Blood pressure cuff and sphygmomanometer

Abstract

The blood pressure measuring cuff (20) of the present invention comprises: an outer fabric (21) extending in a longitudinal direction (X) in a strip shape and used for wrapping around a measured part (90); a pressing fluid bag (23) extending along the longitudinal direction (X) and arranged on a side of the outer fabric (21) facing the measured part (90) and used for pressing the measured part (90); a sound acquisition fluid bag (22) arranged between the outer fabric (21) and the pressing fluid bag (23) in a thickness direction (Z) perpendicular to the outer fabric (21) and acquiring sound from the measured part (90) via the pressing fluid bag (23); a first fluid piping (38) connected to the pressing fluid bag (23) in a fluid-flowable manner; and a second fluid piping (37) separated from the first fluid piping (38) and connected to the sound acquisition fluid bag (22) in a fluid-flowable manner.

Description

Technical Field

[0001] The present invention relates to a blood pressure measurement cuff, and more particularly to a blood pressure measurement cuff that compresses a measured area to obtain Korotkoff sounds. The present invention also relates to a sphygmomanometer equipped with such a blood pressure measurement cuff that measures blood pressure based on Korotkoff sounds. Background Art

[0002] In the past, as a blood pressure measurement cuff of this type, for example, as disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 58-155841), a blood pressure measurement cuff is known, comprising: a blood blocking cuff for compressing a measured portion (upper arm); and a sound collecting cuff, which is arranged in a portion of the blood blocking cuff on the side facing the measured portion. Similarly, as disclosed in Patent Document 2 (Japanese Patent Application Laid-Open No. 2012-61104), a blood pressure measurement cuff is known, comprising: a blood blocking air bag for compressing a measured portion (upper arm); and first and second Korotkoff sound detection air bags, which are arranged in a portion of the blood blocking air bag on the side facing the measured portion.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 58-155841

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2012-61104 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, the blood pressure measuring cuffs of Patent Documents 1 and 2 have the following problem: since the sound collecting cuff (or the first and second Korotkoff sound detection air bags) is only arranged in a part of the area on the side of the blood blocking cuff (or the blood blocking air bag) facing the measured part, if the wearing position (especially the circumferential position) of the cuff relative to the measured part (upper arm) is offset, the sound collection is unstable.

[0009] Therefore, the present invention aims to provide a blood pressure measurement cuff that compresses a measured area to obtain Korotkoff sounds, and that can stably obtain Korotkoff sounds. Another object of the present invention is to provide a sphygmomanometer equipped with such a blood pressure measurement cuff that can measure blood pressure with high accuracy.

[0010] Technical means to solve the problem

[0011] In order to solve the above problems, the blood pressure measurement cuff disclosed in the present invention obtains Korotkoff sounds by compressing the measured part, and is characterized in that:

[0012] have:

[0013] The outer cloth is in the form of a strip extending in the length direction and is used to wrap around the part to be measured;

[0014] a pressing fluid bag, provided on a side of the outer fabric facing the measured part and extending along the longitudinal direction, for pressing the measured part;

[0015] a sound acquisition fluid bag disposed between the outer cloth and the pressing fluid bag in a thickness direction perpendicular to the outer cloth, and acquiring sound from the measured portion via the pressing fluid bag;

[0016] a first fluid pipe connected to the pressing fluid bag so that fluid can flow therethrough; and

[0017] The second fluid pipe is separate from the first fluid pipe and is connected to the sound acquisition fluid bag so that fluid can flow therethrough.

[0018] In this specification, the "measured site" includes upper limbs such as the upper arm and wrist, or lower limbs such as the ankle, and typically refers to a rod-shaped site.

[0019] The “side facing the measurement site” refers to the side facing the measurement site when the blood pressure measurement cuff is wrapped around the measurement site and worn (referred to as “worn state”).

[0020] For a blood pressure cuff, the "longitudinal direction" refers to the direction in which the outer fabric extends in a strip-like shape, corresponding to the circumferential direction around the measurement site when worn. The "width direction," described below, refers to the direction perpendicular to the longitudinal direction within the plane of the outer fabric, corresponding to the direction along which an artery passes through the measurement site when worn. Furthermore, the "thickness direction" refers to the direction perpendicular to both the longitudinal and width directions (i.e., the outer fabric), corresponding to the direction perpendicular to the outer circumference of the measurement site when worn.

[0021] In the disclosed blood pressure measurement cuff, the pressing fluid bag is fluidically connected to a pressure device (typically comprising a pump or a valve) disposed externally of the blood pressure measurement cuff via the first fluid piping. The sound acquisition fluid bag is fluidically connected to a sound detection device (typically comprising a microphone) disposed externally of the blood pressure measurement cuff via the second fluid piping. The blood pressure measurement cuff is worn so that the cuff is wrapped around the measured part in the longitudinal direction of the cuff. In this worn state, the pressing fluid bag, the sound acquisition fluid bag, and the outer fabric are arranged in sequence in the thickness direction relative to the measured part. In this worn state, during blood pressure measurement, air is supplied to the pressing fluid bag via the first fluid piping from the pressure device. As a result, the pressing fluid bag is pressurized. During this pressurization process, the outer fabric restricts the expansion of the pressing fluid bag and the sound acquisition fluid bag as a whole in a direction away from the measured part. Therefore, the pressing fluid bag expands in a direction that presses the measured part. As a result, the measured part is compressed, and the artery passing through the measured part is blocked. Next, air is slowly discharged from the pressing fluid bag through the first fluid piping by the pressure device. As a result, the pressing fluid bag is slowly decompressed. For example, during this decompression process, the sound acquisition fluid bag acquires sound from the measured part via the pressing fluid bag. Furthermore, the sound detection device detects the sound acquired by the sound acquisition fluid bag through the second fluid piping. Moreover, based on the output of the sound detection device corresponding to the sound from the sound acquisition fluid bag, Korotkoff sounds are extracted and the blood pressure of the measured part is measured.

[0022] Thus, in this blood pressure measurement cuff, the sound acquisition fluid bag acquires sound from the measured area via the pressing fluid bag. When worn, the pressing fluid bag extends circumferentially along the measured area. Therefore, even if the cuff's wearing position relative to the measured area (particularly its circumferential position) is offset, the level of sound entering the pressing fluid bag from the artery passing through the measured area is minimally affected. As a result, compared to conventional examples, sound collection by the sound acquisition fluid bag is more stable. Therefore, Korotkoff sounds can be stably acquired.

[0023] In one embodiment of the blood pressure measurement cuff, a first fluid system including the pressing fluid bag and the first fluid pipe and a second fluid system including the sound acquisition fluid bag and the second fluid pipe are separated from each other so that fluid cannot flow.

[0024] The blood pressure measurement cuff of this embodiment can prevent the pulse sound (pulse wave) from the first fluid system from mixing into the sound (including Korotkoff sound components) passing through the second fluid system. Therefore, Korotkoff sounds can be acquired more stably.

[0025] In one embodiment of the blood pressure measurement cuff, it is characterized in that:

[0026] The sound acquisition fluid bag includes a pair of sheets facing each other in the thickness direction, the pair of sheets being joined together to form a bag shape.

[0027] A spacer is provided in a gap between the pair of sheets facing each other to prevent the pair of sheets from coming into close contact.

[0028] In one embodiment of the blood pressure measurement cuff, a spacer is provided in the gap between the pair of sheets facing each other, thereby preventing the pair of sheets from coming into close contact. Therefore, the sound acquisition fluid bag can stably acquire sounds from the measured area via the compression fluid bag. As a result, Korotkoff sounds can be more stably acquired.

[0029] In the blood pressure measurement cuff according to one embodiment, the spacer is composed of a protrusion integrally formed on the sheet.

[0030] In the blood pressure measurement cuff of this embodiment, the spacer can be configured simply.

[0031] In one embodiment of the blood pressure measurement cuff, it is characterized in that:

[0032] The pressing fluid bag includes a pair of sheets facing each other in the thickness direction, the pair of sheets being joined together in an annular shape to form a bag shape.

[0033] The sound acquisition fluid bag includes a pair of sheets facing each other in the thickness direction, the pair of sheets being joined together in an annular shape to form a bag shape.

[0034] The sheet on the pressing fluid bag side of the pair of sheets of the sound acquisition fluid bag is shared with the sheet on the sound acquisition fluid bag side of the pair of sheets of the pressing fluid bag.

[0035] "Join" means to connect together by welding, bonding, etc.

