JP2016174799A - Blood pressure measurement apparatus and calibration method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic blood pressure measurement apparatus which reduces the burden on a subject following calibration and time and effort of calibration.SOLUTION: A blood pressure measurement apparatus determines the timing of the blood stream generation at which the blood stream starts to be generated with relaxation of the state where the radial artery is blocked by using, for example, the measurement result of a first ultrasonic probe 20-1, obtains the systolic blood pressure from a detection value of a pressure sensor 27 at the determined timing of the blood stream generation by referring to a given relation between the pressing pressure in the blood stream generation and the systolic blood pressure, obtains the pulse pressure by using the measurement results of the first ultrasonic probe 20-1 and a second ultrasonic probe 20-2, and calibrates the correlation characteristics between the blood vessel diameter and blood pressure of the radial artery by using the obtained systolic blood pressure and pulse pressure.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a blood pressure measurement device that measures the blood pressure of a subject.

  As a measurement method for measuring the blood pressure of a subject, a method is known in which a blood vessel diameter (blood vessel diameter) is measured noninvasively to obtain blood pressure in an estimated manner. As one of them, there is a method of calculating the blood pressure from the stiffness parameter β representing the hardness of the blood vessel and the blood vessel diameter, taking the relationship between the blood pressure change and the blood vessel diameter change as a nonlinear function. When measuring blood pressure by such a method, in order to maintain measurement accuracy, it is necessary to separately measure blood pressure using a cuff type sphygmomanometer or the like and calibrate the correlation characteristic between the blood vessel diameter and blood pressure. For example, Patent Document 1 discloses a technique for calibrating correlation characteristics under pressure by a cuff type sphygmomanometer.

JP 2013-144098 A

For example, the calibration is performed every time measurement is performed once, and is performed at regular time intervals when continuous measurement is performed. For this reason, the technique disclosed in Patent Document 1 that involves pressurization using a cuff type sphygmomanometer during calibration of the correlation characteristics has a problem that the arm or the like is strongly pressed each time calibration is performed, and the burden on the subject is large. In addition, since a cuff sphygmomanometer is required for each calibration, it is necessary to go to the place where the cuff sphygmomanometer is installed or to prepare a cuff sphygmomanometer.
The present invention has been made in view of these circumstances.

  A first invention for solving the above problems includes a first ultrasonic probe installed on the skin surface above the radial artery, a second ultrasonic probe installed on the skin surface above the radial artery, A measurement result of any one of the pressure sensor, the first ultrasonic probe, and the second ultrasonic probe, which is installed on the skin surface above the radial artery and detects the pressure applied to the radial artery. To determine the timing when the state where the radial artery is blocked by the pressing pressure is relaxed and blood flow begins to occur (hereinafter referred to as “when blood flow occurs” in the claims), and Referring to a given relationship between the pressing pressure at the time of flow generation (hereinafter referred to as “pressing pressure at the time of blood flow generation”) and the systolic blood pressure at the time of flow generation, Above Obtaining a systolic blood pressure from the detection value of the force sensor; obtaining a pulse pressure using measurement results of the first ultrasonic probe and the second ultrasonic probe; and obtaining the obtained systolic blood pressure and the A blood pressure measurement apparatus comprising: an arithmetic processing unit that executes calibration of a correlation characteristic between a blood vessel diameter of the radial artery and blood pressure using a pulse pressure.

  As another form, a first ultrasonic probe installed on the skin surface above the radial artery, a second ultrasonic probe installed on the skin surface above the radial artery, and a skin surface above the radial artery A calibration method for calibrating a correlation characteristic between a blood vessel diameter of the radial artery and a blood pressure, the apparatus comprising: a pressure sensor for detecting a pressure applied to the radial artery; Using the measurement result of any one of the first ultrasonic probe and the second ultrasonic probe, the timing at the time of blood flow generation is determined, and the position between the pressing pressure at the time of blood flow generation and the systolic blood pressure is determined. Referring to a given relationship, obtaining a systolic blood pressure from the detected value of the pressure sensor at the determined timing at the time of blood flow generation, and the first ultrasonic probe and the second ultrasonic probe Pulse pressure using measurement results And determining, it is possible to construct a calibration method comprising the calibrated correlation characteristics between the blood vessel diameter and blood pressure of the radial artery using the systolic blood pressure and the pulse pressure was determined.

  According to the first invention and another aspect, the timing at the time of blood flow generation can be determined using the measurement result of either the first ultrasonic probe or the second ultrasonic probe. Then, referring to the given relationship between the pressure applied during blood flow generation and the systolic blood pressure, calibration is performed from the pressure applied to the radial artery of the pressure sensor obtained as the detected value of the pressure sensor during blood flow generation. The systolic blood pressure to be used can be obtained. In addition, the pulse pressure is obtained using the measurement results of the first ultrasonic probe and the second ultrasonic probe, and the correlation characteristic between the radial diameter of the radial artery and the blood pressure is calibrated using the obtained systolic blood pressure and pulse pressure. can do. According to this, since the calibration is possible by performing the ultrasonic measurement by the first ultrasonic probe and the second ultrasonic probe and the detection by the pressure sensor, the cuff type sphygmomanometer is used for each calibration. Compared to the case, the burden on the subject can be greatly reduced, and the labor of calibration can also be reduced.

  According to a second aspect of the invention, the arithmetic processing unit performs the blood flow determination by an ultrasonic Doppler method using any one of the first ultrasonic probe and the second ultrasonic probe. 1 is a blood pressure measurement device according to a first aspect of the present invention, which determines the timing of occurrence.

  According to the second invention, blood flow can be determined by the ultrasonic Doppler method to determine the timing when blood flow occurs.

  In a third aspect of the invention, the arithmetic processing unit performs blood flow determination by the ultrasonic Doppler method using a grating lobe component of any one of the first ultrasonic probe and the second ultrasonic probe. The blood pressure measurement device of the second invention.

  According to the third aspect, blood flow determination can be performed using the grating lobe component generated during measurement of either the first ultrasonic probe or the second ultrasonic probe.

  According to a fourth aspect of the present invention, the first ultrasonic probe and the second ultrasonic probe are installed at positions spaced apart from each other along a traveling direction of the radial artery, The pulse wave velocity is obtained from the predetermined distance and the measurement results of the first ultrasonic probe and the second ultrasonic probe, and the pulse pressure is obtained by a predetermined calculation using the pulse wave velocity. The blood pressure measurement device according to any one of the first to third inventions.

  According to the fourth invention, the measurement results of the first ultrasonic probe and the second ultrasonic probe are obtained by installing the first ultrasonic probe and the second ultrasonic probe at a predetermined distance. The pulse wave velocity can be obtained using the pulse wave velocity, and the pulse pressure can be obtained by performing an operation using the pulse wave velocity.

