WO2024117133A1

WO2024117133A1 - Vitals measurement device, vitals measurement method, and vitals measurement system

Info

Publication number: WO2024117133A1
Application number: PCT/JP2023/042571
Authority: WO
Inventors: 知紀八田; 貴之内田
Original assignee: テルモ株式会社
Priority date: 2022-12-01
Filing date: 2023-11-28
Publication date: 2024-06-06

Abstract

This vitals measurement device is provided with: a blood pressure measurement unit that has a cuff to be worn around a wrist or a finger of a user and measures a blood pressure value of the user; and a measurement unit that is placed on a breast area of the user and integrally includes a vibration information detection unit for acquiring vibration information on the breast area body surface of the user.

Description

Vital Sign Measuring Device, Vital Sign Measuring Method, and Vital Sign Measuring System

This disclosure relates to a vital sign measuring device, a vital sign measuring method, and a vital sign measuring system.

Devices that a user wears on a finger or wrist to measure blood pressure have been developed. Devices have also been proposed that have the function of measuring other vital information in addition to blood pressure measurement. For example, Patent Document 1 discloses a vital sign measuring device that can simultaneously measure the subject's heart sounds and/or respiratory sounds in addition to blood pressure, electrocardiogram, blood oxygen saturation, and pulse rate. Patent Document 2 discloses a measuring device that can calculate the pressure value of the respiratory variation of the subject's systolic blood pressure by measuring the subject's pulse pressure and pulse wave. Patent Document 3 describes acquiring physiological information including a respiratory waveform, and activating a blood pressure measuring means to measure blood pressure when this physiological information meets a predetermined condition.

JP 2019-037686 A JP 2016-137087 A JP 2009-039352 A

　Conventional electronic blood pressure monitors mainly use the oscillometric method. In the oscillometric method, air is pressurized into a cuff wrapped around a measurement site such as the upper arm, wrist, or fingertip to compress the blood vessels, and the air is gradually released to reduce the pressure, and the blood pressure value is obtained by detecting the vibrations of the blood vessel walls, which depend on the arterial pressure, as vibrations generated in the cuff. However, it is known that the blood pressure value measured during the cuff decompression process is affected by fluctuations due to the height of the measurement site. Therefore, if the height of the measurement site is not constant, it becomes an obstacle to accurate blood pressure measurement. For accurate measurement, the measurement site is aligned with the height of the heart. The technologies disclosed in the above-mentioned cited documents 1 to 3 do not have a mechanism for ensuring that the height of the measurement site is necessarily at the height of the heart when measuring blood pressure, regardless of whether the user is using the device correctly or not.

Therefore, the purpose of this disclosure, which has been made with these points in mind, is to improve the accuracy of blood pressure measurements using a vital sign measurement device that is worn on the user's finger or wrist to measure blood pressure.

A vital sign measuring device according to one aspect of the present disclosure is (1) a vital sign measuring device that includes a measuring unit that has a cuff that is attached to the wrist or finger of a user and that integrally includes a blood pressure measuring unit that measures the blood pressure value of the user, and a vibration information detecting unit that is placed on the chest of the user and obtains vibration information from the surface of the user's chest.

As an embodiment of the present disclosure, (2) in the vital sign measuring device of (1) above, it is preferable to include a determination unit that determines whether the measuring unit is placed on the body surface near the user's heart based on the vibration information.

As an embodiment of the present disclosure, (3) in the vital sign measuring device of (2) above, it is preferable that the vibration information includes at least one of heart sounds, apical pulsation, and lung sounds.

As an embodiment of the present disclosure, (4) in the vital sign measuring device of (2) or (3) above, it is preferable that the blood pressure measuring unit is configured to start measuring the blood pressure value after the determining unit determines that the measuring unit has been placed on the body surface of the user near the heart.

As an embodiment of the present disclosure, (5) in any of the vital sign measuring devices (2) to (4) above, it is preferable to provide a guidance unit that guides the measuring unit in a direction that increases the amplitude of vibration of the vibration information when it is determined that the measuring unit is not positioned on the body surface near the user's heart.

As an embodiment of the present disclosure, (6) in any of the vital sign measuring devices (1) to (5) above, it is preferable that the vibration information detection unit includes a motion sensor that detects chest movement associated with breathing, and further includes a correction unit that corrects the blood pressure value based on the user's respiratory cycle detected by the motion sensor.

As an embodiment of the present disclosure, (7) in the vital sign measuring device of (6) above, it is preferable that the motion sensor has an outer periphery that contacts the chest surface when detecting chest movement and a detection unit that is positioned back from the outer periphery, and detects chest movement based on at least one change in the pressure between the chest surface and the detection unit, the contact area between the chest surface and the detection unit, the distance between the chest surface and the detection unit, and the strain applied to the detection unit.

As an embodiment of the present disclosure, (8) in the vital sign measuring device of (6) or (7) above, it is preferable that the motion sensor detects the depth of breathing of the user, and the correction unit corrects the blood pressure value based on the depth of breathing in addition to the breathing cycle.

As an embodiment of the present disclosure, (9) in any of the vital sign measuring devices (6) to (8) above, it is preferable that the blood pressure measuring unit is configured to measure the blood pressure value of the user in accordance with the breathing cycle of the user detected by the motion sensor.

As an embodiment of the present disclosure, (10) in any of the vital sign measuring devices (1) to (9) above, it is preferable to include a contact means for contacting the vibration information detection unit with the chest surface of the user.

As an embodiment of the present disclosure, (11) in any of the vital sign measuring devices (1) to (10) above, it is preferable to include a pressing pressure unit for pressing the vibration information detection unit against the chest surface of the user.

As an embodiment of the present disclosure, (12) in any of the vital sign measuring devices (1) to (11) above, it is preferable to include a cardiac function parameter acquiring unit that acquires parameters related to the cardiac function of the user.

As an embodiment of the present disclosure, (13) in the vital sign measuring device of (12) above, it is preferable that the cardiac function parameter acquisition unit includes a pulse wave sensor provided in the cuff to detect the pulse wave of the user.

As an embodiment of the present disclosure, (14) in the vital sign measuring device of (12) or (13) above, it is preferable that the cardiac function parameter acquisition unit includes an acoustic sensor that detects at least one of heart sounds and apical pulsation on the chest surface of the user.

As an embodiment of the present disclosure, (15) in any of the vital sign measuring devices (12) to (14) above, it is preferable that the cardiac function parameter acquisition unit includes an electrocardiograph that measures the electrocardiogram waveform of the user.

As an embodiment of the present disclosure, (16) in any of the vital sign measuring devices (12) to (15) above, it is preferable that the cardiac function parameter acquisition unit includes a first pulse wave sensor attached to the user's finger and a second pulse wave sensor attached to the user's wrist, either the first pulse wave sensor or the second pulse wave sensor is included in the blood pressure measurement unit, and the pulse wave propagation velocity is calculated based on the time difference between the detection of the pulse waves acquired from the first pulse wave sensor and the second pulse wave sensor.

As an embodiment of the present disclosure, (17) in any of the vital sign measuring devices (12) to (16) above, it is preferable that the cardiac function parameter acquisition unit identifies the cardiac ejection timing and estimates a part of the arterial pressure waveform based on the ejection timing and the corrected blood pressure value.

A vital sign measurement system according to one aspect of the present disclosure is (18) a vital sign measurement system including a blood pressure measurement unit having a cuff attached to a user's wrist or finger and measuring the blood pressure value of the user, a measurement unit that is disposed on the user's chest and integrally includes a vibration information detection unit that acquires vibration information on the user's chest body surface, and a determination unit that determines whether the measurement unit is disposed on the body surface near the user's heart based on the vibration information.

As an embodiment of the present disclosure, (19) in the vital sign measurement system of (18) above, it is preferable that the measurement unit includes a cardiac function parameter acquisition unit that acquires parameters related to the cardiac function of the user, the cardiac function parameter acquisition unit identifies the cardiac ejection timing, and the control device estimates a portion of the arterial pressure waveform based on the ejection timing and the corrected blood pressure value.

As an embodiment of the present disclosure, (20) in the vital sign measurement system of (19) above, it is preferable that the control device estimates the intracardiac pressure based on a portion of the estimated arterial pressure waveform.

