JP5927889B2 - Blood pressure measurement device and blood pressure measurement method - Google Patents

Description

  The present invention relates to an apparatus for measuring a blood pressure of a subject.

  2. Description of the Related Art Conventionally, devices that measure blood flow, blood vessel diameter, and blood pressure using ultrasonic waves, and devices that measure the elasticity of blood vessels have been devised. These devices are characterized in that measurement can be performed without causing pain or discomfort to the subject.

  For example, Patent Document 1 discloses a method of calculating blood pressure from a blood vessel elasticity index called a stiffness parameter and a blood vessel diameter, assuming that a change in blood pressure and a change in blood vessel diameter are nonlinear.

JP 2004-41382 A

  The technique disclosed in Patent Document 1 is a technique for calculating blood pressure based on a correlation characteristic between a blood vessel diameter and blood pressure. However, in relatively thin arteries such as limb arteries, the blood vessels are stiff, and therefore the variation in blood vessel diameter with respect to changes in blood pressure is negligible.

  For example, in the radial artery flowing through the wrist, the change in blood pressure accompanying pulsation is about 50 [mmHg], while the change in blood vessel diameter is about 40 [μm]. Therefore, for example, in order to calculate the blood pressure with an accuracy of 10 [mmHg], a blood vessel diameter measuring method capable of measuring in a unit of at least 8 [μm] is required. However, a blood vessel diameter measuring method that achieves this accuracy is considered difficult in practice.

  The present invention has been made in view of the above-described problems, and an object thereof is to propose a new blood pressure measurement method for improving blood pressure calculation accuracy.

  A first form for solving the above-described problems is that the blood vessel diameter measuring unit that measures the blood vessel diameter of the blood vessel to be measured in the measurement target portion, and the first position and the second position that are different in relative height to the heart A blood vessel diameter difference that is a difference between the first blood vessel diameter and the second blood vessel diameter measured by the blood vessel diameter measuring unit when the measurement target portion is positioned, and a correlation characteristic between a blood pressure and a blood vessel diameter of the measurement target blood vessel; A blood pressure measurement apparatus comprising: a blood pressure estimation unit that estimates a blood pressure of a subject using a hydraulic head pressure difference based on a difference in height direction between the first position and the second position.

  Further, as another form, when measuring the blood vessel diameter of the measurement target blood vessel in the measurement target region, and when the measurement target region is positioned at the first position and the second position having different relative heights with respect to the heart, The difference in blood vessel diameter, which is the difference between the measured first blood vessel diameter and the second blood vessel diameter, the correlation characteristics between the blood pressure and the blood vessel diameter of the blood vessel to be measured, and the difference in the height direction between the first position and the second position. It is good also as comprising the blood pressure measurement method including estimating the blood pressure of a subject using the head pressure difference based on this.

  According to the first aspect and the like, the difference between the first blood vessel diameter and the second blood vessel diameter measured when the measurement target site is located at the first position and the second position having different relative heights with respect to the heart. The blood pressure of the subject is estimated using a certain blood vessel diameter difference, a correlation characteristic between the blood pressure and the blood vessel diameter of the blood vessel to be measured, and a hydraulic head pressure difference based on a difference in height direction between the first position and the second position. .

  Since the weight of blood in the blood vessel from the heart to the measurement target site (so-called hydrohead pressure) according to the relative height of the measurement target site with respect to the height of the heart is added to the blood pressure, A difference occurs in the measured blood pressure between the first position and the second position having different heights. By utilizing this characteristic, by using the blood vessel diameter difference between the first blood vessel diameter and the second blood vessel diameter, the correlation characteristic between the blood pressure and the blood vessel diameter of the blood vessel to be measured, and the head pressure difference between the first position and the second position. The blood pressure of the subject can be estimated with high accuracy.

  Further, as a second mode, in the blood pressure measurement device according to the first mode, the blood pressure estimation unit has a characteristic value that conforms to a relationship between the blood pressure difference and the blood vessel diameter difference that is regarded as the blood pressure difference. A blood pressure measurement device that estimates the blood pressure of the subject based on the correlation characteristics may be configured.

  According to the second embodiment, the blood pressure of the subject is determined by a simple method of determining from the correlation characteristics a characteristic value that matches the relationship between the blood pressure difference and the blood vessel diameter difference in which the head pressure difference is regarded as a blood pressure difference. Can be estimated.

  Further, as a third form, in the blood pressure measurement device of the first or second form, the first blood vessel diameter and the second blood vessel diameter are diastolic blood vessel diameters, and the blood pressure estimating unit The diastolic blood pressure estimation unit that estimates the diastolic blood pressure of the subject using the blood vessel diameter difference and the hydrocephalic pressure difference, the diastolic blood pressure, and the pulsation of the blood vessel diameter measured by the blood vessel diameter measurement unit The blood pressure measurement device may include a systolic blood pressure estimation unit that estimates the systolic blood pressure of the subject using the fluctuation range accompanying the above and the correlation characteristics.

  According to the third embodiment, the first blood vessel diameter and the second blood vessel diameter are diastolic blood vessel diameters. The diastolic blood pressure of the subject is estimated using the correlation characteristic, the blood vessel diameter difference, and the hydrocephalic pressure difference, and the fluctuation range associated with the diastolic blood pressure and the pulsation of the blood vessel diameter measured by the blood vessel diameter measurement unit And the correlation characteristic are used to estimate the systolic blood pressure of the subject. If the diastolic blood pressure can be estimated using the technique of the above form, the systolic blood pressure of the subject can be easily derived from the fluctuation range accompanying the pulsation of the blood vessel diameter and the correlation characteristics.

  Further, as a fourth form, in the blood pressure measurement device according to the first or second form, the first blood vessel diameter and the second blood vessel diameter are systolic blood vessel diameters, and the blood pressure estimating unit Using the blood vessel diameter difference and the hydrocephalus pressure difference, the systolic blood pressure estimation unit that estimates the systolic blood pressure of the subject, the systolic blood pressure, and the pulsation of the blood vessel diameter measured by the blood vessel diameter measurement unit The blood pressure measurement device may include a diastolic blood pressure estimation unit that estimates the diastolic blood pressure of the subject using the fluctuation range associated with the blood pressure and the correlation characteristic.

  According to the fourth embodiment, the first blood vessel diameter and the second blood vessel diameter are systolic blood vessel diameters. Then, using the correlation characteristic, the blood vessel diameter difference, and the hydrocephalic pressure difference, the subject's systolic blood pressure is estimated, and the fluctuation range accompanying the pulsation of the blood pressure measured by the blood vessel diameter measuring unit and the systolic blood pressure. And the correlation characteristic are used to estimate the diastolic blood pressure of the subject. If the systolic blood pressure can be estimated using the method of the above-described form, the diastolic blood pressure of the subject can be easily derived from the fluctuation range accompanying the pulsation of the blood vessel diameter and the correlation characteristics.

