JP7529212B2 - Blood Pressure Cuffs and Sphygmomanometers - Google Patents

Description

This invention relates to a cuff for measuring blood pressure, and more specifically to a cuff for measuring blood pressure that compresses the area to be measured to block blood flow. This invention also relates to a blood pressure monitor equipped with such an efficient cuff for measuring blood pressure.

This type of blood pressure cuff generally has the problem that an edge effect (a phenomenon in which the pressure is stronger in the center of the air bag that makes up the cuff and decreases toward the edge of the air bag) occurs, causing the shapes of the pressure pulse waves acquired at the center and edges of the air bag to differ, resulting in a mixed pressure pulse wave waveform being detected, which reduces the signal-to-noise ratio (S/N) and reduces the accuracy of blood pressure measurement.

As a conventional blood pressure measurement cuff that addresses this issue, for example, as disclosed in Patent Document 1 (JP Patent Publication 2007-125247), there is known a cuff for blood pressure measurement that includes a cuff for blood pressure blocking that compresses the artery at the blood pressure measurement site, a cuff for pulse wave detection that is disposed approximately in the center below the cuff for blood pressure blocking (opposing the blood pressure measurement site) and detects pulse waves, and a sub-cuff that is disposed below the cuff for blood pressure blocking (opposing the blood pressure measurement site) closer to the heart (upstream) than the approximately center. In this blood pressure measurement cuff, when the pressure of the cuff for blood pressure blocking is slightly higher than the systolic blood pressure, the sub-cuff blocks blood flow that attempts to enter the upstream part below the cuff for blood pressure blocking, thereby improving the S/N ratio of the detection of pulse waves (vibrations due to changes in the volume of the artery) by the cuff for pulse wave detection.

JP 2007-125247 A

However, in the blood pressure measurement cuff disclosed in Patent Document 1, vibrations caused by pulse waves from the arteries on both ends of the measurement site are absorbed into the pulse wave detection cuff. This creates a problem in that it is not possible to effectively prevent a decrease in the S/N ratio due to the edge effect.

The object of this invention is to provide a blood pressure measurement cuff that compresses the measurement site to block blood flow and that can effectively prevent a decrease in the S/N ratio caused by the edge effect. The object of this invention is to provide a blood pressure monitor equipped with such a blood pressure measurement cuff.

In order to solve the above problems, the blood pressure measurement cuff disclosed herein comprises:
A blood pressure measurement cuff that compresses a measurement site to block blood flow,
A belt-shaped outer cloth surrounding the measurement site;
a first air bag provided along a surface of the outer cloth facing the measurement site and facing a specific closed region of the measurement site;
The first air bag is
an outer air bag having, within a plane along the outer fabric, a first shape corresponding to the entirety of the specific closed region or an annular second shape corresponding to an outer peripheral region of the specific closed region;
an inner air bag disposed inside the outer air bag having the first shape, corresponding to an inner area surrounded by an outer peripheral area of the specific closed area, or in an empty area surrounded by a ring of the outer air bag having the second shape,
a damper layer provided along a surface of the first air bag facing the measurement site and configured to damp vibrations;
The present invention is characterized in that it is provided with a second air bag that is provided along the surface of the damper layer facing the measured portion, corresponding to a central area that occupies a part of the specific closed area that includes the center of the inner area, and that detects pulse wave information based on pulse waves from a part of an artery that passes through the specific closed area and is present in the central area.

In this specification, "the side of ~ facing the part to be measured" means the side facing the part to be measured when the blood pressure measurement cuff is attached around the part to be measured (worn state).

"Specific closed area" refers to the closed area of the above-mentioned measurement site that is the subject of compression.

The "first shape" and "second shape" of the outer air bag refer to the planar shape in the plane along the outer fabric.

In addition, the "peripheral region of a specific closed region" refers to a ring-shaped region that runs along the outer edge of the specific closed region.

"Pulse wave information" from pulse waves means information that represents changes in pressure (including vibrations) due to changes in arterial volume.

The portion of the artery that passes through the specific closed area and is in the central area is referred to as the "central portion" as appropriate.

The blood pressure measurement cuff disclosed herein is attached by surrounding the measurement site with the band-shaped outer cloth in a state in which the first air bag corresponds to the specific closed area of the measurement site. For example, the shape and dimensions of the damper layer are set to be the same as those of the second air bag in a plane along the outer cloth, and the damper layer is provided to correspond to the second air bag. In this case, in the attached state, the outer air bag of the first air bag and the outer cloth are arranged in this order in the thickness direction (direction perpendicular to the outer surface of the measurement site) relative to the outer peripheral area (annular area) of the specific closed area of the measurement site. The first air bag (the part of the outer air bag where the inner air bag exists in the first shape, and the inner air bag in the second shape) and the outer cloth are arranged in this order in the thickness direction relative to the inner area (excluding the central area) of the specific closed area of the measurement site. In the thickness direction, the second air bag, the damper layer, the first air bag (the part of the outer air bag where the inner air bag is located in the first shape, and the inner air bag in the second shape), and the outer fabric are arranged in this order relative to the central region of the specific closed region of the measurement site.

In this worn state, when blood pressure is measured, air is supplied from a pump provided outside the blood pressure measurement cuff through an air pipe to the outer air bag and the inner air bag constituting the second air bag and the first air bag. At this time, the expansion of the second air bag and the first air bag (the outer air bag and the inner air bag) in a direction away from the measured part is regulated by the outer cloth as a whole. Therefore, the second air bag, the outer air bag and the inner air bag expand in a direction to press the specific closed area of the measured part. As a result, the specific closed area of the measured part is compressed, and the artery passing through the specific closed area is blocked. In detail, the outer air bag presses the outer air bag on the outer peripheral area of the specific closed area of the measured part, and the upstream end and downstream end of the artery passing through the specific closed area are compressed. The inner region (excluding the central region) of the specific closed region is pressed by the first air bag (the portion of the outer air bag where the inner air bag is present in the first shape, and the inner air bag in the second shape), compressing the upstream transition portion between the upstream end and the central portion of the artery passing through the specific closed region, and the downstream transition portion between the downstream end and the central portion. The central region of the specific closed region of the measurement site is pressed by the second air bag and the first air bag (the portion of the outer air bag where the inner air bag is present in the first shape, and the inner air bag in the second shape) provided via the damper layer, compressing the central portion of the artery passing through the specific closed region. Then, during the pressurization or depressurization process of the second air bag, the outer air bag, and the inner air bag, the second air bag detects pulse wave information based on the pulse wave from the central portion of the artery passing through the specific closed region. Based on this pulse wave information, blood pressure is calculated, for example, by an oscillometric method.

Here, the outer air bag, which presses the outer peripheral region (where the upstream end and downstream end of the artery passing through the specific closed region exist) of the specific closed region, is easily affected by the pulse wave (vibration) of the blood flow that infiltrates from the artery upstream and downstream of the measurement site due to the edge effect. However, in this blood pressure measurement cuff, when the outer air bag has the first shape, it is separated from the second air bag via the inner air bag contained in the outer air bag and the damper layer. Or, when the outer air bag has the second shape, it is separated from the second air bag via the inner air bag arranged in the free area and the damper layer. Therefore, the pulse wave (vibration) acquired by the outer air bag is difficult to transmit to the second air bag in either case. Therefore, in this blood pressure measurement cuff, the second air bag can detect pulse wave information mainly based on the pulse wave only from the central part of the artery passing through the specific closed region. This effectively prevents a decrease in the S/N ratio caused by the edge effect, thereby improving the accuracy of blood pressure measurements.

In one embodiment of the blood pressure measurement cuff, the damper layer comprises:
a central segment provided in a plane along the outer fabric and corresponding to the second air bag;
The outer fabric is characterized in having a triple-section structure including an upstream segment and a downstream segment each connected to the central segment, the upstream segment and the downstream segment each extending from the central segment to positions corresponding to both edges of the first air bag in a width direction perpendicular to the longitudinal direction in which the outer fabric extends in a band shape.

Here, for blood pressure measurement cuffs, the "longitudinal direction" means the direction in which the outer cloth extends in a band-like shape, which corresponds to the circumferential direction surrounding the measurement site when the cuff is worn. The "width direction" means the direction perpendicular to the longitudinal direction in a plane along the outer cloth, which corresponds to the direction in which the artery passes through the measurement site when the cuff is worn. The "upstream side" and "downstream side" mean the upstream side and downstream side, respectively, of the blood flow through the artery. The "thickness direction" mentioned above means the direction perpendicular to both the longitudinal direction and the width direction (i.e., the outer cloth), which corresponds to the direction perpendicular to the outer peripheral surface of the measurement site when the cuff is worn.

In this embodiment of the blood pressure measurement cuff, since the damper layer has the above-mentioned triple structure, in the worn state, the upstream or downstream segment of the damper layer, the outer air bag of the first air bag, and the outer cloth are arranged in this order in the thickness direction relative to the outer peripheral region (annular region) of the specific closed region of the measured part. In the thickness direction relative to the inner region (excluding the central region) of the specific closed region of the measured part, the upstream or downstream segment of the damper layer, the first air bag (the part of the outer air bag where the inner air bag is located in the first shape, and the inner air bag in the second shape), and the outer cloth are arranged in this order. In the thickness direction relative to the central region of the specific closed region of the measured part, the second air bag, the central segment of the damper layer, the first air bag (the part of the outer air bag where the inner air bag is located in the first shape, and the inner air bag in the second shape), and the outer cloth are arranged in this order. The central segment is connected to the upstream and downstream segments, so there is no relative positional shift between the central segment, the upstream segment, and the downstream segment.