A vital sign measurement method according to one aspect of the present disclosure (21) is a method for simultaneously measuring the user's blood pressure by attaching a cuff on the wrist or finger of a user to a blood pressure measurement unit provided in a measurement unit, and measuring the blood pressure of the user, and placing a vibration information detection unit provided integrally with the blood pressure measurement unit in the measurement unit on the user's chest, and acquiring vibration information from the surface of the user's chest.

The present disclosure makes it possible to improve the accuracy of blood pressure measurements using a vital sign measuring device that is worn on a user's finger or wrist to measure blood pressure.

FIG. 1 is a block diagram showing the configuration of a vital sign measuring device according to the first embodiment. FIG. 2 is a block diagram showing a configuration of a control device including the control unit shown in FIG. FIG. 3 is a perspective view showing an example of the measurement unit of FIG. FIG. 4 is a diagram for explaining a measurement method using the vital sign measuring device of FIG. FIG. 5 is a flow chart showing a measurement procedure using the vital sign measuring device of FIG. FIG. 6 is a block diagram showing the configuration of a vital sign measuring device according to the second embodiment. FIG. 7 is a cross-sectional view showing a schematic configuration of a first example of the measurement unit in FIG. FIG. 8 is a bottom view of the detection section of the second example of the measurement section of FIG. FIG. 9 is a cross-sectional view showing a schematic configuration of a third example of the measuring unit of FIG. FIG. 10 is a cross-sectional view showing a schematic configuration of a fourth example of the measuring unit of FIG. FIG. 11 is a graph showing an example of respiratory variation in blood pressure. FIG. 12 is a diagram showing an example of a respiratory cycle, a cuff pressure, a blood pressure waveform, a K sound waveform, and an electrocardiogram waveform. FIG. 13 is a flowchart showing a measurement procedure using the vital sign measuring device of FIG. FIG. 14 is a block diagram showing the configuration of a vital sign measuring device according to the third embodiment. FIG. 15 shows a portion of a plotted point and estimated arterial pressure waveform using the vital sign measuring device of FIG. FIG. 16 is a flowchart showing a measurement procedure using the vital sign measuring device of FIG. FIG. 17 is a cross-sectional view showing a modified example of the measuring section. FIG. 18 is a cross-sectional view showing the measurement portion of FIG. 17 during blood pressure measurement. FIG. 19 is a cross-sectional view showing a modified example of the measuring unit. FIG. 20 is a diagram for explaining a measurement method of a vital sign promotion device having a measurement unit equipped with another pulse wave sensor to be worn on the wrist.

Embodiments of the present disclosure are described below with reference to the drawings.

In each figure, identical or similar components may be given the same reference numerals. In the description of each embodiment, the description of parts that are identical or similar to those in the embodiments already described may be omitted or simplified as appropriate.

[First embodiment]
An overview of a vital sign measuring device 1 according to a first embodiment will be described with reference to Figures 1 to 3. The vital sign measuring device 1 is a device that allows a user to measure vital sign information including blood pressure by himself/herself. The user is, for example, a patient undergoing home treatment.

The vital sign measuring device 1 according to this embodiment includes a measuring unit 10 and a control unit 21. The measuring unit 10 and the control unit 21 may be provided in the same housing. The control unit 21 may be provided in a control device 20 (see FIG. 2) that is different from the measuring unit 10. A system including the measuring unit 10 and the control device 20 is called a vital sign measuring system.

The vital sign measuring device 1 measures blood pressure at the measuring site on the finger or wrist by adjusting the height of the measuring unit 10 to the height of the heart by acquiring vibration information from the chest 11. By adjusting the height of the measuring unit 10 to the height of the heart of the user, who is the subject of blood pressure measurement, the accuracy of blood pressure measurement is improved. "Blood pressure" refers to the pressure that the blood flow exerts on the inside (vascular wall) of the blood vessel 12 (artery) as blood moves through the blood vessel 12. "Blood pressure value" refers to the specific blood pressure value obtained by measurement. "Arterial pressure" refers to the pressure that the blood flow pumped out of the heart exerts on the arterial wall.

The measurement unit 10 comprises a blood pressure measurement unit 30 that measures the user's blood pressure, and a vibration information detection unit 31 that acquires vibration information from the chest surface 11a, which is the surface of the user's chest 11. The blood pressure measurement unit 30 and the vibration information detection unit 31 are integrally arranged in the same measurement unit 10. In this disclosure, "integrally" means that the blood pressure measurement unit 30 and the vibration information detection unit 31 are integrated in terms of hardware in the normal usage state. For example, the blood pressure measurement unit 30 and the vibration information detection unit 31 are arranged in the same housing.

The blood pressure measurement unit 30 includes a cuff control unit 32, a cuff 33, a cuff pressure measurement unit 34, and a blood flow detection unit 35.

The cuff control unit 32 is a processor that controls the cuff 33. The cuff control unit 32 is configured to be able to send and receive data with the control unit 21. When the control unit 21 exists in the same housing as the measurement unit 10, the control unit 21 and the cuff control unit 32 may be the same component configured by the same processor. When the measurement unit 10 and the control unit 21 exist in different hardware, the cuff control unit 32 and the control unit 21 can send and receive information via a network such as a LAN (local area network) or the Internet.

The cuff 33 is attached to the measurement site on the finger 13 or the wrist, and presses against one point of the blood vessel 12. In the present embodiment, the measurement site is hereinafter described as the finger 13. In the present application, the term "cuff" refers to an inflatable body that inflates and contracts under external control to press against the measurement site where blood pressure is measured. The cuff 33 can be referred to as an inflatable part. The pressure applied inside the cuff 33 is called the cuff pressure. The cuff 33 may be configured to include a rubber bag into which air can be injected and discharged. The cuff 33 can be positioned to at least partially surround the measurement site when measuring blood pressure. The user can measure blood pressure by inserting the finger 13 into the cuff 33. The accuracy of blood pressure measurement is further improved by adjusting the height of the cuff 33 to the height of the user's heart, which is the subject of blood pressure measurement.

The cuff pressure measurement unit 34 includes a sensor that detects the cuff pressure. The cuff pressure measurement unit 34 is configured to be able to send and receive information to and from the control unit 21. The cuff pressure measurement unit 34 may be integrated with the cuff 33. For example, the cuff pressure measurement unit 34 may include a pressure sensor provided inside the cuff 33.

The blood flow detection unit 35 includes a blood flow sensor that detects blood flow occurring at a location of the blood vessel 12 compressed by the cuff 33. The blood flow detection unit 35 is attached to the finger 13 downstream of the cuff 33. The blood flow detection unit 35 may include a pressure sensor that detects fluctuations in cuff pressure (pressure pulse wave) reflecting the vibration of the blood vessel wall, an acoustic sensor that detects the sound generated by blood flowing downstream of the cuff 33, a PPG sensor that detects volume changes in the blood vessel 12 by an optical method, or an ultrasonic sensor that measures blood flow by an ultrasonic Doppler method. "PPG" is an abbreviation of photoplethysmogram, which means a photoelectric volume pulse wave. The blood flow detection unit 35 can detect waveforms corresponding to pressure pulse waves and K sounds (Korotkoff sounds). In this application, a sensor that detects the vibration of the blood vessel 12 caused by the heart pumping blood, the volume change of the blood vessel 12, or the change in the speed of the blood flow through the blood vessel 12 is called a pulse wave sensor. The blood flow detection unit 35 is configured to be able to send and receive information to and from the control unit 21. As a modification of this embodiment, the blood flow detection unit 35 may be integrated with the cuff 33. Alternatively, the blood flow detection unit 35 may be disposed in the main body of the measurement unit 10 as shown in FIG. 3.

The vibration information detection unit 31 includes a sensor that detects vibration information acquired on the user's chest surface 11a. The vibration information includes at least one of heart sounds, apical pulsation, lung sounds, and information on the movement of the chest 11 accompanying the user's breathing. Lung sounds include respiratory sounds and adventitious sounds. The vibration information is information acquired near the position of the user's heart. An acoustic sensor can be used to detect heart sounds, apical pulsation, and lung sounds.

The data storage unit 36 includes at least one of a semiconductor memory, a magnetic memory, and an optical memory. The data storage unit 36 can sequentially store data detected by the cuff pressure measurement unit 34, the blood flow detection unit 35, and the vibration information detection unit 31. The data stored in the data storage unit 36 is used for processing by the control unit 21.

