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Title:
A BLOOD PRESSURE METER AND CUFF
Document Type and Number:
WIPO Patent Application WO/2015/122100
Kind Code:
A1
Abstract:
A blood pressure cuff according to the present invention includes: an occlusion component configured to occlude an artery; and a compliance fluid bag that contains an incompressible fluid and that overlies the occlusion component, wherein the compliance fluid bag, with respect to a width direction of the occlusion component, overlaps with the occlusion component at least on an upstream side of the artery from a center of a width of the occlusion component, the width of the occlusion component being a length of the occlusion component along an axis around which the blood pressure cuff is placed.

Inventors:
ALTINTAS, Ersin (7-1 Shiba 5-chome, Minato-k, Tokyo 01, 10880, JP)
KUBO, Masahiro (7-1 Shiba 5-chome, Minato-k, Tokyo 01, 10880, JP)
ABE, Katsumi (7-1 Shiba 5-chome, Minato-k, Tokyo 01, 10880, JP)
TAKOH, Kimiyasu (7-1 Shiba 5-chome, Minato-k, Tokyo 01, 10880, JP)
IMAI, Hiroshi (7-1 Shiba 5-chome, Minato-k, Tokyo 01, 10880, JP)
OHNO, Yuji (7-1 Shiba 5-chome, Minato-k, Tokyo 01, 10880, JP)
TOCHIKUBO, Osamu (3-9-1 Fukuura, Kanazawa-ku, Yokohama-sh, Kanagawa 04, 23600, JP)
Application Number:
JP2014/083489
Publication Date:
August 20, 2015
Filing Date:
December 11, 2014
Export Citation:
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Assignee:
NEC CORPORATION (7-1 Shiba 5-chome, Minato-ku Tokyo, 01, 10880, JP)
International Classes:
A61B5/022
Domestic Patent References:
WO2011059429A12011-05-19
Foreign References:
US3527204A1970-09-08
US20100106029A12010-04-29
US20090163823A12009-06-25
US20100292587A12010-11-18
US20100106029A12010-04-29
US6969356B22005-11-29
Other References:
THOMAS G. PICKERING ET AL.: "Recommendations for blood pressure measurement in humans and experimental animals. Part 1: Blood pressure measurement in humans: A statement for professionals from the subcommittee of professional and public education of the American Heart Association council of high blood pressure research", CIRCULATION, vol. 111, 2005, pages 697 - 716, XP055145015, DOI: doi:10.1161/01.CIR.0000154900.76284.F6
M. RAMSEY: "Blood pressure monitoring: Automated oscillometric devices", J. CLIN. MONIT., vol. 7, 1991, pages 56 - 67, XP009180620
Attorney, Agent or Firm:
MIYAZAKI, Teruo et al. (11F Toranomon-Twin-Building West, 10-1 Toranomon 2-chome, Minato-k, Tokyo 01, 10500, JP)
Download PDF:
Claims:
[CLAIMS]

1 . A blood pressure cuff comprising:

an occlusion component configured to occlude an artery; and a compliance fluid bag that contains an incompressible fluid and that overlies said occlusion component,

wherein said compliance fluid bag, with respect to a width direction of said occlusion component, overlaps with said occlusion component at least on an upstream side of said artery from a center of a width of said occlusion component, said width of said occlusion component being a length of said occlusion component along an axis around which said blood pressure cuff is placed.

2. The blood pressure cuff according to claim 1 , wherein:

when, regarding said width of said occlusion component, a center position of the width is defined as 0% and each of positions of two ends of the width is defined as 50%, a portion of an entire overlap of said occlusion component and said compliance fluid bag or the entire overlap thereof being in the range of 15% to 50% of the upstream side of said artery in said width direction of said occlusion component.

3. The blood pressure cuff according to claim 2, wherein a portion of overlap of said occlusion component and said compliance fluid bag is equal to or greater than 10% of an entire width of said occlusion component.

4. The blood pressure cuff according to any one of claims 1 to 3, wherein:

when, taking said blood pressure cuff as a reference, it is defined that a surface at which said blood pressure cuff contacts a subject is an inside and that an opposite side of said surface is an outside, and said compliance fluid bag is arranged on the outside of said occlusion component.

5. The blood pressure cuff according to any one of claims 1 to 3, wherein:

when, taking said blood pressure cuff as a reference, it is defined that a surface at which said blood pressure cuff contacts a subject is an inside and that an opposite side of said surface is an outside, and

said occlusion component is arranged on the outside said compliance fluid bag.