In this worn state, when blood pressure is measured, as described above, air is supplied from a pump provided outside the blood pressure measurement cuff through an air pipe to the outer air bag and the inner air bag constituting the second air bag and the first air bag. At this time, as described above, the expansion of the second air bag and the first air bag (the outer air bag and the inner air bag) in a direction away from the measured part is regulated by the outer cloth as a whole. Therefore, the second air bag, the outer air bag and the inner air bag expand in a direction to press the specific closed area of the measured part. As a result, the specific closed area of the measured part is compressed, and the artery passing through the specific closed area is blocked. In detail, the outer peripheral area of the specific closed area of the measured part is pressed by the outer air bag through the upstream segment or downstream segment of the damper layer, and the upstream end and downstream end of the artery passing through the specific closed area are compressed. The inner region (excluding the central region) of the specific closed region is pressed by the first air bag (the portion of the outer air bag where the inner air bag is present in the first shape, and the inner air bag in the second shape) via the upstream segment or downstream segment of the damper layer, compressing an upstream transition portion between the upstream end and the central portion of the artery passing through the specific closed region, and a downstream transition portion between the downstream end and the central portion. The central region of the specific closed region of the measurement site is pressed by the second air bag and the first air bag (the portion of the outer air bag where the inner air bag is present in the first shape, and the inner air bag in the second shape) provided via the central segment of the damper layer, compressing the central portion of the artery passing through the specific closed region. Then, during the pressurization or depressurization process of the second air bag, the outer air bag, and the inner air bag, the second air bag detects pulse wave information based on pulse waves from the central portion of the artery passing through the specific closed region. Based on this pulse wave information, blood pressure is calculated, for example, using the oscillometric method.

Here, the outer air bag, which compresses the outer peripheral region (where the upstream and downstream ends of the artery passing through the specific closed region exist), is susceptible to the influence of the pulse waves (vibrations) of the blood flow that infiltrate from the upstream and downstream arteries of the measured part due to the edge effect, as described above. However, in this blood pressure measurement cuff, the upstream or downstream segment of the damper layer is interposed between the ends of the outer peripheral region corresponding to the upstream and downstream sides of the artery and the outer air bag. Therefore, the pulse waves (vibrations) of the blood flow that attempt to infiltrate the outer air bag due to the edge effect from the ends of the outer peripheral region corresponding to the upstream and downstream sides of the artery are attenuated by the upstream or downstream segment and are not easily transmitted to the outer air bag. Furthermore, when the outer air bag has the first shape, it is separated from the second air bag via the inner air bag contained in the outer air bag and the central segment of the damper layer. Alternatively, when the outer air bag has the second shape, it is separated from the second air bag by the inner air bag arranged in the free area and the central segment of the damper layer. Therefore, in either case, the pulse wave (vibration) acquired by the outer air bag is attenuated by the inner air bag and the central segment of the damper layer, and is not easily transmitted to the second air bag. Therefore, in this blood pressure measurement cuff, the second air bag can detect pulse wave information mainly from only the pulse wave from the central part of the artery passing through the specific closed area. Therefore, it is possible to effectively prevent a decrease in the S/N ratio due to the edge effect, and as a result, the accuracy of blood pressure measurement can be improved.

In one embodiment of the blood pressure measurement cuff,
The inner air bag, the central segment of the damper layer, and the second air bag are characterized in that they are positioned downstream along the direction in which the artery passes within the specific closed area relative to the outer air bag.

In this embodiment of the blood pressure measurement cuff, the inner air bag, the central segment of the damper layer, and the second air bag are arranged in a biased downstream direction along the direction of the artery within the specific closed area relative to the outer air bag. Therefore, the second air bag is arranged in the specific closed area in a region that is relatively far from the upstream end of the artery that passes through the specific closed area. This makes it difficult for the pulse wave (vibration) from the upstream end of the artery acquired by the outer air bag to be transmitted to the second air bag within the specific closed area. Therefore, in this blood pressure measurement cuff, the decrease in the S/N ratio due to the edge effect can be more effectively prevented, and as a result, the accuracy of blood pressure measurement can be further improved.

In one embodiment of the blood pressure measurement cuff,
a shape and a size of the damper layer are set to be the same as a shape and a size of the second air bag, in a plane along the outer fabric,
The inner air bag, the damper layer and the second air bag are characterized in that they are arranged within the specific closed area, biased toward the downstream side along the direction in which the artery passes, relative to the outer air bag.

In this embodiment of the blood pressure measurement cuff, the inner air bag, the damper layer (having the same shape and dimensions as the second air bag), and the second air bag are arranged in a biased downstream direction along the direction in which the artery passes within the specific closed area relative to the outer air bag. Therefore, the second air bag is arranged in the specific closed area in a region that is relatively far from the upstream end of the artery that passes through the specific closed area. This makes it difficult for the pulse wave (vibration) from the upstream end of the artery acquired by the outer air bag to be transmitted to the second air bag within the specific closed area. Therefore, in this blood pressure measurement cuff, the decrease in the S/N ratio due to the edge effect can be more effectively prevented, and as a result, the accuracy of blood pressure measurement can be further improved.

In one embodiment of the blood pressure measurement cuff,
the outer bladder has the second shape;
the inner air bag is disposed in the void space surrounded by the ring of the outer air bag,
The inner peripheral edge of the outer air bag and the outer peripheral edge of the inner air bag adjacent to the inner peripheral edge have bellows shapes corresponding to each other in the thickness direction perpendicular to the outer cloth, and are fitted together.

In this embodiment of the blood pressure measurement cuff, the inner peripheral edge of the outer air bag and the outer peripheral edge of the inner air bag adjacent to the inner peripheral edge have bellows shapes that correspond to each other in the thickness direction perpendicular to the outer cloth, and are fitted together. Therefore, when air is supplied to the second air bag, the outer air bag, and the inner air bag in the worn state, the bellows shape stretches in the thickness direction, making it easy for the outer air bag and the inner air bag to expand in the thickness direction. Therefore, the specific closed area of the measurement site can be easily compressed. In addition, as a result of the outer air bag and the inner air bag being fitted together, even if air is supplied to the second air bag, the outer air bag, and the inner air bag in the worn state, the relative position of the inner air bag to the outer air bag is maintained in a plane along the outer cloth, and as a result, the relative position of the second air bag is also maintained via the damper layer.

In one embodiment of the blood pressure measurement cuff,
the outer bladder has the second shape;
the inner air bag is disposed in the void space surrounded by the ring of the outer air bag,
The inner peripheral edge of the outer air bag and the outer peripheral edge of the inner air bag adjacent to the inner peripheral edge are welded to each other entirely or partially along the ring.

In this embodiment of the blood pressure measurement cuff, the inner peripheral edge of the outer air bag and the outer peripheral edge of the inner air bag adjacent to the inner peripheral edge are welded to each other all around or partially along the ring. Therefore, even if air is supplied to the second air bag, the outer air bag, and the inner air bag in the worn state, the relative position of the inner air bag to the outer air bag is maintained in a plane along the outer cloth, and as a result, the relative position of the second air bag is also maintained via the damper layer. In addition, since a welded portion is interposed between the outer air bag and the inner air bag, the pulse wave (vibration) acquired by the outer air bag is not directly transmitted to the inner air bag. Therefore, the pulse wave (vibration) acquired by the outer air bag is even more difficult to transmit to the second air bag. As a result, the accuracy of blood pressure measurement can be further improved.

In one embodiment of the blood pressure measurement cuff,
within a plane along the outer cloth, an inner peripheral edge of the outer air bag and an outer peripheral edge of the inner air bag are each formed in a rectangular shape with rounded corners along the ring, and include a side that intersects with the artery and passes through the specific closed region, and a side that is distant from the artery,
The side of the inner peripheral edge of the outer air bag away from the artery and the side of the outer peripheral edge of the inner air bag away from the artery are partially welded to each other, while the side of the inner peripheral edge of the outer air bag that intersects with the artery and the side of the outer peripheral edge of the inner air bag that intersects with the artery are spaced apart from each other.

"Rounded rectangle" means a rectangle or square with rounded corners.

In this embodiment of the blood pressure measurement cuff, the side of the inner periphery of the outer air bag away from the artery and the side of the outer periphery of the inner air bag away from the artery are partially welded to each other. Therefore, even if air is supplied to the second air bag, the outer air bag, and the inner air bag in the worn state, the relative position of the inner air bag to the outer air bag is maintained in a plane along the outer cloth, and as a result, the relative position of the second air bag is also maintained via the damper layer. Meanwhile, the side of the inner periphery of the outer air bag that intersects with the artery and the side of the outer periphery of the inner air bag that intersects with the artery are spaced apart from each other. As a result, compared to when the edge of the inner periphery of the outer air bag that crosses the artery and the edge of the outer periphery of the inner air bag that crosses the artery are welded to each other, the transmission path of the pulse wave (vibration) from the part of the outer air bag that is most susceptible to the influence of the pulse wave (vibration) of the blood flow that infiltrates from the artery upstream and downstream of the measurement site due to the edge effect (the part that crosses the artery) to the second air bag is longer. Therefore, the pulse wave (vibration) acquired by the outer air bag is even less likely to be transmitted to the second air bag. Therefore, with this blood pressure measurement cuff, it is possible to more effectively prevent a decrease in the S/N ratio due to the edge effect, and as a result, the accuracy of blood pressure measurement can be further improved.

In one embodiment of the blood pressure measurement cuff,
an air pipe for supplying air to the outer air bag, the inner air bag, and the second air bag is connected to each of the air pipes;
The air pipes are connected to each other via a filter that attenuates pulse waves so that air can flow between them.

In the blood pressure measurement cuff of this embodiment, air pipes that supply air to the outer air bag, the inner air bag, and the second air bag are connected to each other in a manner that allows air to flow between them via a filter that attenuates pulse waves. Therefore, by supplying air from one pump to one of the air pipes, air can be supplied to the outer air bag, the inner air bag, and the second air bag. This allows the number of pumps (i.e., the number of components of the blood pressure monitor) to be reduced compared to the case where air is supplied from separate pumps to the outer air bag, the inner air bag, and the second air bag. In addition, in the blood pressure measurement cuff of this embodiment, a filter that attenuates pulse waves is interposed between the air pipes. This filter can prevent the pulse waves (vibrations) acquired by the outer air bag and/or the inner air bag from being mixed into the second air bag via the air pipe. Therefore, the accuracy of blood pressure measurement can be maintained at a high level.