  In a fifth aspect of the present invention, the arithmetic processing unit is configured to determine the vascular property of the radial artery based on the pulse wave velocity and the measurement result of any one of the first ultrasonic probe and the second ultrasonic probe. The blood pressure measurement device according to a fourth aspect of the present invention obtains the pulse pressure by executing the calculation for obtaining the pulse pressure based on the value.

  According to the fifth invention, the calculation for obtaining the pulse pressure is performed by calculating the pulse wave velocity and the vascular properties of the radial artery obtained from the measurement result of any of the first ultrasonic probe and the second ultrasonic probe. Based on the value.

  A sixth invention is the blood pressure measurement device according to any one of the first to fifth inventions, further comprising a setting unit that sets the relationship between the pressing pressure at the time of blood flow generation and the systolic blood pressure.

  According to the sixth invention, prior to calibrating the correlation characteristic between the radial diameter of the radial artery and the blood pressure, the relationship between the pressing pressure at the time of blood flow generation and the systolic blood pressure can be set.

  According to a seventh aspect of the present invention, a blood vessel diameter of the radial artery is obtained using a measurement result of any of the first ultrasonic probe and the second ultrasonic probe, and blood pressure is obtained using the correlation characteristic. The blood pressure measurement device according to any one of the first to sixth inventions, comprising a blood pressure calculation unit for calculating.

  According to the seventh aspect of the present invention, the calibrated radial artery blood vessel diameter and blood pressure are obtained from the radial artery blood vessel diameter obtained using the measurement result of either the first ultrasonic probe or the second ultrasonic probe. The blood pressure can be calculated by using the correlation characteristic with.

The figure which shows the structural example of a blood-pressure measurement system. The schematic diagram which shows the schematic structural example of a 1st ultrasonic probe and a 2nd ultrasonic probe. The figure which shows the correlation characteristic of the blood vessel diameter and blood pressure. The figure which shows the rough flow of blood-pressure measurement. The figure explaining the detection procedure of the pressing pressure at the time of the blood flow generation performed by 1st calibration. The figure which shows the relationship between the pressing pressure at the time of the blood flow generation | occurrence | production at rest and after load, and systolic blood pressure. The block diagram which shows the main function structural examples of a blood-pressure measurement apparatus. The flowchart which shows the flow of a blood-pressure measurement process. The flowchart which shows the flow of a 1st calibration process. The flowchart which shows the flow of a 2nd calibration process. The schematic diagram which shows the schematic structural example of the 1st ultrasonic probe in a modification, and a 2nd ultrasonic probe. The figure which shows the example of mounting | wearing with the 1st ultrasonic probe in a modification, a 2nd ultrasonic probe, and a pressure sensor.

  Hereinafter, an embodiment for carrying out the blood pressure measurement device and the calibration method of the present invention will be described. It should be noted that the present invention is not limited to the embodiments described below, and modes to which the present invention can be applied are not limited to the following embodiments. In the description of the drawings, the same parts are denoted by the same reference numerals.

[overall structure]
FIG. 1 is a diagram illustrating a configuration example of a system related to blood pressure measurement according to the present embodiment. The blood pressure measurement system of the present embodiment is configured by connecting a blood pressure measurement device (ultrasonic blood pressure monitor) 1 that measures blood pressure without pressure using ultrasonic waves so as to be communicable with a cuff type blood pressure monitor 5. .

  The cuff type sphygmomanometer 5 is attached to the subject 100 by wrapping a cuff 51 that senses blood pressure around the upper arm, and measures the maximum blood pressure (systolic blood pressure) and the minimum blood pressure (diastolic blood pressure). The cuff type sphygmomanometer 5 is used when the blood pressure measurement device 1 is calibrated for the first time. After the first calibration, the cuff 51 is removed from the subject 100 and the blood pressure measuring device 1 is used alone to measure blood pressure as needed. The second and subsequent calibrations can be performed by the blood pressure measurement device 1 alone.

  The blood pressure measurement device 1 is for estimating blood pressure from the blood vessel diameter of the radial artery, which is a blood vessel to be measured, and includes two ultrasonic probes 20-1 and 20-2 that perform ultrasonic measurement, Is provided.

  FIG. 2 is a schematic diagram illustrating a schematic configuration example of the two ultrasonic probes 20-1 and 20-2. As shown in FIG. 2, one ultrasonic probe 20-1 that is a first ultrasonic probe is configured by incorporating two ultrasonic sensors 23 a and 23 b into an outer case 221, and the second ultrasonic probe The other ultrasonic probe 20-2 is configured by incorporating an ultrasonic sensor 23c and a pressure sensor 27 into an exterior case 212. Here, the pressure sensor 27 is integrated with the ultrasonic probe 20-2, but may be configured as a separate body.

  These two ultrasonic probes 20-1 and 20-2 can be freely mounted on the wrist of the subject 100, which is a measurement target site, by a holding sheet 40 in which an adhesive layer is formed on one mounting surface, for example. . Each of the ultrasonic probes 20-1 and 20-2 has three ultrasonic sensors 23a incorporated therein at a position where the distance between the ultrasonic sensors 23a and 23c is the predetermined inter-probe distance D1 shown in FIG. , 23b, 23c are held by the holding sheet 40 so that the ultrasonic wave transmitting / receiving surfaces are arranged in a straight line and exposed to the mounting surface side. In ultrasonic measurement, the mounting surface of the holding sheet 40 is set to the skin surface (biological surface) of the measurement target part in a state where the arrangement direction of the ultrasonic sensors 23a, 23b, and 23c is aligned with the traveling direction of the radial artery 120. Affix to 110. Thereby, the ultrasonic sensors 23a, 23b, and 23c are respectively installed on the skin surface 110 above the radial artery 120, and the ultrasonic sensor 23a and the ultrasonic sensor 23c are positioned with a distance D1 between the probes. Note that “upward” as used herein means a term used in the instruction manual. That is, it means the position of the skin surface closest to the radial artery, and the position where ultrasound can be transmitted to and received from the radial artery from the skin surface.

  One ultrasonic sensor 23a of the first ultrasonic probe 20-1 is exposed to the ultrasonic element substrate 24a housed in the exterior case 221 and the mounting surface of the holding sheet 40 to form an ultrasonic transmission / reception surface. Acoustic lens 26a.

  The ultrasonic element substrate 24a is an ultrasonic transmission / reception unit in which ultrasonic elements (for example, thin film piezoelectric elements) 25a that transmit and receive ultrasonic waves are arranged in a two-dimensional array, and receives reflected waves received by the ultrasonic element 25a. A signal is output to the main unit 30 as needed. The acoustic lens 26a is disposed so as to cover the entire surface of the ultrasonic element substrate 24a on the side where the ultrasonic elements 25a are arranged. The acoustic lens 26a, together with an acoustic matching layer (not shown) provided between the acoustic lens 26a and the ultrasonic element substrate 24a, matches the acoustic impedance between the ultrasonic element 25a and the measurement target site, It is used for assisting and adjusting the beam direction and convergence.