The control unit 21 controls the entire vital sign measuring device 1. The control unit 21 is configured to be able to send and receive information to and from each component of the measuring unit 10. The control unit 21 may perform various information processing based on the data stored in the data storage unit 36. The control unit 21 includes a determination unit 21a that determines whether the measuring unit 10 is placed on the body surface near the user's heart based on the vibration information detected by the vibration information detection unit 31. The vicinity of the heart is a position that contacts the user's chest body surface 11a and is, for example, within 7 cm from the position where the user's heart is located (within 7 cm around the user's heart). Within this range, the error of the measured blood pressure value is within a relatively small range of 5 mmHg. The determination unit 21a may be a module included in the program executed by the control unit 21. When the determination unit 21a determines that the measuring unit 10 is placed on the body surface near the user's heart, the control unit 21 causes the measuring unit 10 to start measuring the blood pressure value.

When the control unit 21 is included in a control device 20 separate from the measurement unit 10, the control device 20 can be a computer. The control device 20 can be, for example, a dedicated device, a general-purpose device such as a PC, or a server device belonging to a cloud computing system or other computing system. "PC" is an abbreviation for personal computer. Furthermore, the control device 20 can be a smartphone equipped with a specified application. The measurement unit 10 and the control device 20 can be capable of communicating with each other via wireless or wired communication means.

As shown in FIG. 2, the control device 20 includes a control unit 21, a memory unit 22, a communication unit 23, an input unit 24, and an output unit 25.

The control unit 21 includes at least one processor, at least one programmable circuit, at least one dedicated circuit, or any combination of these. The processor is a general-purpose processor such as a CPU or GPU, or a dedicated processor specialized for a specific process. "CPU" is an abbreviation for central processing unit. "GPU" is an abbreviation for graphics processing unit. An example of the programmable circuit is an FPGA. "FPGA" is an abbreviation for field-programmable gate array. An example of the dedicated circuit is an ASIC. "ASIC" is an abbreviation for application specific integrated circuit. The control unit 21 executes processes related to the operation of the control unit 20 while controlling each part of the control unit 20.

The memory unit 22 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or any combination thereof. The semiconductor memory is, for example, a RAM or a ROM. "RAM" is an abbreviation for random access memory. "ROM" is an abbreviation for read only memory. The RAM is, for example, an SRAM or a DRAM. "SRAM" is an abbreviation for static random access memory. "DRAM" is an abbreviation for dynamic random access memory. The ROM is, for example, an EEPROM. "EEPROM" is an abbreviation for electrically erasable programmable read only memory. The memory unit 22 functions, for example, as a main memory device, an auxiliary memory device, or a cache memory. The memory unit 22 stores data used in the operation of the control device 20 and data obtained by the operation of the control device 20.

The communication unit 23 includes at least one communication interface. The communication interface is, for example, a LAN interface, an interface compatible with a mobile communication standard such as LTE, the 4G standard, or the 5G standard, or an interface compatible with a short-range wireless communication standard such as Bluetooth (registered trademark). "LTE" is an abbreviation for Long Term Evolution. "4G" is an abbreviation for 4th generation. "5G" is an abbreviation for 5th generation. The communication unit 23 receives data used in the operation of the control device 20, and transmits data obtained by the operation of the control device 20.

The input unit 24 includes at least one input interface. The input interface is, for example, a physical key, a capacitive key, a pointing device, a touch screen integrated with a display, an imaging device such as a camera, or a microphone. The input unit 24 accepts an operation to input data used in the operation of the control device 20. Instead of being provided in the control device 20, the input unit 24 may be connected to the control device 20 as an external input device. As a connection interface, for example, an interface compatible with standards such as USB, HDMI (registered trademark), or Bluetooth (registered trademark) can be used. "USB" is an abbreviation for Universal Serial Bus. "HDMI (registered trademark)" is an abbreviation for High-Definition Multimedia Interface.

The output unit 25 includes at least one output interface. The output interface is, for example, a display or a speaker. The display is, for example, an LCD or an organic EL display. "LCD" is an abbreviation for liquid crystal display. "EL" is an abbreviation for electro luminescence. The output unit 25 outputs data obtained by the operation of the control device 20. The output unit 25 may be connected to the control device 20 as an external output device instead of being provided in the control device 20. As the connection interface, for example, an interface compatible with standards such as USB, HDMI (registered trademark), or Bluetooth (registered trademark) can be used.

The functions of the control device 20 are realized by executing the program according to this embodiment in a processor serving as the control unit 21. That is, the functions of the control device 20 are realized by software. The program causes a computer to execute the operations of the control device 20, thereby causing the computer to function as the control device 20. That is, the computer functions as the control device 20 by executing the operations of the control device 20 in accordance with the program.

The program may be stored on a non-transitory computer-readable medium. Examples of non-transitory computer-readable media include flash memory, magnetic recording devices, optical disks, magneto-optical recording media, and ROMs. The program may be distributed, for example, by selling, transferring, or lending portable media such as SD cards, DVDs, or CD-ROMs on which the program is stored. "SD" is an abbreviation for Secure Digital. "DVD" is an abbreviation for digital versatile disc. "CD-ROM" is an abbreviation for compact disc read only memory. The program may be distributed by storing it in the storage of a server and transferring it from the server to other computers. The program may be provided as a program product.

The computer temporarily stores in its main storage device, for example, a program stored in a portable medium or a program transferred from a server. The computer then reads the program stored in the main storage device with a processor, and executes processing in accordance with the read program with the processor. The computer may read the program directly from the portable medium and execute processing in accordance with the program. The computer may execute processing in accordance with the received program each time a program is transferred to the computer from the server. Processing may be executed by a so-called ASP-type service that does not transfer a program from the server to the computer, but instead realizes functions only by issuing execution instructions and obtaining results. "ASP" is an abbreviation for application service provider. A program is information used for processing by a computer, and includes those equivalent to a program. For example, data that is not a direct command to a computer but has properties that define computer processing falls under "those equivalent to a program."

Some or all of the functions of the control device 20 may be realized by a programmable circuit or a dedicated circuit as the control unit 21. In other words, some or all of the functions of the control device 20 may be realized by hardware.

Next, the configuration of the measurement unit 10 will be further described with reference to Figure 3. The measurement unit 10 has a cuff 33 provided on one side surface of the main body 37 (hereinafter referred to as the "first surface S1"), and a vibration information detection unit 31 provided on the other side surface (hereinafter referred to as the "second surface S2").

The main body 37 is a housing that houses the circuitry related to the measurement of the measurement unit 10, a small pump that sends air into the cuff 33, and, if the control unit 21 is in the same hardware as the measurement unit 10, the processor of the control unit 21. The main body 37 may be a rectangular parallelepiped as shown in FIG. 3, but is not limited to this.

The cuff 33 is a rectangular or strip-shaped component having a bag made of an elastic material such as rubber, with both ends fixable to the first surface S1 of the main body 37, into which air is injected. A space is formed between the cuff 33 and the main body 37 into which the user can insert and remove his/her finger 13. When measuring blood pressure, the user inserts his/her finger 13 between the cuff 33 and the main body 37, and then air is injected into the cuff 33 to pressurize it, and the pressure is then gradually reduced, allowing the user's blood pressure to be measured.

The cuff 33 may include a cuff pressure measuring unit 34 and a blood flow detection unit 35. The blood flow detection unit 35 may be disposed on a main body 37, the upper part of which is covered by the cuff 33.

During measurement using the vital sign measuring device 1, as shown in FIG. 4, the user inserts the finger 13 into the cuff 33 and presses the second surface S2 of the main body 37, on which the vibration information detection unit 31 is provided, against the chest body surface 11a, which is the surface of the user's chest 11. For example, the vibration information detection unit 31 is an acoustic sensor (piezoelectric sensor or microphone) that detects at least one of heart sounds, apical pulsation, and lung sounds. The vibration information detection unit 31 may be a heart sound sensor. In that case, the vibration information detection unit 31 detects heart sounds including mitral valve closure sounds. The ejection timing may be determined based on the timing at which the mitral valve closure sound is detected. The determination unit 21a of the control unit 21 can determine whether the measurement unit 10 is placed on the body surface near the user's heart based on at least one of heart sounds, apical pulsation, and lung sounds detected by the vibration information detection unit 31. The determination unit 21a may estimate the distance between the heart and the measurement unit 10 from the amplitude (size) of the detected vibration (sound) and the vibration pattern (waveform). In addition, the vibration information detection unit 31 may acquire the third sound, etc., which is used in the diagnosis of heart disease.

