blood pressure P (t) from the digital data d (t).

  The parameters u, r, and C included in Equation 1 and Equation 2 match the blood pressure value calculated by this embodiment with the blood pressure value of the subject obtained in advance by another method such as the cuff method or the tonometry method. Determine as follows. This process is called calibration. Blood pressure measurement devices such as the cuff method and tonometry method used for calibration are not portable, but once calibrated, the parameters obtained can be used for a while. For example, calibration can be performed at a clinic, hospital, or home, and using the parameters obtained there, continuous measurement of blood pressure for several days can be performed while sending a daily life according to this embodiment.

  FIG. 8 shows a flowchart of blood pressure calculation according to the present embodiment.

  In step S101, the parameters u, r, and C included in Equation 1 and Equation 2 are calibrated. For this purpose, first, the blood pressure value of the subject is measured in advance by another method such as the cuff method, and the measured blood pressure value is input from the input unit 10 and stored in the storage unit 7. On the other hand, the pulse wave detection means 2 detects time-series data of the voltage corresponding to the pulse wave of the same subject. The detected time-series data of the voltage is converted into digital data d (t) by the circuit unit 5 and sent to the calculation unit 8 via the communication unit 6 and the communication unit 9. Parameters u, r, and C are determined from the digital data d (t) so that the blood pressure value obtained by Equation 1 and Equation 2 matches the blood pressure value obtained in advance by the cuff method, for example. The parameters determined as described above are stored in the storage unit 7 and are used when calculating blood pressure values in subsequent steps.

  When calibrating the above parameters, it is desirable that the measurement by the pulse wave detection means 2 and the measurement by another method such as the cuff method be performed under the same conditions at the closest time possible. Further, in order to increase the accuracy of calibration, it is desirable to perform measurement and result matching by both methods a plurality of times. In order to perform measurement with high accuracy, it is desirable to perform measurement without moving the body in a hospital, clinic, home, or the like.

  In step S102, the pulse wave detector 2 acquires time series data of a voltage corresponding to the pulse wave. The time-series data at this time can be time-series data obtained by acquiring a plurality of voltages in a time series in one heartbeat. Further, the time series data can be a plurality of heartbeats. After this step, it can be performed while sending a normal daily life. Note that the pulse wave detection means 2 after step S102 needs to maintain the mounting state in step S101. This is because the parameter u in Equation 1 varies depending on the mounting state of the pulse wave detection means 2.

  In step S103, the voltage data acquired in step S102 is converted into digital data d (t) by the circuit unit 5 and transmitted to the processing means 3. The transmission from the communication unit 6 to the communication unit 9 is preferably wireless communication so that there is no sense of incongruity in daily life. Also, it is desirable to transmit a certain amount of data collectively to reduce power consumption during transmission. For example, it is desirable to transmit the data for each heartbeat collectively.

  In step S104, for example, blood pressure for one heartbeat is calculated from the digital data d (t) of the voltage data transmitted in step S103, the parameters u, r, and C determined in step S101, and equations 1 and 2. . The procedure for calculating the blood pressure is performed by solving Equation 2, that is, integrating. At this time, the blood flow velocity V (t) based on the digital data d (t) is included in the integrand. In general, since integration has an effect of reducing noise, a low-noise blood pressure value can be obtained by calculating blood pressure by such a method.

  In step S105, it is determined whether or not the sensing by the pulse wave detection means 2 is to be terminated. This determination is made based on, for example, whether or not the processing means has shifted to an operation for ending the processing. If the process ends (YES), the flowchart ends. If not finished (NO), step S102 and subsequent steps are repeated. As described above, the blood pressure is continuously calculated.

  Since the pulse wave detection means 2 which is a pulse wave sensor of this embodiment is an electromagnetic pulse wave sensor using a permanent magnet, it consumes low power. For example, it does not have a light source that requires power consumption like the photoelectric pulse wave sensor of FIG. Therefore, even a small battery can continue to operate for a sufficiently long period. In addition, since the electromagnetic pulse wave sensor has a simple structure, it can be easily downsized. Therefore, since it is only necessary to attach a small electromagnetic pulse wave sensor to the skin surface, it is possible to live daily life without a sense of incongruity.