  The ultrasonic sensor 23a is used to acquire the diameter of the radial artery 120, and transmits ultrasonic waves in a beam direction perpendicular to the traveling direction of the radial artery 120 (arrow A11). Hereinafter, the ultrasonic sensor 23a is also referred to as a “blood vessel diameter acquisition sensor 23a” as appropriate.

  Further, the other ultrasonic sensor 23b of the first ultrasonic probe 20-1 includes an ultrasonic element substrate 24b and an acoustic lens 26b, similarly to the ultrasonic sensor 23a. The functions of the ultrasonic element substrate 24b and the acoustic lens 26b are the same as those of the ultrasonic sensor 23a. However, the ultrasonic sensor 23b is used for blood flow determination of the radial artery 120 and the like, and the lens of the acoustic lens 26b. Combined with the characteristics, the ultrasonic beam is transmitted obliquely (downward or reverse direction) with respect to the traveling direction of the radial artery 120 (arrow A12). Hereinafter, the ultrasonic sensor 23b is also referred to as a “blood flow acquisition sensor 23b” as appropriate.

  The ultrasonic sensor 23c of the second ultrasonic probe 20-2 can be realized by the same configuration as the blood vessel diameter acquisition sensor 23a, and includes an ultrasonic element substrate 24c and an acoustic lens 26c. The ultrasonic sensor 23c is used together with the ultrasonic sensor 23a to obtain a pulse pressure, and transmits an ultrasonic beam perpendicular to the traveling direction of the radial artery 120 (arrow A13). Hereinafter, the ultrasonic sensor 23c is also referred to as a “pulse pressure calculating sensor 23c” as appropriate.

  Further, the pressure sensor 27 of the second ultrasonic probe 20-2 is disposed, for example, outside the outer periphery of the ultrasonic element substrate 24c, and outputs the detected value to the main body device 30 as needed. The pressure sensor 27 is installed on the skin surface 110 above the radial artery 120 by mounting the ultrasonic probes 20-1 and 20-2.

  In the blood pressure measurement device 1 configured as described above, each of the ultrasonic probes 20-1 and 20-2 has ultrasonic waves of several MHz to several tens of MHz by the ultrasonic sensors 23 a, 23 b, and 23 c incorporated therein. A pulse signal or a burst signal is transmitted, and a reflected wave including a reflected wave from the anterior wall of the radial artery and a reflected wave from the posterior wall of the blood vessel is received. On the other hand, the main body device 30 amplifies and processes the received signal of the reflected wave, and performs processing for generating reflected wave data related to the in-vivo structure of the subject 100 for each of the ultrasonic sensors 23a, 23b, and 23c. This ultrasonic measurement is repeatedly executed at a predetermined measurement cycle (for example, a frame rate of 300 to 500 frames per second).

  The reflected wave data includes images of so-called A mode, B mode, M mode, and color Doppler mode. The A mode is a mode in which the amplitude of the reflected wave (A mode image) is displayed with the first axis as the distance in the depth direction from the predetermined skin surface position and the second axis as the received signal intensity of the reflected wave. The B mode is a mode for displaying a two-dimensional image (B mode image) of the in vivo structure visualized by converting the reflected wave amplitude (A mode image) obtained while scanning the skin surface position into a luminance value. is there.

  Here, the main body device 30 sets a region of interest (tracking point) in the reflected wave data (for example, an A mode image) as a target, thereby tracking the region of interest between different frames and calculating a displacement. "It can be performed. The tracking is performed for each reflected wave data obtained as a result of ultrasonic measurement by the ultrasonic sensors 23a, 23b, and 23c. For example, the position of the radial artery is detected from the B-mode image of the short-axis cross section of the blood vessel using a technique such as pattern matching for detecting a circle, and an A-mode image corresponding to the reflected wave amplitude on the scanning line passing near the blood vessel center is obtained. Choose the target. Then, in the selected A-mode image, a region of interest is set on the anterior wall of the blood vessel, tracking is performed, and the displacement in the depth direction from the skin surface of the anterior blood vessel accompanying pulsation or the like is calculated. Similarly, a region of interest is set on the rear wall of the blood vessel on the same ultrasonic beam for tracking, and the fluctuation waveform of the blood vessel wall on each of the front wall of the blood vessel and the rear wall of the blood vessel (because the waveform indicates the displacement accompanying pulsation). A blood vessel diameter is acquired for each frame by acquiring a displacement waveform. In addition, the wall thickness of the blood vessel is obtained for each frame by calculating the displacement of the outer membrane position and the lumen-intima boundary position of the blood vessel wall. Further, even if the maximum diameter position of the blood vessel cross-sectional circle deviates from the set ultrasonic beam due to pulsation, the deflection angle of the ultrasonic beam is controlled so that it can follow the position.

  Moreover, the main body device 30 acquires blood flow volume in the radial artery as needed based on the received signal of the reflected wave received by the blood flow volume acquisition sensor 23b, and performs blood flow determination. The blood flow determination can be realized by applying a known technique, and can be performed using, for example, an ultrasonic Doppler method.

[Overview]
In order to calculate the blood pressure from the blood vessel diameter, a correlation characteristic that links the blood vessel diameter and the blood pressure can be used. FIG. 3 is a diagram showing a correlation characteristic between the blood vessel diameter and the blood pressure. As indicated by a curve L11 in FIG. 3, the blood vessel diameter and the blood pressure can be linked with a certain nonlinear correlation characteristic. The correlation characteristic between the blood vessel diameter and the blood pressure can be expressed by a correlation equation represented by the following equation (1) from the pressure applied to the blood vessel and the blood vessel diameter at each blood pressure.
P (D) = Pd · exp [β (D / Dd−1)] (1)
However, β = ln (Ps / Pd) / (Ds / Dd−1) (2)

  In correlation equation (1), “Ps” is systolic blood pressure (maximum blood pressure), and “Pd” is diastolic blood pressure (minimum blood pressure). “Ds” is a systolic blood vessel diameter that is a blood vessel diameter at the time of systolic blood pressure, and “Dd” is a diastolic blood vessel diameter that is a blood vessel diameter at the time of diastolic blood pressure. “Β” is a vascular elasticity index value called a stiffness parameter. FIG. 3 shows a plot P11 determined by the systolic blood vessel diameter Ds and the systolic blood pressure Ps in a certain heartbeat, and a plot P13 determined by the diastolic blood vessel diameter Dd and the diastolic blood pressure Pd.