In another aspect, the blood pressure monitor of the present disclosure comprises:
A blood pressure monitor that measures blood pressure by compressing a measurement site,
The blood pressure measurement cuff,
a pressure control unit that supplies air to the second air bag, the outer air bag, and the inner air bag through air piping from a pump provided outside the blood pressure measurement cuff, thereby controlling the pressing force applied to the specific closed area;
a pressure detection unit that detects the pressure of the second air bag;
and a blood pressure calculation unit that calculates blood pressure by an oscillometric method based on an output from the pressure detection unit.

In the blood pressure monitor disclosed herein, the blood pressure measurement cuff is attached by surrounding the measurement site with the band-shaped outer cloth, with the first air bag corresponding to the specific closed area of the measurement site. In this attached state, the pressure control unit supplies air to the second air bag, the outer air bag and the inner air bag constituting the first air bag, through air piping from a pump provided outside the blood pressure measurement cuff, to control the pressure on the specific closed area. Then, during the process of pressurizing or depressurizing the second air bag, the outer air bag and the inner air bag, the pressure detection unit detects the pressure of the second air bag. The blood pressure calculation unit calculates the blood pressure by the oscillometric method based on the output of the pressure detection unit.

Thanks to the blood pressure measurement cuff, this blood pressure monitor can detect pulse wave information mainly from the pulse wave from the central part of the artery passing through the specific closed area using the second air bag. This effectively prevents a decrease in the S/N ratio due to the edge effect, and as a result, the accuracy of blood pressure measurement can be improved.

As is clear from the above, the blood pressure measurement cuff and blood pressure monitor disclosed herein can effectively prevent a decrease in the S/N ratio due to the edge effect, thereby improving the accuracy of blood pressure measurement.

1 is a diagram showing a schematic block configuration of a blood pressure monitor equipped with a blood pressure measurement cuff according to a first embodiment of the present invention; Fig. 2(A) is a schematic diagram showing the planar layout of the blood pressure measurement cuff in an unfolded state. Fig. 2(B) is a diagram showing a cross section taken along line IIB-IIB in Fig. 2(A) with the outer cloth constituting the cuff omitted. Fig. 2(C) is a diagram showing a cross section taken along line IIC-IIC in Fig. 2(A) with the outer cloth constituting the cuff omitted. 11 is a view showing one embodiment in which the outer air bag and the inner air bag forming the cuff are welded together. FIG. 13 is a view showing another embodiment in which the outer air bag and the inner air bag forming the cuff are welded together. FIG. 13 is a view showing an embodiment in which the inner air bag forming the cuff has a bellows-shaped side surface. FIG. FIG. 2 is a diagram showing a state in which the cuff is attached around the outer periphery of a rod-shaped measurement site. FIG. 4 is a diagram showing a flow of blood pressure measurement using the sphygmomanometer. 6(A), 6(B) and 6(C) are views showing the manner in which the damper layer of the cuff is deformed, corresponding to FIGS. 2(A), 2(B) and 2(C), respectively. Fig. 7(A) is a schematic diagram showing the planar layout of a blood pressure measurement cuff of the second embodiment in a deployed state. Fig. 7(B) is a diagram showing a cross section taken along line VIIB-VIIB in Fig. 7(A) with the outer cloth constituting the cuff omitted. Fig. 7(C) is a diagram showing a cross section taken along line VIIC-VIIC in Fig. 7(A) with the outer cloth constituting the cuff omitted. FIG. 8 is a diagram showing a state in which the cuff of FIG. 7 is attached around the outer periphery of a rod-shaped measurement site. 8 is a diagram showing a planar layout of a first modified example of the blood pressure measurement cuff of FIG. 7, corresponding to FIG. 7(A). FIG. 8 is a diagram showing a planar layout of a second modified example of the blood pressure measurement cuff of FIG. 7, corresponding to FIG. 7(A). FIG. 11(A), 11(B), and 11(C) are diagrams showing a third modified example of the blood pressure measurement cuff of FIG. 7, corresponding to FIG. 7(A), FIG. 7(B), and FIG. 7(C), respectively. 8 is a diagram showing a cross-sectional structure of a fourth modified example of the blood pressure measurement cuff of FIG. 7, corresponding to FIG. 7(B). FIG. FIG. 3 is a diagram showing a measurement state in a verification experiment for comparing the performance of the blood pressure measurement cuff in FIG. 2 with the performance of a general blood pressure measurement cuff. 5 is a diagram illustrating an example of the pressure (cuff pressure) Pc of the second air bag and a pulse wave signal Pm detected by a pressure sensor mounted on the blood pressure monitor. FIG. FIG. 15 is an enlarged time axis view of the vicinity of time t2 at which the systolic blood pressure (SBP) was obtained in FIG. 14, comparing the pulse wave signal Pm obtained using the blood pressure cuff in FIG. 2 with the pulse wave signal Pm' obtained using a general blood pressure cuff. FIG. 15 is an enlarged time axis view of the vicinity of time t3 at which the diastolic blood pressure (DBP) was obtained in FIG. 14, comparing the pulse wave signal Pm obtained using the blood pressure cuff in FIG. 2 with the pulse wave signal Pm' obtained using a general blood pressure cuff.

The following describes in detail the embodiment of the present invention with reference to the drawings.

Figure 1 shows a schematic block diagram of a blood pressure monitor 100 equipped with a blood pressure measurement cuff 20 according to a first embodiment of the present invention. This blood pressure monitor 100 is roughly divided into a cuff 20 that is attached to a rod-shaped measurement site 90 (see Figure 4) such as the upper arm or wrist, and a main body 10.

(Configuration of blood pressure measurement cuff)
4 shows a state in which the cuff 20 is attached around the outer circumference of the measurement site (upper arm in this example) 90. In this example, a cross section along an artery 91 passing through the measurement site 90 is shown. As can be seen from FIG. 4, the cuff 20 generally includes a band-shaped outer cloth 21 located at the outermost periphery, a first air bag 210 provided along the surface of the outer cloth 21 facing the measurement site 90, a damper layer 280L provided along the surface of the first air bag 210 facing the measurement site 90, and a second air bag 220 provided along the surface of the damper layer 280L facing the measurement site 90. In this example, the first air bag 210 includes an outer air bag 211 and an inner air bag 212 provided inside the outer air bag 211.

Figure 2(A) shows a schematic planar layout of the cuff 20 when it is unfolded. For ease of understanding, in Figure 2(A), a rod-shaped measurement site 90 (shown by a two-dot chain line) is shown extending in the left-right direction. Figure 2(B) shows a cross section taken along line IIB-IIB in Figure 2(A) with the outer cloth 21 of the cuff 20 omitted. Figure 2(C) shows a cross section taken along line IIC-IIC in Figure 2(A) with the outer cloth 21 of the cuff 20 omitted.

Here, with regard to the cuff 20, the "longitudinal direction" refers to the direction in which the outer cloth 21 extends in a band-like shape, which corresponds to the circumferential direction surrounding the measurement site 90 when the cuff is worn (see FIG. 4). The "width direction" refers to the direction perpendicular to the longitudinal direction in a plane along the outer cloth 21, which corresponds to the direction in which the artery 91 passes through the measurement site 90 when the cuff is worn. The "upstream side" and "downstream side" refer to the upstream side and downstream side, respectively, of the blood flow flowing through the artery 91. The "thickness direction" refers to the direction perpendicular to both the longitudinal direction and the width direction (i.e., the outer cloth 21), which corresponds to the direction perpendicular to the outer peripheral surface of the measurement site 90 when the cuff is worn.

In this example, the outer cloth 21 has a band-like shape (a rectangle with rounded corners in this example) that extends in the longitudinal direction (the vertical direction in FIG. 2(A)) along the plane of the paper in FIG. 2(A). The outer cloth 21 can be curved or bent, but is configured to be substantially non-stretchable in order to restrict the second air bag 220 and the first air bag 210 (the outer air bag 211 and the inner air bag 212) from expanding in a direction away from the measurement site 90 during blood pressure measurement. Here, the "cloth" is not limited to being woven, and may be made of one or more layers of resin. The longitudinal dimension of the outer cloth 21 is set to be longer than the circumference of the upper arm as the measurement site 90.

As shown in FIG. 2(A), the outer air bag 211 constituting the first air bag 210 has a rectangular shape with rounded corners (called the "first shape") that corresponds to the entire area of the specific closed area 90A that extends continuously in the measurement area 90 in a plane along the outer cloth 21. When the outer air bag 211 having this first shape is curved and abutted along the outer periphery of the measurement area 90 shown in FIG. 2(A), it corresponds to and matches the specific closed area 90A on the measurement area 90. In this example, the outer air bag 211 has a longitudinal dimension L of 24 cm and a width dimension W of 13 cm in a plane along the outer cloth 21.

The inner air bag 212 is provided inside the outer air bag 211 as described above, and is arranged in correspondence with the inner area 90i surrounded by the outer peripheral area 90s of the specific closed area 90A as shown in FIG. 2(A). Here, the outer peripheral area 90s refers to a ring-shaped area along the periphery of the specific closed area 90A, and in this example corresponds to the area shown by diagonal lines in FIG. 2(A) between the outer peripheral edge 211o of the outer air bag 211 and the outer peripheral edge 212o of the inner air bag 212. That is, when the outer air bag 211 is curved and abutted along the outer periphery of the measured part 90 shown in FIG. 2(A), the ring-shaped area shown by diagonal lines corresponds to the outer peripheral area 90s on the measured part 90, and the inner air bag 212 corresponds to the inner area 90i on the measured part 90. The inner air bag 212 has a rectangular shape with rounded corners, similar to the outer air bag 211. In this example, the inner air bag 212 is set to a longitudinal dimension of 22 cm and a width dimension of 6 cm in a plane along the outer cloth 21. As can be seen from Figs. 2(A) and 2(B), in this example, the inner air bag 212 is arranged in a biased manner toward the downstream side (the right side in Fig. 2(A)) along the direction in which the artery 91 passes within the specific closed area 90A relative to the outer air bag 211. In more detail, if the vertical line passing through the center of the inner air bag 212 is C, the left-right distance between the left side of the outer peripheral edge 211o of the outer air bag 211 and the vertical line C is set to X1 = 7 cm, and the left-right distance between the right side of the outer peripheral edge 211o of the outer air bag 211 and the vertical line C is set to X2 = 6 cm. On the other hand, as can be seen from Figs. 2(A) and 2(C), the center of the outer air bag 211 and the center of the inner air bag 212 coincide with each other in the longitudinal direction of the outer cloth 21.