  Further, in the case of a sphygmomanometer that is always worn using a pulse wave transmission delay, only one blood pressure value can be obtained for each heartbeat at most. On the other hand, according to this embodiment, a continuous blood pressure waveform, that is, a plurality of blood pressure values within one heartbeat can be obtained. It acquires pulse wave data corresponding to a plurality of blood flow velocities within one heartbeat by an electromagnetic pulse wave sensor, and uses a relational expression between blood flow velocity and blood pressure based on this data to perform a plurality of samplings within one heartbeat. This is because a continuous blood pressure waveform corresponding to the point can be obtained.

  Further, when using the pulse wave transmission delay, as shown in FIG. 12, at least the electrocardiographic sensor 102 and one pulse wave sensor 101A or 101B, or two pulse wave sensors 101A and 101B are required. However, according to the present embodiment, the blood pressure can be calculated with only one electromagnetic pulse wave sensor.

As described above, according to this embodiment, it is possible to perform continuous blood pressure measurement with reduced discomfort in daily life and low power consumption.
(Third embodiment)
FIG. 9 is a diagram showing a cross-sectional structure of the sensor portion 4 ′ of the pulse wave detection means 2 that is a pulse wave sensor according to the third embodiment of the present invention. A cross section 15 of the body in FIG. 9 is a cross section perpendicular to the cross section 14 of the body in FIG. The permanent magnet 50 ′ disposed on the skin surface 16 has a horseshoe shape.

  Magnetic field lines 55 ′ are generated from the north pole to the south pole of the permanent magnet 50 ′. Immediately below the north pole, the magnetic field lines 55 'penetrate the blood 23 from top to bottom, and below the south pole, the blood 23 penetrates from bottom to top. Since the blood flow directions 25 under the N pole and under the S pole are the same, the voltage generated in the vicinity of the N pole and the polarity of the voltage generated in the vicinity of the S pole are opposite to each other according to Fleming's law.

  FIG. 10 shows a bottom view of the structure of FIG. 9 as viewed from below. The magnetic field lines 55N immediately below the magnetic pole 51, which is the N pole, penetrate the blood 23 in the front direction of the drawing, and the magnetic lines 55S immediately below the magnetic pole 52, which is the S pole, penetrate the blood 23 toward the back of the drawing. For this reason, the polarity of the voltage generated between the electrode 62 ′ and the electrode 61 is opposite to the polarity of the voltage generated between the electrode 62 ′ and the electrode 63. The electrode 62 ′ is shared by the magnetic pole 51 and the magnetic pole 52. Therefore, voltages having opposite polarities are generated in the electrode 61 and the electrode 63 with respect to the electrode 62 '. This corresponds to connecting the voltages generated in the vicinity of the magnetic pole 51 and the magnetic pole 52 in series. By connecting the electrode 62 'to the reference input of the instrumentation amplifier and connecting the electrode 61 and the electrode 63 to the plus input and the minus input of the instrumentation amplifier, respectively, it is possible to amplify the sensitivity with low noise. This instrumentation amplifier is incorporated as the amplification unit 17 of the circuit unit 5 of FIG.

  The biological signal is easily affected by so-called hum noise from a commercial AC power supply. According to the electromagnetic pulse wave sensor of this embodiment, there is an advantage that in-phase noise such as hum noise, that is, noise added in phase to both the positive input and the negative input of the instrumentation amplifier can be removed.