  If the stiffness parameter β can be obtained, the correlation equation (1) that links the blood vessel diameter D and the blood pressure P (D) can be determined. Once correlation equation (1) is determined, blood pressure P (D) can be calculated by substituting blood vessel diameter D into correlation equation (1).

  FIG. 4 is a diagram showing a rough flow of blood pressure measurement including calibration. In the blood vessel measurement of the present embodiment, the correlation equation (1) is determined at every predetermined calibration timing to calibrate the correlation characteristic between the radial diameter of the radial artery and the blood pressure, and the correlation equation (1) is used between the calibration timings. To calculate blood pressure as needed. There are two types of calibration, a first calibration and a second calibration. The first calibration is performed only in the first calibration, and the cuff sphygmomanometer 5 is used at that time.

Specifically, as shown in FIG. 4, in the first calibration, first, as a first calibration, a relational expression (hereinafter referred to as a “pressing pressure-blood pressure relational expression” representing the relationship between the pressing pressure at the time of blood flow generation and the systolic blood pressure. Is set (step S11). Next, as the second calibration, using the pressing pressure-blood pressure relational expression set in step S11, the correlation expression (1) representing the correlation characteristic between the radial diameter of the radial artery and the blood pressure is set (step S13). After the second calibration, the blood pressure is calculated from the blood vessel diameter acquired by tracking the ultrasonic measurement result of the blood vessel diameter acquisition sensor 23a, for example, using the correlation equation (1) at a predetermined measurement timing (step) S15). The blood pressure may be calculated from the blood vessel diameter acquired by tracking the ultrasonic measurement result of the pulse pressure calculation sensor 23c. At the second and subsequent calibration timings, the process returns to step S13, and the correlation equation (1) is set again by performing only the second calibration without performing the first calibration.
Hereinafter, the outline of the first calibration and the second calibration will be described in order.

1. First Calibration Each ultrasonic probe 20-1, 20-2 is placed on the skin surface above the radial artery by attaching the mounting surface of the holding sheet 40 to the wrist of the subject 100. In the first calibration, the cuff 51 is wound around the upper arm of the subject 100 and the cuff sphygmomanometer 5 is attached (see FIG. 1).

  FIG. 5 is a diagram for explaining the procedure for detecting the pressing pressure during blood flow generation performed in the first calibration. In FIG. 5, only the second ultrasonic probe 20-2 is illustrated, and the first ultrasonic probe 20-1 and the holding sheet 40 that holds the ultrasonic probes 20-1 and 20-2 are illustrated. The illustration is omitted.

  As shown in FIG. 5A, when detecting the pressing pressure at the time of blood flow generation, a user such as the subject 100 or a medical worker uses the second ultrasonic probe 20-2 including the pressure sensor 27. The skin surface 110 is pressed with a finger from above so as to press against the radial artery 120 (arrow A2). As a result, the radial artery 120 is partially sandwiched between the second ultrasonic probe 20-2 (acoustic lens 26c) and the radial 130, and the radial artery portion directly below the second ultrasonic probe 20-2 is Block. As shown in FIG. 5B, after the portion immediately below is completely blocked, the blocking portion is opened by gradually weakening the pressing force of the finger.

  In this process, the main body device 30 monitors the blood flow volume acquired based on the received signal of the reflected wave from the blood flow volume acquisition sensor 23b (not shown in FIG. 5) of the first ultrasonic probe 20-1. The blood flow of the radial artery 120 is determined. Then, the main body device 30 performs the blood flow determination, thereby determining the above-described occlusion state and the timing when the blood flow starts to occur after the occlusion state and then the occlusion state relaxes. For example, when the blood flow becomes zero or falls below a predetermined threshold (when the blockage condition is satisfied), it is determined as a blockage, and then the blood flow is no longer zero or exceeds the predetermined threshold When the blood flow occurs (when the blood flow generation condition is satisfied), it is determined that the blood flow is occurring. In addition, at the timing when it is determined to be in the closed state, the user is notified of this through a display process or the like, and an instruction is given to gradually weaken the finger pressing force. And the detected value of the pressure sensor 27 at the timing determined to be the time of blood flow generation is obtained as the pressing pressure at the time of blood flow generation. The pressing pressure at the time of blood flow generation correlates with the systolic blood pressure. Defining the correlation is one of the purposes of the first calibration.

  In the first calibration, in two states (the first state and the second state) in which the subject 100 has a different load state, the pressing pressure at the time of blood flow generation is detected according to the above-described procedure, and the cuff type sphygmomanometer 5 is used to obtain systolic blood pressure. For example, the rest state (no load state) is set as the first state, and the state immediately after the load with a predetermined exercise load is set as the second state. In addition, not only this but the state which applied the exercise load of a different grade is good also as a 1st state and a 2nd state, respectively, and the state before and after leaving predetermined time, such as immediately after getting up and after breakfast, is the first state. It is good also as a 1st state and a 2nd state. Moreover, it is good also as acquiring the pressing pressure at the time of blood-flow generation | occurrence | production, and systolic blood pressure in three or more different states, respectively.

  Then, a pressing pressure-blood pressure relational expression is set from the pressing pressure and systolic blood pressure during blood flow generation in the first state, and the pressing pressure and systolic blood pressure during blood flow generation in the second state. FIG. 6 plots the pressing pressure and systolic blood pressure during blood flow generation obtained when the first state is resting, and the pressing pressure and systolic blood pressure during blood flow generation obtained after loading the second state. FIG. In this embodiment, the pressing pressure-blood pressure relational expression is set as a straight line L3 connecting the plots. In addition, when detecting the pressing pressure at the time of blood flow generation and measuring the systolic blood pressure in three or more different states, the pressing pressure-blood pressure relational expression may be set by linearly approximating each plot. The pressing pressure-blood pressure relational expression need not be a linear expression, and the pressing pressure-blood pressure relational expression may be set by performing polynomial approximation or exponential approximation.

2. Second Calibration In the second calibration, the stiffness parameter β is obtained and the correlation equation (1) is set. For this purpose, first, the pressing pressure at the time of blood flow generation is detected according to the procedure described with reference to FIG. Then, using the pressing pressure-blood pressure relational expression set in the first calibration, a systolic blood pressure corresponding to the detected pressing pressure at the time of blood flow generation is specified and set as the systolic blood pressure Ps.