  Further, as a fifth mode, in the blood pressure measurement device according to the first mode, the blood pressure estimation unit may calculate the correlation characteristics, the blood vessel diameter difference, and the pulsation of the blood vessel diameter measured by the blood vessel diameter measurement unit. A blood pressure measurement device that estimates the diastolic blood pressure and systolic blood pressure of the subject using the accompanying fluctuation width and the hydrocephalic pressure difference may be configured.

  According to the fifth aspect, by using the correlation characteristics, the blood vessel diameter difference, the fluctuation range associated with the pulsation of the blood vessel diameter measured by the blood vessel diameter measuring unit, and the hydrocephalic pressure difference, the subject can be expanded. The systolic blood pressure and the systolic blood pressure can be estimated.

  As a sixth aspect, in the blood pressure measurement device according to any one of the first to fifth aspects, the blood vessel diameter measurement unit is configured to continuously measure a blood vessel diameter, and the blood pressure estimation unit includes: The blood pressure measurement device calculates the blood vessel diameter difference from the difference between the first blood vessel diameter when the measurement target portion is located at the first position and the second blood vessel diameter when the measurement target site is located at the second position. It is good also as comprising.

  According to the sixth aspect, the blood vessel diameter measuring unit is configured to be able to continuously measure the blood vessel diameter. Then, the blood pressure estimation unit calculates the blood vessel diameter difference from the difference between the first blood vessel diameter when the measurement target site is located at the first position and the second blood vessel diameter when the measurement target site is located at the second position. A blood vessel diameter difference is calculated by independently measuring the first blood vessel diameter when the measurement target region is positioned at the first position and the second blood vessel diameter when the measurement target region is positioned at the second position. Instead, by calculating the blood vessel diameter difference from the difference between the first blood vessel diameter and the second blood vessel diameter obtained by continuously measuring the blood vessel diameter, the calculation accuracy of the blood vessel diameter difference is improved, and thus blood pressure estimation Accuracy can be improved.

(1) Schematic configuration diagram of an ultrasonic sphygmomanometer. (2) A state diagram in which an ultrasonic sphygmomanometer is attached. Explanatory drawing of a 1st position and a 2nd position. Explanatory drawing of the correlation characteristic of a blood vessel diameter and blood pressure. Explanatory drawing of the principle of blood pressure estimation. Explanatory drawing of the principle of blood pressure estimation. The block diagram which shows an example of a function structure of an ultrasonic sphygmomanometer. The flowchart which shows the flow of a main process. The flowchart which shows the flow of an ultrasonic blood pressure measurement process. The flowchart which shows the flow of a blood-pressure estimation process. The flowchart which shows the flow of a 2nd blood pressure estimation process.

  As an embodiment to which the present invention is applied, an embodiment of a blood pressure measurement device that measures the blood pressure of a subject using the subject's wrist as the measurement target site and the measurement target artery as the radial artery will be described. However, it is needless to say that embodiments to which the present invention is applicable are not limited to the embodiments described below.

1. Schematic Configuration FIG. 1A is a configuration diagram of a system related to blood pressure measurement according to the present embodiment. This blood pressure measurement system includes an ultrasonic sphygmomanometer 1 that can be used by being attached to a wrist of a subject, and a cuff type sphygmomanometer 3 that is used by being wrapped around an upper arm. Is done.

  The cuff type sphygmomanometer 3 wraps a cuff that senses blood pressure around the upper arm of the subject and measures the blood pressure of the brachial artery. In the present embodiment, the cuff sphygmomanometer 3 is used for calibrating the ultrasonic sphygmomanometer 1. After the calibration, the cuff type sphygmomanometer 3 is removed, and the blood pressure is measured using the ultrasonic sphygmomanometer 1 alone.

  The ultrasonic sphygmomanometer 1 is configured so that the main body can be attached to a measurement target part (particularly, a wrist) of a subject using a belt-like part 15. The belt-shaped portion 15 is a mounting tool for mounting the apparatus main body on the measurement target site of the subject, and includes a band having a hook-and-loop fastener, a clip for holding the measurement site, and the like. The main body of the ultrasonic sphygmomanometer 1 is configured by connecting a first part 1A and a second part 1B via a hinge part 11.

  In the first part 1A, an operation button 12, a liquid crystal display 13, and a speaker 14 are provided.

  The operation button 12 is used by the subject to input a blood pressure measurement start instruction and various amounts related to blood pressure measurement.

  The liquid crystal display 13 displays the blood pressure measurement result by the ultrasonic sphygmomanometer 1. As a display method, the blood pressure measurement value may be displayed as a numerical value, or may be displayed as a graph or the like.

  From the speaker 14, various kinds of voice guidance related to blood pressure measurement are output as sound. In the present embodiment, it is necessary to measure blood pressure with the cuff sphygmomanometer 3 in executing the calibration process. Therefore, for example, a voice guidance for instructing attachment / detachment of the cuff type sphygmomanometer 3 may be output from the speaker 14.

  The sensor part 20 is provided in the 2nd site | part 1B. The sensor unit 20 includes an ultrasonic sensor 21 and an atmospheric pressure sensor 23 (see FIG. 6).

  The ultrasonic sensor 21 is an ultrasonic transmission / reception unit in which ultrasonic transducers are arranged in an array. The ultrasonic sensor 21 transmits an ultrasonic pulse signal or burst signal of several MHz to several tens of MHz from the transmission unit toward the measurement target blood vessel. Then, the reception unit receives the reflected waves from the front wall and the rear wall of the measurement target blood vessel, and measures the blood vessel diameter of the measurement target blood vessel from the reception time difference between the reflection waves of the front wall and the rear wall.

  Although not shown, the main body of the ultrasonic sphygmomanometer 1 incorporates a control board for controlling the devices in an integrated manner. On the control board, a microprocessor, a memory, a circuit for transmitting and receiving ultrasonic waves, an internal battery, and the like are mounted.

  FIG. 1 (2) is a diagram showing a state in which the ultrasonic sphygmomanometer 1 is mounted on the wrist of the left hand of the subject. As shown in FIG. 1 (2), the ultrasonic sphygmomanometer 1 is attached to the wrist of a subject in such a posture that the main body portion faces the inside of the wrist. At this time, the second part 1B provided with the sensor unit 20 is mounted so as to be on the thumb side of the wrist of the subject. This is because the measurement target blood vessel is the radial artery flowing on the thumb side of the wrist, and the sensor unit 20 is positioned directly above the radial artery.

2. Principle FIG. 2 is a diagram showing the relationship between the ultrasonic sphygmomanometer 1 mounted on the wrist of a subject and the height direction. The state in which the ultrasonic sphygmomanometer 1 is attached to the wrist of the left arm of the subject is illustrated. The weight of blood in the blood vessel from the heart to the wrist that is the measurement target site (so-called hydrohead pressure) is added to the blood pressure. Therefore, a difference occurs in the measured blood pressure depending on the arm height.

