JP2017109063A - Blood Pressure Measurement System - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact blood pressure measurement device capable of measuring without any constraint, and a data management system.SOLUTION: A blood pressure measurement system 1 is configured to reflect not only a time parameter of a pulse wave waveform measured by a pulse wave sensor 5, but also a phenomenon in which the pulse wave is generated by shrinkage and expansion of a blood vessel which is reflected on a data processing device 3 which is additionally provided, for determining a maximum blood pressure value and a minimum blood pressure value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a blood pressure measurement system and a data management system, and is particularly suitable for application to a blood pressure measurement system that calculates and outputs a blood pressure value based on a pulse wave waveform obtained by a pulse wave sensor.

  2. Description of the Related Art Conventionally, a blood pressure measuring apparatus using a Manchette method that obtains the maximum blood pressure and the minimum blood pressure based on the sound of applying a cuff pressure to the arm and recovering the pulse wave while reducing the pressure is often used. As a method for measuring the absolute value of blood pressure, there is an invasive method called a blood-opening method in which a pressure sensor is inserted into an artery to directly measure the blood pressure. All of these impose pressure and invasive burdens on the subject. Therefore, as a blood pressure measurement that does not place a burden on the examinee, a pulse wave is detected using a light emitting element and a light receiving element, and a maximum blood pressure and a minimum blood pressure are calculated by calculation from the data.

  For example, in Patent Document 1, as an arterial blood pressure measurement device, an arterial waveform is captured by a sensor composed of a light emitting element and a light receiving element, and a cycle time and the like are also obtained using a differential zero cross point for each beat of the captured arterial waveform. It is disclosed to calculate the maximum blood pressure and the minimum blood pressure for each beat while taking into account.

  However, according to the method of Patent Document 1, the maximum blood pressure value and the minimum blood pressure value can be obtained by calculation only by attaching a light emitting element and a light receiving element to a fingertip or the like. Since the value and the minimum blood pressure value are obtained, there is a possibility that the phenomenon that the pulse wave is formed by the contraction and expansion of the blood vessel may not be reflected, and there is an insufficient aspect as a model for calculating the pulse wave.

  For this reason, the applicant of the present application has proposed a blood pressure measurement apparatus that further improves the accuracy of blood pressure measurement by using a phenomenon in which a pulse wave is formed by blood vessel contraction and expansion as a model for blood pressure calculation (Patent Document 2). ).

Japanese Patent No. 4680411 International Publication No. 2015/151132

  By the way, in recent years, various electronic devices have been made into small ASICs (Application Specific Integrated Circuits), and are now being applied to wearable vital sensors.

  The blood pressure measurement device in Patent Document 2 described above is configured to be a non-invasive type that is configured to press a switch with a fingertip or a band type that wraps around the fingertip and applies a pressing force to the subject. However, it is difficult to say that it is completely non-contact because it requires pressing.

  On the other hand, recently, the construction of sensor networks is becoming mainstream, in which biometric information from vital sensors is collected on a server via a wireless network, analyzed according to uses such as medical diagnosis, and fed back to patients and the like.

  Therefore, it is desirable to always wear the vital sensor on the body of the subject and monitor the blood pressure 24 hours a day, 365 days a year. For this purpose, it is necessary to propose a non-contact type blood pressure measuring device without pressing. .

  Furthermore, in August 2014, the Institute of Electrical and Electronics Engineers (IEEE) published standards for cuff-free blood pressure measurement devices as IEEE 1708, and clarified the policy for formulating the standards worldwide. Interest is growing.

  The present invention has been made in consideration of the above points, and provides a blood pressure measurement device and a data management system that can be measured in a small size and completely unconstrained.

  In order to solve this problem, in the blood pressure measurement system according to the present invention, a reflected wave of a wave incident on a blood vessel in a living body is detected from a signal source, and is generated between the incident wave and the reflected wave according to the physical property of the blood vessel. When a phase difference occurs, the phase shift circuit compensates for the phase difference to zero while changing the frequency of the oscillation oscillation, and the periodic time variation of the frequency at which the phase difference is compensated to zero is used as a pulse waveform. A pulse wave measurement device having a blood vessel pulse wave detection unit to output, a first communication unit that transmits a pulse wave waveform obtained from the blood vessel pulse wave detection unit as pulse wave data, and pulse wave data from the first communication unit A pulse wave waveform of a period of blood flow based on the pulse wave data obtained from the second communication unit, a time integral value of the pulse wave waveform during the vasoconstriction time, Time of pulse waveform during vasodilatation time Using the fraction value, the standardized maximum pressure value that universally expresses the energy that the blood vessel pushes out the blood flow during the vasoconstriction time and the energy that the blood vessel pushes out the blood flow and relaxes during the vasodilation time is universally expressed And a blood pressure value calculation unit that outputs a maximum blood pressure value and a minimum blood pressure value based on the normalized maximum pressure value and the normalized minimum pressure value, and a pulse wave measuring device, And a data processing device provided separately.

  Further, in the present invention, the blood pressure value calculation unit in the data processing device is configured to incline the passage of time with respect to the waveform of one cycle as a repetition unit for the pulse wave waveform based on the pulse wave data obtained from the second communication unit. A one-cycle waveform calculator that corrects and tilt-corrects one-cycle pulse waveform, and the one-cycle pulse waveform has the highest pulse waveform with the time of one cycle and the starting point of one cycle as the time origin. Value of the vasoconstriction time, the time integral value of the pulse wave waveform from the time origin to the vasoconstriction time, and the time of the pulse waveform until the vascular dilation time at the end of one cycle excluding the vasoconstriction time A basic parameter calculation unit for calculating an integral value as a basic parameter, and using the basic parameter, the number of pulse waves per 60 seconds, a standardized maximum pressure value of vascular contraction time, and a standardized minimum pressure of vascular dilation time A secondary parameter calculation unit that calculates a value, a first coefficient that associates between a maximum blood pressure value obtained by an invasive method or a Manchette method and a normalized maximum pressure value calculated based on a pulse wave waveform, and an invasive method or A storage unit for preliminarily obtaining and storing a second coefficient for associating a minimum blood pressure value obtained by the Manchette method and a normalized minimum pressure value calculated based on a pulse wave waveform; and a basic parameter from the basic parameter calculation unit Based on the normalized maximum blood pressure value and the normalized minimum blood pressure value from the secondary parameter calculation unit, and the first coefficient and the second coefficient read from the storage unit, the maximum blood pressure value and the minimum blood pressure based on the pulse wave waveform A blood pressure value output unit for calculating and outputting the value.