[0036] In this embodiment of the blood pressure measurement cuff, the sheet on the pressing fluid bag side of the pair of sheets of the sound acquisition fluid bag and the sheet on the sound acquisition fluid bag side of the pair of sheets of the pressing fluid bag are shared. Therefore, since the pressing fluid bag and the sound acquisition fluid bag are composed of three sheets, the structure is simplified.

[0037] In one embodiment of the blood pressure measurement cuff, it is characterized in that:

[0038] The measured part is the upper arm,

[0039] The dimension of the compression fluid bag in the longitudinal direction is set within a range of 167 mm to 380 mm, and the dimension in the width direction perpendicular to the longitudinal direction of the compression fluid bag along the surface of the outer fabric is set within a range of 90 mm to 180 mm.

[0040] The lengthwise dimension of the sound acquisition fluid bag is set within a range of 41.8 mm to 380 mm, and the widthwise dimension of the sound acquisition fluid bag is set within a range of 45 mm to 180 mm.

[0041] The lengthwise dimension and the widthwise dimension are collectively referred to as "plane direction dimension" as appropriate.

[0042] In this embodiment of the blood pressure measurement cuff, by setting the planar dimensions of the compression fluid bag, it can be worn by subjects with various arm circumferences. Furthermore, even if the cuff is misaligned with respect to the upper arm, the measured part (particularly the circumferential position), the compression fluid bag can be stably positioned facing the artery passing through the upper arm. Furthermore, by setting the planar dimensions of the sound acquisition fluid bag, for example, when the pair of sheets are made of a general polyurethane resin, the natural vibration frequency of the sound acquisition fluid bag can be made approximately the same level as the main frequency component of Korotkoff sounds. Therefore, the sound acquisition fluid bag can effectively acquire Korotkoff sound components from the measured part.

[0043] In one embodiment of the blood pressure measurement cuff, it is characterized in that:

[0044] The measured part is the wrist,

[0045] The dimension of the compression fluid bag in the longitudinal direction is set to 140 mm, and the dimension in the width direction perpendicular to the longitudinal direction of the compression fluid bag along the surface of the outer fabric is set to 60 mm.

[0046] The lengthwise dimension of the sound acquisition fluid bag is set within a range of 35 mm to 140 mm, and the widthwise dimension of the sound acquisition fluid bag is set within a range of 30 mm to 60 mm.

[0047] In the blood pressure measurement cuff of this embodiment, the sound acquisition fluid bag can efficiently acquire Korotkoff sound components from the measurement site.

[0048] In one embodiment of the blood pressure measurement cuff, it is characterized in that:

[0049] The length of the sound acquisition fluid bag in the longitudinal direction is set to 1 / 2 of the length of the compression fluid bag in the longitudinal direction.

[0050] The dimension of the sound acquisition fluid bag in the width direction is set to be the same as the dimension of the pressing fluid bag in the width direction.

[0051] In the blood pressure measurement cuff of this embodiment, the sound acquisition fluid bag can efficiently acquire Korotkoff sound components from the measurement site.

[0052] In another aspect, the blood pressure monitor of the present disclosure measures blood pressure by using Korotkoff sounds emitted from a measured part, and is characterized in that:

[0053] have:

[0054] The blood pressure measurement cuff;

[0055] a pressure device connected to the first fluid pipe in a fluid-flowable manner, and configured to supply fluid to the pressing fluid bag through the first fluid pipe to increase the pressure, or to discharge fluid from the pressing fluid bag through the first fluid pipe to reduce the pressure;

[0056] a sound detection device connected to the second fluid pipe so as to be fluid-transmissive, and detecting sound from the sound acquisition fluid bag through the second fluid pipe;

[0057] a first fluid system including the pressing fluid bag and the first fluid tube and a second fluid system including the sound acquisition fluid bag and the second fluid tube are kept fluid-incompatible with each other; and

[0058] The blood pressure calculation unit opens and closes the atmosphere release valve as the pressure device pressurizes or depressurizes the compression fluid bag, and calculates the blood pressure of the measurement site based on the output of the sound detection device corresponding to the sound from the sound acquisition fluid bag.

[0059] "Pressure equipment" typically includes pumps and valves.

[0060] A "sound detection device" typically comprises a microphone.

[0061] In the sphygmomanometer disclosed herein, the blood pressure measurement cuff is worn so as to wrap around the measured area. In this worn position, during blood pressure measurement, the pressure device supplies air to the pressing fluid bag via the first fluid piping. This causes the pressing fluid bag to be pressurized. During this pressurization process, the expansion of the pressing fluid bag and the sound acquisition fluid bag, together away from the measured area, is limited by the outer fabric as a whole. Consequently, the pressing fluid bag expands in a direction that presses against the measured area. This compresses the measured area, blocking blood flow to the artery passing through it. Next, air is slowly expelled from the pressing fluid bag via the first fluid piping by the pressure device. This gradually reduces the pressure on the pressing fluid bag. For example, during this decompression process, the sound acquisition fluid bag acquires sound from the measured area via the pressing fluid bag. Furthermore, the sound detection device detects the sound acquired by the sound acquisition fluid bag via the second fluid piping. Furthermore, the blood pressure calculation unit extracts Korotkoff sounds based on the output of the sound detection device corresponding to the sound from the sound acquisition fluid bag and calculates the blood pressure of the measurement site.

[0062] In this blood pressure monitor, Korotkoff sounds can be stably acquired by the blood pressure measurement cuff, and thus blood pressure can be measured with high accuracy.

[0063] In one embodiment of the sphygmomanometer, it is characterized in that:

[0064] The sphygmomanometer includes an atmospheric release valve connected to the second fluid pipe so that fluid can flow therethrough, and capable of closing or releasing the second fluid pipe to atmospheric pressure.

[0065] The blood pressure calculation unit closes the atmosphere release valve to seal the second fluid system after the blood pressure measurement cuff is placed on the measurement site and before the pressure device starts pressurizing the pressing fluid bag.

[0066] In this embodiment of the blood pressure monitor, the sound acquisition fluid bag can be maintained with an appropriate amount of air during the pressurization and depressurization processes by the blood pressure calculation unit. The sound acquisition fluid bag can effectively acquire Korotkoff sound components from the measured area. Consequently, blood pressure can be measured with even higher accuracy.

[0067] Effects of the Invention

[0068] As can be seen from the above, the blood pressure measurement cuff of the present disclosure can stably acquire Korotkoff sounds. In addition, the blood pressure monitor of the present disclosure can measure blood pressure with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a diagram showing the appearance of a blood pressure monitor equipped with a blood pressure measurement cuff according to one embodiment of the present invention.

[0070] Figure 2 It is a diagram showing the block configuration of the blood pressure monitor.

[0071] Figure 3 (A) is a diagram schematically showing a planar layout of a sound acquisition fluid bag and a compression fluid bag built into the cuff when the cuff is unfolded. Figure 3 (B) is a diagram schematically showing the cross-section of the sound acquisition fluid bag and the pressing fluid bag in an exploded state.

[0072] Figure 4 (A) is a diagram schematically showing a manner in which the cuff is wrapped around the outer circumference of the left upper arm, which is the measurement site, and is worn. Figure 4 (B) is a diagram schematically showing a K-sound signal (indicating Korotkoff sounds) acquired by the sound detection device (microphone) through the sound acquisition fluid bag. Figure 4 (C) is a diagram schematically showing the pressure fluctuation component acquired by the pressure sensor through the pressing fluid bag.

[0073] Figure 5 This is a diagram showing the flow of blood pressure measurement using the sphygmomanometer.

[0074] Figure 6 (A) is a diagram showing a method for setting the longitudinal and width dimensions of the sound acquisition fluid bag. Figure 6 (B) is a graph showing the amplitude of the K-sound signal when the longitudinal dimension of the sound acquisition fluid bag is set to various values. Figure 6 (C) is a graph showing the amplitude of the K-sound signal when the width dimension of the sound acquisition fluid bag is set to various values.

[0075] Figure 7 (A) is a diagram showing three ways in which the wearing position of the cuff relative to the measured site, in particular, the circumferential position of the sound acquisition fluid bag, can be changed. Figure 7 (B) is a graph showing the amplitude of the K-sound signal when the circumferential position of the sound acquisition fluid bag of the cuff (Example) is changed into three different positions. Figure 7(C) is a graph showing the amplitude of the K-sound signal when the circumferential position of the sound acquisition fluid bag of the cuff of Comparative Example 1 (the sound acquisition fluid bag is arranged below the compression fluid bag) is changed into three types.