In this example, as shown in FIG. 3(A), the regions 213 and 214 where the outer air bag 211 and the inner air bag 212 face each other are welded together. This prevents the inner air bag 212 from shifting relative to the outer air bag 211. In particular, when the outer air bag 211 and the inner air bag 212 are inflated, the inner air bag 212 is prevented from shifting left and right in FIG. 3(A). As a result, the accuracy of blood pressure measurement can be maintained at a high level. Note that, as shown in FIG. 3(B), the regions where the outer air bag 211 and the inner air bag 212 are welded together may be dot-like regions 213a, 213b, 214a, and 214b, rather than the continuously expanding regions 213 and 214. The embodiment of FIG. 3(B) can also achieve the same effect as the embodiment of FIG. 3(A).

As shown in FIG. 2A, the second air bag 220 is provided in a plane along the outer cloth 21 in correspondence with the central region 90c that occupies a portion of the specific closed region 90A that includes the center of the inner region 90i. The second air bag 220 has a rectangular shape with rounded corners, similar to the outer air bag 211 and the inner air bag 212. In this example, the second air bag 220 is set to a longitudinal dimension of 6 cm and a width dimension of 3 cm in a plane along the outer cloth 21. In this example, as can be seen from FIG. 2A, FIG. 2B, and FIG. 2C, the center of the inner air bag 212 and the center of the second air bag 220 coincide in a plane along the outer cloth 21. As a result, the second air bag 220 is biased toward the downstream side (the right side in FIG. 2A) along the direction in which the artery 91 passes within the specific closed region 90A, similar to the inner air bag 212. However, the second air bag 220 covers the center of the specific closed area 90A (i.e., the center of the outer air bag 211).

The outer air bag 211, inner air bag 212, and second air bag 220 are each made by placing a pair of sheets made of polyurethane resin opposite each other and welding the outer edges of the pair of sheets together.

In this example, the damper layer 280L has a triplet structure including a central segment 283 provided in a plane along the outer cloth 21 in correspondence with the second air bag 220, and an upstream segment 281 and a downstream segment 282 provided connected to both sides of the central segment 283 in the width direction of the cuff 20. The central segment 283 has a rectangular shape of approximately the same dimensions as the second air bag 220 in a plane along the outer cloth 21. The upstream segment 281 has a rectangular shape of approximately the same dimensions as the central segment 283 in the longitudinal direction of the cuff 20 and extends from the central segment 283 to a position corresponding to the left edge of the outer air bag 211 in the width direction of the cuff 20 (in FIG. 2A). The downstream segment 282 has approximately the same dimensions as the central segment 283 in the longitudinal direction of the cuff 20, and has a rectangular shape extending from the central segment 283 in the width direction of the cuff 20 to a position corresponding to the right edge (in FIG. 2A) of the outer air bag 211. As a result, the central segment 283 of the damper layer 280L is biased toward the downstream side (right side in FIG. 2A) along the direction in which the artery 91 passes within the specific closed area 90A, similar to the second air bag 220 and the inner air bag 212, relative to the outer air bag 211.

In this example, the damper layer 280L is fabricated by placing a pair of polyurethane resin sheets (in this example, rectangular in shape; they may be rectangular in shape with rounded corners) facing each other, and welding the outer edges of the pair of sheets to the area 284 separating the central segment 283 from the upstream segment 281, and the area 285 separating the central segment 283 from the downstream segment 282. As a result, the central segment 283 and the upstream segment 281 are connected via the welded area 284. The central segment 283 and the downstream segment 282 are connected via the welded area 285. Therefore, there is no relative positional displacement between the central segment 283 and the upstream segment 281 and the downstream segment 282. In this example, 10 to 20 milliliters of air (typically about 15 milliliters) is contained between each pair of sheets that make up the central segment 283, the upstream segment 281, and the downstream segment 282 as a material that dampens the vibration of the pulse wave. This allows the damper layer 280L to be easily fabricated. Note that instead of air, silicone gel or silicone rubber, which efficiently dampens the vibration of the pulse wave, may be contained between each pair of sheets that make up the central segment 283, the upstream segment 281, and the downstream segment 282.

The central segment 283, the upstream segment 281, and the downstream segment 282 of the damper layer 280L are each adhered to the opposing surfaces of the outer air bag 211 with an adhesive (not shown). The second air bag 220 is also adhered to the opposing surface of the central segment 283 with an adhesive (not shown). This prevents the damper layer 280L and the second air bag 220 from shifting relative to the outer air bag 211.

In this example, as shown in FIG. 2A, air pipes 37c, 37e, and 37g are connected to the outer air bag 211, the inner air bag 212, and the second air bag 220, respectively, so that they can be ventilated. The outer air bag 211, the inner air bag 212, and the second air bag 220 can be inflated by supplying air through these air pipes 37c, 37e, and 37g, and can be deflated by discharging air through these air pipes 37c, 37e, and 37g. The second air bag 220 is further connected to an air pipe 38 so that it can be ventilated. Pulse wave information based on the pulse wave acquired by the second air bag 220 can be detected through this air pipe 38 (described in detail below).

(Main body configuration)
1, the main body 10 is equipped with a control unit 110, a display 50, an operation unit 52, a memory 51 as a storage unit, a power supply unit 53, a pressure sensor 31, a pump 32, and a valve 33. The main body 10 further is equipped with an oscillation circuit 310 that converts the output from the pressure sensor 31 into a frequency, a pump drive circuit 320 that drives the pump 32, and a valve drive circuit 330 that drives the valve 33.

In this example, the display 50 includes a display and an indicator, and displays predetermined information (e.g., blood pressure measurement results) according to a control signal from the control unit 110.

In this example, the operation unit 52 has a measurement switch 52A for receiving an instruction to start measuring blood pressure, and a memory switch 52B for recalling past blood pressure measurement results. These measurement switch 52A and memory switch 52B input operation signals to the control unit 110 in response to instructions from the user.

Memory 51 stores program data for controlling sphygmomanometer 100, setting data for setting various functions of sphygmomanometer 100, and blood pressure measurement result data. Memory 51 is also used as a work memory when a program is executed.

The control unit 110 includes a CPU (Central Processing Unit) and controls the overall operation of the blood pressure monitor 100. Specifically, the control unit 110 acts as a pressure control unit in accordance with a program for controlling the blood pressure monitor 100 stored in the memory 51, and controls the driving of the pump 32 and the valve 33 in response to an operation signal from the operation unit 52. The control unit 110 also acts as a blood pressure calculation unit, calculates a blood pressure value, and controls the display 50 and the memory 51. A specific method of measuring blood pressure will be described later.

The power supply unit 53 supplies power to the control unit 110, the pressure sensor 31, the pump 32, the valve 33, the display 50, the memory 51, the oscillator circuit 310, the pump drive circuit 320, and the valve drive circuit 330.

The pump 32 supplies air to increase the pressure (cuff pressure) in each of the air bags 211, 212, and 220 that make up the cuff 20. The valve 33 opens and closes to control the cuff pressure by discharging or sealing the air in each of the air bags 211, 212, and 220. The pump drive circuit 320 drives the pump 32 based on a control signal provided by the control unit 110. The valve drive circuit 330 opens and closes the valve 33 based on a control signal provided by the control unit 110.

In this example, the air pipe 37a connected to the pump 32 and the air pipe 37b connected to the valve 33 join together and are connected to the air pipe 37c connected to the outer air bag 211. The air pipe 37d branched from the air pipe 37c is connected to the air pipe 37e connected to the inner air bag 212 in a manner that allows air to flow through it, via an air chamber 41 serving as a filter that attenuates pulse waves. Furthermore, the air pipe 37f branched from the air pipe 37e is connected to the air pipe 37g connected to the inner air bag 212 in a manner that allows air to flow through it, via a thin tube 42 serving as a filter that attenuates pulse waves. In this way, the air pipes 37c and 37e are connected to each other, and the air pipes 37e and 37g are connected to each other in a manner that allows air to flow through them. Therefore, by supplying air from one pump 32 to one of the air pipes 37c, 37e, and 37g (in this example, the air pipe 37c), air can be supplied to the outer air bag 211, the inner air bag 212, and the second air bag 220, respectively. This allows the number of pumps (i.e., the number of components of the blood pressure monitor) to be reduced compared to when air is supplied from separate pumps to the outer air bag 211, the inner air bag 212, and the second air bag 220. Note that air pipes 37a to 37g are collectively referred to as reference numeral 37.

The air chamber 41 is configured to have a larger capacity than the capacity per unit length of the air pipes 37d and 37e. The air chamber 41 attenuates the transmission of the pulse wave acquired by the outer air bag 211 to the inner air bag 212 and the second air bag 220 during blood pressure measurement. The thin tube 42 is configured to have a smaller capacity than the capacity per unit length of the air pipes 37d and 37e. The thin tube 42 attenuates the transmission of the pulse wave acquired by the inner air bag 212 to the second air bag 220 during blood pressure measurement. Therefore, during blood pressure measurement, the pulse wave (vibration) acquired by the outer air bag 211 can be prevented from being mixed into the pulse wave (vibration) from the artery passing through the measurement site 90 detected by the second air bag 220 via the air pipe 37. As a result, the accuracy of blood pressure measurement can be maintained at a high level.

The pressure sensor 31 and the oscillation circuit 310 act as a pressure detection unit that detects the pressure in the second air bag 220. The pressure sensor 31 is, for example, a piezo-resistance pressure sensor, and detects the pressure (cuff pressure) in the second air bag 220 that constitutes the cuff 20 through the air piping 38. In this example, the oscillation circuit 310 oscillates based on an electrical signal value based on a change in electrical resistance due to the piezo-resistance effect from the pressure sensor 31, and outputs a frequency signal having a frequency corresponding to the electrical signal value of the pressure sensor 31 to the control unit 110. In this example, an air piping 38 for detecting the pressure in the second air bag 220 is provided in addition to the air piping 37 that supplies or exhausts air into each of the air bags 211, 212, and 220 that constitute the cuff 20. Therefore, during blood pressure measurement, the pulse wave (vibration) acquired by the external air bag 211 can be prevented from being mixed with the pulse wave (vibration) from the artery passing through the measurement site 90 detected by the second air bag 220. As a result, blood pressure measurement accuracy can be maintained at a higher level.