  Thus, based on the pulse wave waveform measured by the pulse wave measuring device, the data processing device calculates the maximum blood pressure value and the minimum blood pressure value, and the blood pressure is a phenomenon in which a pulse wave is formed by contraction and expansion of the blood vessel. By using the calculation model, the pulse wave data can be directly converted into blood pressure without calibration. In addition, since the pulse wave measuring device can be applied as a wearable device with a small size and wireless communication, the subject can always wear it and measure blood pressure.

  Furthermore, in the present invention, a power supply unit that is provided in the first communication unit of the pulse wave measurement device and supplies power in a predetermined power supply method in a non-contact manner according to an instruction from the control unit, and a second communication in the data processing device And a power receiving unit that receives power supplied from the power supply unit of the first communication unit in a contactless manner, and a voltage adjustment unit that adjusts the power received by the power receiving unit to a predetermined voltage value. did.

  As a result, the pulse wave measuring device can be further reduced in size, and can be worn as a wearable device at all times or for a long period of time on the subject.

  Further, in the present invention, the second communication unit in the data processing device is connectable to an external server via a predetermined communication network, and the pulse wave data and the blood pressure value transmitted from the first communication unit of the pulse wave measuring device. The maximum blood pressure value and the minimum blood pressure value output from the calculation unit are accumulated and managed in time series.

  As a result, in the blood pressure measurement system, the server is accessed via the communication network, and the pulse wave data, the maximum blood pressure value, and the minimum blood pressure value of the inspected person recorded in the server are read out in time series. It is possible for the examinee to grasp the health management, illness prediction, and psychological state using lifetime pulse data from the time of measurement to a long period.

  ADVANTAGE OF THE INVENTION According to this invention, while applying a pulse wave measurement to a wearable apparatus, the blood pressure measurement system which can convert the measured pulse wave data into a blood pressure directly without calibration is realizable.

It is a block diagram which shows the function structure of the blood pressure measurement system which concerns on embodiment of this invention. It is a flowchart which shows the process sequence of the blood pressure measurement in the blood pressure measurement system which concerns on embodiment of the same invention. It is an approximate line figure showing a pulse wave waveform acquired in a pulse wave measuring device concerning the embodiment. It is a frequency characteristic figure of the phase shift circuit in the pulse wave measuring device concerning the embodiment. In the data processor concerning the embodiment, it is an approximate line figure which made a pulse wave waveform suitable for digital processing. In the data processor concerning the embodiment, it is an approximate line figure showing time change of a pulse wave waveform made into a digital signal. In the data processor concerning the embodiment, it is a figure which takes out the pulse wave waveform of one cycle, and shows a waveform parameter. In the data processor concerning the embodiment, it is a figure which shows the matching relational expression with respect to the maximum blood pressure value calculated | required by arranging the pulse wave data measured by the invasive method. In the data processor concerning the embodiment, it is a figure which shows the matching relational expression with respect to the diastolic blood pressure value calculated | required by arranging the pulse wave data measured by the invasive method. FIG. 9 is a diagram in which maximum blood pressure values calculated from pulse wave waveforms are superimposed on FIG. 8. FIG. 10 is a diagram in which the maximum blood pressure values calculated from the pulse waveform are superimposed on FIG. 9. It is a table | surface which shows the relationship between the product in which the pulse wave measuring apparatus corresponding to the to-be-tested person's body part concerning the embodiment is mounted.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Principle of the phase shift method according to the present invention The phase shift method according to the present invention detects a reflected wave of a wave incident on an object from a signal source, and changes the physical property of the object between the incident wave and the reflected wave. By changing the frequency of the phase difference generated in response to the phase shift circuit, the phase difference is compensated to zero, and the physical property of the object is obtained from the amount of frequency change that compensates the phase difference to zero.

  That is, in order to maintain closed loop self-oscillation consisting of a detection sensor, an amplifier and a phase shift circuit connected in series, the frequency of the closed loop is changed to compensate for the phase difference to zero.

  Japanese Patent No. 4348467 discloses a cuff-free sphygmomanometer that applies a phase shift method to measure a phase difference that appears between an input signal and an output signal when light is incident on a living body. In other words, the frequency of self-oscillation oscillation that occurs by compensating the phase difference to zero by the feedback loop is measured, and the frequency when the incident light from the living body is received by the probe element and the light is not incident on the living body Deviation between the frequency and the frequency is detected, and this is output as a biological material property. Then, the phase difference between the input waveform to the light emitting element and the output waveform from the light receiving element is converted into a frequency deviation by the phase shift method. In this way, it is possible to use a measuring instrument with much higher accuracy in quantitative measurement of frequency than in quantitative measurement of phase difference.

  In such a cuff-free sphygmomanometer, since the pulsation of the blood vessel correlates with the intravascular pressure (blood pressure), the shape of the pulse wave also correlates with the intravascular pressure. Therefore, it can be seen that when the pulse wave characteristic is converted into a frequency by forming a resonance phenomenon using the phase shift method, a spring constant including the blood vessel characteristic (that is, a spring constant indicating the hardness of the blood vessel wall) is reflected.

(2) Configuration of control system of blood pressure measurement system As shown in FIG. 1, the blood pressure measurement system 1 includes a pulse wave measurement device 2 that is directly or indirectly attached to the skin surface of a human body through clothing, etc. The data processing device 3 calculates a maximum blood pressure value and a minimum blood pressure value by a predetermined calculation process based on pulse wave data from the pulse wave measuring device 2.