[0076] Figure 8A This figure shows the power spectrum of the sound acquired by the microphone when the cuff (Example) acquires the sound from the measured part (K sound is present).

[0077] Figure 8B This figure shows the power spectrum of the sound acquired by the microphone when the cuff (Example) does not acquire the sound from the measured part (no K sound).

[0078] Figure 9A A diagram showing the power spectrum of the sound acquired by the microphone when the cuff of Comparative Example 2 (the air tube of the compression fluid bag and the sound acquisition fluid bag is shared) acquires sound from the measurement site (including K sounds).

[0079] Figure 9B This figure shows the power spectrum of the sound acquired by the microphone when the cuff of Comparative Example 2 does not acquire the sound from the measured part (no K sound).

[0080] Figure 10 This is a graph showing the background noise (sound pressure level) of the sound acquired by the microphone before and after the opening and closing of the atmosphere release valve connected to the sound acquisition fluid bag in a fluid-flowable manner during blood pressure measurement by the sphygmomanometer.

[0081] Figure 11 The diagram shows the cuff pressure and K-sound signal obtained by the sphygmomanometer according to the blood pressure measurement flow when the cuff (Example) is worn on the measured area and the atmosphere release valve is closed before pump pressurization begins.

[0082] Figure 12 Graphs showing the cuff pressure and K-sound signal obtained by the sphygmomanometer according to the blood pressure measurement flow when the atmosphere release valve is closed before the cuff (Example) is attached to the measured area (Comparative Example 3).

[0083] Figure 13 (A) is a diagram schematically showing a planar layout of a sound acquisition fluid bag and a pressing fluid bag built into the cuff of Modification 1 when the cuff is unfolded. Figure 13 (B) is a diagram schematically showing the cross-section of the sound acquisition fluid bag and the pressing fluid bag in an exploded state.

[0084] Figure 14(A) is a diagram schematically showing a planar layout of a sound acquisition fluid bag and a pressing fluid bag built into the cuff of Modification 2 when the cuff is unfolded. Figure 14 (B) is a diagram schematically showing the cross-section of the sound acquisition fluid bag and the pressing fluid bag in an exploded state.

[0085] Figure 15 (A) is a diagram schematically showing a planar layout of a sound acquisition fluid bag and a pressing fluid bag built into the cuff of Modification 3 when the cuff is unfolded. Figure 15 (B) is a diagram schematically showing the cross-section of the sound acquisition fluid bag and the pressing fluid bag in an exploded state. DETAILED DESCRIPTION

[0086] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0087] (Schematic Structure of a Sphygmomanometer)

[0088] Figure 1 The appearance of a blood pressure meter 100 equipped with a blood pressure measurement cuff 20 according to an embodiment of the present invention is shown. The blood pressure meter 100 generally comprises a cuff 20 wrapped around a rod-shaped measurement site 90 (see FIG. 1 ) such as an upper arm or wrist. Figure 4 and the main body 10, via the air piping 38 as a first fluid piping, the air piping 37 as a second fluid piping and the cuff 20 are fluidically connected.

[0089] (Structure of a blood pressure cuff)

[0090] according to Figure 1 It can be seen that the cuff 20 is formed by sewing (or welding) the peripheral edge portions 20s of the outer fabric 21 and the inner fabric 29 having a shape corresponding to the outer fabric 21 facing each other.

[0091] Figure 3 (A) schematically shows the planar layout of the sound acquisition fluid bag 22 and the pressing fluid bag 23 built into the cuff 20 in a state where the cuff 20 is deployed. Figure 3 (B) schematically shows the cross-section of the sound acquisition fluid bag 22 and the pressing fluid bag 23 in the decomposed state. Here, regarding the cuff 20, the longitudinal direction X refers to the direction in which the outer fabric 21 extends in a strip shape, which is equivalent to the direction in which the cuff 20 is worn (refer to Figure 4The circumferential direction of the measurement site 90 is wound around the outer fabric 21 (A). The width direction Y is the direction perpendicular to the longitudinal direction X within the plane of the outer fabric 21 and corresponds to the direction in which the artery 91 passes through the measurement site 90 when the wearer is wearing the outer fabric. Furthermore, the thickness direction Z is the direction perpendicular to both the longitudinal direction X and the width direction Y (i.e., the outer fabric 21) and corresponds to the direction perpendicular to the outer circumferential surface of the measurement site 90 when the wearer is wearing the outer fabric 21.

[0092] according to Figure 3 As can be seen from (B), in this example, the cuff 20 includes a compressing fluid bag 23 and a sound acquisition fluid bag 22, which is separate from the compressing fluid bag 23, between the inner fabric 29 and the outer fabric 21. The compressing fluid bag 23 is placed on one side of the inner fabric 29 primarily to compress the measurement site 90. The sound acquisition fluid bag 22 is placed between the outer fabric 21 and the compressing fluid bag 23 to acquire sound from the measurement site 90 via the compressing fluid bag 23. In this example, the sound acquisition fluid bag 22 is partially bonded to the compressing fluid bag 23 and does not shift relative to the compressing fluid bag 23. The compressing fluid bag 23 is partially bonded to the outer fabric 21 and does not shift relative to the outer fabric 21.

[0093] according to Figure 3 As can be seen from (A), the compression fluid bag 23 has a roughly rectangular shape with rounded corners extending along the longitudinal direction X within the plane of the outer fabric 21. The dimension of the compression fluid bag 23 in the longitudinal direction X is set to L1 = 235 mm, and the dimension of the compression fluid bag 23 in the width direction Y is set to W1 = 125 mm. The sound acquisition fluid bag 22 has a roughly rectangular shape with smaller rounded corners than the compression fluid bag 23 within the plane of the outer fabric 21. The dimension of the sound acquisition fluid bag 22 in the longitudinal direction X is set to L2 = 125 mm, and the dimension of the sound acquisition fluid bag 22 in the width direction Y is set to W2 = 125 mm. The specific method for setting these plane dimensions L1, W1, L2, and W2 will be described later. In this example, the center of the compression fluid bag 23 coincides with the center of the sound acquisition fluid bag 22.

[0094] according to Figure 3 As shown in (B), the pressing fluid bag 23 comprises a pair of sheets 23a and 23b facing each other in the thickness direction Z. The peripheral edges 23as and 23bs of these sheets 23a and 23b are joined together in an annular shape (welded in this example) as indicated by arrow M2, forming a bag shape. The sound acquisition fluid bag 22 comprises a pair of sheets 22a and 22b facing each other in the thickness direction Z. The peripheral edges 22as and 22bs of these sheets 22a and 22b are joined together in an annular shape as indicated by arrow M1, forming a bag shape. In this example, the sheets 23a, 23b, 22a, and 22b are made of polyurethane resin.

[0095] The pair of sheets 23a and 23b constituting the pressing fluid bag 23 have respective Figure 3 (A) has roughly rectangular protrusions 23at and 23bt protruding in the width direction (-Y direction). With the air piping 38 sandwiched between the protrusions 23at and 23bt, the air piping 38 is connected to the pressing fluid bag 23 in a fluid-circulating manner by fully welding the portions 23tm and 23tm (indicated by oblique lines) of the protrusions 23at and 23bt corresponding to the sides of the air piping 38. The pressing fluid bag 23 can be expanded by being supplied with air through the air piping 38 and can be contracted by being exhausted from the air. Similarly, the pair of sheets 22a and 22b constituting the sound acquisition fluid bag 22 have, at corresponding positions, Figure 3 The device (A) has generally rectangular protrusions 22at and 22bt protruding in the width direction (-Y direction). With the air tube 37 sandwiched between the protrusions 22at and 22bt, the air tube 37 is fully welded to the protrusions 22at and 22bt, corresponding to the sides of the air tube 37 (indicated by hatching). This connects the air tube 37 to the sound acquisition fluid bag 22 in a fluid-permeable manner. Sound acquired by the sound acquisition fluid bag 22 is transmitted to the main body 10 via the air tube 37 (described in detail later).

[0096] A plurality of protrusions 22p, 22p, ..., serving as spacers, are provided in the gap between the pair of sheets 22a, 22b that form the sound acquisition fluid bag 22. In this example, these protrusions 22p, 22p, ... are short cylindrical in shape and integrally formed on the sheet 22b positioned on the side of the pressing fluid bag 23. This allows for a simple spacer configuration. In this example, these protrusions 22p, 22p, ... are dispersed at approximately equal intervals along the surface (XY plane) of the outer fabric 21. This prevents the pair of sheets 22a, 22b from coming into close contact during blood pressure measurement. Therefore, as described later, the sound acquisition fluid bag 22 can stably acquire sound from the measured area 90 via the pressing fluid bag 23. As a result, Korotkoff sounds can be stably acquired.