(How the blood pressure measurement cuff is worn)
As shown in Fig. 4 (a cross section along an artery 91 passing through a measurement site 90), the cuff 20 is attached by surrounding the measurement site 90 with the band-shaped outer cloth 21 in a state where the first air bag 210 corresponds to a specific closed area 90A to be compressed in the measurement site (upper arm in this example) 90. In addition, in the attached state, the outer cloth 21 is fixed by a hook-and-loop fastener (not shown) so as not to loosen. In this attached state, the upstream segment 281 or downstream segment 282 of the damper layer 280L, the outer air bag 211 of the first air bag 210, and the outer cloth 21 are arranged in this order in the thickness direction (direction perpendicular to the outer peripheral surface of the measurement site 90) with respect to the outer peripheral area 90s (annular area) of the specific closed area 90A of the measurement site 90. In the inner region 90i (excluding the central region 90c) of the specific closed region 90A of the measurement site 90, the upstream segment 281 or the downstream segment 282 of the damper layer 280L, the first air bag 210 (in this example, the outer air bag 211 containing the inner air bag 212), and the outer cloth 21 are arranged in this order in the thickness direction. In the central region 90c of the specific closed region 90A of the measurement site 90, the second air bag 220, the central segment 283 of the damper layer 280L, the first air bag 210 (in this example, the outer air bag 211 containing the inner air bag 212), and the outer cloth 21 are arranged in this order in the thickness direction.

(Blood pressure measurement)
FIG. 5 shows an operational flow when a user measures blood pressure using the sphygmomanometer 100.

When the cuff 20 is attached to the measurement site 90 and the user issues a command to start measurement using the operation unit 52 provided on the main body 10, the control unit 110 performs initialization (step S1 in FIG. 5). Specifically, the control unit 110 initializes the processing memory area, turns off (stops) the pump 32, and adjusts the pressure sensor 31 to 0 mmHg (sets the atmospheric pressure to 0 mmHg) with the valve 33 open.

Next, the control unit 110, acting as a pressure control unit, closes the valve 33 via the valve drive circuit 330 (step S2), and then turns on (starts) the pump 32 via the pump drive circuit 320 to start pressurizing the cuff 20 (step S3). That is, the control unit 110 supplies air from the pump 32 to the cuff 20 (the outer air bag 211, the inner air bag 212, and the second air bag 220) through the air piping 37. At the same time, the pressure sensor 31 acts as a pressure detection unit, detecting the pressure of the second air bag 220 through the air piping 38. The control unit 110 controls the pressurization speed by the pump 32 based on the output of the pressure sensor 31.

At this time, the expansion of the second air bag 220, the outer air bag 211, and the inner air bag 212 shown in FIG. 4 in a direction away from the measured part 90 is regulated by the outer cloth 21 as a whole. Therefore, the second air bag 220, the outer air bag 211, and the inner air bag 212 expand in a direction to press the specific closed area 90A of the measured part 90. As a result, the specific closed area 90A of the measured part 90 is compressed, and the artery 91 passing through the specific closed area 90A is blocked. In detail, the outer peripheral area 90s of the specific closed area 90A of the measured part 90 is pressed by the outer air bag 211 via the upstream segment 281 or the downstream segment 282 of the damper layer 280L, and the upstream end 91u and downstream end 91d of the artery 91 passing through the specific closed area 90A are compressed. The inner region 90i (excluding the central region 90c) of the specific closed region 90A is pressed by the first air bag 210 (in this example, the portion of the outer air bag 211 where the inner air bag 212 is located) via the upstream segment 281 or downstream segment 282 of the damper layer 280L, compressing the upstream transition portion 91iu between the upstream end portion 91u and the central portion 91c of the artery 91 passing through the specific closed region 90A and the downstream transition portion 91id between the downstream end portion 91d and the central portion 91c. Here, the portion of the artery 91 passing through the specific closed region 90A that is located in the central region 90c is referred to as the central portion 91c. In addition, the central region 90c of the specific closed region 90A of the measurement site 90 is pressed by the second air bag 220 and the first air bag 210 (in this example, the portion of the outer air bag 211 where the inner air bag 212 is located) provided via the central segment 283 of the damper layer 280L, compressing the central portion 91c of the artery 91 passing through the specific closed region 90A.

Next, in step S4 of FIG. 5, the control unit 110 determines whether the pressure (cuff pressure Pc shown in the upper part of FIG. 14) of the cuff 20 (in this example, the second air bag 220) has reached a predetermined value (predetermined pressure) Pu based on the output of the pressure sensor 31. Here, this predetermined pressure Pu may be set to, for example, 300 mmHg so as to sufficiently exceed the expected blood pressure value of the subject, or may be set to the subject's blood pressure value measured last time plus 40 mmHg. The control unit 110 continues pressurizing until the cuff pressure Pc reaches the above-mentioned predetermined pressure Pu, and when the cuff pressure Pc reaches the above-mentioned predetermined pressure Pu (Yes in step S4), it stops the pump 32 (step S5). Next, the control unit 110 gradually opens the valve 33 via the valve drive circuit 330 (step S6). This reduces the cuff pressure Pc at an approximately constant speed. Here, the cuff pressure Pc detected through the air pipe 38 is superimposed on the pulse wave signal (fluctuation component) Pm (shown enlarged at the bottom of FIG. 14) as pulse wave information based on the pulse wave.

During this decompression process, the pressure sensor 31 functions as a pressure detector and extracts, through a filter, the pressure of the second air bag 220, in other words, the pulse wave signal (fluctuation component) Pm as pulse wave information due to the pulse wave from the artery 91 (particularly the central portion 91c facing the second air bag 220) passing through the specific closed area 90A shown in FIG. 4. The control unit 110 functions as a blood pressure calculation unit and attempts to calculate blood pressure values (systolic blood pressure SBP (Systolic Blood Pressure) and diastolic blood pressure DBP (Diastolic Blood Pressure)) using a known oscillometric method based on the pulse wave signal Pm acquired at this point (step S7 in FIG. 5).

At this point, if the blood pressure value still cannot be calculated due to insufficient data (NO in step S8), steps S6 to S8 are repeated until the blood pressure value can be calculated.

Once the blood pressure value has been calculated in this manner (Yes in step S8), the control unit 110 functions as a pressure control unit and performs control to open the valve 33 and rapidly exhaust the air in the cuff 20 (the outer air bag 211, the inner air bag 212, and the second air bag 220) (step S9). In the example of FIG. 14, the pump 32 is stopped at time t1, the systolic blood pressure SBP is obtained at time t2, and the diastolic blood pressure DBP is obtained at time t3.

After this, the control unit 110 controls the display 50 to display the calculated blood pressure value (step S10) and stores the blood pressure value in the memory 51.

In addition, blood pressure calculation may be performed during the pressurization process of the cuff 20, rather than during the depressurization process.

4, the outer air bag 211 compressing the outer peripheral region 90s (where the upstream end 91u and downstream end 91d of the artery 91 passing through the specific closed region 90A) is susceptible to the influence of the pulse wave (vibration) of the blood flow that infiltrates due to the edge effect from the upstream artery 91 and the downstream artery 91 of the measurement site 90. However, in this cuff 20, the upstream segment 281 or the downstream segment 282 of the damper layer 280L is interposed between the ends 91u and 91d of the outer peripheral region 90s that correspond to the upstream and downstream sides of the artery 91 and the outer air bag 211. Therefore, blood flow pulse waves (vibrations) D1, D2 that attempt to infiltrate into the outer air bag 211 due to the edge effect from ends 91u, 91d of the outer peripheral region 90s that correspond to the upstream and downstream sides of the artery 91 are attenuated by the upstream segment 281 or the downstream segment 282 and are not easily transmitted to the outer air bag 211. In other words, if the pulse waves (vibrations) transmitted to the outer air bag 211 due to the edge effect are D1', D2', then D1'<D1 and D2'<D2. Furthermore, the outer air bag 211 is separated from the second air bag 220 via the inner air bag 212 contained in the outer air bag 211 and the central segment 283 of the damper layer 280L. Therefore, the pulse waves (vibrations) D1', D2' acquired by the outer air bag 211 are attenuated by the inner air bag 212 and the central segment 283 of the damper layer 280L, and are not easily transmitted to the second air bag 220. In other words, if the pulse wave (vibration) transmitted to the second air bag 220 due to the edge effect is D3, then D3 < (D1' + D2'). Therefore, in this cuff 20, the second air bag 220 can detect pulse wave information mainly from only the pulse wave from the central portion 91c of the artery 91 that passes through the specific closed area 90A. This effectively prevents a decrease in the S/N ratio due to the edge effect, and as a result, the accuracy of blood pressure measurement can be improved.

In addition, as described above, in the cuff 20, the inner air bag 212, the central segment 283 of the damper layer 280L, and the second air bag 220 are arranged in a biased manner toward the downstream side along the direction in which the artery 91 passes within the specific closed area 90A relative to the outer air bag 211. Therefore, the second air bag 220 is arranged in the specific closed area 90A in a region that is relatively far from the upstream end 91u of the artery 91 passing through the specific closed area 90A. This makes it difficult for the pulse wave (vibration) D1 from the upstream end 91u of the artery 91 acquired by the outer air bag 211 to be transmitted to the second air bag 220 within the specific closed area 90A. Therefore, in this cuff 20, the decrease in the S/N ratio due to the edge effect can be more effectively prevented, and as a result, the accuracy of blood pressure measurement can be further improved.