  The pulse wave measuring device 2 includes a pulse wave sensor 5, a bias circuit 6, a closed loop circuit 7, and a wireless communication unit 8. The pulse wave sensor 5 uses a light emitting element 10 made of an optical semiconductor that converts current into light, and a light receiving element 11 made of a photon counter that detects the intensity of light with high accuracy, and generates a pulse wave waveform of blood flow flowing through the blood vessel. To detect.

  In this pulse wave sensor 5, the intersection P between the emission optical axis of the light emitting element 10 and the incident optical axis of the light receiving element 11 is set at a predetermined height position with respect to the surface of the light transmitting plate 12. Since the predetermined height position of the intersection point P is the blood flow pulse wave measuring apparatus 2, it is desirable to set it near the distance from the human skin surface to the blood vessel position.

  In addition, a light shielding unit 13 is disposed between the light emitting element 10 and the light receiving element 11, and suppresses the occurrence of a disturbance to the received light due to the light from the light emitting element 10 traveling around the light receiving element 11.

  The bias circuit 6 generates a bias voltage supplied between the anode and the cathode of the light emitting element 10 of the pulse wave sensor 5, connects a resistance element to the output of the light receiving element 11, and converts the current flowing through the light receiving element 11 into a voltage. It has the function to do.

  The closed loop circuit 7 inputs the current output from the light receiving element 11 to the phase shift circuit 17 via the DC cut capacitor 15 and the subsequent amplifier 16. When there is a phase difference between the input signal and the output signal, the phase shift circuit 17 has a function of changing the oscillation frequency of the self-excited oscillation circuit to make the phase difference zero and maintaining the self-excited oscillation. . The detailed configuration and operation of the phase shift circuit 17 is disclosed in Japanese Patent Application Laid-Open No. 9-146991.

  Thus, in the closed loop circuit 7, the blood flow-light receiving element 11-DC cut capacitor 15-amplifier 16-phase shift circuit 17-light emitting element 10-the above-described closed loop of blood flow is formed near the skin surface of the human body. The closed loop circuit 7 forms a self-excited oscillation circuit by the amplifier 16 and the phase shift circuit 17.

  The oscillation frequency of the self-excited oscillation circuit as pulse wave data output from the phase shift circuit 17 is supplied to the wireless communication unit 8. The wireless communication unit 8 transmits the pulse wave data to the wireless communication unit of the data processing apparatus by a communication method compliant with a short-range wireless communication standard such as IEEE 802.15 standard.

  The wireless communication unit 8 of the pulse wave measuring device 2 receives wireless power supply from the wireless communication unit 20 of the data processing device 3 by a predetermined non-contact power supply method. As this non-contact power supply method, an “electromagnetic induction method” using electromagnetic induction in which an electromotive force is generated in the other adjacent medium through the magnetic flux generated when a current is passed through one of two adjacent coils, The “electromagnetic resonance method” using the resonance phenomenon of the above, and the “radio wave method” that is a technology for converting electric power into electromagnetic waves and transmitting / receiving them through an antenna, can be mentioned.

  The data processing device 3 includes a wireless communication unit 20, a control unit 21, a display unit 22, and a storage unit 23. Based on the pulse wave data transmitted from the pulse wave measurement device 2, the maximum blood pressure value and the minimum blood pressure value Calculate the pulse rate.

  In the data processing device 3, the pulse wave data received from the wireless communication unit 20 is supplied to the control unit 21. The control unit 21 includes a frequency adjustment unit 30 that adjusts the frequency of the pulse wave data to a default frequency, a one-cycle waveform calculation unit 31 that calculates a one-cycle waveform of repetition of the pulse wave data, and a blood pressure calculation based on the one-cycle waveform. A basic parameter calculation unit 32 for calculating a basic parameter for blood pressure, a secondary parameter calculation unit 33 for calculating a secondary parameter for blood pressure calculation, and a maximum blood pressure value and a minimum blood pressure using the basic parameter and the secondary parameter. A blood pressure calculation output unit 34 for calculating and outputting the value and the pulse rate.

  These functions can be realized by executing software, specifically, by executing a blood pressure calculation program. Some of these functions may be configured by hardware. Here, the control unit is configured by one IC chip with a built-in processor that processes functions that can be realized by software. Thereby, the circuit block can be reduced in size.

  The storage unit 23 that communicates with the control unit 21 is a memory that stores a program executed by the control unit 21 and has a function of temporarily storing pulse wave data. An association coefficient file 35 for storing a coefficient for associating a blood pressure value calculated based on the pulse wave waveform detected by the element 11 and a blood pressure value obtained by the invasive method or the Manchette method is stored. The detailed contents of the coefficient will be described later in association with the basic parameters and secondary parameters of the pulse waveform.

  The control unit 21 transmits the frequency adjustment signal calculated based on the pulse wave data to the wireless communication unit 8 of the pulse wave measuring device 2 via the wireless communication unit 20. This frequency adjustment signal is a signal for changing the circuit constant of the phase shift circuit 17 so that the oscillation frequency of the self-excited oscillation circuit as pulse wave data becomes a predetermined default frequency.

  The phase shift circuit 17 of the closed loop circuit 7 in the pulse wave measuring device 2 determines the oscillation frequency of the self-excited oscillation circuit as pulse wave data detected from the blood flow near the skin surface by the subject based on the frequency adjustment signal. Even if it varies considerably, an increase in the dynamic range of signal processing can be suppressed by adjusting to the default frequency.

  The wireless communication unit 20 of the data processing device 3 can be connected to an external server 41 via a predetermined communication network (network) 40, and the pulse wave data transmitted from the pulse wave measuring device 2 and the blood pressure of the control unit 21. The maximum blood pressure value and the minimum blood pressure value are accumulated and managed from the calculation output unit 34 in time series. Therefore, in the data processing device 3, the control unit 21 reads out the subject's pulse wave data, the maximum blood pressure value, and the minimum blood pressure value recorded in the server 41 in time series so that the subject can perform measurement. It is possible to understand health management, disease prediction, and psychological state using life-long pulse data for a long period of time.

(3) Processing by the blood pressure measurement program of the data processing device For each function in the control of the control unit 21 of the data processing device 3, the contents of the coefficient file 35 of the storage unit 23, etc., the processing procedure SP0 of the blood pressure measurement program shown in FIG. The details will be described.