  In the state of the arm indicated by the alternate long and short dash line, the height of the wrist is approximately the same as the height of the heart. In this state, the water head pressure is almost zero. On the other hand, in the state of the arm shown by the solid line, since the wrist is at a position lower than the heart, the blood pressure is measured in a state where the weight of blood due to the drop from the heart to the wrist is added. Therefore, if the blood pressure is measured with the arm lowered, the measured value of the blood pressure is higher than when the blood pressure is measured at the height of the heart.

  For example, when the arm is raised above the head, the height of the wrist is higher than that of the heart, so the blood weight is subtracted and the blood pressure is measured. As a result, the measured value of blood pressure is lower than when blood pressure is measured at the height of the heart.

  In this embodiment, paying attention to this characteristic, the first blood vessel diameter and the second blood vessel diameter measured when the measurement target part is positioned at the first position and the second position having different relative heights with respect to the heart are used. Thus, a method for estimating the blood pressure of the subject is proposed. In this embodiment, a case where the position of the heart height is the first position and the position of the wrist height when the arm is lowered is the second position will be described as an example.

FIG. 3 is a diagram illustrating an example of a correlation characteristic between a blood vessel diameter and blood pressure. The blood vessel diameter and blood pressure can be linked with a certain nonlinear correlation characteristic. Specifically, using the pressure applied to the blood vessel and the blood vessel diameter at each blood pressure, for example, the correlation characteristic can be expressed by a correlation equation such as the following equation (1).
P = Pd · exp [β (D / Dd−1)] (1)
Where β = ln (Ps / Pd) / (Ds / Dd−1)

  However, “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 called a stiffness parameter.

  In FIG. 3, the coordinate value composed of the diastolic blood vessel diameter and blood pressure when the first position is the measurement position is plotted as a white circle coordinate value P1 on the correlation equation. In addition, the coordinate value composed of the diastolic blood vessel diameter and blood pressure when the second position is the measurement position is plotted on the correlation equation as the coordinate value P2 of the black circle.

Since the second position is lower than the first position, the blood pressure at point P2 is higher than that at point P1. This increase in blood pressure is caused by the difference “ΔPH” in the head pressure (hereinafter referred to as “head pressure difference”). The hydraulic head pressure difference “ΔPH” can be calculated by the equation “ΔPH = ρgΔh” using the height difference “Δh” between the first position and the second position. However, “ρ” is the density of blood. The blood density “ρ” is about 1.055 ± 0.005 [g / cm ³ ] in terms of gender differences, and can therefore be regarded as a constant. “G” is a gravitational acceleration.

  The height difference “Δh” can be estimated based on the measurement result of the atmospheric pressure sensor 23. That is, the atmospheric pressure (first atmospheric pressure) measured by the atmospheric pressure sensor 23 when the measurement target region is positioned at the first position and the atmospheric pressure (first atmospheric pressure) measured by the atmospheric pressure sensor 23 when the measurement target region is positioned at the second position. From the atmospheric pressure difference from the second atmospheric pressure), the height difference “Δh” is estimated according to a conventionally known method. If the height difference “Δh” is determined, the head pressure difference “ΔPH” is also determined.

  “ΔDHd” is a diastolic blood vessel diameter “Dd1” (hereinafter referred to as “first diastolic blood vessel diameter”) measured when the measurement target region is positioned at the first position, and a measurement target at the second position. This is a difference from the diastolic blood vessel diameter “Dd2” (hereinafter referred to as “second diastolic blood vessel diameter”) measured when the site is located, and in this embodiment, referred to as “diastolic blood vessel diameter difference”. . The diastolic blood vessel diameter difference “ΔDHd” can be measured using the ultrasonic sensor 21.

  Further, in FIG. 3, the coordinate value composed of the blood vessel diameter and blood pressure in the systole when the first position is the measurement position is plotted as a white triangle coordinate value Q1 on the correlation equation. Further, the coordinate value composed of the blood vessel diameter and blood pressure in the systole when the second position is set as the measurement position is plotted on the correlation equation as the coordinate value Q2 of the black triangle. Regarding the systolic blood pressure, the systolic blood pressure at the second position is higher due to the hydraulic head pressure difference “ΔPH”.

  “ΔDHs” includes a systolic blood vessel diameter “Ds1” (hereinafter referred to as “first systolic blood vessel diameter”) measured in a state where the measurement target region is the first position, and a second measurement target region. This is the difference from the systolic blood vessel diameter “Dd2” (hereinafter referred to as “second systolic blood vessel diameter”) measured in the position, and is referred to as “systolic blood vessel diameter difference” in this embodiment. The systolic blood vessel diameter difference “ΔDHs” can be measured using ultrasonic waves.

  The purpose of this embodiment is to estimate the blood pressure of the subject. As a blood pressure estimation method, (1) firstly estimating diastolic blood pressure, and using the estimated diastolic blood pressure to estimate systolic blood pressure; and (2) first estimating and estimating systolic blood pressure. There is a method for estimating diastolic blood pressure using systolic blood pressure. Here, a case where blood pressure is estimated by the method (1) will be described.

  FIG. 4 is an explanatory diagram of a method for estimating diastolic blood pressure. Consider an L-shaped pattern having the diastolic blood vessel diameter difference “ΔDHd” described in FIG. 3 as a base and the head pressure difference “ΔPH” as a height. Specifically, consider a pattern as shown at the top of the graph of FIG. At this time, the characteristic value R is the vertex of the line segment having the height of the hydraulic head pressure difference “ΔPH”, and the characteristic value S is a value corresponding to the leftmost point of the line segment having the base of the diastolic blood vessel diameter difference “ΔDHd”. .

  At this time, for example, the characteristic value R and the characteristic value S that minimize the error with respect to the blood vessel radial direction are determined while sliding the characteristic value R on the correlation equation. That is, a characteristic value that matches the relationship between the blood pressure difference and the blood vessel diameter difference in which the head pressure difference is regarded as a blood pressure difference is determined from the correlation characteristic.

  This will be specifically described. The blood vessel diameter corresponding to the characteristic value R is “Dd1”, and the blood vessel diameter corresponding to the characteristic value S is “Dd2”. The blood pressure corresponding to the characteristic value R is “P”. Further, the blood vessel diameter corresponding to the coordinate value obtained by substituting the blood pressure “P−ΔPH” obtained by subtracting the hydraulic head pressure difference “ΔPH” from the blood pressure “P” into the correlation equation is set to “Dd3”. At this time, the diastolic error is defined by “Ed = Dd2−Dd3”, and the characteristic value R is slid on the correlation equation so as to reduce the diastolic error “Ed”.