The main body 37 may be provided with a guidance section 37a. When the determination section 21a determines that the measurement section 10 is not positioned on the chest body surface 11a near the user's heart, the guidance section 37a guides the user to move the measurement section 10 to a position where the vibration information can be obtained, that is, to the chest body surface 11a near the user's heart, under the control of the control section 21. The guidance section 37a may include, for example, multiple LEDs. "LED" is an abbreviation for light-emitting diode. The guidance section 37a may display differently when the measurement section 10 is located near the heart and when it is not located near the heart. For example, a blue LED is lit in the former case, and a red LED is lit in the latter case. Also, for example, when the measurement section 10 is being positioned near the heart but guidance by the guidance section 37a is necessary to obtain vibration information, a yellow LED may be lit. The guidance section 37a may display differently when the amplitude of the detected vibration is increasing and decreasing. While watching the induction section 37a, the user can move the measurement section 10 in the direction that increases the amplitude of the vibration.

The guidance unit 37a is not limited to an LED, and may be a small display. Instead of or in addition to an LED or a small display, the guidance unit 37a may be equipped with a speaker that gives voice guidance instructions. Furthermore, the guidance unit 37a may utilize a display that is the output unit 25 of the control device 20, rather than the main body 37.

The measurement unit 10 may further include a cardiac function parameter acquisition unit 38 on the second surface S2 of the main body 37, the cardiac function parameter acquisition unit 38 including a sensor that acquires parameters related to the user's cardiac function. The cardiac function parameter acquisition unit 38 is a detection unit of a different type from the vibration information detection unit 31, and includes an electrocardiograph that acquires an electrocardiogram waveform, and an acoustic sensor that acquires heart sounds and/or apical beats. In the first embodiment, the cardiac function parameter acquisition unit 38 is not an essential component.

When the cardiac function parameter acquisition unit 38 is an electrocardiograph, two electrodes of the electrocardiograph may be arranged on the second surface S2 of the main body 37, sandwiching the vibration information detection unit 31. Alternatively, one electrode may be arranged on the second surface S2 of the main body 37, and another electrode may be arranged on the first surface S1 of the main body 37 or at a location that contacts the finger 13 or hand. The electrocardiogram waveform is used to measure parameters related to cardiac function, such as the pre-ejection period. The pre-ejection period is also abbreviated as "PEP." The electrocardiogram waveform is also used to estimate intracardiac pressure. In this disclosure, "intracardiac pressure" means the pressure applied to blood vessels inside the heart or near the heart. More specifically, the intracardiac pressure is the systolic pressure, diastolic pressure, or mean pressure in each part of the heart. Intracardiac pressure includes, for example, pulmonary artery pressure (systolic pressure, diastolic pressure, mean pressure), right atrial pressure (systolic pressure, diastolic pressure, mean pressure), right ventricular pressure (systolic pressure, diastolic pressure, end-diastolic pressure), left atrial pressure (systolic pressure, diastolic pressure, mean pressure), left ventricular pressure (systolic pressure, diastolic pressure, end-diastolic pressure), and femoral artery pressure. Pulmonary artery pressure is also abbreviated as "PAP."

When the cardiac function parameter acquisition unit 38 acquires heart sounds and/or apical beats, the cardiac function parameter acquisition unit 38 may acquire the third sound, etc., which is used to diagnose cardiac disease.

(Blood pressure measurement procedure)
The steps of blood pressure measurement using the vital sign measuring device 1 according to this embodiment will be described with reference to Fig. 5. The steps shown in the flowchart of Fig. 5 correspond to the vital sign measuring method according to this embodiment. Step 101 is a step executed by the user. Steps S102 to S108 are steps executed by each part of the vital sign measuring device 1 in response to instructions from the control unit 21.

In step S101, a user who is measuring their own blood pressure places the measurement unit 10 of the vital sign measuring device 1 on the chest 11. With the finger 13 inserted into the cuff 33, the user faces the second surface S2 of the main body 37 toward the chest surface 11a and presses the vibration information detection unit 31 against the chest surface 11a.

In step S102, the vital sign measuring device 1 detects that the measuring unit 10 has been placed on the chest 11. Specifically, the vibration information detecting unit 31 detects vibration information from the user's chest surface 11a.

In step S103, the determination unit 21a of the control unit 21 determines whether or not the measurement unit 10 is placed on the chest surface 11a near the user's heart based on the detected vibration information. If it is determined that the measurement unit 10 is not located on the chest surface 11a near the heart (step S103: NO), the control unit 21 may prompt the user to move the position of the measurement unit 10 by displaying or sounding the guidance unit 37a. In this case, the procedure in FIG. 5 returns to step S101.
In step S103, if the determination unit 21a determines that the measurement unit 10 is placed on the chest surface 11a in the vicinity of the user's heart, the process proceeds to the next step S104.

In step S104, the cuff control unit 32 pressurizes the cuff 33 to an initial pressure. The initial pressure may be approximately the same as the initial pressure in typical non-invasive blood pressure measurements. The initial pressure may be approximately 30 to 40 mmHg added to the systolic blood pressure obtained by a normal measurement of the user. The process of step S104 may be executed using a command from the control unit 21 to the cuff control unit 32 as a trigger.

In step S105, the cuff control unit 32 starts depressurizing the cuff 33. The cuff control unit 32 may gradually reduce the cuff pressure at a constant depressurization speed V, or may gradually slow down the depressurization speed V. When the depressurization speed V is constant, the depressurization speed V may be any speed. As an example, the depressurization speed is 3 mmHg/sec. The process of step S105 may be executed with a command from the control unit 21 to the cuff control unit 32 as a trigger.

In step S106, the blood flow detection unit 35 detects blood flow occurring at the location of the blood vessel 12 that is compressed by the cuff 33. Specifically, the blood flow detection unit 35 detects the fluctuation in cuff pressure and the K sound that occurs when blood flow breaks through the cuff 33. The blood flow detection unit 35 outputs signals indicating the waveforms of the pressure pulse wave and the K sound.

In step S107, the cuff pressure measurement unit 34 detects the cuff pressure. After depressurization of the cuff 330 begins in step S105, the cuff pressure when blood flow is first detected (when the pressure pulse wave suddenly increases, or when the K sound begins to be generated) is the systolic blood pressure. The cuff pressure measurement unit 34 outputs a signal indicating the pressure to the data storage unit 36.

In step S108, if blood flow was detected in the previous step S106 (step S108: NO), the control unit 21 returns to step S106 and repeats the procedure of steps S106 to S108. As a result, acquisition of the cuff pressure is repeated while blood flow is detected. When the cuff pressure gradually decreases, the pressure pulse wave suddenly decreases in step S106, or the K sound is no longer detected. The cuff pressure when blood flow can no longer be detected (when the pulse pressure waveform suddenly decreases, or when the K sound is no longer detected) is the minimum blood pressure.

In step S108, if blood flow is no longer detected in the previous step S106 (step S108: YES), the control unit 21 stops reducing the cuff pressure and detecting blood flow, and ends the process. This causes the user's blood pressure data, including the systolic blood pressure and diastolic blood pressure, to be stored in the data storage unit 36. The control unit 21 can display the systolic blood pressure and diastolic blood pressure stored in the data storage unit 36 to the user via the output unit 25.

As described above, according to this embodiment, the vital sign measuring device 1 can determine whether or not the measuring unit 10 is placed on the body surface near the user's heart using the vibration information obtained from the vibration information detection unit 31. The vital sign measuring device 1 measures blood pressure when the measuring unit 10 is placed on the body surface near the user's heart, and therefore can reduce measurement errors caused by the difference between the height of the blood pressure measuring unit 30 and the height of the heart.

In addition, the vital sign measuring device 1 has a guidance section 37a that guides the user to move the measuring section 10 closer to the position of the user's heart, making it possible to perform measurements with little error.

Furthermore, if the vital sign measuring device 1 has the cardiac function parameter acquisition unit 38 shown in FIG. 3, in addition to measuring blood pressure, it can measure cardiac function parameters other than blood pressure, such as electrocardiogram waveforms, either simultaneously with blood pressure measurement or in parallel with a short time lag.