  First, the control unit 21 of the data processing device 3 supplies power from the wireless communication unit 20 in accordance with the measurement time desired by the examinee, so that the pulse wave sensor 5 passes through the wireless communication unit 8 of the pulse wave measurement device 2. Operate. In addition, when the person to be inspected always desires measurement, the start-up control of the control unit 21 as described above is unnecessary.

  In the pulse wave sensor 5, the light from the light emitting element 10 is incident on the human skin surface via the translucent plate 12, and is reflected at an intersection P with blood vessels in the vicinity of the skin surface, and the reflected light is transmitted through the translucent plate. Light is received by the light receiving element 11 via 12. In the closed loop circuit 7, a blood flow-light receiving element 11-DC cut capacitor 15-amplifier 16-phase shift circuit 17-light emitting element 10-closed loop of the blood flow in the vicinity of the human skin surface is formed.

  This closed loop forms a self-excited oscillation circuit by the amplifier 16 and the phase shift circuit 17. When there is a phase difference between the detection electric signal output from the light receiving element 11 corresponding to the input signal and the driving electric signal supplied to the light emitting element 10 corresponding to the output signal, the phase shift circuit 17 The oscillation frequency of the self-excited oscillation circuit is changed so that the phase difference is zero.

  The change in the oscillation frequency reflects the change in the blood flow, and the waveform of the time change is the pulse wave waveform F1 (SP10). The pulse waveform F1 is shown as shown in FIG. 3, for example, with time on the horizontal axis and voltage on the vertical axis. The pulse wave waveform F1 has a substantially constant voltage amplitude regardless of the passage of time, and the frequency changes every moment. This frequency change corresponds to the magnitude of contraction and dilation in the blood vessel.

The dynamic range of the frequency change in the pulse wave waveform F1 varies depending on the examinee. Since there is an individual difference in the center frequency of the pulse wave waveform F1, if the data processing of the pulse wave waveform F1 proceeds as it is, both the memory capacity and the dynamic range of the signal processing circuit become large. Therefore, the frequency adjustment of unifying the default frequency f _D with predetermined center frequency of the pulse waveform F1 is performed (SP11). This processing procedure is executed by the function of the frequency adjustment unit 30 of the control unit 21.

Specifically, a frequency adjustment signal for changing the circuit constant is output from the control unit 21 of the data processing device 3 to the phase shift circuit 17 of the pulse wave measuring device 2. The default frequency f _D can be determined in consideration of the sampling period of pulse wave data, the number of data sets necessary for averaging the dispersion of pulse wave data, the processing speed of the circuit block, the memory capacity, and the like. it can. Here, the sampling frequency of pulse wave data is 250 times per second, the number of data sets required for variation averaging is 30, the number of data processing bits is 16 bits, the processing speed is 10 MHz, and the default frequency f _D is 4 kHz. .

The default frequency f _D is assumed to be different from the operation center frequency f _θ of the phase shift circuit 17. FIG. 4 is a diagram showing the frequency characteristics of the gain and phase of the phase shift circuit 17. Gain characteristics of the phase shift circuit 17, the gain symmetrically is set to have a bandpass characteristic which decreases around the operating central frequency f _theta. Therefore, in the vicinity of operating center frequency f _theta, gain hardly changes even if the frequency changes.

Since the pulse wave waveform is a waveform showing a temporal change in the oscillation frequency of the self-excited oscillation circuit, it is necessary to detect the frequency change with high sensitivity. Therefore, the default frequency f _D is set at a frequency where the gain / frequency gradient is large, avoiding the vicinity where the gain / frequency gradient is small. In FIG. 4, the default frequency f _D is set on the higher frequency side than the operation center frequency of the phase shift circuit, but it may be set on the lower frequency side than the operation center frequency.

In this default frequency f _D, samples the pulse waveform data. (1/4 kHz) = 250 μs, but this is divided into 16 and sampled every 250 kHz to count the frequency of the pulse wave waveform. Since the pulse waveform is an analog waveform, it is binarized using A / D conversion by a comparator having an appropriate threshold value, converted into a digital waveform, and the digital waveform is sampled. FIG. 5 shows an example of an A / D converted pulse wave waveform.

  Sampling is performed for 4 ms with a sampling timing of 4 kHz for the digital waveform. That is, 16-bit sampling is performed on the digital waveform. The 16-bit sampling data is taken as one set, 30 sets of sampling data are taken as one set for the same subject, and 30 sets of sampling data are acquired for the same subject. The acquired 30 sets of sampling data are temporarily stored in the storage unit. Data smoothing is performed using the stored 30 sets of sampling data. As the smoothing process, a method of taking a moving average between adjacent sampling data can be used. In this way, abnormal data and the like in 16-bit sampling data are removed, and highly reliable sampling data is obtained (SP12).

FIG. 6 shows an example of sampling data for 16 bits after the smoothing process. The horizontal axis represents time and the vertical axis is the frequency deviation from the default frequency f _D. As shown in FIG. 6, the sampling data has periodicity but has a slope with respect to time. This inclination is due to the measurement state of the subject.

  Therefore, for 16-bit sampling data corresponding to the pulse wave waveform F1, determination is made for one cycle in order to extract a waveform of one cycle as a repetition unit (SP13). Since one period is a repetition period of blood flow and a period of heartbeat, an approximate value is known from experience. Therefore, the sampled data is differentiated to obtain the obtained zero cross point. Then, an appropriate determination time interval is set, and the interval between zero cross points is determined as one cycle.

  When sampling data for one period is obtained, tilt correction is performed (SP14). Inclination correction is performed by correcting each sampling data so that the value of Δf at the zero crossing point that is the starting point of one cycle of sampling data is equal to the value of Δf of the zero crossing point that is the end point of one cycle. Do. The above-described procedure for calculating and acquiring the pulse waveform F2 for one period for which the inclination correction has been performed is executed by the function of the one-period waveform calculating unit of the control unit.