6. The blood pressure cuff according to any one of claims 1 to 5, further comprising:

a pulse wave detection component provided between said compliance fluid bag and a subject for measuring arterial pulse waves.

7. The blood pressure cuff according to any one of claims 1 to 6, comprising:

a plurality of compliance fluid bags,

wherein at least one compliance fluid bag from among said plurality of compliance fluid bags overlaps with said occlusion component on said upstream side.

8. The blood pressure cuff according to claim 4, further comprising: a flexible hard support arranged on the outside of said compliance fluid bag.

9. The blood pressure cuff according to claim 5, further comprising: a flexible hard support arranged on the outside of said occlusion component.

10. The blood pressure cuff according to claim 4 or 5, further comprising:

an occlusion support component provided on the inside or outside of said occlusion component, at said upstream side of said artery in said width direction of said occlusion component,

wherein said occlusion support component is connected so as to allow input of air to said occlusion component or output of said air from said occlusion component.

1 1 . The blood pressure cuff according to claim 7, further comprising:

a plurality of said compliance fluid bags,

wherein said plurality of compliance fluid bags are arranged separated on said upstream side and said downstream side with respect to said width direction of said occlusion component.

12. The blood pressure cuff according to claim 1 1 , wherein:

said plurality of compliance fluid bags are connected through a flexible sheet or configured on a flexible sheet.

13. The blood pressure cuff according to any one of claims 1 to 12, wherein said occlusion component is an inflatable/deflatable bag with air.

14. A blood pressure meter including a blood pressure cuff in any one of claims 1 to 13.

Description:
[DESCRIPTION]

[Title of Invention]

A BLOOD PRESSURE METER AND CUFF

[Technical Field]

[0001 ] This invention is related to a blood pressure meter and cuff.

[Background Art]

[0002] Blood pressure is one of the vital signs (i.e. blood pressure, breathe, temperature, heart pulse etc.) in humans or animals, and it is one of the strongest parameters to monitor and to diagnose the medical conditions and the diseases such as heart diseases and hypertension. For a reliable medical evaluation and treatment, blood pressure measurement accuracy less than ± 5 mmHg is necessary from a body portion. Since, the blood pressure value is strongly dependent on the vertical distance from the heart level; blood pressure measurement from upper arm at the level of heart is universally recognized by medical professionals for a more reliable and accurate measurement. This is generally achieved by a structure called "cuff, which is wrapped (or placed) around upper arm of human.

[0003] Usual cuffs are composed of bags or bladders inflated/deflated (or pressurized/depressurized) by air through a pressure control unit. In order to measure the blood pressure, there can be different methods such as detection of Korotkoff sounds usually achieved by a stethoscope by medical professionals, oscillometric techniques detecting the oscillations in the inflatable air bag due to pressure oscillations caused by artery, and techniques depending on Doppler Effect. Korotkoff sounds and oscillometric detections are widely accepted and employed in commercial blood pressure monitors, meters or devices (i.e. sphygmomanometer). In the case of automatic or electronic blood pressure meter, oscillometric methods are usually employed due to its improved signal to noise ratio capabilities. Furthermore, this method allows visualizing blood pressure wave or pulse wave, and it improves the medical evaluation of a subject.

[0004] The cuff size for an upper arm type blood pressure monitor is an important consideration. The ideal cuff should have a bag width at least 40% of the arm circumference, and double of the width is recommended for the length of the bag. For a small adult with an arm circumference of 22 to 26 cm, 12 cm bag width is recommended, while for a standard adult with an arm circumference of 27 to 34 cm (or more), 16 cm bag width is recommended [NPL 1 , page 705], However, these considerations are probably based on cuffs composed of single air bag (bladder) suffering from cuff-edge problems.

[0005] A cuff with a bag having 12 cm width is used in most of the medical checks. These checks are usually fast and less than 5 minutes. Even though, comfortability is not an issue during medical checks, a cuff width around 12 cm is not comfortable for daily uses and/or for continuous blood pressure measurements, i.e. ambulatory blood pressure measurement (ABPM). It is a known fact that blood pressure measurement results can be affected by white-coat hypertension and cause erroneous results and treatments. The blood pressure measurements out of hospitals, at homes or during daily life are recommended for more reliable results especially to predict the risks of cardiovascular events and to diagnose the white-coat hypertension [NPL 1 ]. However, current cuffs have large width and they are stressful to the user during daily life. A smaller cuff width without sacrificing the accuracy is appreciated for daily life measurements and it remains as a problem.