[0097] The outer fabric 21 is bendable or flexible, but is constructed to be substantially non-stretchable to prevent the sound acquisition fluid bag 22 and the compression fluid bag 23 from expanding away from the measurement site 90 during blood pressure measurement. Meanwhile, the inner fabric 29 is bendable or flexible and is designed to easily expand and contract to facilitate compression of the compression fluid bag 23 against the measurement site 90 during blood pressure measurement. The outer fabric 21 and inner fabric 29 are not limited to woven fabrics; they can also be constructed from one or more layers of resin. The lengthwise dimensions (X) of the outer fabric 21 and inner fabric 29 are set to be longer than the circumference of the measurement site 90 (in this example, the upper arm). The widthwise dimensions (Y) of the outer fabric 21 and inner fabric 29 are set to be slightly larger than the widthwise dimensions (Y) of the compression fluid bag 23 (and the sound acquisition fluid bag 22). The inner fabric 29 is provided to protect the sound acquisition fluid bag 22 and the compression fluid bag 23 and can be omitted for blood pressure measurement.

[0098] (Structure of the main body)

[0099] like Figure 2 As shown, the main body 10 is equipped with a control unit 110, a display 50, an operation unit 52, a memory 51 serving as a storage unit, a power supply unit 53, a pressure sensor 31, a pump 32 and a control valve 33 serving as pressure devices, a microphone 35 serving as a sound detection device, and an air release valve 34. In this example, the air pipe 38a connected to the pressure sensor 31, the air pipe 38b connected to the pump 32, and the air pipe 38c connected to the control valve 33 merge to form a single air pipe 38 connected to the compression fluid bag 23 in a fluid-free manner. The air pipe 38, serving as the first fluid pipe, is a general term encompassing these air pipes 38a, 38b, and 38c. Furthermore, the air pipe 37a connected to the microphone 35 and the air pipe 37b connected to the air release valve 34 merge to form a single air pipe 37 connected to the sound acquisition fluid bag 22 in a fluid-free manner. The air pipe 37 as the second fluid pipe is a general term including these air pipes 37 a and 37 b .

[0100] like Figure 1As shown in FIG, the display 50 and the operating unit 52 are arranged on the front panel 10f of the main body 10. In this example, the display 50 is composed of an LCD (Liquid Crystal Display) and displays predetermined information based on control signals from the control unit 110. In this example, systolic blood pressure SYS (unit: mmHg), diastolic blood pressure DIA (unit: mmHg), and pulse rate PULSE (unit: beats / minute) are displayed. Furthermore, the display 50 may be composed of an organic EL (Electro Luminescence) display or may include an LED (Light Emitting Diode).

[0101] In this example, the operation unit 52 comprises a measurement switch (denoted by the same reference numeral 52 for simplicity) for receiving an instruction to start (START) or stop (STOP) blood pressure measurement. The operation unit 52 inputs an operation signal corresponding to the user's instruction to the control unit 110. Specifically, when the measurement switch 52 is pressed, an operation signal to start blood pressure measurement is input to the control unit 110, which then starts the blood pressure measurement (described later) (the measurement automatically stops when the blood pressure measurement is complete). If the measurement switch 52 is pressed during blood pressure measurement, the control unit 110 immediately stops the blood pressure measurement.

[0102] Figure 2 The memory 51 shown in FIG stores program data for controlling the sphygmomanometer 100, setting data for setting various functions of the sphygmomanometer 100, and data of blood pressure measurement results. The memory 51 is also used as a work memory when the program is executed.

[0103] The control unit 110 includes a CPU (Central Processing Unit) and controls the overall operation of the sphygmomanometer 100. Specifically, the control unit 110 functions as a pressure control unit based on a program for controlling the sphygmomanometer 100 stored in the memory 51. It controls the pump 32 and control valve 33, which serve as pressure devices, based on an operation signal from the operation unit 52. Furthermore, the control unit 110 functions as a blood pressure calculation unit, calculating the blood pressure value based on the output of the microphone 35 and controlling the display 50 and memory 51. The specific blood pressure measurement method will be described later.

[0104] In this example, the pressure sensor 31 is a piezo-resistive pressure sensor that outputs the pressure of the compression fluid bag 23 contained within the cuff 20 (referred to as "cuff pressure Pc") as resistance due to the piezo-resistive effect via the air tube 38. In this example, the control unit 110 includes an oscillation circuit that oscillates at a frequency corresponding to the resistance from the pressure sensor 31, and calculates the cuff pressure Pc based on this oscillation frequency.

[0105] The pump 32 supplies air to the compression fluid bladder 23 built into the cuff 20 through the air tube 38 based on a control signal supplied from the control unit 110. This increases the pressure (cuff pressure Pc) of the compression fluid bladder 23.

[0106] The control valve 33 is a normally open electromagnetic control valve, and is opened and closed based on a control signal supplied from the control unit 110 to discharge air from or seal air into the compression fluid bladder 23 through the air tube 38 to control the cuff pressure.

[0107] The microphone 35 detects the sound acquired by the sound acquisition fluid bag 22 through the air pipe 37 and outputs an electrical signal corresponding to the sound to the control unit 110. In this example, the control unit 110 performs filtering including fast Fourier transform (FFT) on the electrical signal output by the microphone 35 and extracts the K sound signal (denoted by Ks) representing Korotkoff sounds. Figure 4 As shown in (B), the K sound signal Ks is typically obtained as a pulse signal that fluctuates with respect to the reference level ba. Figure 4 In (B), Ap-p represents the peak-to-peak amplitude of the K-sound signal Ks.

[0108] Figure 2 The atmosphere release valve 34 shown in FIG is composed of a normally open electromagnetic control valve, and is opened and closed based on a control signal provided from the control unit 110 to open or close the second fluid system FS2 including the sound acquisition fluid bag 22 and the air piping 37 to the atmosphere.

[0109] In this example, the first fluid system FS1, which includes the compression fluid bag 23, air tubing 38, pressure sensor 31, pump 32, and control valve 33, and the second fluid system FS2, which includes the sound acquisition fluid bag 22, air tubing 37, microphone 35, and atmosphere release valve 34, are separated from each other so that fluid cannot flow between them. These separations are also maintained within the main body 10. This prevents pulse sounds (pulse wave frequencies) from the first fluid system FS1 from mixing with sounds (including Korotkoff sound components) passing through the second fluid system FS2 (particularly the air tubing 37). Consequently, Korotkoff sounds can be stably acquired.

[0110] The power supply unit 53 supplies power to the control unit 110 , the display 50 , the memory 51 , the pressure sensor 31 , the pump 32 , the control valve 33 , the microphone 35 , and the atmosphere release valve 34 .

[0111] (How to wear a blood pressure cuff)

[0112] like Figure 4 As shown in (A) (a cross section along an artery 91 passing through the measured part 90), the cuff 20 is worn in a manner such that it is wrapped around the outer peripheral surface of the measured part 90 (in this example, the upper arm) in the longitudinal direction X of the cuff 20. When worn, the outer fabric 21 is fixed to prevent it from loosening by a surface fastener (not shown). Figure 4 In (A), for simplicity, the inner fabric 29 is omitted from illustration. Furthermore, the compression fluid bag 23 and the sound acquisition fluid bag 22 are each depicted as ellipsoidal. In this worn state, the inner fabric 29 (not shown), the compression fluid bag 23, the sound acquisition fluid bag 22, and the outer fabric 21 are arranged in the thickness direction Z relative to the outer circumference of the measurement site 90. Furthermore, since the air tubes 37 and 38 extend downstream (in the -Y direction) of the blood flow through the artery 91, they do not interfere with wearing the device.

[0113] (Blood pressure measurement)

[0114] Figure 5 The flowchart shows the operation flow when the user measures blood pressure using the blood pressure monitor 100 .

[0115] When the cuff 20 is worn on the measured part 90, the user instructs the start of measurement via the measurement switch 52 provided on the main body 10 ( Figure 5 In step S1), the control unit 110 performs initialization ( Figure 5 Specifically, the control unit 110 initializes the processing memory area and, while stopping the pump 32 and opening the control valve 33, performs a 0 mmHg adjustment on the pressure sensor 31 (setting the atmospheric pressure to 0 mmHg). At this time, the atmospheric release valve 34 is open.