  In FIG. 4, the characteristic value R1 is the diastolic error “Ed> 0”, and the absolute value thereof is also a relatively large value. When the characteristic value is slid from R1 to R2, the absolute value of the diastolic error “Ed” becomes smaller than that of the characteristic value R1. Further, when the characteristic value is slid from R2 to R3, the diastolic error “Ed” becomes almost zero. When the characteristic value is slid further upward from this state, the diastolic error “Ed” becomes a negative value. When the characteristic value R is slid upward along the correlation equation (characteristic values R4 and R5), the absolute value of the diastolic error “Ed” gradually increases.

  Therefore, by searching for a characteristic value that minimizes the absolute value of the diastolic error “Ed” while changing the blood pressure value on the correlation equation, the head pressure difference “ΔPH” and the diastolic blood vessel diameter difference “ΔDHd” It is possible to obtain a blood pressure that conforms to a fixed pattern. In FIG. 4, the characteristic values R3 and S3 are characteristic values that minimize the absolute value of the diastolic error “Ed”. In this case, the blood pressure corresponding to the characteristic value R3 is estimated as the diastolic blood pressure.

  FIG. 5 is an explanatory diagram of a method for estimating systolic blood pressure. If the diastolic blood pressure is estimated according to the principle explained in FIG. 4, the blood vessel diameter corresponding to the estimated diastolic blood pressure is obtained from the correlation equation and is set as the diastolic blood vessel diameter. Next, the blood vessel diameter fluctuation amount “ΔD” accompanying pulsation is measured using ultrasonic waves. The blood vessel diameter obtained by adding the blood vessel diameter fluctuation amount “ΔD” to the diastolic blood vessel diameter is defined as the systolic blood vessel diameter. Finally, the blood pressure obtained by substituting the systolic blood vessel diameter into the correlation equation is estimated as the systolic blood pressure.

3. Functional Configuration FIG. 6 is a block diagram illustrating an example of a functional configuration of the ultrasonic sphygmomanometer 1. The ultrasonic sphygmomanometer 1 includes a processing unit 100, an ultrasonic sensor 21, an atmospheric pressure sensor 23, an operation unit 200, a display unit 300, a sound output unit 400, a communication unit 500, a clock unit 600, and a memory. Part 800.

  The ultrasonic sensor 21 is an ultrasonic transmission / reception unit and includes an ultrasonic transmission / reception circuit. For example, according to the transmission / reception control signal output from the transmission / reception control unit 120, the transmission / reception circuit transmits and receives ultrasonic waves by switching between the ultrasonic transmission mode and the reception mode in a time division manner.

  The transmission / reception circuit includes an ultrasonic oscillation circuit that generates a pulse signal of a predetermined frequency, a transmission delay circuit that delays the generated pulse signal, and the like as a configuration for transmission. The reception configuration includes a reception delay circuit that delays the reception signal, a filter that extracts a predetermined frequency component from the reception signal, an amplifier that amplifies the reception signal, and the like.

  The atmospheric pressure sensor 23 is a sensor that measures atmospheric pressure. The atmospheric pressure sensor 23 converts the measurement result of atmospheric pressure into an electrical signal and outputs it to the processing unit 100.

  The processing unit 100 is a control device and an arithmetic device that comprehensively control each unit of the ultrasonic sphygmomanometer 1, and is a microprocessor such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor), or an ASIC (Application Specific Integrated). Circuit) and the like.

  The processing unit 100 includes a transmission / reception control unit 120, a blood vessel diameter calculation unit 130, and a blood pressure estimation unit 140 as main functional units. However, these functional units are only described as one embodiment, and all the functional units are not necessarily required as essential components.

  The transmission / reception control unit 120 controls transmission / reception of ultrasonic waves by the ultrasonic sensor 21. Specifically, a transmission / reception control signal is output to the ultrasonic sensor 21 to perform control for switching between the transmission mode and the reception mode.

  The blood vessel diameter calculation unit 130 calculates the blood vessel diameter of the measurement target blood vessel based on the signal processing result input from the ultrasonic sensor 21. Specifically, the blood vessel diameter of the measurement target blood vessel is calculated by detecting the reception time difference between the reflected waves of the ultrasonic waves from the front wall and the rear wall of the measurement target blood vessel.

  The ultrasonic sensor 21, the transmission / reception control unit 120, and the blood vessel diameter calculation unit 130 constitute a blood vessel diameter measurement unit 110 that measures the blood vessel diameter of the measurement target blood vessel in the measurement target region. The blood vessel diameter measuring unit 110 is configured to continuously measure the blood vessel diameter. As a technique for continuously measuring the blood vessel diameter, for example, a phase difference tracking method can be applied. In addition, since the phase difference tracking method itself is conventionally well-known, description is abbreviate | omitted for the detail.

  The blood pressure estimation unit 140 estimates the blood pressure of the subject using the blood vessel diameter calculated by the blood vessel diameter calculation unit 130 and the correlation equation representing the correlation characteristic between the blood pressure and the blood vessel diameter stored in the calibration data 820. To do. The blood pressure estimation unit 140 includes a diastolic blood pressure estimation unit 141 that estimates diastolic blood pressure, and a systolic blood pressure estimation unit 143 that estimates systolic blood pressure.

  The operation unit 200 is an input device having a button switch or the like, and outputs a signal of a pressed button to the processing unit 100. By operating the operation unit 200, various instructions such as a blood vessel diameter measurement start instruction are input. The operation unit 200 corresponds to the operation button 12 in FIG.

  The display unit 300 includes an LCD (Liquid Crystal Display) or the like, and is a display device that performs various displays based on a display signal input from the processing unit 100. Information such as blood pressure calculated by the blood pressure estimation unit 140 is displayed on the display unit 300. The display unit 300 corresponds to the liquid crystal display 13 of FIG.

  The sound output unit 400 is a sound output device that outputs various sounds based on the sound output signal input from the processing unit 100. The sound output unit 400 corresponds to the speaker 14 of FIG.

  The communication unit 500 is a communication device for transmitting and receiving information used inside the device to and from an external information processing device under the control of the processing unit 100. As a communication method of the communication unit 500, a form of wired connection via a cable compliant with a predetermined communication standard, a form of connection via an intermediate device also used as a charger called a cradle, or short-range wireless communication is used. Various systems such as a wireless connection type can be applied. In the present embodiment, the communication unit 500 transmits and receives data to and from the cuff sphygmomanometer 3 using short-range wireless communication.

  The clock unit 600 includes a crystal oscillator including a crystal resonator and an oscillation circuit, and is a time measuring device that measures time. The time measured by the clock unit 600 is output to the processing unit 100 as needed.

  The storage unit 800 includes a storage device such as a ROM (Read Only Memory), a flash ROM, and a RAM (Random Access Memory). The storage unit 800 stores a system program for the ultrasonic sphygmomanometer 1, various programs for realizing various functions such as a transmission / reception control function, a blood vessel diameter measurement function, and a blood pressure estimation function, data, and the like. In addition, it has a work area for temporarily storing data being processed and results of various processes.