  FIG. 7 shows an example of the pulse wave waveform F2. In FIG. 8, the horizontal axis represents time, and the vertical axis represents Δf. The pulse wave waveform F2 has a period of T seconds, and the time when the pulse wave waveform F2 becomes the maximum value is Ta, with the start point of one period as the time origin. In the pulse wave waveform F2, Δf increases abruptly from the time origin to time Ta. Then, from time Ta to time T when one cycle ends, there is a period during which Δf is substantially constant, but Δf decreases as a whole.

  Therefore, as basic parameters characterizing the pulse wave waveform F2, the time T seconds of one cycle, the time Ta seconds when the pulse wave waveform F2 becomes the maximum value with the start point of one cycle as the time origin, and Tb = (T−Ta ) Calculate seconds. Then, a time integration value Sa of the pulse waveform F2 from the time origin to time Ta seconds and a time integration value of the pulse waveform F2 from time Ta to time T which is the end point of one cycle are calculated. These are the basic parameters of the pulse wave waveform F2. The calculation of the basic parameter is executed by the function of the basic parameter calculation unit 32 of the control unit 21 (SP15). Specifically, the peak of the pulse wave waveform F2 is detected to determine Ta, and Tb = (T−Ta) is determined. Then, Sa and Sb are calculated by performing time integration of the pulse wave waveform F2 for each period of Ta and Tb.

  Further, using the basic parameters, the pulse rate per 60 seconds N = (60 / T), and ha = [2 {Sa / (Sa + Sb)} / {Ta / (Ta + Tb) as the normalized maximum pressure value during the Ta period )}] And hb = [2 {Sb / (Sa + Sb)} / {Tb / (Ta + Tb)}] as the normalized minimum pressure value during the period of Tb are calculated as secondary parameters. The calculation of the secondary parameter is executed by the function of the secondary parameter calculation unit 33 of the control unit 21 (SP16).

  Specifically, N, ha, and hb are calculated by calculation using the basic parameters Ta, Tb, Sa, and Sb calculated in S15. Note that these calculated parameters are standardized, and the unit is not necessarily time or pressure.

  As already shown in Japanese Patent No. 4680911, the above basic parameter and secondary parameter further advance the knowledge that blood pressure is closely related to (Ta × Tb). This is because the blood pressure is calculated by reflecting the phenomenon that the pulse wave is formed by the contraction and expansion of the blood vessel.

  That is, the period of Ta is a contraction period in which the blood vessel pushes out the blood flow, and Tb is an expansion period in which the blood vessel pushes out the blood flow and relaxes. For these periods, the time parameter, the integrated value of the waveform, and the normalized pressure value are obtained, and the blood flow receives and releases energy as the blood vessels contract and dilate, thereby forming a pulse wave. This phenomenon can be used as a model for blood pressure calculation.

  Next, a coefficient that associates the blood pressure value with the blood pressure value calculated based on the pulse wave waveform F2 based on the parameters calculated in S15 and S16 for the pulse wave waveform F2 is used. The association coefficients A, α, B, and β are obtained in advance by using the same processing procedure as S15 and S16 for the pulse wave waveform F2 obtained by the invasive method, and the basic parameters and 2 of the pulse wave waveform F2 are obtained. Obtained by associating with the next parameter.

  In order to sort out basic parameters and secondary parameters for many pulse wave waveforms F2 obtained by the invasive method, a relational expression Y including these parameters, which has a close relationship with X = (Ta × Tb), is used. Explored. The search was performed from the viewpoint of whether there is a relational expression Y where YX = constant value. This is because the phenomenon that a pulse wave is formed by the contraction and expansion of blood vessels is universal beyond the individual differences of non-examiners, and X = (Ta × Tb) is already described in Japanese Patent No. 4680911. This is because it is known that the variable is closely related to the above.

As a result of such a search, for the maximum blood pressure value P _H obtained by the invasive method, the relational expression of Y _H = [(N ² × ha) / {P _H × Sa / (Sa + Sb)} ^−1/2 ] is obtained. When used, it was found that Y _H X = a constant value. FIG. 8 shows the result of organizing the pulse waveform data by 10 points of invasive methods. The horizontal axis in FIG. 8 is X = (Ta × Tb), and the vertical axis is Y _H. When Y _H = AX− ^α , in the example of FIG. 8, the correlation coefficient r ² = 0.975 between A = 254, α = 1, 10-point data and Y _H = 254X ⁻¹ . The obtained A and α are stored in the storage unit 23.

Similarly, when the relational expression of Y _L = [{N ² × Sb / (Sa + Sb)} / (P _L × hb) ^−1/2 ] is used for the diastolic blood pressure value P _L obtained by the invasive method, almost Y _L X = found to be a constant value. FIG. 9 shows the result of organizing the pulse wave waveform data by 13 points of invasive methods. The horizontal axis in FIG. 9 is X = (Ta × Tb), and the vertical axis is Y _L. When Y _L = BX− ^β , in the example of FIG. 9, the correlation coefficient r ² = 0.972 between B = 36X, β = 1, 13 points of data and Y _L = 36X ⁻¹ . The obtained B and β are stored in the storage unit 23.

When the relational expression Y _H = AX ^−α in which α obtained in FIG. 8 has a value of approximately 1 and the relational expression Y _L = BX ^−β in which β obtained in FIG. Blood pressure value P _H = [{N ⁴ × (ha) ² } / [A ² × (Ta + Tb) ^−2α × {Sa / (Sa + Sb)}]], and minimum blood pressure value P _L = [N ⁴ × {Sb / (Sa + Sb)} ² ] / [B ² × (Ta + Tb) ^−2β × (hb)]. Therefore, A, α, B, and β stored in the storage unit 23 are read, and the maximum blood pressure value P _H and the minimum blood pressure value P _L are calculated based on the basic parameter and the secondary parameter of the pulse wave waveform F2, and the pulse Together with the number N, it is output to the display unit 22. This processing procedure is executed by the function of the blood pressure calculation output unit 34 of the control unit 21 (SP17).