[0116] Next, the control unit 110 closes the air release valve 34 (step S3). The reason for closing the air release valve 34 at this stage after the cuff 20 is attached to the measured part 90 and before the compression fluid bag 23 begins to pressurize is to seal an appropriate amount of air in the sound acquisition fluid bag 22 in order to acquire Korotkoff sounds from the measured part 90 via the compression fluid bag 23. Figure 10 The figure shows the background noise (sound pressure level) of the sound picked up by the microphone 35 before and after the time t0 when the atmosphere release valve 34 is closed during the blood pressure measurement by the sphygmomanometer 100. Figure 10 It can be seen that closing the atmosphere release valve 34 reduces background noise and contributes to improving the signal-to-noise ratio (S / N ratio) when acquiring Korotkoff sounds.

[0117] Next, the control unit 110 functions as a pressure control unit, closes the control valve 33 (step S4), and drives the pump 32 to begin pressurizing the cuff 20 (step S5). Specifically, the control unit 110 supplies air from the pump 32 to the cuff 20 (the compression fluid bladder 23 built into the cuff 20) via the air piping 38. In conjunction with this, the pressure sensor 31 functions as a pressure detector, detecting the pressure in the compression fluid bladder 23 via the air piping 38. The control unit 110 controls the pressurization speed of the pump 32 based on the output of the pressure sensor 31.

[0118] at this time, Figure 4 The expansion of the pressing fluid bag 23 shown in FIG. (A) and the sound acquisition fluid bag 22 in a direction away from the measurement site 90 is restricted as a whole by the outer fabric 21. Therefore, the pressing fluid bag 23 expands in a direction pressing the opposing region 90A of the measurement site 90. This compresses the region 90A of the measurement site 90 opposing the pressing fluid bag 23, and blood flow is blocked in the artery 91 passing through this region 90A.

[0119] Next, the control unit 110 determines whether the pressure (cuff pressure Pc) of the cuff 20 (in this example, the pressing fluid bag 23) has reached a preset value Pu (for example, Figure 11 Here, the value Pu can be determined to be sufficiently higher than the assumed blood pressure value of the subject, for example, 280 mmHg, or it can be determined to be the blood pressure value of the subject measured last time plus 40 mmHg. Figure 11 As shown, it is pre-set to Pu = 180 mmHg. The control unit 110 continues to pressurize until the cuff pressure Pc reaches the value Pu = 180 mmHg. When the cuff pressure Pc reaches the value Pu, the pump 32 is stopped (step S6). Figure 11 In the example of FIG. 1 , at time t1 , the cuff pressure Pc reaches the value Pu, and the pump 32 stops.

[0120] Next, the control unit 110 slowly opens the control valve 33 ( Figure 5Step S7). As a result, the cuff pressure Pc is decompressed at a substantially constant rate. In this example, during the decompression process, the sound acquisition fluid bag 22 acquires the sound from the measured part 90 via the pressing fluid bag 23. Furthermore, the microphone 35 detects the sound acquired by the sound acquisition fluid bag 22 through the air piping 37. The microphone 35 outputs an electrical signal corresponding to the sound to the control unit 110. The control unit 110 performs filtering including fast Fourier transform (FFT) based on the electrical signal output by the microphone 35, and extracts the K sound signal Ks representing Korotkoff sounds. Figure 11 In the example, the K sound signal Ks begins to be observed at time t2, gradually increases and shows a maximum value, then gradually decreases and disappears at time t3.

[0121] The control unit 110 functions as a blood pressure calculation unit and attempts to calculate blood pressure values ​​(systolic blood pressure SYS (Systolic Blood Pressure) and diastolic blood pressure DIA (Diastolic Blood Pressure)) based on the K-sound signal Ks acquired at that time. Figure 5 Step S8). Figure 11 In the example of FIG, the cuff pressure Pc detected by the pressure sensor 31 at time t2 is calculated as the systolic blood pressure SYS. In addition, the cuff pressure Pc detected by the pressure sensor 31 at time t3 is calculated as the diastolic blood pressure DIA.

[0122] Furthermore, a pulse wave signal (pressure fluctuation component) Pm (in the case of a pulse wave) as pulse wave information based on the pulse wave is superimposed on the cuff pressure Pc detected by the pressure sensor 31 from the compression fluid bag 23 through the air pipe 38. Figure 4 In this example, the control unit 110 calculates the pulse rate PULSE (beats / minute) based on the pulse wave signal Pm.

[0123] If the control unit 110 cannot calculate the blood pressure value and pulse rate due to insufficient data ( Figure 5 (If step S9 is "No"), the processing of steps S7 to S9 is repeated until calculation is possible.

[0124] Once the blood pressure and pulse are calculated ("YES" in step S9), the control unit 110 functions as a pressure control unit, opens the control valve 33, and rapidly discharges the air from the cuff 20 (compression fluid bag 23) (step S10). Furthermore, the air release valve 34 is opened (step S11).

[0125] Then, the control unit 110 displays the calculated blood pressure value and pulse rate on the display 50 (step S12 ), and performs control to store the blood pressure value and pulse rate in the memory 51 .

[0126] In this manner, in the blood pressure monitor 100 equipped with the cuff 20, the sound acquisition fluid bag 22 acquires sound from the measured site 90 via the pressing fluid bag 23. When worn, the pressing fluid bag 23 extends circumferentially around the measured site 90. Therefore, even if the cuff 20 (the pressing fluid bag 23) is misaligned relative to the measured site 90 (particularly in the circumferential direction), the level of sound entering the pressing fluid bag 23 from the artery 91 passing through the measured site 90 is less affected than in conventional examples. Consequently, sound collection by the sound acquisition fluid bag 22 is stable. Therefore, K-sound signals Ks representing Korotkoff sounds can be stably acquired. Consequently, blood pressure can be measured with high accuracy.

[0127] In the above example, blood pressure and pulse rate are calculated while the cuff 20 (pressing fluid bag 23) is depressurized. However, the present invention is not limited thereto and blood pressure and pulse rate may be calculated while the cuff 20 (pressing fluid bag 23) is inflated.

[0128] (Setting the Dimensions of the Pressing Fluid Bag and the Sound Acquisition Fluid Bag in the Surface Direction)

[0129] The planar dimensions of the compression fluid bag 23 and the sound acquisition fluid bag 22 are set based on the cuff size (a cuff specification that determines the planar dimensions of the outer fabric 21 and inner fabric 29). Generally, as shown in the "Cuff Size" column of Table 1 below, cuff sizes are XL (extra large), L (large), M (medium), and S (small) for the upper arm. A wrist size is also available.

[0130] (Table 1)

[0131]

[0132] The compression fluid bag 23's lengthwise dimension L1 in the X direction and widthwise dimension W1 in the Y direction are set to various values, as shown in the "Compression Fluid Bag" column of Table 1, depending on the cuff size corresponding to the subject's arm circumference. Specifically, for an upper arm cuff size of XL (extra large), the lengthwise dimension L1 in the X direction is set to 380.0 mm, and the widthwise dimension W1 in the Y direction is set to 180.0 mm. For an upper arm cuff size of L (large), the lengthwise dimension L1 in the X direction is set to 312.5 mm, and the widthwise dimension W1 in the Y direction is set to 150.0 mm. For an upper arm cuff size of M (medium), the lengthwise dimension L1 in the X direction is set to 235.0 mm, and the widthwise dimension W1 in the Y direction is set to 125.0 mm. For an upper arm cuff size of S (small), the lengthwise dimension L1 in the X direction is set to 167.0 mm, and the widthwise dimension W1 in the Y direction is set to 90.0 mm. When used on the wrist, the length dimension L1 is set to 140 mm in the longitudinal direction X, and the width dimension W1 is set to 60 mm in the width direction Y. By setting the plane dimensions L1 and W1 of the compression fluid bag 23, the cuff 20 can be worn by subjects with various arm and wrist circumferences.