  The storage unit 800 stores a main program 810 that is read by the processing unit 100 and executed as a main process (see FIG. 7), for example. The main program 810 includes an ultrasonic blood pressure measurement program 811 executed as an ultrasonic blood pressure measurement process (see FIG. 8) and a blood pressure estimation program 813 executed as a blood pressure estimation process (see FIG. 9) as subroutines. These processes will be described later in detail using a flowchart.

  The storage unit 800 stores calibration data 820, blood vessel diameter data 830, and blood pressure data 840 as data.

  The calibration data 820 is data in which the correlation characteristic between the blood vessel diameter and the blood pressure obtained by performing the calibration processing is stored, and includes, for example, a correlation formula 821 between the blood vessel diameter and the blood pressure.

  The blood vessel diameter data 830 is data in which the blood vessel diameter measured by the blood vessel diameter measuring unit 110 is stored. This includes diastolic vessel diameter and systolic vessel diameter.

  The blood pressure data 840 is data in which the blood pressure measured by the blood pressure estimation unit 140 is stored. This includes diastolic blood pressure and systolic blood pressure.

4). Processing Flow FIG. 7 is a flowchart showing a flow of main processing executed by the processing unit 100 according to the main program 810 stored in the storage unit 800.

  First, the transmission / reception control unit 120 starts ultrasonic transmission / reception control by outputting an ultrasonic transmission / reception control signal to the ultrasonic sensor 21 (step A1). Then, the processing unit 100 instructs the subject to wear the cuff sphygmomanometer 3 (step A3). The mounting instruction may be realized by displaying a predetermined message or the like on the display unit 300 or may be realized by outputting a predetermined voice guidance or the like from the sound output unit 400.

  Next, the processing unit 100 acquires the diastolic blood pressure “Pd” and the systolic blood pressure “Ps” from the cuff sphygmomanometer 3 via the communication unit 500 and stores them in the storage unit 800 (step A5). The blood vessel diameter calculation unit 130 calculates the diastolic blood vessel diameter “Dd” and the systolic blood vessel diameter “Ds” based on the reflected wave of the ultrasonic wave received by the ultrasonic sensor 21, and the blood vessels in the storage unit 800. The diameter data 830 is stored (step A7).

  Next, the processing unit 100 uses the diastolic blood pressure “Pd” and the systolic blood pressure “Ps” acquired in step A5, and the diastolic blood vessel diameter “Dd” and the systolic blood vessel diameter “Ds” calculated in step A7. Then, the correlation equation 821 indicating the correlation characteristic between the blood vessel diameter and the blood pressure is determined and stored in the calibration data 820 of the storage unit 800 (step A9). Thereafter, the processing unit 100 instructs the subject to remove the cuff sphygmomanometer 3 (step A11).

  Next, the processing unit 100 determines whether or not it is the blood pressure measurement timing (step A13). And when it determines with it being measurement timing (step A13; Yes), an ultrasonic blood pressure measurement process is performed according to the ultrasonic blood pressure measurement program 811 memorize | stored in the memory | storage part 800 (step A15).

FIG. 8 is a flowchart showing the flow of ultrasonic blood pressure measurement processing.
First, the processing unit 100 issues an arm stationary instruction at the first position (heart height position) (step B1). Then, the blood vessel diameter calculation unit 130 calculates the diastolic blood vessel diameter and the systolic blood vessel diameter based on the reflected wave of the ultrasonic wave, and the first diastolic blood vessel diameter “Dd1” and the first systolic blood vessel diameter “Ds1”, respectively. Is stored in the blood vessel diameter data 830 of the storage unit 800 (step B3). Then, the processing unit 100 acquires the atmospheric pressure from the atmospheric pressure sensor 23 and stores it in the storage unit 800 as the first atmospheric pressure (step B5).

  Next, the processing unit 100 issues an arm stationary instruction at the second position (the wrist height position when the arm is vertically lowered) (step B7). Then, the blood vessel diameter calculation unit 130 calculates the diastolic blood vessel diameter and the systolic blood vessel diameter based on the reflected wave of the ultrasonic wave, and the second diastolic blood vessel diameter “Dd2” and the second systolic blood vessel diameter “Ds2”, respectively. Is stored in the blood vessel diameter data 830 of the storage unit 800 (step B9). Then, the processing unit 100 acquires the atmospheric pressure from the atmospheric pressure sensor 23 and stores it in the storage unit 800 as the second atmospheric pressure (step B11).

  Here, during a series of operations in which the subject changes the position of the wrist that is the measurement target site from the first position to the second position, the blood vessel diameter measuring unit 110 uses the phase difference tracking method, for example, to measure the blood vessel diameter. It is effective to measure continuously.

  When the first blood vessel diameter when the wrist is positioned at the first position and the second blood vessel diameter when the wrist is positioned at the second position are measured independently, the measurement accuracy of the blood vessel diameter by ultrasound is sufficient. It may not be. That is, if the absolute value of the blood vessel diameter at each position is used, the blood vessel diameter difference may not be calculated correctly. However, if the blood vessel diameter is continuously measured during a series of operations until the wrist position changes from the first position to the second position, the relative change in the blood vessel diameter from the start position to the end position And the blood vessel diameter difference can be correctly calculated from the blood vessel diameters at the start point position and the end point position.

  Next, the processing unit 100 estimates the height difference “Δh” between the first position and the second position based on the atmospheric pressure difference between the first atmospheric pressure acquired in Step B5 and the second atmospheric pressure acquired in Step B11. (Step B13). Then, the processing unit 100 calculates the hydraulic head pressure difference “ΔPH = ρgΔh” using the estimated height difference “Δh” (step B15).

  Next, the blood pressure estimation unit 140 performs blood pressure estimation processing according to the blood pressure estimation program 813 stored in the storage unit 800 (step B17). Then, the processing unit 100 ends the ultrasonic blood pressure measurement process.

FIG. 9 is a flowchart showing the flow of blood pressure estimation processing.
First, the diastolic blood pressure estimation unit 141 calculates a diastolic blood vessel diameter difference “ΔDHd” (step C1). Specifically, using the first diastolic blood vessel diameter “Dd1” calculated in step B3 and the second diastolic blood vessel diameter “Dd2” calculated in step B9, diastole is performed according to “ΔDHd = Dd1−Dd2”. The blood vessel diameter difference is calculated.

  Next, the diastolic blood pressure estimation unit 141 initially sets the blood pressure to “Pn” (step C3). As an initial value of blood pressure, an arbitrary value can be set in the first blood pressure measurement, and the blood pressure value measured last time can be set in the second and subsequent measurements.

  Thereafter, the diastolic blood pressure estimation unit 141 calculates a blood vessel diameter “Dn1” corresponding to “Pn” using the correlation equation 821 stored in the calibration data 820 (step C5). In addition, the diastolic blood pressure estimation unit 141 calculates the blood vessel diameter “Dn2” corresponding to “Pn−ΔPH” using the correlation equation 821 (step C7).