FIG. 10 shows the result of recalculating Y _H with respect to the maximum blood pressure value P _H calculated using A and α stored in the storage unit 23 and overlaying the data with the invasive method of FIG. The horizontal and vertical axes in FIG. 10 are the same as those in FIG. The black circles are the same as the data obtained by the invasive method of FIG. 8, and the white circles are Y _H values calculated based on the data calculated using the control unit 21 of the data processing device 3 for 23 examinees. As shown in FIG. 10, the correlation with respect to Y _H = 254X ⁻¹ is substantially the same as the 10 black dots in the invasive method and the 23 white circles by the control unit 21 of the data processing device 3.

Similarly, Y _L is recalculated for the diastolic blood pressure value P _L calculated using B and β stored in the storage unit 23, and the result of superimposing the data with the invasive method of FIG. 9 is shown in FIG. Show. The horizontal and vertical axes in FIG. 11 are the same as those in FIG. Black circles are the same as the data obtained by the invasive method in FIG. 9, and white circles are Y _L values calculated based on data calculated using the control unit 21 of the data processing device 3 for 27 examinees. As shown in FIG. 11, the correlation with respect to Y _L = 36X ⁻¹ is almost the same as the 13 black circles in the invasive method and the 27 white circles by the control unit 21 of the data processing device 3.

  For this reason, the maximum blood pressure value and the minimum blood pressure value calculated using the data processing device 3 based on the pulse waveform are very well matched with the maximum blood pressure value and the minimum blood pressure value measured by the invasive method. I understand. In parallel with the measurement by the pulse wave measurement device 2, when the maximum blood pressure value and the minimum blood pressure value were measured for the same subject using Manchette electronic blood pressure monitors manufactured by several manufacturers, the values by the data processing device 3 were measured. And we found a good agreement with the Manchette electronic blood pressure monitor.

  In the above, A and α are set to A = 254 and α = 1 from 10 points of invasive method data. However, considering the value of the correlation coefficient, the value of A is practical even in the range of 200 to 270. no problem. In addition, B and β are set to B = 36 and β = 1 from 13 points of invasive method data. However, considering the value of the correlation coefficient, even if the value of B is in the range of 20-60, there is a practical problem. Absent.

  Further, by determining A, α, B, and β from more invasive method data and storing the values in the storage unit 23, the accuracy of the blood pressure value calculated by the control unit 21 of the data processing device 3 is improved. . At that time, A = 254, α = 1, B = 36, and β = 1 are different values. For example, the value of A is in the range of 100 to 400, the value of α is in the range of 0.7 to 1.2, the value of B is in the range of 20 to 80, and the value of β is in the range of 0.7 to 1.2. It may be a value.

  Next, according to the above configuration, the type of living body to be inspected (human body, livestock, etc.), individual differences between examinees (slow pulsation, steep pulsation, etc.) and pulse wave sensors (optical sensors, vibration sensors, It will be explained that the maximum blood pressure value and the minimum blood pressure value can be obtained universally regardless of the type of the displacement sensor or the like and the unit of the detected value of the pulse wave (potential, frequency, mm, etc.).

  First, the phenomenon that a pulse wave is formed by the contraction and expansion of blood vessels is considered to be universal beyond individual differences among examinees. In order to show the maximum pressure value and the minimum pressure value of the pulse wave beyond individual differences of the examinee, standardize the contraction time and expansion time of the blood vessel, and in the energy and expansion time that the blood flow receives from the blood vessel in the contraction time This can be done by normalizing the energy that the bloodstream discharges to the blood vessels.

  As described above, with respect to the pulse waveform F2 of time T seconds in one cycle of blood flow, the time integral value Sa of the pulse waveform F2 during the vasoconstriction time Ta and the vasodilation time Tb = (T−Ta) When the time integral value Sb of the pulse wave waveform F2 between the two is used, the normalized maximum pressure value ha and the normalized minimum pressure value hb received by the blood vessel can be expressed as follows.

  That is, ha = [2 {Sa / (Sa + Sb)} / {Ta / (Ta + Tb)}], hb = [2 {Sb / (Sa + Sb)} / {Tb / (Ta + Tb)}]. {Ta / (Ta + Tb)} and {Tb / (Ta + Tb)} are the standardized contraction time and standardized expansion time of the blood vessel, respectively, and {Sa / (Sa + Sb)} and {Sb / (Sa + Sb)} are respectively The normalized energy that the blood flow receives from the blood vessel during the contraction time and the normalized energy that the blood flow discharges into the blood vessel during the expansion time. The coefficient 2 is a value generated by approximating the change of the pulse wave waveform with a triangle.

  The normalized maximum pressure value ha and the normalized minimum pressure value hb obtained in this way are not the same as the maximum value and the minimum value of the actually measured pulse wave waveform. That is, even if the maximum value of the actually measured pulse wave waveform is small, depending on Sa and Ta, the blood flow receives a large amount of energy from the blood vessel, and the maximum blood pressure value by the invasive method or the Manchette method may be large. Conversely, even if the maximum value of the actually measured pulse wave waveform is a large value, depending on Sa and Ta, the blood flow receives less energy from the blood vessel, and the maximum blood pressure value by the invasive method or the Manchette method may be small.

  The standardized maximum pressure value ha and the standardized minimum pressure value hb are not based on the maximum value or the minimum value of the pulse wave waveform that is likely to cause individual differences among examinees, or the pulse rate, the contraction period of the blood vessel, or the expansion period. This is a universal expression of the phenomenon in which a pulse wave is formed by the contraction and expansion of blood vessels, and it is intended to obtain values close to the maximum and minimum blood pressure values obtained by the invasive method and the Manchette method. is there.

Standardized maximum pressure value ha obtained in this way, the maximum blood pressure value P _H as measured by the actual invasive method, is considered to be linked by universal relation. Similarly, the normalized minimum pressure value hb and the minimum blood pressure value P _L measured by an actual invasive method are considered to be connected by a universal relational expression. Find the universal relation Y. The universal relational expression should be related to X = (Ta × Tb) already known in Japanese Patent No. 4680911.