  The pulse wave detection means having the sensor unit 4 ′ of this embodiment can be used as the pulse wave detection means 2 of the blood measurement system shown in FIG. In addition, as shown in FIG. 3, the pulse wave detection means having the sensor unit 4 ′ of the present embodiment can measure blood pressure on a daily basis by sticking to the arm 12 of the subject. . In the structure shown in FIGS. 9 and 10, the direction of the arrangement of the magnetic poles of the permanent magnet 50 ', that is, the direction of the lines of magnetic force 55 may be opposite.

As described above, according to this embodiment, it is possible to perform continuous blood pressure measurement with reduced discomfort in daily life and low power consumption.
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. In the present embodiment, the blood measurement system and the pulse wave sensor of the second or third embodiment are combined with a method for measuring a pulse wave transmission delay. That is, as shown in FIG. 12, the pulse wave transmission delay is measured by one electrocardiographic sensor 102 and one pulse wave sensor 101A, or two pulse wave sensors 101A and 101B, and thereby the blood pressure value is calculated for each heartbeat. calculate. Using this blood pressure value, the blood pressure value calculated by the blood measurement system of the second embodiment or the third embodiment is calibrated for each heartbeat.

  FIG. 11 shows a flowchart of blood pressure calculation according to the present embodiment. Here, an example in which the first and second electromagnetic pulse wave sensors are used will be described, but one of the electromagnetic pulse wave sensors may be an electrocardiographic sensor.

  In step S201, the parameters u, r, and C included in Equation 1 and Equation 2 are calibrated. This step is the same as step S101 in the flowchart of FIG.

  In step S202, the first electromagnetic pulse wave sensor (pulse wave detecting means 2) acquires time-series data of the voltage corresponding to the pulse wave. Further, the acquired voltage data is converted into digital data d (t) by the circuit unit 5 and transmitted to the processing means 3. The process of step S202 is the same as the process of step S102 and step S103 of FIG. Note that the pulse wave arrival time at the first electromagnetic pulse wave sensor is obtained from the time-series data of the voltage corresponding to the pulse wave using the calculation function of the calculation unit 8 of the processing means 3.

  In step S203, the second electromagnetic pulse wave sensor (pulse wave detecting means 2) acquires time-series data of the voltage corresponding to the pulse wave. This is transmitted to the processing means 3, and the pulse wave arrival time at the second electromagnetic pulse wave sensor is obtained using the calculation function of the calculation unit 8 of the processing means 3. The pulse wave arrival time here can also be obtained using an electrocardiographic sensor instead of the second electromagnetic pulse wave sensor.

  In step S204, the processing means 3 obtains pulse wave transmission delays in the first and second electromagnetic pulse wave sensors, and calculates a blood pressure value based on this. As a method for calculating the blood pressure value from the pulse wave transmission delay, the method of Non-Patent Document 1 can be used.

  In step S205, for example, blood pressure for one heartbeat is calculated from the digital data d (t) of the voltage data transmitted in step S202, the parameters u, r, and C determined in step S201, and equations 1 and 2. . The process of step S205 is the same as the process of step S104 of FIG.

  In step S206, the blood pressure data is calibrated for each heartbeat so that the blood pressure value obtained in step S204 matches the blood pressure data obtained in step S205. For example, the blood pressure data obtained in step S205 is obtained so that the highest blood pressure for each heart beat is obtained in step S204, and the highest blood pressure obtained from the blood pressure data for each heart beat obtained in step S205 matches the highest blood pressure obtained in step S204. Is multiplied by a constant.

  In step S207, it is determined whether or not to end sensing. This determination is made based on, for example, whether or not the processing means 3 has shifted to an operation for ending the processing. If the process ends (YES), the flowchart ends. If not finished (NO), step S202 and subsequent steps are repeated. As described above, the blood pressure is continuously calculated.

  In this embodiment, since the blood pressure value is calibrated for each heartbeat, it is affected by fluctuations in the acquired data in the electromagnetic pulse wave sensor due to body movement, sweating, etc., specifically, fluctuations in the constant u in Equation 1. There is an advantage that it is difficult.