[Second embodiment]
An overview of a vital sign measuring device 1A according to the second embodiment will be described with reference to Fig. 6. The vital sign measuring device 1A not only guides the position of the measuring unit 10A to be close to the user's heart, but also corrects respiratory fluctuations in the measured blood pressure value. Respiratory fluctuations refer to changes in blood pressure that accompany breathing. It is known that human blood pressure decreases when inhaling and increases when exhaling. The range of fluctuations varies depending on the depth of breathing. The depth of breathing refers to the ventilation volume in one breath.

The vital sign measuring device 1A has a measuring unit 10A with a different configuration from the measuring unit 10 of the vital sign measuring device 1 according to the first embodiment. Furthermore, the vital sign measuring device 1A includes a motion sensor 51 that detects the movement of the chest 11 accompanying breathing, as one aspect of the vibration information detection unit 31. The motion sensor 51 can detect the depth of breathing (tidal volume). Furthermore, the vital sign measuring device 1A includes a respiratory cycle calculation unit 21b and a blood pressure value correction calculation unit 21c as functional blocks of the control unit 21. The respiratory cycle calculation unit 21b detects the respiratory cycle based on the movement of the user's chest 11 detected by the motion sensor 51. The blood pressure value correction calculation unit 21c corrects the blood pressure value based on the user's respiratory cycle. The blood pressure value correction calculation unit 21c is a correction unit.

The measuring unit 10A of the vital sign measuring device 1A according to the second embodiment can have various configurations. Configuration examples of the measuring unit 10A will be described with reference to Figs. 7 to 13.

(First example of the measuring section)
A schematic configuration of a first example of the measurement unit 10A will be described with reference to FIG.

As with the measurement unit 10 described with reference to FIG. 3, the measurement unit 10A has a cuff 33 provided on a first surface of the main body 37. A holding portion 52 of a motion sensor 51 is fixed to a second surface of the main body 37. The holding portion 52 has an outer periphery 52a that protrudes toward the chest surface 11a and contacts the chest surface 11a during measurement, and an inner surface of the outer periphery 52a that recedes from the outer periphery 52a toward the blood pressure measurement unit 30. A detection unit 53 is disposed on this inner surface. The detection surface of the detection unit 53 is positioned receding (setbacked) from the surface of the outer periphery 52a that contacts the chest surface 11a.

The detection unit 53 is a pressure sensor that measures the contact pressure on the chest surface 11a. The pressure sensor may be a sensor using a piezoelectric element, but is not limited to this. The detection unit 53 measures the change in pressure sequentially in a time series. The detection unit 53 stores the time series data of pressure in the data storage unit 36 and/or transmits it to the control unit 21.

When performing a measurement using the vital sign measuring device 1A, the user inserts a finger 13 into the cuff 33 and places the bottom surface of the outer periphery 52a of the holding unit 52 in contact with the chest surface 11a. In the human body, the chest 11 expands when inhaling and contracts when exhaling due to the movement of the skeleton and muscles surrounding the lungs. When the chest 11 expands during measurement using the measuring unit 10A, the curvature of the chest surface 11a increases, and the chest surface 11a protrudes from the position where it contacts the outer periphery 52a toward the detecting unit 53 and comes into contact with the detecting unit 53. When the chest 11 contracts, the opposite occurs. Therefore, if the user presses the measuring unit 10A against the chest surface 11a in the same posture, the contact pressure increases when inhaling and decreases when exhaling. Therefore, information about the user's breathing cycle can be obtained from the time-series changes in the contact pressure acquired by the detecting unit 53. Here, the respiratory cycle information includes the length of time it takes for one breath, information on the timing of changes in the respiratory cycle, and the ventilation volume per breath, i.e., cycle information, phase information, and respiratory depth information.

Note that, although not shown in FIG. 7, other sensors such as electrocardiograph electrodes or acoustic sensors shown as the cardiac function parameter acquisition unit 38 in FIG. 3 may be provided on the portion of the outer periphery 52a of the holding unit 52 that contacts the chest surface 11a. The same applies to the second to fourth examples of the measurement unit 10A described below. In the second embodiment, it is not essential to provide a cardiac function parameter acquisition unit 38.

(Second Example of Measuring Unit)
The schematic configuration of a second example of the measurement unit 10A will be described with reference to Fig. 8. Fig. 8 is a bottom view of a detection unit 53 of the measurement unit 10A having a similar configuration to the measurement unit 10A shown in Fig. 7.

In the second example, unlike the detection unit 53 in the first example, the detection unit 53 is configured to include a large number of detection elements 53a arranged in an array. Each detection element 53a is a sensor that detects contact with the chest surface 11a. By counting the number of detection elements 53a in contact with the chest surface 11a, the contact area between the chest surface 11a and the detection unit 53 can be calculated. Each detection element 53a may be a piezoelectric element, or may be a sensor that detects other types of contact.

As a result, when a user performs a measurement using the vital sign measuring device 1A, the user inserts a finger 13 into the cuff 33 in the same manner as the measuring unit 10A of the first example, and contacts the bottom of the outer periphery 52a of the holding unit 52 with the chest surface 11a. When inhaling, the chest surface 11a juts out towards the detection unit 53, increasing the contact area between the chest surface 11a and the detection unit 53, and conversely, when exhaling, the contact area decreases. Therefore, from the time series change in the contact area acquired by the detection unit 53, information on the user's respiratory cycle can be obtained, in the same manner as with the detection unit of the first example.

(Third example of the measuring section)
A schematic configuration of a third example of the measurement unit 10A will be described with reference to Fig. 9. Fig. 9 employs a detection unit 54 different from the detection unit 53 of the first example in the measurement unit 10A shown in Fig. 7.

In the third example of the measurement unit 10A, the detection unit 54 is a distance sensor built into the center of the holding unit 52. The detection unit 54 is positioned retracted toward the blood pressure measurement unit 30 from the position where the outer circumferential portion 52a contacts the chest surface 11a. The detection unit 54 can measure the distance between the detection unit 54 and the user's chest surface 11a. The detection unit 54 includes, for example, an infrared distance sensor, a camera, and an ultrasonic sensor.

As a result, when a user performs a measurement using the vital sign measuring device 1A, the user inserts a finger 13 into the cuff 33 in the same manner as the measuring unit 10A of the first example, and contacts the bottom of the outer periphery 52a of the holding unit 52 with the chest surface 11a. When inhaling, the chest surface 11a juts out towards the detection unit 53, so the distance between the chest surface 11a and the detection unit 54 becomes smaller, and conversely, when exhaling, the distance becomes larger. Therefore, information about the user's respiratory cycle can be obtained from the time series change in the distance between the chest surface 11a and the detection unit 54 acquired by the detection unit 54.

(Fourth Example of Measuring Unit)
A schematic configuration of a fourth example of the measurement unit 10A will be described with reference to Fig. 10. Fig. 10 employs a holding unit 52 and a detection unit 55 different from the detection unit 53 of the first example in the measurement unit 10A shown in Fig. 7.

In the fourth example of the measuring unit 10A, the holding unit 52 is made of a material that is stretchable and elastic. The detection unit 55 can be a strain sensor embedded in the holding unit 52 in a direction along the chest surface 11a during measurement. The detection unit 55 outputs deformations such as expansion and contraction applied to the holding unit 52 as electrical signals to the data storage unit 36 and/or the control unit 21.

As a result, when a user performs a measurement using the vital sign measuring device 1A, the user inserts a finger 13 into the cuff 33 in the same manner as the measuring unit 10A of the first example, and contacts the outer periphery 52a of the holding unit 52 with the chest surface 11a. When inhaling and exhaling, the user's chest expands and contracts, causing deformations such as stretching and contraction to be applied to the detection unit 55 embedded in the holding unit 52 via the outer periphery 52a pressed against the chest surface 11a. Therefore, the control unit 21 can obtain information about the user's respiratory cycle from the time-series changes in the strain detected by the detection unit 55.