Therefore, an attempt was made to search for a relational expression in which XY = a constant value. From the trial and error, the relational expression Y _H between the normalized maximum pressure value ha and the maximum blood pressure value P _H measured by an actual invasive method is Y _H = [(N ² × ha) / {P _H × Sa / (Sa + Sb)} ^−1/2 ] was found to be XY _H = A (constant value). A is a constant value of XY _H = A, and N is the pulse rate. When this relational expression is rewritten, P _H = {N ⁴ × (ha) ² } / [A ² × (Ta × Tb) ⁻² × {Sa / (Sa + Sb)}], where P _H is the fourth power of N It can be seen that there is a relationship that is proportional to the square of ha, proportional to the square of ha, proportional to the square of X = (Ta × Tb), and inversely proportional to the normalized energy in the contraction time.

Further, when a relational expression in which XY = a constant value is searched for the normalized minimum pressure value hb, from the trial and error, between the normalized minimum pressure value hb and the minimum blood pressure value P _L measured by an actual invasive method. the relationship _{Y L, Y L = {N} 2 × Sb / (Sa + Sb)} / (P L × hb) -1/2] was found to be XY _L = B (constant value).

B is a constant value of XY _L = B, and N is the pulse rate. When this relational expression is rewritten, P _H = [N ⁴ × {Sa / (Sa + Sb) ² ] / ([B ² × (Ta × Tb) ⁻² × hb]], and P _L is proportional to the fourth power of N. , Hb, proportional to the square of X = (Ta × Tb), and proportional to the square of the normalized energy in the extended time.

Ideally, the relational expressions Y _H and Y _L should be searched so that XY _H = A and XY _L = B. However, depending on the characteristics of the pulse wave sensor and the conversion process, Y _H and Y _L May not be in a good inverse proportion to X. Some variation is allowed from the correlation coefficient of statistical processing. Therefore, if α and β are close to 1 even in the relational expressions Y _H and Y _L that satisfy Y _H X ^α = A and Y _L X ^β = B, the relational expressions may be used. α, A, β, and B are coefficients that differ depending on the pulse wave sensor or the like.

  In the present embodiment, as a coefficient, the value of A is a value in the range of 100 to 400, and the value of α is 0.7 to 1.2 so as to be associated with the maximum blood pressure value and the minimum blood pressure value by the invasive method or the Manchette method in advance. The value of the range, the value of B was a value in the range of 20-80, and the value of β was a value in the range of 0.7-1.2. Particularly, it is desirable that the value of A is a value in the range of 200 to 270, the value of α is 1, the value of B is a value in the range of 20 to 60, and the value of β is 1.

  In the above description, the reflection type light receiving light sensor in which light is incident on the surface of the human body by the light emitting element 10 and the reflected light is received by the light receiving element 11 has been described as the pulse wave sensor 5. Instead of this, a transmissive light emitting / receiving sensor in which light is incident on the human body by the light emitting element 10 and the transmitted light is received by the light receiving element 11 may be used. Further, instead of the light emitting / receiving element, an ultrasonic probe may be used in which an ultrasonic wave is incident on the human body by an ultrasonic vibrator and the reflected ultrasonic wave is detected by the vibration detecting element.

  As described above, when a sensor having a waveform input unit and a waveform detection unit is used, a phase shift method can be used. For example, when an ultrasonic probe is used as an ultrasonic pulse wave sensor, an amplifier is connected to the vibration detection element, a phase shift circuit is disposed between the output terminal of the amplifier and the ultrasonic transducer, and the human body A self-excited oscillation circuit composed of a blood flow section, a vibration detection element, an amplifier, a phase shift circuit, and an ultrasonic transducer, and a frequency adjustment section that adjusts the center frequency of the oscillation frequency to a default frequency. it can.

In addition, a simple sensor that does not use the phase shift method may be used as the pulse wave sensor. For example, any device that detects a pulse wave waveform, such as a displacement sensor or a vibration detection sensor, can be used as a pulse wave sensor. Even if the pulse wave sensor is replaced, the relational expression of Y _H and Y _L does not change. What needs to be changed is α, A, β, B. In other words, various pulse wave detection sensors can be used by changing the values of α, A, β, and B.

Although the case of the human body as the living body has been described, the normalization maximum pressure value ha and the standard as described above can be used as long as a pulse wave waveform is formed by contraction and expansion of blood vessels even in a living body other than the human body. It is possible to obtain relational expressions Y _H and Y _L that relate the normalized minimum pressure value hb to the maximum blood pressure value P _H and the minimum blood pressure value P _L by the invasive method.

(4) Application development of the pulse wave measuring device to wearable devices The part of the pulse wave measuring device 2 according to the present invention that is worn on the body of the subject is affected by the movement of the human body while wearing it constantly or for a long time. Difficult parts are desirable.

  Unlike conventional pulse wave measurement devices, it does not need to be pressed against the skin surface and can be contactless, so it can be worn as long as there is a blood vessel in the vicinity of the skin surface. Can be widely applied.

  At that time, it is effective to attach a pulse wave measurement device to the part of the subject's body where the movement of the skin surface is the least during the activity, especially a bandage type pulse wave measurement device on the bone surface layer in the center of the chest It is desirable to paste. Ideally, it should be worn for a relatively long time (always when possible), and a sticking type such as a bandage is particularly desirable.

  In addition, as a site where blood vessels exist near the skin surface, the head (particularly the face), chest, hands (including fingers), arms, legs (particularly the soles), and legs are widely targeted. As the pulse wave measuring device corresponding to each of these parts, a device that is small and capable of wireless communication and power reception, such as a bandage type or a device built-in type, may be applied.

  Specifically, as shown in the table of FIG. 12, it is desirable to wear the pulse wave measuring device 2 described in the right column corresponding to each part of the body. For example, in the head centered on the face, the pulse wave measuring device 2 may be mounted on a nose pad or a temple of glasses. In the chest, the pulse wave measuring device 2 may be mounted on a necklace, a tie, a neck strap ID card, or a shirt lining. In particular, as described above, it is desirable to be able to attach to a site near the bone surface layer at the center of the chest.

  Further, in the hand or arm, the pulse wave measuring device 2 may be mounted on a wristwatch, a wristband, a ring or the like. Particularly in the palm (gripping part), a pulse wave measuring device for an object to be inspected for a predetermined time, such as a steering wheel of a car, a handle of a two-wheeled vehicle, a handle of a bag, a handle of a toothbrush or a shaver, a writing instrument, a PC mouse, etc. 2 may be mounted.