In addition, in the blood pressure monitor 100 (cuff 20), an air chamber 41 as a filter is inserted between the air pipes 37d and 37e, and a thin tube 42 as a filter is inserted between the air pipes 37d and 37e. Therefore, during blood pressure measurement, the pulse wave (vibration) acquired by the outer air bag 211 and/or the inner air bag 212 can be prevented from being mixed into the second air bag 220 through the air pipe 37. Furthermore, in the blood pressure monitor 100 (cuff 20), an air pipe 38 for detecting the pressure in the second air bag 220 is provided in addition to the air pipe 37 that supplies or exhausts air into each of the air bags 211, 212, and 220 that constitute the cuff 20. Therefore, during blood pressure measurement, the pulse wave (vibration) acquired by the outer air bag 211 and/or the inner air bag 212 can be prevented from being mixed into the pulse wave (vibration) from the artery passing through the measurement site 90 detected by the second air bag 220. This allows blood pressure measurement to be kept highly accurate.

In addition, the air pipes 37c, 37e, and 37g may be completely separated from each other, rather than being connected to each other in a manner that allows air to flow through them via a filter (air chamber 41, thin tube 42, etc.). This further prevents the pulse wave (vibration) acquired by the external air bag 211 from being mixed into the pulse wave (vibration) detected by the second air bag 220 via the air pipe 37.

In the above example, the inner air bag 212 is made by placing a pair of sheets made of polyurethane resin facing each other and welding the outer edges of the pair of sheets together. However, this is not limited to this. For example, as in the inner air bag 212' shown in FIG. 3C, the pair of sheets (rectangles with rounded corners) may have bellows-shaped side surfaces 212s that are expandable in the thickness direction along the entire circumference of the outer edges. With this configuration, the inner air bag 212' does not prevent the outer air bag 211 from expanding and contracting in the thickness direction when worn.

In the above example, the damper layer 280L has a triple structure including a central segment 283, and an upstream segment 281 and a downstream segment 282 connected to both sides of the central segment 283 in the width direction of the cuff 20. However, this is not limited to this. For example, Fig. 6(A), Fig. 6(B), and Fig. 6(C) show the deformed damper layer 280L of the cuff 20 in a manner corresponding to Fig. 2(A), Fig. 2(B), and Fig. 2(C), respectively. In this example, the shape and dimensions of the damper layer 280 are set to be the same as those of the second air bag 220 in the plane along the outer cloth 21. That is, the damper layer 280 shown in Fig. 6 has a rectangular shape with rounded corners and the same dimensions as the second air bag 220. In this example, the damper layer 280 is made of a material that is spatially continuous and integral, such as silicone gel or silicone rubber, which efficiently damps the vibration of the pulse wave. This makes it possible to easily manufacture the damper layer 280. The damper layer 280 is adhered to the opposing surface of the outer air bag 211 with an adhesive (not shown). The second air bag 220 is also adhered to the opposing surface of the damper layer 280 with an adhesive (not shown). This prevents the damper layer 280 and the second air bag 220 from shifting relative to the outer air bag 211.

When this damper layer 280 is provided, the upstream segment 281 and downstream segment 282 are omitted, so if the pulse wave (vibration) transmitted to the external air bag 211 due to the edge effect during blood pressure measurement is D1', D2', then D1' ≒ D1 and D2' ≒ D2. However, since the damper layer 280 attenuates the vibration of the pulse wave with high efficiency, if the pulse wave (vibration) transmitted to the second air bag 220 due to the edge effect is D3, then D3 << (D1' + D2'). Therefore, it is possible to effectively prevent a decrease in the S/N ratio due to the edge effect, and as a result, it is possible to improve the accuracy of blood pressure measurement.

(Blood pressure measurement cuff according to the second embodiment)
Fig. 7(A) shows a schematic planar layout of a blood pressure measurement cuff 20A of a second embodiment, which is different from the cuff 20 described above, in an unfolded state. Fig. 7(B) shows a cross section taken along line VIIB-VIIB in Fig. 7(A) with the outer cloth 21 of the cuff 20A omitted. Fig. 7(C) shows a cross section taken along line VIIC-VIIC in Fig. 7(A) with the outer cloth 21 of the cuff 20A omitted. Fig. 8 shows a state in which the cuff 20A is attached around the outer circumference of a measurement site (upper arm in this example) 90, corresponding to Fig. 4. The same components as those in the first embodiment are denoted by the same reference numerals.

As can be seen from FIG. 8, the cuff 20A generally comprises a band-shaped outer cloth 21 located at the outermost periphery, a first air bag 210A provided along the surface of the outer cloth 21 facing the measured area 90, a damper layer 280 provided along the surface of the first air bag 210A (particularly the inner air bag 212A) facing the measured area 90, and a second air bag 220 provided along the surface of the damper layer 280 facing the measured area 90.

In this example, as can be seen from FIG. 7(A), the first air bag 210A includes an outer air bag 211A having an annular shape (called the "second shape") that corresponds to the outer peripheral region 90s (see FIG. 4 for its planar layout) of the specific closed region 90A, and an inner air bag 212A arranged in an open region 211w surrounded by the ring of the outer air bag 211A. The inner air bag 212A has a rectangular shape with rounded corners that corresponds to the shape of the open region 211w.

7(A) and 7(B), similar to the previous example, the inner air bag 212A is positioned toward the downstream side (the right side in FIG. 2(A)) along the direction of the artery 91 in the specific closed area 90A relative to the outer air bag 211A. In more detail, if the vertical line passing through the center of the inner air bag 212A is C, the left-right distance between the left side of the outer peripheral edge 211o of the outer air bag 211A and the vertical line C is set to X1 = 7 cm, and the left-right distance between the right side of the outer peripheral edge 211o of the outer air bag 211A and the vertical line C is set to X2 = 6 cm. On the other hand, as can be seen from FIG. 7(A) and 7(C), the center of the outer air bag 211A and the center of the inner air bag 212A coincide with each other in the longitudinal direction of the outer cloth 21.

In this example, the inner peripheral edge 211i of the outer air bag 211A and the outer peripheral edge 212o of the inner air bag 212A adjacent to the inner peripheral edge 211i are welded to each other along the entire circumference of the outer air bag 211A. For ease of understanding, the welded portion 211m is shaded in Figures 7(A) to 7(C) and 8. This welding prevents the inner air bag 212A from shifting relative to the outer air bag 211A. In particular, when the outer air bag 211A and the inner air bag 212A are inflated, the inner air bag 212A is prevented from shifting left and right in Figure 8, for example. As a result, high accuracy of blood pressure measurement can be maintained.

The second air bag 220 in this cuff 20A is configured exactly the same as the second air bag 220 described in Figures 2(A) to 2(C). The damper layer 280 in this cuff 20A is configured exactly the same as the damper layer 280 described in Figures 6(A) to 6(C). The damper layer 280 is adhered to the opposing surface of the inner air bag 212A by adhesive (not shown). The second air bag 220 is also adhered to the opposing surface of the damper layer 280 by adhesive (not shown). The other points in this cuff 20A are configured exactly the same as in the above-mentioned cuff 20, and the same components are given the same reference numerals and redundant explanations are omitted. Note that in Figure 7(A), the air piping is omitted for simplicity, but the air piping is connected to this cuff 20A as in Figure 2(A). This cuff 20A is connected to the main body 10 of the blood pressure monitor 100 in the same manner as shown in FIG. 1.

8, the cuff 20A is attached by surrounding the measurement site 90 with the band-shaped outer cloth 21, with the first air bag 210A corresponding to the specific closed area 90A to be compressed in the measurement site (upper arm in this example). In this attached state, the outer air bag 211A constituting the first air bag 210A and the outer cloth 21 are arranged in this order in the thickness direction (direction perpendicular to the outer surface of the measurement site 90) with respect to the outer peripheral area 90s (annular area) of the specific closed area 90A of the measurement site 90. The inner air bag 212A constituting the first air bag 210A and the outer cloth 21 are arranged in this order in the thickness direction with respect to the inner area 90i (excluding the central area 90c) of the specific closed area 90A of the measurement site 90. In the central region 90c of the specific closed region 90A of the measurement site 90, the second air bag 220, the damper layer 280, the inner air bag 212A, and the outer cloth 21 are arranged in this order in the thickness direction.

In this wearing state, when blood pressure is measured, the expansion of the second air bag 220, the outer air bag 211A, and the inner air bag 212A shown in FIG. 8 in a direction away from the measured part 90 is restricted by the outer cloth 21 as a whole. Therefore, the second air bag 220, the outer air bag 211A, and the inner air bag 212A expand in a direction to press the specific closed area 90A of the measured part 90. As a result, the specific closed area 90A of the measured part 90 is compressed, and the artery 91 passing through the specific closed area 90A is blocked. In detail, the outer peripheral area 90s of the specific closed area 90A of the measured part 90 is pressed by the outer air bag 211A, and the upstream end 91u and downstream end 91d of the artery 91 passing through the specific closed area 90A are compressed. The inner region 90i (excluding the central region 90c) of the specific closed region 90A is pressed by the inner air bag 212A constituting the first air bag 210A, and an upstream transition portion 91iu between the upstream end portion 91u and the central portion 91c of the artery 91 passing through the specific closed region 90A and a downstream transition portion 91id between the downstream end portion 91d and the central portion 91c are compressed. Also, the central region 90c of the specific closed region 90A of the measurement site 90 is pressed by the second air bag 220 and the inner air bag 212A constituting the first air bag 210A provided via the damper layer 280, and the central portion 91c of the artery 91 passing through the specific closed region 90A is compressed. During the process of pressurizing or depressurizing the second air bag 220, the outer air bag 211A, and the inner air bag 212A, the second air bag 220 detects a pulse wave signal Pm (see FIG. 14) as pulse wave information based on a pulse wave from the central portion 91c of the artery 91 passing through the specific closed area 90A. Based on this pulse wave signal Pm, the blood pressure is calculated by the oscillometric method.