The human breathing cycle includes an inhalation period and an exhalation period. As shown in FIG. 11, human blood pressure is lower during the inhalation period. For this reason, for example, as shown by the open circle in FIG. 12, the blood pressure value measured during the inhalation period is lower than the blood pressure value that would have been obtained during the exhalation period. If the timing of detecting the systolic or diastolic blood pressure is during the inhalation period, the blood pressure value is measured as being lower. The respiratory cycle calculation unit 21b and the blood pressure value correction calculation unit 21c of this embodiment correct the blood pressure value during the inhalation period to the blood pressure value that would have been obtained during the exhalation period. Note that the method of correcting the blood pressure value is not limited to this, and a method of correcting the blood pressure value during the exhalation period to the blood pressure value during the inhalation period, or a method of correcting both the blood pressure values during the inhalation period and the exhalation period may also be adopted.

Note that ECG in FIG. 12 is an abbreviation of electrocardiogram, which means an electrocardiogram measured by an electrocardiograph. An electrocardiograph is also called an ECG sensor. The cardiac output timing is obtained from the signal of the electrocardiograph. The output timing is treated as the reference timing of the heart. The reference timing is a timing that can be identified for each heartbeat. In this embodiment, an electrocardiograph is not an essential component.

The measurement unit 10A detects the movement of the chest 11 based on at least one change in the pressure between the chest surface 11a and the detection unit 53, the contact area between the chest surface 11a and the detection unit 53, the distance between the chest surface 11a and the detection unit 54, and the strain applied to the detection unit 55. The respiratory cycle calculation unit 21b is configured to determine the respiratory cycle, the timing (phase) of breathing, and the depth of breathing based on time-series data indicating the movement of the chest 11 obtained from the motion sensor 51.

The blood pressure value correction calculation unit 21c corrects the blood pressure values measured by the blood pressure measurement unit 30, particularly the systolic and diastolic blood pressures, based on the respiratory cycle, breathing timing (phase), and breathing depth determined by the respiratory cycle calculation unit 21b. Specifically, the blood pressure value correction calculation unit 21c corrects the blood pressure values measured during the inspiration period according to the elapsed time during the inspiration period. For example, the blood pressure value correction calculation unit 21c corrects the cuff pressure value during inspiration by adding a correction value y calculated by the following formula:
y = A sin(2πft)
Note that this formula is just an example, and the correction formula for correcting respiratory variation in blood pressure is not limited to this.

In the above formula, the amplitude A corresponds to the correction value range. The amplitude A is determined based on the depth of breathing. For example, the amplitude A is set to 10 mmHg. The blood pressure value correction calculation unit 21c may set the amplitude A based on waveform data showing the blood pressure waveform obtained by performing an invasive blood test. In other words, the correction value range may be determined based on the blood pressure waveform obtained by an invasive blood test. In that case, the input unit 24 of the control device 20 may be used as an interface for inputting the blood pressure waveform. The frequency f corresponds to the reciprocal of the respiratory cycle. The time t is the elapsed time from the start of inspiration to the blood flow timing. For example, if A = 10 mmHg, f = 0.2 Hz, and t = 0.5 seconds, then y = 10 sin (2π × 0.2 × 0.5) ≒ 5.9 mmHg. The blood pressure value correction calculation unit 21c can calculate the corrected systolic and diastolic blood pressures.

(Procedure for measuring blood pressure with compensation for respiratory variation)
The procedure for blood pressure measurement using the vital sign measuring device 1A according to this embodiment will be described with reference to Fig. 13. The procedure shown in Fig. 13 has many parts in common with the procedure shown in Fig. 5 of the first embodiment, so a description of the parts in common with the flowchart in Fig. 5 will be omitted and only the differences will be described.

Steps S201 to S205 are the same as steps S101 to S105 in FIG. 5.

In step S206, the motion sensor 51 starts detecting the movement of the user's chest. Step S206 may be performed before step S205.

Subsequent steps S207 to S209 are basically the same as steps S106 to S108 in FIG. 5, but during steps S207 to S209, the motion sensor 51 continuously detects the motion of the user's chest 11. The motion sensor 51 outputs time-series data on the motion of the chest 11 to the data storage unit 36 and/or the control unit 21. After blood flow is no longer detected in step S209 (step S209: YES), the control unit 21 proceeds to the processing of step S210.

In step S210, the respiratory cycle calculation unit 21b of the control unit 21 estimates a respiratory waveform based on data indicating chest movement detected by the movement sensor 51. The respiratory waveform includes information on the respiratory cycle, the timing (phase) at which inspiration and expiration begin, and the depth (amplitude) of breathing.

In step S211, the blood pressure value correction calculation unit 21c of the control unit 21 calculates a blood pressure value based on the above-mentioned correction equation y=A sin(2πft) having a period and amplitude corresponding to the respiratory waveform estimated in step S210.
and corrects the blood pressure value based on the cuff pressure measured by the cuff pressure measurement unit 34. The blood pressure value corrected by the blood pressure value correction calculation unit 21c is not influenced by the breathing state of the user, i.e., both or either of the time of inhalation and exhalation, and a consistent blood pressure value can be calculated.

As described above, the vital sign measuring device 1A according to this embodiment, in addition to the effects of the vital sign measuring device 1 according to the first embodiment, eliminates fluctuations in the measurement results caused by respiratory fluctuations in blood pressure measurement, enabling consistent measurements. This increases the reliability of the measured blood pressure values, including the systolic and diastolic blood pressures.

Note that, unlike the procedure shown in FIG. 13, the motion sensor 51 may detect the motion of the chest 11 of the user, and the control unit 21 may estimate the respiratory cycle before starting to inflate the cuff 33. The control unit 21 may measure the blood pressure value in accordance with the detected respiratory cycle of the user. For example, the control unit 21 may synchronize the start of depressurization of the cuff 33 with a predetermined timing of the respiratory cycle. For example, the control unit 21 may match the start of depressurization of the cuff 33 with the start of the expiratory period of the user. This allows the tendency of fluctuations in the systolic and diastolic blood pressures caused by respiratory fluctuations to be similar between measurements when the user performs multiple measurements. In addition, the control unit 21 may adjust the timing of starting depressurization of the cuff 33 so that the time when the systolic and/or diastolic blood pressure of the user is obtained is the expiratory period (or the inhalation period). This allows blood pressure measurement to be performed in a manner that is less susceptible to the influence of respiratory fluctuations that differ from measurement to measurement.

[Third embodiment]
An overview of a vital sign measuring device 1B according to the third embodiment will be described with reference to Fig. 14. The vital sign measuring device 1B guides the position of a measuring unit 10B to be close to the user's heart and corrects respiratory variation in the measured blood pressure value, and also estimates an arterial pressure waveform from the blood pressure value corrected for respiratory variation.

In FIG. 14, components that are the same as or similar to the vital sign measuring device 1 according to the first embodiment shown in FIG. 1 and the vital sign measuring device 1A shown in FIG. 6 are given the same reference numerals as the vital

sign measuring devices

1 and 1A. Furthermore, for components that are the same as or similar to the vital

sign measuring devices

1 and 1A, descriptions that overlap with the first and second embodiments will be omitted.

The vital sign measuring device 1B includes a cardiac function parameter acquiring unit 38 as an essential component of the measuring unit 10B. In this embodiment, the cardiac function parameter acquiring unit 38 is an electrocardiograph or a cardiac sound sensor capable of identifying the cardiac pumping timing for each heartbeat. For example, the pumping timing is the timing at which the Q wave is detected by the electrocardiograph. In contrast, the timing at which blood flow is detected at the user's measurement site by the blood flow detecting unit 35 is called the blood flow timing. For example, the blood flow timing can be identified from the waveform of the K sound detected by the blood flow detecting unit 35. The time interval from when the Q wave is detected by the electrocardiograph to when the K sound is detected by the blood flow detecting unit 35 is displayed as a time difference in FIG. 12. The cardiac function parameter acquiring unit 38 may be a cardiac sound sensor. In that case, the cardiac function parameter acquiring unit 38 detects heart sounds including the mitral valve closure sound. The pumping timing may be determined based on the timing at which the mitral valve closure sound is detected.