  Furthermore, in the foot or leg, a pulse wave measuring device 2 such as a shoe insole, a sock, a shoe, an ankle band, or trousers may be mounted. In addition to this, the pulse wave measuring device 2 may be mounted on an item carried by the inspected person, and examples thereof include a smartphone (mobile phone) and its cover case, a tablet and its cover case.

  The above describes the case where the pulse wave measuring device 2 is mounted non-invasively on the examinee. However, the present invention is not limited to this. For example, a catheter (an optical device signal is emitted from the tip) using an endoscope. The same effect can be obtained even if it is mounted invasively on the subject as in FIG.

  As described above, in the present embodiment, the wireless communication unit 8 of the pulse wave measuring device 2 is supplied with power from the wireless communication unit 20 of the data processing device 3 by non-contact power supply using a predetermined power supply method. However, the present invention is not limited to this, and an ultra-small battery may be mounted inside the pulse wave measuring device 2. This battery may be a primary battery, and in the case of a secondary battery, it can be charged via the wireless communication unit 8 by the above-described non-contact power feeding.

  In the present embodiment, the pulse wave sensor 5 in the pulse wave measuring device 2 has been described as applying the light emitting element 10 made of an optical semiconductor element and the light receiving element 11 made of a photon counter. Not limited to this, if it can detect the pulse waveform of the blood flow through the blood vessel, it can emit light of various wavelengths from ultraviolet rays (wavelength: 10 to 400 nm) to far infrared rays (wavelength: 0.7 to 1,000 μm). You may make it apply widely to a light emitting element and the light receiving element which has the light reception capability corresponding to the said light emitting element.

  DESCRIPTION OF SYMBOLS 1 ... Blood pressure measuring system, 2 ... Pulse wave measuring device, 3 ... Data processing device, 5 ... Pulse wave sensor, 6 ... Bias circuit, 7 ... Closed loop circuit, 8, 20 ... Wireless communication part, 17... Phase shift circuit, 21... Control unit, 22... Display unit, 23... Storage unit, 30... Frequency adjustment unit, 31. ... secondary parameter calculation unit, 34 ... blood pressure calculation output unit, 40 ... communication network, 41 ... server.

Claims (4)

When a reflected wave of a wave incident on a blood vessel in a living body from a signal source is detected and a phase difference generated according to the physical property of the blood vessel occurs between the incident wave and the reflected wave, a self-oscillation vibration is generated by a phase shift circuit. A blood vessel pulse wave detecting unit that compensates for a phase difference to zero while changing the frequency of the output, and outputs a periodic time change of the frequency in which the phase difference is compensated to zero as a pulse wave waveform;
A pulse wave measuring device comprising: a first communication unit that transmits the pulse wave waveform obtained from the blood vessel pulse wave detection unit as pulse wave data;
A second communication unit that receives the pulse wave data from the first communication unit;
About the pulse wave waveform of the period of the blood flow based on the pulse wave data obtained from the second communication unit, the time integral value of the pulse wave waveform during the vasoconstriction time and the vascular dilation time The normalized maximum pressure value that universally expresses the energy that the blood vessel pushes out the blood flow during the vasoconstriction time using the time integral value of the pulse wave waveform, and the energy that the blood vessel pushes out the blood flow during the vasodilation time and relaxes A standardized minimum pressure value that universally expresses the blood pressure value, and outputs a maximum blood pressure value and a minimum blood pressure value based on the normalized maximum pressure value and the normalized minimum pressure value, A blood pressure measurement system comprising: the pulse wave measurement device; and a data processing device provided separately. The blood pressure value calculation unit in the data processing device,
With respect to the pulse waveform based on the pulse wave data obtained from the second communication unit, the inclination with respect to the passage of time is corrected with respect to the waveform of one period as a repetition unit, and the pulse waveform with one period corrected for inclination is obtained. A one-cycle waveform calculator;
With respect to a pulse wave waveform of one cycle, the time of one cycle, the vasoconstriction time at which the pulse waveform becomes the maximum value with the start point of one cycle as the time origin, and the time of the pulse waveform from the time origin to the vasoconstriction time A basic parameter calculation unit that calculates an integral value and a time integral value of a pulse wave waveform up to the vascular dilation time that is the end point of one cycle excluding the vasoconstriction time, as a basic parameter;
A secondary parameter calculation unit for calculating a pulse wave number per 60 seconds, a standardized maximum pressure value of the vasoconstriction time, and a standardized minimum pressure value of the vasodilator time using basic parameters;
A first coefficient relating the maximum blood pressure value obtained by the invasive method or the Manchette method and the normalized maximum pressure value calculated based on the pulse wave waveform, and the minimum blood pressure value and the pulse wave obtained by the invasive method or the Manchette method A storage unit that preliminarily obtains and stores a second coefficient that associates the normalized minimum pressure value calculated based on the waveform;
Based on the basic parameters from the basic parameter calculation unit, the normalized maximum blood pressure value and the normalized minimum blood pressure value from the secondary parameter calculation unit, and the first coefficient and the second coefficient read from the storage unit, The blood pressure measurement system according to claim 1, further comprising: a blood pressure value output unit that calculates and outputs a maximum blood pressure value and a minimum blood pressure value based on a pulse wave waveform. A power feeding unit that is provided in the first communication unit in the pulse wave measurement device, and that supplies power in a predetermined power feeding method in a non-contact manner in response to an instruction from the control unit;
A power receiving unit that is provided in the second communication unit in the data processing device and receives power supplied from the power feeding unit of the first communication unit in a non-contact manner, and a power received by the power receiving unit is a predetermined voltage. The blood pressure measurement system according to claim 1, further comprising: a voltage adjustment unit that adjusts the value. The second communication unit in the data processing device is
It is possible to connect to an external server via a predetermined communication network,
The pulse wave data transmitted from the first communication unit of the pulse wave measuring device and the maximum blood pressure value and the minimum blood pressure value output from the blood pressure value calculating unit are accumulated and managed in time series. Item 4. The blood pressure measurement system according to any one of Items 1 to 3.

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