Here, the outer air bag 211A, which compresses the outer peripheral region 90s (where the upstream end 91u and downstream end 91d of the artery 91 passing through the specific closed region 90A) of the specific closed region 90A shown in FIG. 8, is susceptible to the influence of the blood flow pulse waves (vibrations) that infiltrate from the upstream artery 91 and the downstream artery 91 due to the edge effect from the measured part 90. However, in this cuff 20A, the welded part 211m is interposed between the outer air bag 211A and the inner air bag 212A. Therefore, the blood flow pulse waves (vibrations) D1 and D2 that attempt to infiltrate the outer air bag 211A due to the edge effect from the ends 91u and 91d corresponding to the upstream and downstream sides of the artery 91 of the outer peripheral region 90s are attenuated by the welded part 211m and are not easily transmitted to the inner air bag 212A. That is, if the pulse waves (vibrations) transmitted to the inner air bag 212A due to the edge effect are D1" and D2", then D1"<D1 and D2"<D2. Furthermore, the inner air bag 212A is separated from the second air bag 220 via the damper layer 280. Therefore, the pulse waves (vibrations) D1" and D2" acquired by the inner air bag 212A are attenuated by the damper layer 280 and are further less likely to be transmitted to the second air bag 220. That is, if the pulse wave (vibration) transmitted to the second air bag 220 due to the edge effect is D3, then D3<<(D1"+D2"). Therefore, in this cuff 20A, the second air bag 220 can detect pulse wave information mainly from only the pulse wave from the central portion 91c of the artery 91 passing through the specific closed region 90A. Therefore, it is possible to effectively prevent a decrease in the S/N ratio due to the edge effect, and as a result, it is possible to improve the accuracy of blood pressure measurement.

In addition, as described above, in the cuff 20A, the inner air bag 212A, the damper layer 280, and the second air bag 220 are arranged in a biased manner toward the downstream side along the direction in which the artery 91 passes within the specific closed region 90A relative to the outer air bag 211A. Therefore, the second air bag 220 is arranged in the specific closed region 90A in a region that is relatively far from the upstream end 91u of the artery 91 passing through the specific closed region 90A. This makes it difficult for the pulse wave (vibration) D1 from the upstream end 91u of the artery 91 acquired by the outer air bag 211A to be transmitted to the second air bag 220 within the specific closed region 90A. Therefore, in this cuff 20A, the decrease in the S/N ratio due to the edge effect can be more effectively prevented, and as a result, the accuracy of blood pressure measurement can be further improved.

(First Modification)
Fig. 9 shows a planar layout of a blood pressure measurement cuff 20B as a first modified example obtained by modifying cuff 20A in Fig. 7, in correspondence with Fig. 7(A). Note that in Fig. 9, the same components as those in Fig. 7 are given the same reference numerals and redundant explanations will be omitted (the same applies to Figs. 10, 11, and 12).

In this cuff 20B, the inner peripheral edge 211i of the outer air bag 211A and the outer peripheral edge 212o of the inner air bag 212A adjacent to the inner peripheral edge 211i are partially welded to each other along the ring of the outer air bag 211A. Specifically, the upper side 211i1 forming the inner peripheral edge 211i of the outer air bag 211A and the upper side 212o1 forming the outer peripheral edge 212o of the inner air bag 212A are welded at the center of those sides (the welded part is indicated by the symbol 211m1). The lower side 211i2 forming the inner peripheral edge 211i of the outer air bag 211A and the lower side 212o2 forming the outer peripheral edge 212o of the inner air bag 212A are welded at the center of those sides (the welded part is indicated by the symbol 211m2). The left side 211i3 forming the inner peripheral edge 211i of the outer air bag 211A and the left side 212o3 forming the outer peripheral edge 212o of the inner air bag 212A are welded at the center of those sides (the welded part is indicated by the symbol 211m3). The right side 211i4 forming the inner peripheral edge 211i of the outer air bag 211A and the right side 212o4 forming the outer peripheral edge 212o of the inner air bag 212A are welded at the center of those sides (the welded part is indicated by the symbol 211m4).

These welded points 211m1-211m4 prevent the inner air bag 212A from shifting relative to the outer air bag 211A. In particular, when the outer air bag 211A and the inner air bag 212A are inflated, the inner air bag 212A is prevented from shifting left and right, for example, in FIG. 9. Also, because the welded points 211m1-211m4 are interposed between the outer air bag 211A and the inner air bag 212A, the pulse wave (vibration) acquired by the outer air bag 211A is not transmitted directly to the inner air bag 212A. Moreover, the points at which the pulse wave (vibration) is transmitted from the outer air bag 211A to the inner air bag 212A are limited to the four welded points 211m1-211m4. As a result, compared to the cuff 20A in FIG. 7, within the specific closed area 90A, the pulse wave (vibration) acquired by the external air bag 211A is even less likely to be transmitted to the second air bag 220. Therefore, with this cuff 20B, it is possible to more effectively prevent a decrease in the S/N ratio due to the edge effect, and as a result, the accuracy of blood pressure measurement can be further improved.

(Second Modification)
FIG. 10 shows a planar layout of a blood pressure measurement cuff 20C as a second modified example of the cuff 20A in FIG. 7, in a manner corresponding to FIG. 7A.

In this cuff 20C, the side of the inner periphery 211i of the outer air bag 211A that is far from the artery 91 and the side of the outer periphery 212o of the inner air bag 212A that is far from the artery 91 are partially welded to each other. Meanwhile, the side of the inner periphery 211i of the outer air bag 211A that intersects with the artery 91 and the side of the outer periphery 212o of the inner air bag 212A that intersects with the artery 91 are spaced apart from each other. Specifically, the upper side 211i1 that forms the inner periphery 211i of the outer air bag 211A and the upper side 212o1 that forms the outer periphery 212o of the inner air bag 212A are welded at the center of those sides (the welded part is indicated by the symbol 211m1). The lower side 211i2 forming the inner peripheral edge 211i of the outer air bag 211A and the lower side 212o2 forming the outer peripheral edge 212o of the inner air bag 212A are welded at the center of those sides (the welded part is indicated by the symbol 211m2). Meanwhile, the left side 211i3 forming the inner peripheral edge 211i of the outer air bag 211A and the left side 212o3 forming the outer peripheral edge 212o of the inner air bag 212A are spaced apart from each other. The right side 211i4 forming the inner peripheral edge 211i of the outer air bag 211A and the right side 212o4 forming the outer peripheral edge 212o of the inner air bag 212A are spaced apart from each other.

The above-mentioned welded points 211m1 and 211m2 prevent the internal air bag 212A from shifting relative to the external air bag 211A. In particular, when the external air bag 211A and the internal air bag 212A are inflated, the internal air bag 212A is prevented from shifting left and right, for example, in FIG. 10. In addition, since the welded points 211m1 and 211m2 are interposed between the external air bag 211A and the internal air bag 212A, the pulse wave (vibration) acquired by the external air bag 211A is not directly transmitted to the internal air bag 212A. Moreover, compared to the case of the cuff 20B in FIG. 9, the points where the pulse wave (vibration) is transmitted from the external air bag 211A to the internal air bag 212A are limited to the welded points 211m1 and 211m2. As a result, the transmission paths (indicated by dashed lines) C1, C1', C2, C2' of the pulse wave (vibration) from the portions 211A3, 211A4 of the outer air bag 211A that are most susceptible to the influence of the pulse wave (vibration) of the blood flow that infiltrates from the artery upstream and downstream of the measurement site 90 due to the edge effect (portions that intersect with the artery 91) to the second air bag 220 become longer. Therefore, the pulse wave (vibration) acquired by the outer air bag 211A is even less likely to be transmitted to the second air bag 220. Therefore, with this cuff 20C, it is possible to more effectively prevent a decrease in the S/N ratio due to the edge effect, and as a result, the accuracy of blood pressure measurement can be further improved.

(Third Modification)
Figures 11(A), 11(B), and 11(C) correspond to Figures 7(A), 7(B), and 7(C), respectively, and show a blood pressure measurement cuff 20D as a third modified example of the cuff 20A of Figure 7. Figure 11(B) shows a cross section taken along line XIB-XIB in Figure 11(A) with the outer cloth 21 of cuff 20D omitted. Figure 11(C) shows a cross section taken along line XIC-XIC in Figure 11(A) with the outer cloth 21 of cuff 20D omitted.

In this cuff 20D, instead of the outer air bag 211A and inner air bag 212A that constitute the first air bag 210A, an outer air bag 211B and inner air bag 212B that constitute the first air bag 210B are provided.

In this example, as can be seen from FIG. 11(A), the first air bag 210B includes an outer air bag 211B having an annular shape (second shape) that corresponds to the outer peripheral region 90s (see FIG. 4 for the plan layout) of the specific closed region 90A, and an inner air bag 212B arranged in an open region 211w surrounded by the ring of the outer air bag 211B. The inner air bag 212B has a rectangular shape with rounded corners that corresponds to the shape of the open region 211w. In this example, in a plane along the outer cloth 21, the outer air bag 211B is set to a longitudinal dimension of 23 cm and a width dimension of 12 cm. The inner air bag 212B is slightly larger than the second air bag 220, and is set to a longitudinal dimension of 7 cm and a width dimension of 4 cm.

The outer air bag 211B has bellows-shaped side surfaces 211t1 and 211t2 that can expand and contract in the thickness direction along the entire circumference of the outer peripheral edge 211o and the inner peripheral edge 211i. The inner air bag 212B has bellows-shaped side surfaces 212t that can expand and contract in the thickness direction along the entire circumference of the outer peripheral edge 211o. The bellows-shaped side surface 211t2 of the inner peripheral edge 211i of the outer air bag 211B and the bellows-shaped side surface 212t of the outer peripheral edge 211o of the inner air bag 212B have corresponding unevenness. In this example, the inner peripheral edge 211i of the outer air bag 211B and the outer peripheral edge 212o of the inner air bag 212B adjacent to this inner peripheral edge 211i are fitted together.

According to this configuration, when air is supplied to the second air bag 220, the outer air bag 211B, and the inner air bag 212B in the worn state, the bellows-shaped sides 211t1, 211t2, and 212t stretch in the thickness direction, so that the outer air bag 211B and the inner air bag 212B easily expand in the thickness direction. Therefore, the specific closed area 90A of the measurement site 90 can be easily compressed. In addition, as a result of the outer air bag 211B and the inner air bag 212B being fitted together, even if air is supplied to the second air bag 220, the outer air bag 211B, and the inner air bag 212B in the worn state, the relative position of the inner air bag 212B to the outer air bag 211B is maintained in the plane along the outer cloth 21, and as a result, the relative position of the second air bag 220 is also maintained via the damper layer 280.