The arterial pressure waveform estimation unit 21d of the control unit 21 acquires the ejection timing and blood flow timing stored for each heartbeat from the measurement unit 1B, and calculates the time difference between the ejection timing and blood flow timing. The arterial pressure waveform estimation unit 21d generates plot data by associating the time difference for each heartbeat with the blood pressure value corrected by the blood pressure value correction calculation unit 21c. The control unit 21 estimates a part of the arterial pressure waveform indicating the change in arterial pressure over time based on the generated plot data. That is, the arterial pressure waveform estimation unit 21d estimates a part of the arterial pressure waveform based on the time difference between the ejection timing acquired by the cardiac function parameter acquisition unit 38 and the blood flow timing acquired by the blood flow detection unit 35, and the blood pressure value measured by the cuff pressure measurement unit 34 and corrected for respiratory fluctuations. Specifically, the arterial pressure waveform estimation unit 21d performs spline interpolation on the plotted points to estimate the arterial pressure waveform curve.

When the human heart beats, the pressure in the left ventricle of the heart rises and the aortic valve opens, causing blood to flow into the aorta. The blood that passes through the aortic valve reaches the arteries in the wrist and fingertips with a delay from the opening of the aortic valve. For this reason, the arterial pressure waveforms in the wrist and fingers are curves that are the arterial pressure waveform near the aortic valve shifted by the amount of delay. Therefore, the arterial pressure waveform estimation unit 21d can estimate the arterial pressure waveform near the aortic valve from the arterial pressure waveform at the measurement site.

FIG. 15 shows an example of a portion of the arterial pressure waveform estimated by the arterial pressure waveform estimation unit 21d. In FIG. 15, the data shown by the open circles corresponds to the data shown by the open circles in FIG. 12. These data are shifted to the higher pressure side by correction.

(Procedure for estimating arterial pressure waveform from blood pressure measurement)
The procedure for blood pressure measurement and arterial pressure waveform estimation using the vital sign measuring device 1B according to this embodiment will be described with reference to Fig. 16. The procedure shown in Fig. 16 has many parts in common with the procedure shown in Fig. 13 of the second embodiment, so a description of the parts in common with the flowchart in Fig. 13 will be omitted and only the differences will be described.

Steps S301 to S306 are the same as steps S201 to S206 in FIG. 13.

In step S307, the cardiac function parameter acquisition unit 38 starts detecting cardiac output, and thereafter repeatedly detects cardiac output. Specifically, the cardiac function parameter acquisition unit 38 is an electrocardiograph, and repeatedly measures the user's electrocardiogram waveform. The cardiac function parameter acquisition unit 38 outputs the cardiac output timing each time it measures an electrocardiogram waveform.

Steps S308 to S312 are the same as steps S206 to S211 in FIG. 13, respectively.

In step S313, the arterial pressure waveform estimation unit 21d estimates the arterial pressure waveform based on the time difference between the cardiac pumping timing detected by the cardiac function parameter acquisition unit 38 and the blood flow timing acquired by the blood flow detection unit 35, and the blood pressure value corrected in step S312.

As described above, according to this embodiment, the arterial pressure waveform, which indicates the change in arterial pressure over time, can be estimated non-invasively and with high accuracy. The arterial pressure waveform can be used to estimate intracardiac pressures, including the pulmonary artery pressure waveform, the left ventricular pressure waveform, and LVEDP. "LVEDP" is an abbreviation for left ventricular end-diastolic pressure.

Below, we will explain modified examples of the

measurement units

10, 10A, and 10B that can be applied to the first to third embodiments.

(Modification 1 of the measurement unit)
The measurement unit 10C in FIG. 17 includes a blood pressure measurement unit 30 and a vibration information detection unit 31. The blood pressure measurement unit 30 includes a cuff 61 through which the user passes the finger 13 during measurement, and a housing 62 that covers the periphery of the cuff 61 when the user passes the finger 13 and has an opening at a lower part 62a of the cuff 61. The vibration information detection unit 31 includes an elastic body 63 and a detection unit 64 provided at the opening part of the housing 62. The elastic body 63 is a membrane-like or thin plate-like member made of an elastic material such as rubber, which is provided so as to cover the opening part of the housing 62. The cuff 61 and the elastic body 63 constitute a pressing pressure unit for pressing the detection unit 64 against the chest surface 11a of the user. The detection unit 64 is, for example, a piezoelectric sensor for detecting heart sounds. The detection unit 64 corresponds to the vibration information detection unit 31 in FIG. 1. Further, electrode pads 65 of an electrocardiograph, which is the cardiac function parameter acquisition unit 38, are provided on the underside of the lower portion 62a of the housing 62. When the cuff 61 is not pressurized and inflated, the underside of the electrode pads 65, which faces the user's chest body surface 11a, is located closer to the user's chest body surface 11a than the underside of the detection unit 64. The electrode pads 65 are not an essential component when this measurement unit 10C is used in the first and second embodiments.

With reference to FIG. 18, the measurement of blood pressure values using the measurement unit 10C of FIG. 17 will be described. When the cuff 61 is pressurized with the finger 13 inserted during measurement, the cuff 61 expands and pushes down the elastic body 63. This causes the detection unit 64 to be pressed against the chest surface 11a of the user. This allows the detection unit 64 to be pressed against the chest surface 11a with a stable pressure, making it possible to accurately acquire heart sounds. Furthermore, since the measurement unit 10C has a blood pressure measurement unit 30, a vibration information detection unit 31, and a cardiac function parameter acquisition unit 38, it is possible to measure a large amount of vital information with a single measurement unit 10C. The measurement unit 10C can be used in any of the first to third embodiments.

Furthermore, as another embodiment, the measurement unit 10C may be configured to place suction cups on the electrode pads 65 and to bring the vibration information detection unit 31 and the electrode pads 65 into close contact with the user's chest surface 11a. The suction cups are a means for bringing the vibration information detection unit 31 into close contact with the user's chest surface 11a. By providing the suction cups, the measurement unit 10C can be stably positioned on the chest surface 11a, enabling even more stable measurement of blood pressure values, heart sounds, and other vital information.

(Modification 2 of the measurement unit)
Another modified example of the measurement unit will be described with reference to Fig. 19. The measurement unit 10D in Fig. 19 has a cuff 71 arranged on a housing 72 as the blood pressure measurement unit 30. The cuff 71 has a configuration similar to that of the cuff 33 of the first embodiment shown in Fig. 3. The housing 72 has a hat-like shape with a recessed central portion 72a of a flat plate-like member. The upper surface of the central portion 72a of the housing 72 is a flat plane, and the cuff 71 is arranged on this central portion 72a.

A balloon 73 that can be expanded and contracted by injecting and expelling air from an external pump is placed in the recess in the central portion 72a of the housing 72 when viewed from below. A membrane-like or thin-plate-like elastic body 74 made of rubber or the like is placed on the opening side of the recess in the housing 72, which is the side of the balloon 73 facing the chest body surface 11a during measurement. Furthermore, a detection unit 75 is placed on the side of the elastic body 74 facing the chest body surface 11a. The detection unit 75 is, for example, a piezoelectric sensor for detecting heart sounds. The detection unit 75 corresponds to the vibration information detection unit 31 in FIG. 1. The balloon 73 and elastic body 74 are included in a pressing pressure unit for pressing the detection unit 75 against the chest body surface 11a of the user.

Furthermore, electrode pads 76 of an electrocardiograph constituting the cardiac function parameter acquisition unit 38 are provided on the outer peripheral portion 72b, which is the outer peripheral side of the recess of the housing 72 and faces the chest body surface 11a. When the balloon 73 is not pressurized and expanded, the underside of the electrode pads 76, which faces the user's chest body surface 11a, is located closer to the user's chest body surface 11a than the underside of the detection unit 75. The electrode pads 76 are not an essential component when this measurement unit 10D is used in the first and second embodiments.

When measuring, the measuring unit 10D pressurizes the cuff 71 with the finger 13 inserted, and at the same time, air is injected into the balloon 73. The balloon 73 expands as a result of the air being injected, and presses down on the elastic body 74. This causes the detection unit 75 to be pressed against the user's chest surface 11a. Therefore, the detection unit 75 is pressed against the chest surface 11a with a stable pressure. In addition, since the measuring unit 10D has a detection unit 75 that detects vibration information and electrode pads 76, it is possible to measure a variety of vital information including blood pressure, vibration information, and electrocardiogram waveforms with a single measuring unit 10D.

The measurement unit 10D makes it possible to press the detection unit 75 against the user's chest surface 11a using a pressing pressure unit provided separately from the cuff 71. Therefore, when using the measurement unit 10D, the pressure applied to the detection unit 75 can be controlled independently of the pressure applied to the cuff 71. This allows the detection unit 75 to be pressed against the user's chest surface 11a with a more stable pressure, making it possible to perform more stable measurements and obtain heart sounds with high accuracy.