  Next, the diastolic blood pressure estimation unit 141 uses the diastolic blood vessel diameter difference “ΔDHd” calculated in step C1, the blood vessel diameter “Dn1” calculated in step C5, and the blood vessel diameter “Dn2” calculated in step C7. Then, the diastolic error “Ed = (Dn1−Dn2) −ΔDHd” is calculated (step C9).

  Thereafter, the diastolic blood pressure estimation unit 141 determines whether or not the sign of the diastolic error “Ed” calculated in step C9 is inverted (step C11), and when it is determined that it is not inverted (step C11). No), the sign of the diastolic error “Ed” is determined (step C13).

  When it is determined that the sign is positive (step C13; positive), the diastolic blood pressure estimation unit 141 adds 1 [mmHg] to the current blood pressure setting value “Pn” and sets the setting value “Pn”. Update (step C15). If it is determined that the sign is negative (step C13; negative), the diastolic blood pressure estimation unit 141 subtracts 1 [mmHg] from the current blood pressure setting value “Pn” to obtain the setting value “Pn”. "Is updated (step C17). After these steps, the diastolic blood pressure estimation unit 141 returns to step C5.

  When it is determined in step C11 that the positive / negative sign of the diastolic error “Ed” has been inverted (step C11; Yes), the diastolic blood pressure estimation unit 141 before and after the positive / negative sign is inverted. The smaller absolute value of “Pn” is estimated as the diastolic blood pressure and stored in the blood pressure data 840 of the storage unit 800 (step C19).

  Next, the systolic blood pressure estimation unit 143 calculates a blood vessel diameter fluctuation range “ΔD” accompanying pulsation (step C21). Specifically, using the second diastolic blood vessel diameter “Dd2” and the second systolic blood vessel diameter “Ds2” obtained in step B9, the blood vessel diameter fluctuation width is calculated as “ΔD = Ds2−Dd2”.

  Thereafter, the systolic blood pressure estimation unit 143 estimates and stores the systolic blood pressure using the correlation equation 821, the diastolic blood pressure estimated in step C19, and the vascular diameter fluctuation range “ΔD” calculated in step C21. The blood pressure data 840 of the unit 800 is stored (step C23). Then, the blood pressure estimation unit 140 ends the blood pressure estimation process.

  Returning to the main process in FIG. 7, after performing the ultrasonic blood pressure measurement process, the processing unit 100 uses the latest diastolic blood pressure estimated value and systolic blood pressure estimated value stored in the storage unit 800, and The display is updated (step A17).

  Thereafter, the processing unit 100 determines whether or not to end the blood pressure measurement (step A19). If it is determined that the measurement is not yet ended (step A19; No), it is determined whether or not it is the calibration timing. (Step A21). Various timings can be set as the calibration timing in this case. For example, it may be determined that it is the calibration timing when the time measured by the clock unit 600 reaches a predetermined time (for example, 8:00 in the morning).

  If it determines with it being a calibration timing (step A21; Yes), the process part 100 will return to step A3. Then, calibration using the cuff type sphygmomanometer 3 is performed again. If it is determined that it is not the calibration timing (step A21; No), the processing unit 100 returns to step A13. If it determines with complete | finishing the measurement of blood pressure in step A19 (step A19; Yes), the process part 100 will complete | finish a main process.

5. In the ultrasonic sphygmomanometer 1, the first blood vessel diameter and the second blood vessel measured by the blood vessel diameter measuring unit 110 when the measurement target part is located at the first position and the second position where the relative height to the heart is different. A blood vessel diameter difference that is a difference in blood vessel diameter, a correlation formula 821 that defines a correlation characteristic between a blood pressure and a blood vessel diameter of a measurement target blood vessel, and a hydraulic head pressure difference based on a difference in height direction between the first position and the second position. The blood pressure estimation unit 140 estimates the blood pressure of the subject.

  The relative height of the measurement target region with respect to the height of the heart adds the weight of blood in the blood vessel from the heart to the measurement target region (so-called hydrohead pressure) to the blood pressure. A difference occurs in the measured blood pressure between the first position and the second position having different values. Based on this characteristic, by using the correlation characteristics between blood pressure and the blood vessel diameter of the blood vessel to be measured, the blood vessel diameter difference between the first blood vessel diameter and the second blood vessel diameter, and the head pressure difference between the first position and the second position, It becomes possible to correctly estimate the blood pressure of the subject.

  The blood pressure estimation unit 140 estimates a blood pressure of the subject by determining, from the correlation characteristics, a characteristic value that matches the relationship between the blood pressure difference and the blood vessel diameter difference in which the head pressure difference is regarded as a blood pressure difference. Specifically, the diastolic blood pressure estimation unit 141 correlates a pattern (relation between a blood pressure difference and a blood vessel diameter difference) determined by the blood pressure difference in which the hydraulic head pressure difference is regarded as a blood pressure difference and the blood vessel diameter difference in the diastole. The diastolic blood pressure of the subject is estimated by determining which part on Formula 821 is suitable. According to this method, the diastolic blood pressure of the subject can be easily estimated by a method of searching for a portion where the pattern matches on the correlation equation.

  If the diastolic blood pressure is estimated as described above, the systolic blood pressure estimation unit 143 correlates the diastolic blood pressure with the fluctuation width associated with the pulsation of the blood vessel diameter measured by the blood vessel diameter measurement unit 110. 821 is used to estimate the systolic blood pressure of the subject. The systolic blood pressure of the subject can be easily estimated from the fluctuation range associated with the pulsation of the blood vessel diameter and the correlation equation 823.

  The blood vessel diameter measuring unit 110 is configured to be able to continuously measure the blood vessel diameter. Then, the blood pressure estimation unit 140 calculates a blood vessel diameter difference from the difference between the first blood vessel diameter when the measurement target site is located at the first position and the second blood vessel diameter when the measurement target site is located at the second position. A blood vessel diameter difference is calculated by independently measuring the first blood vessel diameter when the measurement target region is positioned at the first position and the second blood vessel diameter when the measurement target region is positioned at the second position. Instead, by calculating the blood vessel diameter difference from the difference between the first blood vessel diameter and the second blood vessel diameter obtained by continuously measuring the blood vessel diameter, the calculation accuracy of the blood vessel diameter difference is improved, and thus blood pressure estimation Accuracy can be improved.

6). Modifications Embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be changed as appropriate without departing from the spirit of the present invention. Hereinafter, modified examples will be described.

6-1. Measurement target artery In the above embodiment, the measurement target artery has been described as the radial artery of the wrist, but other arteries may of course be the measurement target artery. Since the method of this embodiment is particularly effective when a relatively hard blood vessel is a measurement target, for example, a limb artery other than the radial artery may be used as the measurement target artery.