[0006] Mercury type upper arm blood pressure monitor has been accepted as a gold standard [NPL 1 ] . Typical commercially available cuff of mercury type blood pressure monitor has a bag width around 12 cm, and its cross section on a body portion (e.g. an arm or leg) of human (or animal) is shown in FIG. 28 with a scene 10. The FIG. 28 shows a pressurized cuff cross-section along an axis around which the cuff is wrapped, where an occlusion component 11 , a typically air-inflatable bag, is wrapped around an axis or a body portion of arm or leg 12 (of human or animal). The side near to the heart 13 is called as upstream side (or proximal) arid the side near to the hand or foot is called as downstream side (or distal). Occlusion component 11 is used to occlude the underlying artery 14 and to measure blood pressure by pressure oscillations. Blood flow 15 in the artery is blocked by the pressurized occlusion component 11.

[Citation List] [Patent Literature]

[PTL 1] US 2010/0106029 Al

[PTL 2] US 6969356 B2

[Non Patent Literature]

[NPL 1] Thomas G. Pickering et al., "Recommendations for blood pressure measurement in humans and experimental animals. Part 1 : Blood pressure measurement in humans: A statement for professionals from the

subcommittee of professional and public education of the American Heart Association council of high blood pressure research", Circulation, 111, 697-716, 2005

[NPL 2] M. Ramsey, "Blood pressure monitoring: Automated oscillometric devices", J. Clin. Monit., 7, 56-67, 1991

[Summary of Invention]

[Technical Problem]

[0007] During the pressurization of the cuff, however, the heart continues to pump the blood and it hits to the walls of the occluded artery under the cuff. The blood flow from the heart side reflects back and causes upstream flows 16 in the proximal side. The cuff under the pressurization resembles an ellipsoid in cross-section, and it loses the efficiency of the contact with skin at the edges. This is known as cuff-edge effect 17. It causes a non-uniform pressure distribution 18 over the artery, and it causes a partial occlusion or a narrower occlusion of the artery 19 around the center of the cuff. Due to cuff-edge effects 17, the effective occlusion width is smaller than that of the cuff along the axis around which the cuff is wrapped.

[0008] The object of the present invention is to reduce

significantly the foregoing problem and to enable smaller cuff width leading to relatively more comfortable and compact wearable medical devices.

[Solution to Problem]

[0009] A blood pressure cuff includes: an occlusion component configured to occlude an artery; and a compliance fluid bag that contains an

incompressible fluid and that overlies the occlusion component, wherein the compliance fluid bag, with respect to a width direction of the occlusion component, overlaps with the occlusion component at least on an upstream side of the artery from a center of a width of the occlusion component, the width of the occlusion component being a length of the occlusion component along an axis around which the blood pressure cuff is placed.

[Advantageous Effects of Invention]

[0010] The blood pressure cuff according to the present invention can reduce cuff-edge effect which enables smaller cuff width with potentials of more comfortable medical devices.

[Brief Description of Drawings]

[Fig. 1 A] The structure of the blood pressure meter with a single fluidic connection to the blood pressure cuff;

[Fig. I B] The structure of the blood pressure meter with multiple fluidic connections to the blood pressure cuff;

[Fig. 2] Top views of the first embodiment of the blood pressure cuff;

[Fig. 3] A cross-sectional view of the first embodiment of the blood pressure cuff along an axis, around which the cuff is wrapped;

[Fig. 4] An experimental results of the pressure distribution of a cuff air bag along an axis, around which the cuff is wrapped, with and without a compliance fluid bag (or a compliance enhancer);

[Fig. 5] A cross-sectional view of the second embodiment of the blood pressure cuff along an axis, around which the cuff is wrapped;

[Fig. 6] A cross-sectional view of the second embodiment of the blood pressure cuff along an axis, around which the cuff is wrapped;

[Fig. 7] Another cross-sectional view of the second embodiment of the blood pressure cuff along an axis, around which the cuff is wrapped;

[Fig. 8] A cross-sectional view in a pressurized condition of the second embodiment of the blood pressure cuff set up to upper arm; (however, artery is open for simpler visualization)

[Fig. 9] A cross-sectional view in a pressurized condition of the second embodiment of the blood pressure cuff set up to upper arm, where compliance fluid bag can contain multiple bags; (however, artery is open for simpler visualization)

[Fig. 10] A cross-sectional view of a third embodiment of the blood pressure cuff where a pulse wave detection component is positioned under the compliance fluid bag at the downstream side;

[Fig. 1 1 ] A cross-sectional view of fourth embodiment of the blood pressure cuff where the occlusion component at the top of compliance fluid bag towards a body portion is supported at the bottom at the upstream side by an occlusion support component through a fluidic connection;