[0133] Figure 6(A) shows how to set the dimension L2 in the longitudinal direction X and the dimension W2 in the width direction Y of the sound acquisition fluid bag 22. Regarding the dimension L2 in the longitudinal direction X of the sound acquisition fluid bag 22, for example, when decreasing from its maximum value, as indicated by arrows X1 and X1', the center of the sound acquisition fluid bag 22 in the longitudinal direction X decreases in unison with the center of the pressing fluid bag 23 in the longitudinal direction X. Regarding the dimension W2 in the width direction Y of the sound acquisition fluid bag 22, for example, when decreasing from its maximum value, as indicated by arrow Y1, the downstream side 22d of the sound acquisition fluid bag 22 decreases in unison with the downstream side 23d of the pressing fluid bag 23. This is to minimize the mixing of pulse sounds (pulse wave frequencies) from the upstream side of the artery 91 into the sound acquisition fluid bag 22. In this example, the dimension L2 in the longitudinal direction X and the dimension W2 in the width direction Y of the sound acquisition fluid bag 22 are set to various values, as shown in the "Sound Acquisition Fluid Bag" column of Table 1, depending on the cuff size corresponding to the subject's arm circumference. Specifically, when the upper arm cuff size is XL, the dimension L2 in the longitudinal direction X of the sound acquisition fluid bag 22 is set within the range of 95 mm to 380 mm, while the dimension W2 in the width direction Y of the sound acquisition fluid bag 22 is set within the range of 90 mm to 180 mm. When the upper arm cuff size is L, the dimension L2 in the longitudinal direction X of the sound acquisition fluid bag 22 is set within the range of 78.1 mm to 312.5 mm, while the dimension W2 in the width direction Y of the sound acquisition fluid bag 22 is set within the range of 75 mm to 150 mm. For the upper arm cuff size M, the dimension L2 of the sound acquisition fluid bag 22 in the longitudinal direction X is set to a range of 58.8 mm to 235 mm, and the dimension W2 of the sound acquisition fluid bag 22 in the width direction Y is set to a range of 62.5 mm to 125 mm. For the upper arm cuff size S, the dimension L2 of the sound acquisition fluid bag 22 in the longitudinal direction X is set to a range of 41.8 mm to 167 mm, and the dimension W2 of the sound acquisition fluid bag 22 in the width direction Y is set to a range of 45 mm to 90 mm. For the wrist cuff size, the dimension L2 of the sound acquisition fluid bag 22 in the longitudinal direction X is set to a range of 35 mm to 140 mm, and the dimension W2 of the sound acquisition fluid bag 22 in the width direction Y is set to a range of 30 mm to 60 mm.

[0134] Figure 6 (B) Figure 6(C) shows the peak-to-peak amplitude Ap-p (unit: volt) of the K-sound signal Ks when the dimension L2 in the longitudinal direction X and the dimension W2 in the width direction Y of the sound acquisition fluid bag 22 are set to various values. In addition, the compression fluid bag 23 is fixedly set to a dimension L1 = 235.0 mm in the longitudinal direction X and a dimension W1 = 125.0 mm in the width direction Y (these are equivalent to the setting values ​​when the upper arm cuff size is M). Figure 6 As shown in Figure (B), under the condition that the dimension W2 in the width direction Y is 125 mm, the average amplitude Ap-p value for the longitudinal dimension L2 of the sound acquisition fluid bag 22 in the longitudinal direction X is approximately 0.80 volts when L2 = 235 mm, approximately 0.85 volts when L2 = 125 mm, approximately 0.68 volts when L2 = 60 mm, and approximately 0.48 volts when L2 = 30 mm. Furthermore, d1, d2, d3, d4, and d5 indicate the range of amplitude Ap-p variation at various L2 settings in this case. The results show that the amplitude Ap-p reaches its maximum value for the longitudinal dimension L2 of the sound acquisition fluid bag 22 at L2 = 125 mm, which is half the longitudinal dimension L1 (= 235 mm) of the compression fluid bag 23, indicating a favorable condition. Furthermore, under the condition of dimension L2 in the longitudinal direction X = 235 mm, the average value of the amplitude Ap-p for dimension W2 in the width direction Y of the sound acquisition fluid bag 22 is approximately 0.80 volts when W2 = 125 mm, approximately 0.68 volts when W2 = 60 mm, and approximately 0.56 volts when W2 = 30 mm. Furthermore, d1', d2', and d3' represent the range of amplitude Ap-p variation at various W2 settings in this case. The results show that the amplitude Ap-p reaches its maximum value when W2 = 125 mm, which corresponds to dimension W1 (= 125 mm) in the width direction Y of the compression fluid bag 23, indicating an advantageous condition. The reason why setting L2 = 125 mm and W2 = 125 mm is advantageous is that, for example, when the pair of sheets 22a and 22b forming the sound acquisition fluid bag 22 are made of a common polyurethane resin, the natural vibration frequency of the sound acquisition fluid bag 22 is approximately the same level as the main frequency component of Korotkoff sounds. Consequently, the sound acquisition fluid bag 22 can effectively acquire Korotkoff sound components from the measurement site 90.

[0135] In Verification Experiments 1 to 3 described below, the cuff 20 was set to have a dimension L1 of 235 mm in the longitudinal direction X of the compression fluid bag 23 and a dimension W1 of 125 mm in the width direction Y of the compression fluid bag 23, as described above. The sound acquisition fluid bag 22 was set to have a dimension L2 of 125 mm in the longitudinal direction X and a dimension W2 of 125 mm in the width direction Y of the sound acquisition fluid bag 22.

[0136] (Verification Experiment 1)

[0137] In order to verify the structure of arranging the sound acquisition fluid bag 22 on the pressing fluid bag 23 (refer to Figure 4 (A)) The present inventors conducted the following verification experiment to demonstrate the effect of stably acquiring Korotkoff sounds even if the wearing position (particularly the circumferential position) of the cuff 20 relative to the measured portion 90 is shifted.

[0138] Figure 7 (A) shows that the wearing position of the cuff 20 relative to the measured part 90, in particular, the circumferential position of the sound acquisition fluid bag 22 is changed into three modes as shown in P1, P2, and P3. Figure 7 (A) corresponds to a cross-section of the left upper arm, serving as the measurement site 90, viewed from the upstream side of the artery 91. Circumferential position P2 corresponds to the position where the center of the sound acquisition fluid bag 22 faces the artery 91. Circumferential position P3 corresponds to a position on the opposite side of the measurement site 90 from circumferential position P2. Circumferential position P1 corresponds to a position midway between circumferential positions P2 and P3 around the measurement site 90. Figure 7 (B) shows the peak-to-peak amplitude Ap-p (in volts) of the K-sound signal Ks when the circumferential position of the sound acquisition fluid bag 22 of the cuff 20 is changed to three different positions, as shown by P1, P2, and P3. In this case, the average value of the amplitude Ap-p at circumferential position P1 is approximately 0.82 volts, the average value of the amplitude Ap-p at circumferential position P2 is approximately 0.80 volts, and the average value of the amplitude Ap-p at circumferential position P3 is approximately 0.64 volts. As a result, the change (maximum difference) Dv1 in the average value of the amplitude Ap-p due to the changes in circumferential positions P1, P2, and P3 is approximately 0.18 volts. Furthermore, dv1, dv2, and dv3 indicate the deviation range of the amplitude Ap-p at each circumferential position P1, P2, and P3 in this case.

[0139] As a cuff of Comparative Example 1, the present inventors prepared a cuff having a sound acquisition fluid bag 22 disposed below a compression fluid bag 23, similarly to the conventional example. The cuff of Comparative Example 1 is configured similarly to the cuff 20 described above except for this point. Figure 7(C) shows the amplitude Ap-p (unit: volts) of the K-sound signal Ks when the circumferential position of the sound acquisition fluid bag 22 of the cuff of Comparative Example 1 is changed to three different positions, as shown in P1, P2, and P3. In this case, the average value of the amplitude Ap-p at circumferential position P1 is approximately 0.73 volts, the average value of the amplitude Ap-p at circumferential position P2 is approximately 1.28 volts, and the average value of the amplitude Ap-p at circumferential position P3 is approximately 0.92 volts. As a result, the change (maximum difference) Dv2 in the average value of the amplitude Ap-p due to the changes in circumferential positions P1, P2, and P3 is approximately 0.55 volts. Furthermore, dv1′, dv2′, and dv3′ show the range of variation in the amplitude Ap-p at each circumferential position P1, P2, and P3 in this case.

[0140] Compare Figure 7 (B) Figure 7 As can be seen from the results of (C), the change amount Dv1 in the former is smaller than the change amount (maximum difference) Dv2 in the latter. Specifically, in the cuff 20, even if the cuff 20 (pressing fluid bag 23) is misaligned relative to the measured site 90 (particularly in the circumferential direction), the level of sound entering the pressing fluid bag 23 from the artery 91 passing through the measured site 90 is less affected than in the conventional example. As a result, in the cuff 20, sound collection by the sound acquisition fluid bag 22 is stable, enabling stable acquisition of K-sound signals Ks representing Korotkoff sounds.