6-2. In the above embodiment, the blood vessel diameter measurement method has been described as a measurement method using ultrasonic waves. However, the blood vessel diameter measurement method is not limited to this. For example, a method of irradiating light of a predetermined wavelength from a light emitting element toward an artery to be measured and measuring a blood vessel diameter based on the reflected light may be adopted.

6-3. Ultrasonic Sphygmomanometer In the above-described embodiment, the ultrasonic sphygmomanometer 1 used by being worn on the wrist of the subject has been described as an example. However, for example, the ultrasonic sphygmomanometer 1 used by wrapping around the upper arm is also used. Good. In this case, the cuff blood pressure meter 3 can be attached to the upper arm of one arm to measure blood pressure, and the ultrasonic blood pressure monitor 1 can be attached to the upper arm of the other arm to measure blood pressure. It is.

  Further, the ultrasonic sphygmomanometer 1 and the cuff sphygmomanometer 3 do not necessarily have to be mounted on the same arm for measurement. By separating the arm on which the ultrasonic sphygmomanometer 1 and the cuff sphygmomanometer 3 are attached, while measuring the systolic blood pressure and the diastolic blood pressure with the cuff sphygmomanometer 3 attached to one arm, The systolic blood vessel diameter and the diastolic blood vessel diameter may be continuously measured by the attached ultrasonic sphygmomanometer 1.

  In this case, by averaging the measured systolic blood vessel diameter and diastolic blood vessel diameter, respectively, and determining the correlation equation using the average value of the systolic blood vessel diameter and the average value of the diastolic blood vessel diameter, The correlation equation can be appropriately calibrated. By calculating the blood pressure using the correlation equation thus obtained, blood pressure calculation accuracy can be further improved.

6-4. Measurement Position In the above embodiment, the case where measurement is performed with the position of the height of the heart as the first position and the position of the height of the wrist when the arm is lowered as the second position is exemplified. However, it is not always necessary to perform measurement using these positions as the first position and the second position. In order to further increase the height difference between the first position and the second position, for example, the position of the wrist height when the arm is raised above the head is the first position, and the height of the wrist when the arm is lowered It is good also as measuring as a 2nd position.

6-5. In the above-described embodiment, the ultrasonic sphygmomanometer 1 is provided with the atmospheric pressure sensor 23, and the elevation difference between the first position and the second position is estimated based on the measurement result of the atmospheric pressure sensor 23. However, for example, an acceleration sensor may be provided in the ultrasonic sphygmomanometer 1 instead of the atmospheric pressure sensor 23, and the height difference may be estimated based on the vertical acceleration measured by the acceleration sensor. The atmospheric pressure sensor 23 and the acceleration sensor may be used in combination.

6-6. In the above embodiment, the case where the correlation equation represented by the equation (1) is applied as an example of the correlation equation representing the correlation property between the blood vessel diameter and the blood pressure has been described. Of course, a correlation equation that approximates the diameter and blood pressure in a linear relationship or a correlation equation other than the equation (1) approximated in a non-linear relationship may be applied.

  In addition, the correlation characteristic data stored in the storage unit 800 does not necessarily have to be correlation expression data, and may be data (lookup table) in which the correlation characteristic between the blood vessel diameter and the blood pressure is defined in a table format. Of course.

6-7. Calibration timing In the above-described embodiment, it has been described that the calibration process is performed at a timing such as the first time of blood pressure measurement or a fixed time, but this calibration timing can be set as appropriate. For example, the property of the blood vessel to be measured by the subject may change due to a sudden change in temperature. Therefore, the temperature at the time of blood pressure measurement may be stored, and the calibration process may be performed with the timing at which the temperature difference between the temperature at the previous measurement and the temperature at the current measurement exceeds a predetermined threshold as the calibration timing.

6-8. Communication Method In the above embodiment, the communication method between the ultrasonic sphygmomanometer 1 and the cuff sphygmomanometer 3 is wireless communication, but may be wired communication by connecting with a cable. Alternatively, the subject may perform blood pressure measurement using the cuff type sphygmomanometer 3, and the measured value may be manually input to the ultrasonic sphygmomanometer 1.

6-9. Blood Pressure Estimation Method In the above embodiment, the diastolic blood pressure estimation unit 141 estimates the diastolic blood pressure of the subject using the correlation formula, the diastolic blood vessel diameter difference, and the hydrocephalic pressure difference. Then, after that, the systolic blood pressure estimation unit 143 correlates the diastolic blood pressure estimated by the diastolic blood pressure estimation unit 141 with the fluctuation range associated with the pulsation of the blood vessel diameter measured by the blood vessel diameter measurement unit 110. As described above, it is assumed that the systolic blood pressure of the subject is estimated. However, this procedure can be reversed.

  That is, the systolic blood pressure estimation unit 143 estimates the systolic blood pressure of the subject using the correlation formula, the systolic blood vessel diameter difference, and the hydrocephalic pressure difference. Then, after that, the diastolic blood pressure estimation unit 141 uses the systolic blood pressure estimated by the systolic blood pressure estimation unit 143, the fluctuation range associated with the pulsation of the blood vessel diameter measured by the blood vessel diameter measurement unit 110, and a correlation formula. Is used to estimate the diastolic blood pressure of the subject.

  In this case, following the principle described with reference to FIG. 4, a characteristic value determined by the pattern determined by the systolic blood vessel diameter difference “ΔDHs” and the hydrocephalic pressure difference “ΔPH” is determined according to the correlation equation, and determined by the determined characteristic value. Blood pressure is estimated as systolic blood pressure. Then, following the principle explained in FIG. 5, the blood vessel diameter (systolic blood vessel diameter) corresponding to the estimated systolic blood pressure is obtained from the correlation equation, and the blood vessel diameter fluctuation width “ΔD” is subtracted from the systolic blood vessel diameter. Calculate the diastolic blood vessel diameter. Then, the diastolic blood pressure is estimated by substituting the calculated diastolic blood vessel diameter into the correlation equation.

  In addition, instead of estimating one blood pressure after estimating one blood pressure as described above, the correlation between the blood pressure and the blood vessel diameter, and the blood vessel diameter difference related to each of the diastolic blood vessel diameter and the systolic blood vessel diameter It is also possible to simultaneously estimate the diastolic blood pressure and the systolic blood pressure of the subject by using the fluctuation range associated with the pulsation of the blood vessel diameter and the hydrocephalic pressure difference.

  FIG. 10 is a flowchart showing the flow of the second blood pressure estimation process executed in this case by the blood pressure estimation unit 140 of the processing unit 100 instead of the blood pressure estimation process of FIG.

  First, the blood pressure estimation unit 140 sets a plurality of diastolic blood pressure candidate values (step D1). Although the candidate value of the diastolic blood pressure to be set can be arbitrarily selected, for example, a predetermined number of candidate values are set in increments of 1 [mmHg].