Furthermore, as another embodiment, the measurement unit 10D in FIG. 19 may be configured to place suction cups on the electrode pads 76 and bring the detection unit 75 into close contact with the user's chest surface 11a. The suction cups are a means for bringing the detection unit 75, which is the vibration information detection unit 31, into close contact with the user's chest surface 11a.

(Modification 3 of the measurement unit)
A measurement unit 10E shown in Fig. 20 further includes a pulse wave sensor 81 (second pulse wave sensor) that is attached to the wrist of the user and detects pulse waves in the measurement unit 10 of the first embodiment. This measurement unit 10E includes a pulse wave sensor (first pulse wave sensor) that is attached to a finger 13 as a blood flow detection unit 35 included in a blood pressure measurement unit 30. The control unit 21 can calculate the pulse wave velocity of the user based on the time difference between the pulse wave detected by the blood flow detection unit 35 and the pulse wave detected by the pulse wave sensor 81. The pulse wave velocity is used as an index for measuring blood vessel blockage and arteriosclerosis.

Although the embodiments of the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art would easily be able to make various modifications or changes based on the present disclosure. Therefore, it should be noted that these modifications or changes are included in the scope of the present disclosure. For example, the functions included in each component or step can be rearranged so as not to cause logical inconsistencies, and multiple components or steps can be combined into one or divided. Although the embodiments of the present disclosure have been described mainly in terms of the device, the embodiments of the present disclosure can also be realized as a method including steps executed by each component of the device. The embodiments of the present disclosure can also be realized as a method, a program executed by a processor provided in the device, or a storage medium having a program recorded thereon. It should be understood that these are also included in the scope of the present disclosure.

In all of the above embodiments, blood pressure is measured on a finger, but the vital sign measuring device of the present disclosure also includes a device that measures blood pressure on the wrist. Also, in the above third embodiment, blood pressure measurement and arterial pressure waveform estimation are performed by the same control unit, but these may be performed by separate hardware. For example, a computer located in a remote location such as a hospital may acquire the measurement data stored in the memory unit 22 of the control device 20 and estimate the arterial pressure waveform.

REFERENCE SIGNS

LIST

1, 1A, 1B Vital

sign measuring device

10, 10A, 10B, 10C, 10D, 10E Measuring unit 11 Chest 11a Chest surface 12 Blood flow 13 Finger 20 Control device 21 Control unit 21a Determination unit 21b Respiratory cycle calculation unit 21c Blood pressure value correction calculation unit (correction unit)
21d Arterial pressure waveform estimation unit 22 Memory unit 23 Communication unit 24 Input unit 25 Output unit 30 Blood pressure measurement unit 31 Vibration information detection unit 32 Cuff control unit 33 Cuff 34 Cuff pressure measurement unit 35 Blood flow detection unit 36 Data storage unit 37 Main unit 37a Lead unit 38 Cardiac function parameter acquisition unit 51 Motion sensor (vibration information detection unit)
52 Holding portion 52a Outer periphery 53 Detection portion 53a Detection element 54 Detection portion 55 Detection portion 61 Cuff (pressing portion)
62 Housing 62a Outer periphery bottom 63 Elastic body (pressing pressure part)
64 Detection unit (vibration information detection unit)
65 Electrode pad (cardiac function parameter acquisition unit)
71 Cuff 72 Housing 72a Central portion 72b Outer periphery 73 Balloon (pressing portion)
74 Elastic body (pressing part)
75 Detection unit (vibration information detection unit)
76 Electrode pad (cardiac function parameter acquisition unit)
81 Pulse wave sensor (second pulse wave sensor)

Claims

A blood pressure measurement unit having a cuff attached to a wrist or a finger of a user and measuring a blood pressure value of the user;
A vital sign measuring device comprising a measuring unit that is integrally formed with a vibration information detecting unit that is placed on the chest of the user and obtains vibration information from the chest surface of the user.
The vital sign measuring device according to claim 1, further comprising a determination unit that determines whether the measuring unit is placed on the body surface near the user's heart based on the vibration information.
The vital sign measuring device according to claim 2, wherein the vibration information includes at least one of heart sounds, apical pulsation, and lung sounds.
The vital sign measuring device according to claim 2, wherein the blood pressure measuring unit is configured to start measuring the blood pressure value after the determining unit determines that the measuring unit is placed on the body surface of the user near the heart.
The vital sign measuring device according to claim 2, further comprising a guidance unit that guides the measuring unit in a direction that increases the amplitude of vibration in the vibration information when it is determined that the measuring unit is not placed on the body surface near the user's heart.
the vibration information detection unit includes a movement sensor that detects chest movement associated with breathing;
The vital sign measuring device according to claim 1 , further comprising a correction unit that corrects the blood pressure value based on a respiratory cycle of the user detected by the motion sensor.
The vital sign measuring device according to claim 6, wherein the motion sensor has an outer periphery that contacts the chest surface when detecting the movement of the chest and a detection unit that is positioned back from the outer periphery, and detects the movement of the chest based on at least one change in the pressure between the chest surface and the detection unit, the contact area between the chest surface and the detection unit, the distance between the chest surface and the detection unit, and the strain applied to the detection unit.
The vital sign measuring device according to claim 6, wherein the motion sensor detects the depth of breathing of the user, and the correction unit corrects the blood pressure value based on the depth of breathing in addition to the breathing cycle.
The vital sign measuring device according to claim 6, wherein the blood pressure measuring unit is configured to measure the blood pressure value of the user in accordance with the breathing cycle of the user detected by the motion sensor.
The vital sign measuring device according to claim 1, further comprising a contact means for contacting the vibration information detection unit with the chest surface of the user.
The vital sign measuring device according to claim 1, further comprising a pressing unit for pressing the vibration information detection unit against the chest surface of the user.
The vital sign measuring device according to claim 1, further comprising a cardiac function parameter acquisition unit that acquires parameters related to the cardiac function of the user.
The vital sign measuring device according to claim 12, wherein the cardiac function parameter acquisition unit includes a pulse wave sensor provided in the cuff to detect the pulse wave of the user.
The vital sign measuring device according to claim 12, wherein the cardiac function parameter acquisition unit includes an acoustic sensor that detects at least one of heart sounds and apical pulsation on the chest surface of the user.
The vital sign measuring device according to claim 12, wherein the cardiac function parameter acquiring unit includes an electrocardiograph that measures the user's electrocardiogram waveform.
The vital sign measuring device according to claim 12, wherein the cardiac function parameter acquiring unit includes a first pulse wave sensor attached to the user's finger and a second pulse wave sensor attached to the user's wrist, either the first pulse wave sensor or the second pulse wave sensor is included in the blood pressure measuring unit, and calculates the pulse wave velocity based on the time difference between the detection of the pulse waves acquired from the first pulse wave sensor and the second pulse wave sensor.
The vital sign measuring device according to claim 12, wherein the cardiac function parameter acquiring unit identifies the cardiac ejection timing and estimates a part of the arterial pressure waveform based on the ejection timing and the corrected blood pressure value.
a blood pressure measuring unit having a cuff attached to a wrist or a finger of a user and measuring a blood pressure value of the user, and a measuring unit integrally including a vibration information detecting unit disposed on the chest of the user and acquiring vibration information on a chest surface of the user;
and a control device including a determination unit that determines whether the measurement unit is placed on the body surface near the user's heart based on the vibration information.
The measurement unit includes a cardiac function parameter acquisition unit that acquires parameters related to cardiac function of the user, and the cardiac function parameter acquisition unit identifies a timing of cardiac ejection;
The vital sign measurement system according to claim 18 , wherein the control device estimates a part of an arterial pressure waveform based on the ejection timing and the corrected blood pressure value.
The vital sign measurement system of claim 19, wherein the control device estimates intracardiac pressure based on a portion of the estimated arterial pressure waveform.
Attaching a cuff to a wrist or finger of a user in a blood pressure measurement unit provided in a measurement unit, and measuring a blood pressure value of the user;
A vital sign measurement method in which a vibration information detection unit, which is integrally provided with the blood pressure measurement unit, is placed on the chest of the user and vibration information is acquired from the chest surface of the user at the same time.