[Fig. 12] A cross-sectional view of the fourth embodiment of the blood pressure cuff where the occlusion component supported at the bottom at the upstream side by attaching an occlusion support component;

[Fig. 13] A cross-sectional view of the fourth embodiment of the blood pressure cuff where the occlusion component is supported by attaching an occlusion support component in a direct contact with the body portion of the subject;

[Fig. 14A] A cross-sectional view of the compliance fluid bag(s) with and without flexible sheet;

[Fig. 14B] A cross-sectional view of the compliance fluid bag(s) with and without flexible sheet;

[Fig. 14C] A top view of the compliance fluid bag(s);

[Fig. 14D] A top view of the compliance fluid bag(s);

[Fig. 15 A] 3D configuration of the flexible sheets in a compliance fluid bag; [Fig. 15B] 3D configuration of the flexible sheets in a compliance fluid bag;

[Fig. 16] A cross-sectional view of fifth embodiment of the blood pressure cuff along the axis around which the cuff is wrapped;

[Fig. 17] A cross-sectional view of the sixth embodiment of the blood pressure cuff along the axis around which the cuff is wrapped;

[Fig. 1 8] A cross-sectional view of the seventh embodiment of the blood pressure cuff along the axis around which the cuff is wrapped;

[Fig. 19] A cross-sectional view of the eighth embodiment of the blood pressure cuff along the axis around which the cuff is wrapped;

[Fig. 20] A cross-sectional view of the ninth embodiment of the blood pressure cuff along the axis around which the cuff is wrapped; [Fig. 21 ] A cross-sectional view of the tenth embodiment of the blood pressure cuff along the axis around which the cuff is wrapped;

[Fig. 22] A cross-sectional view of the eleventh embodiment of the blood pressure cuff along the axis around which the cuff is wrapped;

[Fig. 23A] A cross-sectional view of Working Example 1 of the twelfth embodiment of the blood pressure cuff along the axis around which the cuff is wrapped;

[Fig. 23B] A cross-sectional view of Working Example 2 of the twelfth embodiment of the blood pressure cuff along the around axis around which the cuff is wrapped;

[Fig. 23C] A cross-sectional view of Working Example 3 of the twelfth embodiment of the blood pressure cuff along the axis around which the cuff is wrapped;

[Fig. 23D] A cross-sectional view of Working Example 4 of the twelfth embodiment of the blood pressure cuff along the axis around which the cuff is wrapped;

[Fig. 24] A cross-sectional view of the thirteenth embodiment of the blood pressure cuff along the axis around which the cuff is wrapped;

[Fig. 25A] A cross-sectional view of the prototype blood pressure cuff used in experimentation;

[Fig. 25B] An external schematic view showing the state of measuring blood pressure;

[Fig. 26A] A pie chart showing the overall measurement accuracy of the results of blood pressure measurement by means of the prototype;

[Fig. 26B] A pie chart showing the SBP measurement accuracy measured by means of the prototype;

[Fig. 26C] A pie chart showing the DBP measurement accuracy measured by means of the prototype;

[Fig. 27] A bar graph showing the measurement accuracy of the prototype, a reference blood pressure cuff, and a comparative example; [Fig. 28] A pressurized cross-sectional view of a commercial cuff air bag along an axis, around which the cuff is wrapped;

[Description of Embodiments]

[001 1 ] Exemplary embodiments for carrying out the present invention will be described using drawings in the following. However, although exemplary technical limitations for carrying out the present invention are applied to the exemplary embodiments described below, the scope of the invention is not limited to below.

[0012] The structure of the blood pressure meter 150 is shown in FIG. 1 A and I B, with a single fluidic connection 153 and multiple fluidic

connections 153, 154 to the blood pressure cuff 152. The blood pressure meter 150 is composed of a measurement unit 155 and a blood pressure cuff 152. The blood pressure cuff 152 is set up on a body portion of a subject 151, where blood pressure measurement is going to be done. The measurement unit 155 composes a pressurization and depressurization unit 156, blood pressure measurement unit 157, a control and operation unit 158 and a display unit 159. The pressurization and depressurization unit 156 can contain necessary pump(s), valve(s) and fluidic components to pressurize and depressurize the blood pressure cuff 152, and the blood pressure measurement unit 157 can contain a pressure sensor (or sensors). In FIG. 1 A, pressurization and depressurization unit 156 is connected to the blood pressure cuff 152 through a fluidic single connection 153. The measurement is achieved by blood pressure measurement unit 157 through fluidic connection 160. Pressurization and depressurization unit 156 and blood pressure measurement unit 157 are in electronic communication with control and operation unit 158. The control and operation unit 158 provides saving, processing of the measured signals and the control of overall device with the help of CPU (Central Processing Unit), ROM (Read Only Memory) and RAM (Random Access Memory) elements in itself. The results are displayed in the display unit 159 though LED (Light Emitting Diode) or LCD (Liquid Crystal Display) monitor or like. In FIG. I B, it is shown another possibility where blood pressure cuff 152 is connected to the measurement unit through multiple fluidic connections 153, 154. In FIG. I B, pressurization and depressurization unit 156 is connected to the blood pressure cuff 152