(Fourth Modification)
FIG. 12 shows a cross-sectional structure of a blood pressure measurement cuff 20E as a fourth modified example of the cuff 20A of FIG. 7, in a manner corresponding to FIG. 7B.

This cuff 20E differs from the above-mentioned cuff 20A in that the outer air bag 211A and the inner air bag 212A constituting the first air bag 210A are not welded (connected) to each other, but are separated from each other. The inner air bag 212A is disposed in an empty space 211w surrounded by the ring of the outer air bag 211A. In this cuff 20E, as shown in FIG. 12, the outer air bag 211A and the inner air bag 212A are respectively adhered by adhesives 241, 242 to the surface of the outer cloth 21 facing the measurement site 90.

These adhesives prevent the internal air bag 212A from shifting relative to the external air bag 211A. In particular, when the external air bag 211A and the internal air bag 212A are inflated, the internal air bag 212A is prevented from shifting left and right, for example, in FIG. 12. This improves the accuracy of blood pressure measurement.

In the above-described cuffs 20A, 20B, 20C, and 20D, it is not necessary to adhere the first air bladder 210, 210A to the outer cloth 21. For example, the first air bladder 210, 210A may be engaged with the outer cloth 21 so that the outer cloth 21 and the first air bladder 210, 210A are not separated. Alternatively, the outer cloth 21 and a stretchable inner cloth (not shown) may be configured to face each other in a bag shape, and the first air bladder 210, 210A, the damper layer 280, and the second air bladder 220 may be housed in the bag together. In this case, the first air bladder 210, 210A is arranged along the outer cloth 21, and the second air bladder 220 is arranged along the inner cloth.

(Verification experiment)
FIG. 13 shows a measurement state in a verification experiment for comparing the performance of the blood pressure measurement cuff 20 shown in FIG. 2 with that of a general blood pressure measurement cuff (a cuff constituting a commercially available blood pressure monitor). In this example, the cuff 20 shown in FIG. 2 is attached to the left upper arm as the measurement site 90 of the subject 80. A general blood pressure measurement cuff 900 is attached to the right upper arm as the measurement site 90' for comparison (the general cuff 900 includes only one air bag 920). Air as a fluid is supplied from the pump 32 through the air pipe 37 to the first air bag 210 and the second air bag 220 included in the cuff 20. The pressure of the second air bag 220 (cuff pressure Pc) is detected by the pressure sensor 31 through the air pipe 38. On the other hand, air as a fluid is supplied from the pump 32 to the air bag 920 included in the general cuff 900 through the air pipe 937 provided in parallel with the air pipe 37. The pressure in the air bag 920 (cuff pressure Pc) is detected by a pressure sensor 931 through an air pipe 938 branching off from an air pipe 937 .

In the measurement mode of FIG. 13, the cuff 20 and the cuff 900 were pressurized and depressurized in parallel, and the pulse wave signal Pm obtained by the cuff 20 and the pulse wave signal Pm' obtained by the cuff 900 were observed in parallel. FIG. 15 expands the time axis around the time t2 when the systolic blood pressure (SBP) was obtained in FIG. 14, and shows the pulse wave signal Pm (shown by a solid line) obtained by the cuff 20 in FIG. 2 in comparison with the pulse wave signal Pm' (shown by a dashed line) obtained by the general cuff 900. In the pulse wave signal Pm' obtained by the general cuff 900, there is little difference in amplitude (peak-to-peak) before and after time t2, whereas in the pulse wave signal Pm obtained by the cuff 20 in FIG. 2, there is a relatively large difference in amplitude (peak-to-peak) before and after time t2, and the S/N ratio is improved. 16 shows a comparison of the pulse wave signal Pm (shown by a solid line) obtained by the cuff 20 in FIG. 2 with the pulse wave signal Pm' (shown by a dashed line) obtained by the general cuff 900, with the time axis enlarged around time t3 when the diastolic blood pressure (DBP) was obtained in FIG. 14. The S/N ratio is improved around time t3 as well as around time t2. Moreover, in the pulse wave signal Pm' obtained by the general cuff 900, there is little change in the pulse wave rising portions Pm1', Pm2', and Pm3' around time t3, whereas in the pulse wave signal Pm obtained by the cuff 20 in FIG. 2, there is a relatively large change in the pulse wave rising portions Pm1, Pm2, and Pm3 around time t3 (there is a large change in Pm1 and Pm2, but a small change in Pm3). Therefore, the diastolic blood pressure (DBP) can be easily detected. In this way, it was verified that the cuff 20 in FIG. 2 can effectively prevent a decrease in the S/N ratio due to the edge effect, and can improve the accuracy of blood pressure measurement, compared to the general cuff 900.

In the above example, the outer air bags 211, 211A, 210B, the inner air bags 212, 212', 212A, 212B, the damper layer 280, and the second air bag 220 each have a rectangular shape with rounded corners in the plane along the outer cloth 21, but this is not limited to this. Their planar shapes may be square with rounded corners, oval, circular, etc.

In the above example, the measurement area 90 is the upper arm, but this is not limited to this. The measurement area 90 may be an upper limb other than the upper arm, such as the wrist, or a lower limb, such as the ankle.

The above embodiments are merely examples, and various modifications are possible without departing from the scope of the present invention. Each of the above-mentioned embodiments can be implemented independently, but the embodiments can also be combined with each other. Also, the various features of the different embodiments can be implemented independently, but the features of the different embodiments can also be combined with each other.

10 Main body 20, 20A, 20B, 20C, 20D, 20E Blood pressure measurement cuff 21 Outer cloth 31 Pressure sensor 32 Pump 37, 37a to 37g, 38 Air piping 100 Sphygmomanometer 210, 210A, 210B First air bag 211, 211A, 211B Outer air bag 212, 212', 212A, 212B Inner air bag 220 Second air bag 280, 280L Damper layer

Claims (9)

A blood pressure measurement cuff that compresses a measurement site to block blood flow,
A belt-shaped outer cloth surrounding the measurement site;
a first air bag provided along a surface of the outer cloth facing the measurement site and facing a specific closed region of the measurement site;
The first air bag is
an outer air bag having, within a plane along the outer fabric, a first shape corresponding to the entirety of the specific closed region or an annular second shape corresponding to an outer peripheral region of the specific closed region;
an inner air bag disposed inside the outer air bag having the first shape, corresponding to an inner area surrounded by an outer peripheral area of the specific closed area, or in an empty area surrounded by a ring of the outer air bag having the second shape,
a damper layer provided along a surface of the first air bag facing the measurement site and configured to damp vibrations;
a second air bag that is provided along a surface of the damper layer facing the measurement site and corresponds to a central region of the specific closed region that occupies a portion of the specific closed region that includes the center of the internal region, and detects pulse wave information based on a pulse wave from a portion of an artery that passes through the specific closed region and is present in the central region. 2. The blood pressure measurement cuff according to claim 1,
The damper layer is
a central segment provided in a plane along the outer fabric and corresponding to the second air bag;
A blood pressure measurement cuff characterized in that it has a triplet structure including an upstream segment and a downstream segment each connected to the central segment, the upstream segment and the downstream segment each extending from the central segment to both edges of the first air bag in a width direction perpendicular to the longitudinal direction surrounding the measurement site. 3. The blood pressure measurement cuff according to claim 2,
A blood pressure measurement cuff characterized in that, relative to the outer air bag, the inner air bag, the central segment of the damper layer, and the second air bag are positioned downstream along the direction in which the artery passes within the specific closed area. 2. The blood pressure measurement cuff according to claim 1,
a shape and a size of the damper layer are set to be the same as a shape and a size of the second air bag, in a plane along the outer fabric,
A blood pressure measurement cuff characterized in that the inner air bag, the damper layer and the second air bag are positioned within the specific closed area, biased toward the downstream side along the direction in which the artery passes, relative to the outer air bag. 2. The blood pressure measurement cuff according to claim 1,
the outer bladder has the second shape;
the inner air bag is disposed in the void space surrounded by the ring of the outer air bag,
a cuff for measuring blood pressure, characterized in that the inner peripheral edge of the outer air bag and the outer peripheral edge of the inner air bag adjacent to the inner peripheral edge have bellows shapes that correspond to each other in the thickness direction perpendicular to the outer cloth, and are fitted together. 2. The blood pressure measurement cuff according to claim 1,
the outer bladder has the second shape;
the inner air bag is disposed in the void space surrounded by the ring of the outer air bag,
A blood pressure measuring cuff characterized in that the inner peripheral edge of the outer air bag and the outer peripheral edge of the inner air bag adjacent to the inner peripheral edge are welded to each other entirely or partially along the ring. 7. The blood pressure measurement cuff according to claim 6,
within a plane along the outer cloth, an inner peripheral edge of the outer air bag and an outer peripheral edge of the inner air bag are each formed in a rectangular shape with rounded corners along the ring, and include a side that intersects with the artery and passes through the specific closed region, and a side that is distant from the artery,
a side of the inner peripheral edge of the outer air bag away from the artery and a side of the outer peripheral edge of the inner air bag away from the artery are partially welded to each other, while a side of the inner peripheral edge of the outer air bag that intersects with the artery and a side of the outer peripheral edge of the inner air bag that intersects with the artery are spaced apart from each other. The blood pressure measurement cuff according to any one of claims 1 to 7,
an air pipe for supplying air to the outer air bag, the inner air bag, and the second air bag is connected to each of the air pipes;
The blood pressure measuring cuff is characterized in that the air pipes are connected to each other in a manner that allows air to flow between them via a filter that attenuates pulse waves. A blood pressure monitor that measures blood pressure by compressing a measurement site,
A blood pressure measurement cuff according to any one of claims 1 to 8,
a pressure control unit that supplies air to the second air bag, the outer air bag, and the inner air bag through air piping from a pump provided outside the blood pressure measurement cuff, thereby controlling the pressing force applied to the specific closed area;
a pressure detection unit that detects the pressure of the second air bag;
and a blood pressure calculation unit that calculates blood pressure by an oscillometric method based on an output from the pressure detection unit.

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