  Next, the pulse wave velocity (PWV: Pulse Wave Velocity) is obtained, and the pulse pressure using the pulse wave velocity PWV is calculated to calculate the diastolic blood pressure Pd. Description will be made in order from the calculation of the pulse wave velocity PWV. As shown in FIG. 2, the blood vessel diameter acquisition sensor 23 a of the first ultrasonic probe 20-1 and the pulse pressure calculation sensor 23 c of the second ultrasonic probe 20-2 run the radial artery 120. Along the direction, the probe is placed on the upper skin surface 110 with a distance D1 between the probes. Therefore, the fluctuation waveform of the blood vessel wall acquired from the ultrasonic measurement result of the blood vessel diameter acquisition sensor 23a and the fluctuation waveform of the blood vessel wall acquired from the ultrasonic measurement result of the pulse pressure calculation sensor 23c are referred to. Then, the phase shift amount of each waveform (for example, the difference in generation timing of the maximum amplitude) is calculated. Then, the calculated phase shift amount is calculated as the propagation time during which the pulse wave is transmitted between the ultrasonic probes 20-1 and 20-2, and the pulse wave propagation velocity PWV is obtained by dividing the inter-probe distance L4 by the propagation time. . The timing for obtaining the pulse wave velocity PWV here is based on, for example, the rise or peak position in the fluctuation waveform of the blood vessel wall.

After obtaining the pulse wave propagation velocity PWV, an operation for obtaining the pulse pressure is performed. The calculation for obtaining the pulse pressure is executed based on the ultrasonic measurement result of the pulse pressure calculation sensor 23c, for example. First, the Young's modulus (elastic modulus) of the blood vessel is calculated. In this processing, a relational expression between the pulse wave velocity PWV and the Young's modulus E expressed by the following equation (3) is used. In the following equation (3), h is the wall thickness of the blood vessel, r is the radius of the blood vessel, and ρ is the blood density. The wall thickness h and the radius r of the blood vessel, which are vascular property values, can be acquired from the tracking result performed on the ultrasonic measurement result of the pulse pressure calculation sensor 23c. Since the blood density ρ does not change greatly, it can be treated as a constant, for example, “1.055 [g / cm ³ ]”.

Next, the pulse pressure (blood pressure difference between systolic blood pressure Ps and diastolic blood pressure Pd) is calculated from the Young's modulus. Here, the ratio between the pulse pressure and the rate of change of the blood vessel diameter associated with pulsation or the like is obtained as the pressure strain elastic coefficient Ep of the blood vessel represented by the following equation (4). This pressure strain elastic modulus Ep correlates with Young's modulus and can be considered to be almost equal. In the following formula (4), ΔD is a blood vessel diameter difference between the systolic blood vessel diameter Ds and the diastolic blood vessel diameter Dd. Both the systolic blood vessel diameter Ds and the diastolic blood vessel diameter Dd, which are vascular property values, are used. It can be acquired from the tracking result in the same manner as the wall thickness h of the blood vessel. Therefore, the pulse pressure Ps−Pd can be calculated from the Young's modulus calculated in the previous stage and the values Ds and Dd acquired from the tracking result.

  In place of the ultrasonic measurement result of the pulse pressure calculation sensor 23c, an operation for obtaining the pulse pressure based on the ultrasonic measurement result of the blood vessel diameter acquisition sensor 23a or the ultrasonic measurement result of the blood flow volume acquisition sensor 23b is performed. May be executed. In this case, from the tracking result performed on the ultrasonic measurement result of the blood vessel diameter acquisition sensor 23a and the tracking result performed on the ultrasonic measurement result of the blood flow volume acquisition sensor 23b, the wall thickness h of the blood vessel and the like are determined. Each vascular property value described above is acquired.

  Once the pulse pressure Ps-Pd is obtained, the diastolic blood pressure Pd can be calculated by subtracting the pulse pressure Ps-Pd from the systolic blood pressure Ps specified in the previous stage. Thereafter, the stiffness parameter β is obtained according to the above equation (2), and the correlation equation (1) is set.

[Function configuration]
FIG. 7 is a block diagram illustrating a main functional configuration example of the blood pressure measurement device 1. As shown in FIG. 7, the main body device 30 of the blood pressure measurement device 1 includes an operation unit 31, a display unit 32, a communication unit 33, a processing unit 34, and a storage unit 38. The ultrasonic sensor (vascular diameter acquisition sensor) 23a and the ultrasonic sensor (blood flow acquisition sensor) 23b of the first ultrasonic probe 20-1 are connected to the ultrasonic sensor (second ultrasonic probe 20-2). A pulse pressure calculation sensor) 23c and a pressure sensor 27 are connected to each other.

  The operation unit 31 is realized by various switches such as a button switch, a lever switch, and a dial switch, a touch panel, a trackpad, an input device such as a mouse, and outputs an operation signal corresponding to the operation input to the processing unit 34. .

  The display unit 32 is realized by a display device such as an LCD (Liquid Crystal Display) or an EL display (Electroluminescence display), and displays various screens based on display signals input from the processing unit 34. The display unit 32 displays the measured blood pressure of the subject 100 and the like. For example, in response to a display mode switching operation on the operation unit 31, a current blood pressure display screen, a blood pressure change display screen in which blood pressure changes are graphed based on past logging data, and the like are displayed.

  The communication unit 33 is a communication device for transmitting / receiving data to / from the outside (for example, the cuff type sphygmomanometer 5) under the control of the processing unit 34. As a communication method of the communication unit 33, a wired connection via a cable compliant with a predetermined communication standard, a connection connected via an intermediate device that is also used as a charger, such as a cradle, or wireless communication is used. Various systems such as a wireless connection type can be applied.

  The processing unit 34 is a control device and a calculation device that comprehensively control each unit of the blood pressure measurement device 1, and includes a microprocessor such as a CPU (Central Processing Unit) and a GPU (Graphic Processing Unit), an ASIC (Application Specific Integrated Circuit), and the like. ), An FPGA (Field-Programmable Gate Array), an IC (Integrated Circuit) memory, or the like. The processing unit 34 includes a first ultrasonic measurement control unit 35a, a second ultrasonic measurement control unit 35b, a third ultrasonic measurement control unit 35c, a calibration unit 36, and a blood pressure calculation unit 37. Prepare. Each unit constituting the processing unit 34 may be configured by a dedicated electronic circuit.

  The first ultrasonic measurement control unit 35a is a functional unit for realizing ultrasonic measurement together with the blood vessel diameter acquisition sensor 23a, and controls transmission of ultrasonic waves in a predetermined beam direction and reception of reflected waves. To generate reflected wave data. Further, the first ultrasonic measurement control unit 35a performs processing related to “tracking” for tracking the position of the region of interest between frames of ultrasonic measurement based on the reflected wave data. For example, to detect the position of the radial artery from the B-mode image, select the target A-mode image and set the region of interest on the anterior wall of the blood vessel, the posterior wall of the blood vessel, etc., and track the region of interest between different frames And processing for calculating the displacement of the region of interest. Thereby, functions such as phase difference tracking and echo tracking are realized.

  The second ultrasonic measurement control unit 35b is a functional unit for realizing the ultrasonic measurement together with the blood flow volume acquisition sensor 23b, and performs the same processing as the first ultrasonic measurement control unit 35a. In addition, the second ultrasonic measurement control unit 35b includes a blood flow acquisition unit 351b, which processes a reception signal of a reflected wave from the blood flow acquisition sensor 23b and acquires blood flow in the radial artery as needed. Perform the process.