  As described above, according to this embodiment, it is possible to perform continuous blood pressure measurement with reduced discomfort in daily life and low power consumption.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and it goes without saying that these are also included in the scope of the present invention. Absent.

  Moreover, although a part or all of said embodiment may be described also as the following additional remarks, it is not restricted to the following.

Appendix (Appendix 1)
A pulse wave detection means for detecting in time series a voltage of an electromotive force generated by a blood flow of a subject crossing a magnetic field line; and a processing means for calculating a blood pressure based on the voltage, the pulse wave detection means A blood pressure measurement system comprising: a permanent magnet that generates the lines of magnetic force; and an electrode that detects the voltage.
(Appendix 2)
The permanent magnet has an N pole and an S pole disposed on the skin surface of the subject,
The electrode is
A common electrode for the N pole side and the S pole side, which serves as a reference potential for the electromotive force generated respectively on the N pole side and the S pole side;
A first electrode for detecting a first potential of the electromotive force generated on the N pole side with respect to the common electrode, and the polarity generated on the S pole side having a polarity opposite to the first potential A second electrode for detecting a second potential of the electromotive force,
The blood pressure measurement system according to appendix 1, wherein the voltage is detected by the reference potential, the first potential, and the second potential.
(Appendix 3)
The blood pressure measurement system according to appendix 2, wherein the pulse wave detection means connects the common electrode, the first electrode, and the second electrode to an instrumentation amplifier.
(Appendix 4)
4. The blood pressure measurement system according to claim 1, wherein the pulse wave detection unit detects a plurality of the voltages in at least one heart beat. 5.
(Appendix 5)
5. The blood pressure measurement system according to claim 1, wherein the pulse wave detection unit wirelessly transmits the voltage to the processing unit.
(Appendix 6)
6. The blood pressure measurement system according to claim 1, wherein the processing means calculates the blood pressure in time series.
(Appendix 7)
7. The blood pressure measurement system according to claim 1, wherein the processing means calculates a blood flow velocity based on the voltage, and calculates the blood pressure by solving a differential equation including the blood flow velocity.
(Appendix 8)
The blood pressure measurement system according to appendix 7, wherein the processing unit calibrates the parameters for calculating the blood flow velocity and the blood pressure based on a blood pressure obtained in advance.
(Appendix 9)
The blood pressure measurement system according to appendix 8, wherein the processing means performs the calibration using a blood pressure obtained in advance by a cuff method or a tonometry method.
(Appendix 10)
10. The blood pressure measurement system according to one of appendices 1 to 9, wherein the processing means calibrates the blood pressure with a blood pressure obtained based on a difference in pulse wave arrival times at different parts of the subject.
(Appendix 11)
A pulse wave sensor comprising: a permanent magnet that generates magnetic lines of force; and an electrode that detects a voltage of an electromotive force generated by a blood flow crossing the magnetic lines of force.
(Appendix 12)
The permanent magnet has an N pole and an S pole disposed on the skin surface of the subject,
The electrode is
A common electrode for the N pole side and the S pole side, which serves as a reference potential for the electromotive force generated respectively on the N pole side and the S pole side;
A first electrode for detecting a first potential due to the electromotive force generated on the N pole side with respect to the common electrode, and the polarity generated on the S pole side having a polarity opposite to the first potential A second electrode for detecting a second potential due to an electromotive force,
The pulse wave sensor according to appendix 11, wherein the voltage is detected by the reference potential and the first and second potentials.
(Appendix 13)
The pulse wave sensor according to appendix 12, wherein the common electrode, the first electrode, and the second electrode are connected to an instrumentation amplifier.
(Appendix 14)
14. The pulse wave sensor according to appendix 11 or 13, wherein the voltage is detected in time series.
(Appendix 15)
15. The pulse wave sensor according to one of appendices 11 to 14, wherein the pulse wave sensor detects a plurality of the voltages in at least one heart beat.
(Appendix 16)
16. The pulse wave sensor according to one of appendices 11 to 15, further comprising a circuit unit that converts the voltage into digital data.
(Appendix 17)
The pulse wave sensor according to appendix 16, comprising a communication unit for wirelessly transmitting the digital data.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2014-018432 for which it applied on February 3, 2014, and takes in those the indications of all here.