[0141] Thus, it was verified that the configuration of disposing the sound acquisition fluid bag 22 on the pressing fluid bag 23 enables stable acquisition of Korotkoff sounds even if the cuff 20 is misplaced in the wearing position (particularly the circumferential position) relative to the measured part 90 .

[0142] (Verification Experiment 2)

[0143] In order to verify the effect of preventing pulse sound (pulse wave frequency) from the first fluid system FS1 from mixing into the sound (including Korotkoff sound components) passing through the second fluid system FS2 by a structure in which the first fluid system FS1 and the second fluid system FS2 are separated from each other so that fluid cannot flow, the inventors conducted the following verification experiment.

[0144] Figure 8A The power spectrum of the sound acquired by the microphone 35 when the cuff 20 acquires the sound from the measurement site 90 (there is a K sound) is shown. Figure 8B FIG. 2 shows the power spectrum of the sound acquired by the microphone 35 when the cuff 20 does not acquire the sound from the measured part 90 (no K sound). Figure 8A As can be seen from the figure, the spectrum of Korotkoff sounds appears in the range A1 of about 120Hz to 300Hz. Figure 8B In this manner, the blood pressure monitor 100 including the cuff 20 can reliably acquire the K-sound signal Ks representing the Korotkoff sounds.

[0145] As a cuff of Comparative Example 2, the present inventors produced a cuff in which the air pipes 37 and 38 are shared. The cuff of Comparative Example 2 has the same structure as the cuff 20 except for this point. Figure 9A The power spectrum of the sound acquired by the microphone 35 when the cuff of Comparative Example 2 acquires the sound from the measurement site 90 (there is a K sound) is shown. Figure 9B The power spectrum of the sound acquired by the microphone when the cuff of Comparative Example 2 does not acquire the sound from the measured part 90 (no K sound) is shown. Figure 9A 、 Figure 9B It can be seen from any of the above that the spectrum of Korotkoff sounds does not appear in the range A1 of about 120Hz to 300Hz. The reason for this is that Figure 9A In the above example, the spectrum of Korotkoff sounds is buried in the background noise (including the pulse sound component). Figure 8A 、 Figure 8B 、 Figure 9A 、 Figure 9B The maximum value of the acquired spectrum data was normalized to 10.

[0146] These results demonstrate that a structure in which the first fluid system FS1 and the second fluid system FS2 are separated so that fluid cannot flow between them can prevent pulse sounds (pulse wave frequencies) from the first fluid system FS1 from mixing with sounds (including Korotkoff sound components) passing through the second fluid system FS2. Furthermore, this effect can be achieved even with a structure in which the sound acquisition fluid bag 22 is positioned below the pressing fluid bag 23.

[0147] (Verification Experiment 3)

[0148] In order to verify that the blood pressure is measured, the atmosphere release valve 34 is closed at a stage after the cuff 20 is attached to the measured part 90 and before the compression fluid bag 23 is pressurized. Figure 5 In step S4), an appropriate amount of air is sealed in the sound acquisition fluid bag 22 to acquire Korotkoff sounds from the measured part 90 via the pressing fluid bag 23. The present inventors conducted the following verification experiment.

[0149] As mentioned above, Figure 11 The K-sound signal Ks indicates that the atmosphere release valve 34 is closed at the stage after the cuff 20 is attached to the measured part 90 and before the start of pressurization of the compression fluid bag 23 in the blood pressure measurement process. Figure 5The Korotkoff sounds obtained in the case of step S4). Figure 11 In the example, the K sound signal Ks starts to be observed at time t2, gradually increases to show a maximum value, then gradually decreases and disappears immediately at time t3.

[0150] In contrast, Figure 12 The figure shows the K-sound signal Ks, which represents Korotkoff sounds acquired when the atmosphere release valve 34 is closed before the cuff 20 is attached to the measurement site 90 (Comparative Example 3), that is, when an excess of air remains within the sound acquisition fluid bag 22. In this case, the K-sound signal Ks begins to be observed at time t2′, corresponding to the systolic blood pressure SYS, gradually increases to a maximum value, and then gradually decreases. However, after time t3′, corresponding to the diastolic blood pressure DIA, the K-sound signal Ks does not immediately disappear, but gradually disappears as shown in the dotted line region B1. This is presumably because the frequency component at the time of the diastolic blood pressure DIA is lower than that at the time of the systolic blood pressure SYS, making it more susceptible to the influence of the pulse wave (vibration). Therefore, if the K-sound signal Ks remains after time t3′, it is difficult to determine at which point the cuff pressure corresponds to the diastolic blood pressure DIA.

[0151] Thus, it can be verified that, during blood pressure measurement, the atmosphere release valve 34 ( Figure 5 In step S4), an appropriate amount of air is sealed in the sound acquisition fluid bag 22 to obtain Korotkoff sounds from the measurement site 90 via the pressing fluid bag 23.

[0152] (Variation 1)

[0153] In the cuff 20, as described in Figure 3 (A) Figure 3 As described in (B), the sound acquisition fluid bag 22 and the pressing fluid bag 23 are composed of four sheets 22a, 22b, 23a, and 23b. However, this is not limited to the above.

[0154] Figure 13 (A) Figure 13 (B) and Figure 3 (A) Figure 3 (B) shows the following example: as a cuff 20A of the modified example 1 after the cuff 20 is modified, the sound acquisition fluid bag 22 and the pressing fluid bag 23 are composed of three sheets 22a, 23a, and 23b. Figure 3 (A) Figure 3The same components as those in the cuff of (B) are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate (hereinafter described). Figure 14 (A) Figure 14 (B) Figure 15 (A) Figure 15 The same is true for (B). In addition, Figure 13 In (B), for simplicity, the outer cloth 21 and the inner cloth 29 are omitted (described later). Figure 14 (B) Figure 15 (A) Figure 15 The same is true for (B).

[0155] In the cuff 20A, according to Figure 13 As can be seen from (B), the sound acquisition fluid bag 22A is formed by annularly joining (in this example, welding) the peripheral edge 22as of the sheet 22a and the portion 23ai corresponding to the peripheral edge 22as of the sheet 23a constituting the upper side of the pressing fluid bag 23 (the sheet on the sound acquisition fluid bag 22 side) as indicated by arrow M1 to form a bag. The pressing fluid bag 23 is similar to the pressing fluid bag in the cuff 20. The peripheral edges 23as and 23bs of a pair of sheets 23a and 23b are joined (in this example, welding) to form a bag as indicated by arrow M2. That is, Figure 3 The sheet 22b on the pressing fluid bag 23 side of the pair of sheets 22a, 22b of the sound acquisition fluid bag 22 shown in (B) is omitted because it is shared with the upper sheet 23a of the pair of sheets 23a, 23b of the pressing fluid bag 23. Thus, in this cuff 20A, the sound acquisition fluid bag 22 and the pressing fluid bag 23 are composed of three sheets 22a, 23a, and 23b, simplifying the structure. Furthermore, the joining indicated by arrow M1 is performed first, followed by the joining indicated by arrow M2.

[0156] Furthermore, in the cuff 20A, according to Figure 13 As can be seen from (A), the sheet 23a forming the upper side of the pressing fluid bag 23 has, in addition to the tab 23at, a tab 23at' at a position corresponding to the tab 22at of the sound acquisition fluid bag 22A. With the air tube 37 sandwiched between these tabs 22at and 23at', the air tube 37 and the sound acquisition fluid bag 22A are fluidically connected by fully welding the portions 22tm and 22tm (indicated by hatching) of the tabs 22at and 23at' corresponding to the sides of the air tube 37.

[0157] In the cuff 20A, a plurality of protrusions 22p, 22p, ... serving as spacers are integrally formed above the sheet 23a constituting the upper side of the pressing fluid bag 23. This prevents the sheets 22a, 23a constituting the sound acquisition fluid bag 22A from coming into close contact.

[0158] (Variation 2)

[0159] In the cuffs 20 and 20A, the spacers in the sound acquisition fluid bags 22 and 22A are respectively composed of a plurality of protrusions 22p, 22p, ... formed integrally on the sheet 22b or 23a. However, the present invention is not limited thereto.

[0160] Figure 14 (A) Figure 14 (B) and Figure 13 (A) Figure 13 (B) correspondingly shows an example in which a cuff 20B of Modification 2 is a further modification of the cuff 20A of Modification 1, and the spacer is formed of a sponge sheet 24 .