  The third ultrasonic measurement control unit 35c is a functional unit for realizing the ultrasonic measurement together with the pulse pressure calculation sensor 23c, and can be realized with the same configuration as the first ultrasonic measurement control unit 35a.

  The calibration unit 36 performs processing for calibrating the correlation characteristic between the radial diameter of the radial artery and the blood pressure. The calibration unit 36 includes a first calibration unit 361 that performs a first calibration process (first calibration process) and a second calibration that performs a second calibration process (second calibration process). Part 363.

  The blood pressure calculation unit 37 calculates the blood pressure from the blood vessel diameter using the correlation equation (1) set by the second calibration unit 363.

  The storage unit 38 is realized by various IC (Integrated Circuit) memories such as a ROM (Read Only Memory), a flash ROM, and a RAM (Random Access Memory), and a storage medium such as a hard disk. The storage unit 38 stores in advance a program for operating the blood pressure measurement device 1 and realizing various functions of the blood pressure measurement device 1, data used during the execution of the program, and the like. Alternatively, it is temporarily stored for each processing.

  Further, the storage unit 38 includes a blood pressure measurement program 381, reflected wave data 384, tracking data 385, blood flow data 386, pressing pressure-blood pressure relational expression data 387, correlation expression data 388, and measured blood pressure data. 389 are stored.

  The blood pressure measurement program 381 includes a first calibration program 382 for executing the first calibration process and a second calibration program 383 for executing the second calibration process.

  The reflected wave data 384 stores reflected wave data obtained by ultrasonic measurement repeated for each frame by the ultrasonic sensors 23a, 23b, and 23c. The reflected wave data 384 includes A-mode image data for each frame in which a region of interest is set as a tracking target.

  The tracking data 385 is tracking result data for each of the ultrasonic sensors 23a, 23b, and 23c, and stores the fluctuation waveform, blood vessel diameter, blood vessel wall thickness, and the like of the blood vessel wall, which is the region of interest and is tracked for each frame. . The blood flow data 386 stores a blood flow obtained at any time for blood flow determination.

  The pressing pressure-blood pressure relational expression data 387 is a pressing pressure-blood pressure relational expression that represents the relation between the pressing pressure at the time of blood flow generation and the systolic blood pressure set by the first calibration unit 361 at the first calibration timing. Remember every time.

  The correlation equation data 388 includes correlation equation (1) as data of correlation equation (1) representing the correlation characteristic between the blood vessel diameter of the radial artery and blood pressure set by the second calibration unit 363 at the latest (last) calibration timing. ) Of each parameter β, Ps, and Ds in (1) is stored for each subject.

  The measured blood pressure data 389 stores the blood pressure at each measurement timing calculated by the blood pressure calculation unit 37.

[Process flow]
FIG. 8 is a flowchart showing the flow of blood pressure measurement processing. Note that the processing described here can be realized by the processing unit 34 reading the blood pressure measurement program 381 from the storage unit 38 and executing it.

  In this blood pressure measurement process, first, the first ultrasonic measurement control unit 35a starts ultrasonic measurement using the blood vessel diameter acquisition sensor 23a, and the second ultrasonic measurement control unit 35b uses the blood flow volume acquisition sensor 23b to perform ultrasonic measurement. The ultrasonic measurement is started, and the third ultrasonic measurement control unit 35c starts ultrasonic measurement by the pulse pressure calculation sensor 23c (step S211). Prior to the ultrasonic measurement started here, each ultrasonic sensor 23a, 23b, 23c is placed on the skin surface above the radial artery by attaching the mounting surface of the holding sheet 40 to the wrist of the subject 100. Is done.

  Thereafter, the calibration unit 36 refers to the pressing pressure-blood pressure relational expression data 387, and determines whether the calibration is the first calibration or the second or subsequent calibration depending on whether the pressing pressure-blood pressure relational expression of the subject 100 is not set. judge. If the pressing pressure-blood pressure relational expression is not set and calibration is performed for the first time (step S213: YES), the first calibration unit 361 performs the first calibration process (step S215). FIG. 9 is a flowchart showing the flow of the first calibration process.

  As shown in FIG. 9, in the first calibration process, the first calibration unit 361 first starts when the subject 100 is in the first state (for example, at rest) and in the second state (for example, for example). The process of Loop A is performed respectively (immediately after loading) (steps S311 to S319).

  That is, in the loop A, the first calibration unit 361 uses the blood flow rate acquired by the blood flow rate acquisition unit 351a in the second ultrasonic measurement control unit 35b in the process of the detection procedure described with reference to FIG. Monitoring is performed to determine blood flow (step S312). If the first calibration unit 361 determines that the blood flow is generated as a result of the blood flow determination (step S313: YES), the first calibration unit 361 presses the detection value input from the pressure sensor 27 at that timing when the blood flow is generated. (Step S315). In addition, the first calibration unit 361 prompts the subject 100 to wear the cuff sphygmomanometer 5 to measure the blood pressure by displaying a message on the display unit 32, and the cuff through the communication unit 33. The systolic blood pressure is acquired from the type sphygmomanometer 5 (step S317).

  If the process of the loop A is performed when the state of the subject 100 is the first state and the second state, the first calibration unit 361 performs the procedure described with reference to FIG. Thus, a pressing pressure-blood pressure relational expression is calculated from the pressing pressure and systolic blood pressure during blood flow generation in the first state and the pressing pressure and systolic blood pressure during blood flow generation in the second state (step S321). ). The calculated pressing pressure-blood pressure relational expression is stored in the storage unit 38 as pressing pressure-blood pressure relational expression data 387, whereby the pressing pressure-blood pressure relational expression is set.

  On the other hand, as shown in FIG. 8, in the case where the pressing pressure-blood pressure relational expression has already been set and the second and subsequent calibrations are performed (step S213: NO), the process proceeds to step S217, and the second calibration unit 363 performs the first calibration. Perform the calibration process (2). FIG. 10 is a flowchart showing the flow of the second calibration process.

  As shown in FIG. 10, in the second calibration process, the second calibration unit 363 detects the pressing pressure when blood flow occurs (step S411). The process here can be performed in the same procedure as step S312 to step S315 of FIG. Then, the second calibration unit 363 reads the pressurization pressure-blood pressure relational expression from the pressurization pressure-blood pressure relational expression data 387 and uses the systolic blood pressure corresponding to the pressurization pressure at the time of blood flow detected in step S411. It is specified as the blood pressure Ps (step S413).