  INDUSTRIAL APPLICABILITY The present invention is applicable to a pulse wave sensor that can be always worn on a daily basis, and a blood pressure measurement system that wears the pulse wave sensor and continuously measures blood pressure.

DESCRIPTION OF SYMBOLS 1 Blood pressure measurement system 2 Pulse wave detection means 3 Processing means 4, 4 'Sensor part 5 Circuit part 6 Communication part 7 Memory | storage part 8 Calculation part 9 Communication part 10 Input part 11 Display part 12 Arm 13 Hand 14, 15 Body cross section 16 Skin surface 17 Amplifying unit 18 Filter unit 19 ADC unit 20 Artery 21, 22 Blood vessel wall 23 Blood 25 Blood flow direction 30 Light source 31 Light receiver 40 Irradiation light 41 Reflected light 50, 50 ′ Permanent magnet 51, 52 Magnetic poles 55, 55 ′, 55N, 55S Magnetic field lines 61, 62, 62 ′, 63 Electrodes 71, 72 Wiring 100 Subject 101A, 101B Pulse wave sensor 102 ECG sensor

Claims (10)

A pulse wave detection means for detecting in time series the voltage of the electromotive force generated by the blood flow of the subject crossing the magnetic field lines, and a processing means for calculating blood pressure based on the voltage,
The pulse wave detection unit includes a permanent magnet that generates the magnetic lines of force, and an electrode that detects the voltage. The permanent magnet has an N pole and an S pole disposed on the skin surface of the subject,
The electrode is
A common electrode for the N pole side and the S pole side, which serves as a reference potential for the electromotive force generated respectively on the N pole side and the S pole side;
A first electrode for detecting a first potential of the electromotive force generated on the N pole side with respect to the common electrode, and the polarity generated on the S pole side having a polarity opposite to the first potential A second electrode for detecting a second potential of the electromotive force,
The blood pressure measurement system according to claim 1, wherein the voltage is detected by the reference potential, the first potential, and the second potential. The blood pressure measurement system according to claim 2, wherein the pulse wave detection means connects the common electrode, the first electrode, and the second electrode to an instrumentation amplifier. The blood pressure measurement system according to claim 1, wherein the pulse wave detection unit detects a plurality of the voltages in at least one heartbeat. 5. The blood pressure measurement system according to claim 1, wherein the processing unit calculates a blood flow velocity based on the voltage, and calculates the blood pressure by solving a differential equation including the blood flow velocity. The blood pressure measurement system according to claim 5, wherein the processing unit calibrates the parameters for calculating the blood flow velocity and the blood pressure based on a blood pressure obtained in advance. The blood pressure measurement system according to claim 1, wherein the processing means calibrates the blood pressure with a blood pressure obtained based on a difference in pulse wave arrival times at different sites of the subject. A pulse wave sensor comprising: a permanent magnet that generates magnetic lines of force; and an electrode that detects a voltage of an electromotive force generated by a blood flow crossing the magnetic lines of force. The permanent magnet has an N pole and an S pole disposed on the skin surface of the subject,
The electrode is
A common electrode for the N pole side and the S pole side, which serves as a reference potential for the electromotive force generated respectively on the N pole side and the S pole side;
A first electrode for detecting a first potential due to the electromotive force generated on the N pole side with respect to the common electrode, and the polarity generated on the S pole side having a polarity opposite to the first potential A second electrode for detecting a second potential due to an electromotive force,
9. The pulse wave sensor according to claim 8, wherein the voltage is detected by the reference potential and the first and second potentials. The pulse wave sensor according to claim 9, wherein the common electrode, the first electrode, and the second electrode are connected to an instrumentation amplifier.

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