  Next, the blood pressure estimation unit 140 calculates a diastolic blood vessel diameter difference according to “ΔDHd = Dd1−Dd2” (step D3). Then, the blood pressure estimation unit 140 executes the process of loop A for each candidate value of diastolic blood pressure set in step D1 (steps D5 to D17).

  In the process of loop A, the blood pressure estimation unit 140 calculates the blood vessel diameter “Dn1” corresponding to the candidate value “Pdn” using the correlation equation 821 stored in the calibration data 820 (step D7). Moreover, the blood pressure estimation unit 140 calculates the blood vessel diameter “Dn2” corresponding to the blood pressure “Pdn−ΔPH” using the correlation equation 821 (step D9).

  Next, the blood pressure estimation unit 140 uses the diastolic blood vessel diameter difference “ΔDHd” calculated in step D3, the blood vessel diameter “Dn1” calculated in step D7, and the blood vessel diameter “Dn2” calculated in step D9. The diastolic error “Ed = (Dn1−Dn2) −ΔDHd” is calculated (step D11).

  Thereafter, the blood pressure estimation unit 140 calculates a blood vessel diameter fluctuation range “ΔD = Ds2−Dd2” accompanying pulsation (step D13). Then, the blood pressure estimation unit 140 calculates the systolic blood pressure “Psn” using the correlation equation 821, the candidate value “Pn”, and the blood vessel diameter fluctuation range “ΔD”, and the candidate value of the systolic blood pressure (Step D15). Then, the process proceeds to the next candidate value. If these steps have been performed for all candidate values for diastolic blood pressure, the processing of loop A is terminated (step D17).

  Next, the blood pressure estimation unit 140 calculates a systolic blood vessel diameter difference according to “ΔDHs = Ds1−Ds2” (step D19). And the blood pressure estimation part 140 performs the process of the loop B about each candidate value of systolic blood pressure (steps D21-D29).

  In the process of loop B, the blood pressure estimation unit 140 calculates the blood vessel diameter “Ds1” corresponding to the candidate value “Psn” using the correlation equation 821 (step D23). Moreover, the blood pressure estimation unit 140 calculates the blood vessel diameter “Ds2” corresponding to the blood pressure of “Psn−ΔPH” using the correlation equation 821 (step D25).

  Next, the blood pressure estimation unit 140 uses the systolic blood vessel diameter difference “ΔDHs” calculated in step D19, the blood vessel diameter “Ds1” calculated in step D23, and the blood vessel diameter “Ds2” calculated in step D25. The systolic error “Es = (Ds1−Ds2) −ΔDHs” is calculated (step D27). Then, the blood pressure estimation unit 140 shifts the process to the next candidate value. If these steps have been performed for all candidate values for systolic blood pressure, the processing of loop B is terminated (step D29).

  Thereafter, the blood pressure estimation unit 140 calculates the diastolic error “Ed” calculated for each candidate value “Pdn” of diastolic blood pressure and the systolic error “calculated” for each candidate value “Psn” of systolic blood pressure. The sum of “Es” is calculated between the combinations of the corresponding candidate values (step D31).

  Then, the blood pressure estimation unit 140 estimates the combination of candidate values for which the sum of the errors calculated in step D31 is minimized as a diastolic blood pressure estimated value and a systolic blood pressure estimated value, and stores them in the blood pressure data 840 of the storage unit 800. Store (step D33). Then, the blood pressure estimation unit 140 ends the second blood pressure estimation process.

  DESCRIPTION OF SYMBOLS 1 Ultrasonic sphygmomanometer, 1A 1st site | part, 1B 2nd site | part, 3 Cuff type | mold sphygmomanometer, 11 Hinge part, 12 Operation button, 13 Liquid crystal display, 14 Speaker, 20 Sensor part, 21 Ultrasonic sensor, 23 Barometric pressure sensor , 100 processing unit, 200 operation unit, 300 display unit, 400 sound output unit, 500 communication unit, 600 clock unit, 800 storage unit

Claims (6)

A blood vessel diameter measuring unit for measuring a blood vessel diameter of a measurement target blood vessel in a measurement target part;
A blood vessel diameter that is a difference between the first blood vessel diameter and the second blood vessel diameter measured by the blood vessel diameter measuring unit when the measurement target part is positioned at a first position and a second position having different relative heights to the heart. The difference between the blood pressure and the blood vessel diameter of the blood vessel to be measured , the head pressure difference based on the height difference between the first position and the second position, and the blood vessel diameter measured by the blood vessel diameter measuring unit. A blood pressure estimator that estimates the blood pressure of the subject using a fluctuation range associated with pulsation ,
A blood pressure measurement device comprising: The blood pressure estimation unit estimates a blood pressure of the subject by determining a characteristic value that matches a relationship between the blood pressure difference and the blood vessel diameter difference, which is regarded as the blood pressure difference, from the correlation characteristic,
The blood pressure measurement device according to claim 1. The first blood vessel diameter and the second blood vessel diameter are diastolic blood vessel diameters,
The blood pressure estimation unit
A diastolic blood pressure estimation unit that estimates the diastolic blood pressure of the subject using the correlation characteristic, the blood vessel diameter difference, and the hydrocephalic pressure difference;
Wherein the diastolic blood pressure, before Symbol fluctuation width, and wherein by using the correlation characteristics, the systolic blood pressure estimation section for estimating a systolic blood pressure of the subject,
Having
The blood pressure measurement device according to claim 1 or 2. The first blood vessel diameter and the second blood vessel diameter are systolic blood vessel diameters,
The blood pressure estimation unit
A systolic blood pressure estimation unit that estimates the systolic blood pressure of the subject using the correlation characteristic, the blood vessel diameter difference, and the hydrocephalic pressure difference;
Said systolic blood pressure, the previous SL fluctuation width, wherein by using the correlation characteristics, and diastolic blood pressure estimation unit that estimates a diastolic blood pressure of said subject,
Having
The blood pressure measurement device according to claim 1 or 2. The blood vessel diameter measuring unit is configured to continuously measure the blood vessel diameter,
The blood pressure estimation unit calculates the blood vessel diameter difference from a difference between the first blood vessel diameter when the measurement target site is located at the first position and the second blood vessel diameter when the measurement target site is located at the second position. To
The blood pressure measurement device according to any one of claims 1 to 4 . Measuring the blood vessel diameter of the measurement target blood vessel when the measurement target region is located at the first position;
Measuring the blood vessel diameter of the measurement target blood vessel when the measurement target site is located at a second position where the relative height to the heart is different from the first position;
The difference in blood vessel diameter, which is the difference between the first blood vessel diameter and the second blood vessel diameter, the correlation characteristics between the blood pressure and the blood vessel diameter of the blood vessel to be measured, and the difference in the height direction between the first position and the second position. Estimating the blood pressure of the subject using the hydrocephalus pressure difference based on the above and the fluctuation range associated with the pulsation of the blood vessel diameter ,
Blood pressure measurement method including

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