  Subsequently, the second calibration unit 363 calculates the pulse wave velocity PWV (step S415), and calculates the Young's modulus of the blood vessel from the pulse wave velocity PWV calculated in step S415 using the above equation (3). (Step S417). Then, the second calibration unit 363 calculates the pulse pressure from the Young's modulus calculated in step S417 using the above equation (4) (step S419), and uses the pulse pressure calculated in step S419 to diastolic blood pressure Pd. Is calculated (step S421).

  Thereafter, the second calibration unit 363 performs the tracking result performed on the systolic blood pressure Ps specified in step S413, the diastolic blood pressure Pd calculated in step S421, and the ultrasonic measurement result of the pulse pressure calculation sensor 23c, for example. The stiffness parameter β is obtained from the systolic blood vessel diameter Ds and the diastolic blood vessel diameter Dd obtained from (1), and the correlation equation (1) is set (step S423). At this time, the second calibration unit 363 stores the stiffness parameter β obtained here in the storage unit 38 as the correlation equation data 388 together with the systolic blood pressure Ps specified in step S413 and the diastolic blood pressure Pd calculated in step S421. To do.

  Returning to FIG. After the second calibration process is performed as described above, the blood pressure calculation unit 37 monitors the measurement timing (step S219) and the calibration unit 36 continues until the measurement is finished (step S225: NO). The calibration timing is monitored (step S223).

  When the measurement timing arrives (step S219: YES), the blood pressure calculation unit 37 acquires the blood vessel diameter from, for example, the tracking result of the ultrasonic measurement result of the blood vessel diameter acquisition sensor 23a, and the correlation equation data 388. The blood pressure is calculated according to the correlation equation (1) stored in the storage unit 38 (step S221). Thereby, the blood pressure of the subject 100 is measured without pressure, and the measurement result is displayed on the display unit 32 as appropriate.

  If the calibration timing has come (step S223: YES), the process returns to step S217, the second calibration unit 363 performs the second calibration process, and sets the correlation equation (1) again. Note that the calibration timing may be set as appropriate. For example, if a relatively long period of measurement such as several hours or several days is continuously performed, the calibration timing may be set at predetermined time intervals or at predetermined predetermined times (for example, every time Time) can be used as the calibration timing. The measurement timing is the same, but can be set to an interval (for example, every minute) shorter than the interval of the calibration timing. The measurement timing can be an arbitrary time interval required for continuous blood pressure measurement.

  As described above, according to the present embodiment, the ultrasonic measurement by the ultrasonic sensors 23a, 23b, and 23c of the first ultrasonic probe 20-1 and the second ultrasonic probe 20-2, and the pressure sensor. By performing the detection according to 27, the correlation characteristic between the radial diameter of the radial artery and the blood pressure can be calibrated. Therefore, the burden on the subject can be greatly reduced as compared with the case where a cuff type sphygmomanometer is used for each calibration, and the labor of calibration can be reduced.

  In the above-described embodiment, the first ultrasonic probe 20-1 is configured by incorporating the two ultrasonic sensors 23a and 23b, and one of the ultrasonic sensors 23b is oblique to the traveling direction of the radial artery. By transmitting an ultrasonic beam, blood flow determination using the ultrasonic Doppler method was performed. On the other hand, the blood flow volume in the radial artery is acquired based on the received signal of the reflected wave from the blood vessel diameter acquisition sensor 23a that transmits an ultrasonic beam perpendicular to the traveling direction of the radial artery, and the blood flow is determined. It is also possible. In this case, the first ultrasonic probe only needs to include the ultrasonic sensor 23a.

  In addition, when performing blood flow determination by the ultrasonic Doppler method, a grating lobe component of an ultrasonic beam may be used instead of the reception signal of the reflected wave from the ultrasonic sensor 23b.

  FIG. 11 is a schematic diagram illustrating a schematic configuration example of the first ultrasonic probe 200-1 and the second ultrasonic probe 20-2 in the present modification. In addition, the same code | symbol is attached | subjected to the part similar to the said embodiment. In this modification, the configuration of the first ultrasonic probe 200-1 is different from that of the above embodiment. That is, the first ultrasonic probe 200-1 is configured by incorporating one ultrasonic sensor 23d in the outer case 213, and serves as both the blood vessel diameter acquisition sensor 23a and the blood flow acquisition sensor 23b of the above embodiment. ing. The ultrasonic sensor 23d is configured in the same manner as the blood vessel diameter acquisition sensor 23a of the first embodiment, and includes an ultrasonic element substrate 24d and an acoustic lens 26d, and with respect to the running direction of the radial artery 120. Then, an ultrasonic beam is transmitted vertically (arrow A41).

  Here, ultrasonic elements 25d are two-dimensionally arranged on the ultrasonic element substrate 24d, and are configured to perform ultrasonic measurement. In ultrasonic measurement, grating lobes (arrows A43 and A44) that are generally regarded as unnecessary components may occur. Since this grating lobe occurs when the pitch between adjacent ultrasonic elements 25d is shorter than the wavelength of the ultrasonic wave, the pitch of the ultrasonic element 25d can be as large as the grating lobe according to the wavelength used in ultrasonic measurement. The length is designed so that it does not occur. However, even when the pitch is adjusted, a grating lobe occurs when the ultrasonic sensor 23d is used with a high driving frequency (short ultrasonic wave). Therefore, in the present modification, the main body device 30 temporarily acquires the blood flow volume when detecting the pressing pressure at the time of blood flow generation (when executing steps S312 to S315 in FIG. 9 or step S411 in FIG. 10). In particular, control to increase the drive frequency of the ultrasonic sensor 23d is performed to generate a grating lobe. And the main body apparatus 30 acquires the blood flow volume by the method similar to the above-mentioned embodiment by receiving the reflected wave which the ultrasonic wave of the grating lobe component reflected in the living body, and monitors the acquired blood flow volume. Perform blood flow determination. Other parts can be configured in the same manner as in the above embodiment.

  Moreover, in above-described embodiment, the structure by which the pressure sensor 27 was integrated in the 2nd ultrasonic probe 20-2 was illustrated. On the other hand, the pressure sensor 27 only needs to be installed on the skin surface above the radial artery, and may be separate from the second ultrasonic probe 20-2. FIG. 12 is a diagram illustrating a mounting example of the first ultrasonic probe 200-1, the second ultrasonic probe 200-2, and the pressure sensor 27 in the present modification. FIG. 12 shows a mounting example when the pressure sensor 27 is separated from the second ultrasonic probe 20-2 in the configuration described in the modification of FIG. The second ultrasonic probe 200-2 of the present modification can be configured in the same manner as the second ultrasonic probe 20-2 of the above-described embodiment except that the pressure sensor 27 is a separate body.