[0161] In the cuff 20B, according to Figure 14 As can be seen from (B), a sponge sheet 24 is provided as a spacer in the gap between the pair of sheets 22a and 23a constituting the sound acquisition fluid bag 22B. Figure 14 As can be seen from (A), the sponge sheet 24 has a rectangular shape with rounded corners that is slightly smaller than the sheet 22a on the upper side of the sound acquisition fluid bag 22B. Figure 14 The margin of the joint portion shown by the arrow M1 in (B) is shown in FIG.

[0162] The cuff 20B does not require a sheet material in which the plurality of protrusions 22 p , 22 p , . . . are integrally formed, and can therefore be easily manufactured.

[0163] The sponge sheet 24 may be bonded to one or both of the pair of sheets 22a and 23a constituting the sound acquisition fluid bag 22B, or may not be bonded to the sponge sheet 24.

[0164] (Variation 3)

[0165] In the cuffs 20 , 20A, and 20B, the air tube 37 is connected to the sound acquisition fluid bags 22 , 22 a , and 22 b using the protrusions 22 at , 22 bt or 22 at , 23 at ′, respectively. However, the present invention is not limited thereto.

[0166] Figure 15 (A) Figure 15 (B) and Figure 13 (A) Figure 13 (B) shows an example in which the air tube 37 is connected to the sound acquisition fluid bag 22C using a cap 25 as a cuff 20C of Modification 3, which is a further modification of the cuff 20A of Modification 1.

[0167] In this cuff 20C, a dome-shaped cover 25 is integrally attached to the upper surface of the sheet 22a that forms the upper side of the sound acquisition fluid bag 22C. A through hole 28 is provided in the portion of the sheet 22a corresponding to the cover 25, penetrating the sheet 22a in the thickness direction Z. In this example, the end of the air pipe 37 is airtightly fitted into and attached to the cover 25.

[0168] Compared with the cuffs 20 , 20A, and 20B, the cuff 20C does not require the labor of welding the tabs 22 at and 22 bt or 22 at and 23 at ′, and can therefore be manufactured more easily.

[0169] In the above example, the compression fluid bag 23 and the sound acquisition fluid bags 22, 20A, 20B, and 20C each have a rectangular shape with rounded corners along the surface of the outer fabric 21. However, the shapes are not limited to this. These planar shapes may be squares with rounded corners, ellipses, circles, or the like.

[0170] In the above example, the measured part 90 is the upper arm (particularly the left upper arm), but the present invention is not limited thereto. The measured part 90 may be the right upper arm, an upper limb other than the upper arm such as the wrist, or a lower limb such as the ankle.

[0171] The above embodiments are merely examples and various modifications are possible without departing from the scope of the present invention. The multiple embodiments described above can be established independently of each other, or the embodiments can be combined with each other. In addition, the various features in different embodiments can also be established independently of each other, or the features in different embodiments can be combined with each other.

[0172] Description of Reference Numerals

[0173] 10 main body

[0174] 20, 20A, 20B, 20C blood pressure cuffs

[0175] 21 outer cloth

[0176] 22 Fluid bags for sound acquisition

[0177] 22p protrusion

[0178] 23 Compression fluid bag

[0179] 24 sponge sheets

[0180] 25 hoods

[0181] 31 pressure sensor

[0182] 32 pumps

[0183] 33 control valve

[0184] 34 Atmospheric release valve

[0185] 35 microphones

[0186] 37, 38 air piping

[0187] 100 blood pressure monitor

Claims

1. A blood pressure measurement cuff that obtains Korotkoff sounds by compressing a measured area, characterized in that: have: The outer cloth is in the form of a strip extending in the length direction and is used to wrap around the part to be measured; a pressing fluid bag, provided on a side of the outer fabric facing the measured part and extending along the longitudinal direction, for pressing the measured part; a sound acquisition fluid bag disposed between the outer cloth and the pressing fluid bag in a thickness direction perpendicular to the outer cloth, and acquiring sound from the measured portion via the pressing fluid bag; a first fluid pipe connected to the pressing fluid bag so that fluid can flow therethrough; as well as The second fluid pipe is separate from the first fluid pipe and is connected to the sound acquisition fluid bag so that fluid can flow therethrough.

2. The blood pressure measurement cuff according to claim 1, wherein: A first fluid system including the pressing fluid bag and the first fluid tube and a second fluid system including the sound acquisition fluid bag and the second fluid tube are separated from each other so that fluid cannot flow therethrough.

3. The blood pressure measurement cuff according to claim 1 or 2, wherein: The sound acquisition fluid bag includes a pair of sheets facing each other in the thickness direction, wherein the pair of sheets are joined to each other to form a bag shape. A spacer is provided in a gap between the pair of sheets facing each other to prevent the pair of sheets from coming into close contact.

4. The blood pressure measurement cuff according to claim 3, wherein: The spacer is composed of a protrusion integrally formed on the sheet.

5. The blood pressure measurement cuff according to claim 1 or 2, wherein: The pressing fluid bag includes a pair of sheets facing each other in the thickness direction, wherein the pair of sheets are joined together in an annular shape to form a bag shape. The sound acquisition fluid bag includes a pair of sheets facing each other in the thickness direction, wherein the pair of sheets are joined together in an annular shape to form a bag shape. The sheet material on the pressing fluid bag side of the pair of sheets of the sound acquisition fluid bag is shared with the sheet material on the sound acquisition fluid bag side of the pair of sheets of the pressing fluid bag.

6. The blood pressure measurement cuff according to claim 1 or 2, wherein: The measured part is the upper arm, The dimension of the compression fluid bag in the longitudinal direction is set within a range of 167 mm to 380 mm, and the dimension in the width direction perpendicular to the longitudinal direction of the compression fluid bag along the surface of the outer fabric is set within a range of 90 mm to 180 mm. The lengthwise dimension of the sound acquisition fluid bag is set within a range of 41.8 mm to 380 mm, and the widthwise dimension of the sound acquisition fluid bag is set within a range of 45 mm to 180 mm.

7. The blood pressure measurement cuff according to claim 1 or 2, wherein: The measured part is the wrist, The dimension of the compression fluid bag in the longitudinal direction is set to 140 mm, and the dimension in the width direction perpendicular to the longitudinal direction of the compression fluid bag along the surface of the outer fabric is set to 60 mm. The lengthwise dimension of the sound acquisition fluid bag is set within a range of 35 mm to 140 mm, and the widthwise dimension of the sound acquisition fluid bag is set within a range of 30 mm to 60 mm.

8. The blood pressure measurement cuff according to claim 6, wherein: The length of the sound acquisition fluid bag in the longitudinal direction is set to 1 / 2 of the length of the compression fluid bag in the longitudinal direction. The dimension of the sound acquisition fluid bag in the width direction is set to be the same as the dimension of the pressing fluid bag in the width direction.

9. The blood pressure measurement cuff according to claim 7, wherein: The length of the sound acquisition fluid bag in the longitudinal direction is set to 1 / 2 of the length of the compression fluid bag in the longitudinal direction. The dimension of the sound acquisition fluid bag in the width direction is set to be the same as the dimension of the pressing fluid bag in the width direction.

10. A sphygmomanometer for measuring blood pressure by using Korotkoff sounds emitted from a measured part, characterized in that: have: The blood pressure measurement cuff according to any one of claims 1 to 9; a pressure device connected to the first fluid pipe in a fluid-flowable manner, and configured to supply fluid to the pressing fluid bag through the first fluid pipe to increase the pressure, or to discharge fluid from the pressing fluid bag through the first fluid pipe to reduce the pressure; a sound detection device connected to the second fluid pipe so as to be fluid-transmissive, and detecting sound from the sound acquisition fluid bag through the second fluid pipe; an atmospheric release valve connected to the second fluid pipe so as to allow fluid flow therethrough and capable of closing or opening the second fluid pipe to atmospheric pressure; A first fluid system including the pressing fluid bag and the first fluid pipe and a second fluid system including the sound acquisition fluid bag and the second fluid pipe are kept fluid-incompatible with each other; as well as The blood pressure calculation unit opens and closes the atmosphere release valve as the pressure device pressurizes or depressurizes the compression fluid bag, and calculates the blood pressure of the measurement site based on the output of the sound detection device corresponding to the sound from the sound acquisition fluid bag.

11. The blood pressure monitor according to claim 10, wherein The blood pressure calculation unit closes the atmosphere release valve to seal the second fluid system after the blood pressure measurement cuff is placed on the measurement site and before the pressure device starts pressurizing the pressing fluid bag.

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