  As shown in FIG. 12, in this modification, the pressure sensor unit 270 in which the pressure sensor 27 is housed in the exterior case 214 is connected to the first ultrasonic probe 200-1 and the second ultrasonic probe 200-1 separated by the inter-probe distance D1. It is hold | maintained with the holding | maintenance sheet | seat 40 so that those arrangement | sequence directions may be followed between the ultrasonic probes 200-2. When ultrasonic measurement is performed, the holding sheet 40 is mounted in a state in which the arrangement direction of the ultrasonic probe 200-1, the pressure sensor unit 270, and the ultrasonic probe 200-2 is aligned with the traveling direction of the radial artery 120. The surface is affixed to the skin surface 110. As a result, the ultrasonic probes 200-1 and 200-2 (the ultrasonic sensors incorporated therein) and the pressure sensor 27 are installed on the skin surface 110 above the radial artery 120, respectively. Further, the ultrasonic probes 200-1 and 200-2 (the ultrasonic sensors incorporated therein) are positioned with a distance D1 between the probes. Further, when detecting the pressing pressure at the time of blood flow generation, the user presses the skin surface 110 with a finger from above so as to press the pressure sensor unit 270 against the radial artery 120 (arrow A5).

  Note that the pressure sensor 27 may also be configured separately from the second ultrasonic probe 20-2 in the configuration of FIG. 2 described in the above embodiment.

  In the above-described embodiment, the first calibration is performed using the cuff sphygmomanometer 5 only for the first calibration. However, when a certain long period (for example, one week or one month) has elapsed, the first calibration is performed again. The first calibration may be performed. Even in that case, the cuff type sphygmomanometer 5 is not necessary in the second calibration. Therefore, the burden on the subject can be greatly reduced as compared with the conventional case in which the cuff type sphygmomanometer 5 is always used for each calibration.

  In the above-described embodiment, the pressure sensor 27 is exemplified as a configuration for detecting the pressing pressure at the time of blood flow generation. On the other hand, when the ultrasonic element of the ultrasonic sensor 23c incorporated in the second ultrasonic probe 20-2 is formed of a thin film piezoelectric element or the like, the ultrasonic wave is applied by the pressing pressure that presses the second ultrasonic probe 20-2. Since the output (impedance of the ultrasonic elements arranged on the ultrasonic element substrate 24c) fluctuates, the relationship between the fluctuation amount and the systolic blood pressure is detected and set, and used for calibration from the above-mentioned fluctuation amount. The systolic blood pressure Ps may be specified.

DESCRIPTION OF SYMBOLS 1 Blood pressure measuring device, 20-1, 200-1 1st ultrasonic probe, 20-2, 200-2 2nd ultrasonic probe, 23a, 23b, 23c, 23d Ultrasonic sensor, 27 Pressure sensor, 30 Main body Device, 31 operation unit, 32 display unit, 33 communication unit, 34 processing unit, 35a first ultrasonic measurement control unit, 35b second ultrasonic measurement control unit, 351b blood flow rate acquisition unit, 35c third ultrasonic wave Measurement control unit, 36 calibration unit, 361 first calibration unit, 363 second calibration unit, 37 blood pressure calculation unit, 38 storage unit, 381 blood pressure measurement program, 382 first calibration program, 383 second calibration program, 384 Reflected wave data, 385 tracking data, 386 blood flow data, 387 pressing pressure-blood pressure relational expression data, 388 correlation expression data, 389 measurement Pressure data, 5 cuff-type blood pressure meter

Claims (8)

A first ultrasonic probe placed on the skin surface above the radial artery;
A second ultrasonic probe placed on the skin surface above the radial artery;
A pressure sensor that is placed on the skin surface above the radial artery and detects the pressure applied to the radial artery;
When the measurement result of either the first ultrasonic probe or the second ultrasonic probe is used, the state where the radial artery is blocked by the pressing pressure is loosened and blood flow begins to occur (hereinafter referred to as the blood flow) Determining the timing of “when blood flow occurs” in the claims, and the pressing pressure when the blood flows are generated (hereinafter referred to as “pressing pressure when blood flows”) and the systole Referring to a given relationship with blood pressure, obtaining a systolic blood pressure from the detected value of the pressure sensor at the determined timing at the time of blood flow generation, the first ultrasonic probe and the second An operation for obtaining a pulse pressure using a measurement result of an ultrasonic probe and calibrating a correlation characteristic between a blood vessel diameter of the radial artery and a blood pressure using the obtained systolic blood pressure and the pulse pressure. And the processing section,
A blood pressure measurement device comprising: The arithmetic processing unit determines a timing when the blood flow is generated by performing blood flow determination by an ultrasonic Doppler method using any one of the first ultrasonic probe and the second ultrasonic probe. To
The blood pressure measurement device according to claim 1. The arithmetic processing unit performs blood flow determination by the ultrasonic Doppler method using a grating lobe component of any of the first ultrasonic probe and the second ultrasonic probe.
The blood pressure measurement device according to claim 2. The first ultrasonic probe and the second ultrasonic probe are installed at positions separated by a predetermined distance along the traveling direction of the radial artery,
The calculation processing unit obtains a pulse wave velocity from the predetermined distance and the measurement results of the first ultrasonic probe and the second ultrasonic probe, and performs a predetermined calculation using the pulse wave velocity. Obtaining the pulse pressure,
The blood pressure measurement device according to any one of claims 1 to 3. The arithmetic processing unit is based on the pulse wave velocity and the vascular property value of the radial artery based on the measurement result of any of the first ultrasonic probe and the second ultrasonic probe. The pulse pressure is obtained by executing the calculation for obtaining the pulse pressure.
The blood pressure measurement device according to claim 4. A setting unit for setting the relationship between the pressing pressure at the time of blood flow generation and the systolic blood pressure;
The blood pressure measurement device according to any one of claims 1 to 5, further comprising: A blood pressure calculator that obtains a blood vessel diameter of the radial artery using a measurement result of any of the first ultrasonic probe and the second ultrasonic probe, and calculates a blood pressure using the correlation characteristic;
The blood pressure measurement device according to any one of claims 1 to 6, further comprising: A first ultrasound probe placed on the skin surface above the radial artery, a second ultrasound probe placed on the skin surface above the radial artery, and a skin surface above the radial artery, the rib An apparatus comprising a pressure sensor for detecting pressure applied to an artery is a calibration method for calibrating a correlation characteristic between a blood vessel diameter of the radial artery and blood pressure,
Using the measurement result of either the first ultrasonic probe or the second ultrasonic probe to determine the timing when blood flow occurs;
With reference to a given relationship between the pressing pressure at the time of blood flow generation and the systolic blood pressure, obtaining the systolic blood pressure from the detected value of the pressure sensor at the determined timing at the time of blood flow generation;
Obtaining a pulse pressure using measurement results of the first ultrasonic probe and the second ultrasonic probe;
Using the determined systolic blood pressure and the pulse pressure to calibrate the correlation between the radial diameter of the radial artery and the blood pressure,
Calibration method including:

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