through a fluidic connection 153, and blood pressure measurement unit 157 is connected to the blood pressure cuff 152 through a fluidic connection 154. These both units 156 and 157 are in communication through a fluidic connection 160. Even though it is not shown in the figure, an energy unit is included in control and operation unit 158.

[First exemplary embodiment]

[0013] The blood pressure cuff 100 according to the first exemplary embodiment is shown in FIG. 2 and 3. FIG. 2 is a top view of the blood pressure cuff. The occlusion component 101 has a smaller or equal width to that of compliance fluid bag 102 along the axis around which the cuff is wrapped or placed. Compliance fluid bag 102 can have a length smaller or bigger than the length of the occlusion component 101 along the

circumference of the blood pressure measurement site of a subject such as an arm or a leg (of human or animal). The length of the occlusion

component 101 can be from half of the circumference of the body portion to the full of the body portion. It should apply enough pressure on artery to block the blood flow. It is recommended to be 80% of the circumference of the body portion (NPL 1 ). The length of the compliance fluid bag 102 around the circumference of the body portion can be around 40% of the circumference or bigger than the length of the occlusion component 101. However, it is recommended to have a bigger length than that of the occlusion component 101.

[0014] The cross-section of the invented cuff is illustrated along an axis around which the cuff is wrapped in FIG. 3. FIG. 3 shows a pressurized cuff 100, where an occlusion component 101, is wrapped around an axis of a body portion of a subject such as arm or leg 103 (of human or animal).

[0015] Occlusion component 101 can be electrically actuated polymer material, or it can be pressurized/depressurized by a liquid, or a typical (gas or) air-inflatable bag which is most commonly used can be employed. Due to practicality, air pressurized/depressurized (inflatable/deflatable) occlusion component (i.e. a bag or a bladder) is preferable.

[0016] Compliance material (compliance fluid bag) 102 is under the occlusion component 101 toward a body portion of a subject 103 and it provides a more proper compliance between the body portion of a subject 103 and the occlusion component 101. That is, compliance fluid bag 102 has a function of a compliance enhancer. The width of compliance fluid bag 102 is equal to or larger than that of the occlusion component 101 along the axis around which the cuff is wrapped. The width of compliance fluid bag 102 can be as large as 150% of that of occlusion component 101.

[0017] The width of the occlusion component 101 under pressurization is shown as wl . The elongations of the compliance fluid bag 102 at upstream side and downstream side under pressurization can be equal to or bigger than zero. Although, it is not mentioned in detail, it is possible to use multiple compliance fluid bags under the occlusion component 101. In this case, with or without overlaps between compliance fluid bags, it is appreciated that the outermost width, i.e. the distance from proximal side to distal side of the compliance fluid bags under the occlusion component 101 is equal to or larger than the width of occlusion component 101 along said axis. By doing this, the influences of hydraulic pressure difference and/or gravitational influences at the upstream and downstream side in a blood pressure cuff due to liquid content in the compliance fluid bags can be reduced to some extent, and blood pressure measurement errors can be decreased.

[001 8] The side near to the heart 104 is upstream side (or proximal) and the side near to the hand or foot is downstream side (or distal). Occlusion component 101 is used to occlude the underlying artery 105. Blood flow 106 in the artery is blocked by the pressurized occlusion component 101.

[0019] During the pressurization of the cuff, however, the heart continues to pump the blood and it hits to the walls of the occluded artery under the cuff. The blood flow from the heart side reflects back and causes upstream flows 107 in the proximal side. The cuff under the pressurization resembles an ellipsoid in cross-section, and it loses the efficiency of the contact with skin at the edges. This is known as cuff-edge effect 17 (FIG. 28). However, in this design, the compliance bag improves the compliance between the occlusion component 101 and the body portion of the subject 103. This leads to reduced cuff-edge effect 108, and a more uniform pressure distribution 109 on the artery under the cuff. This more uniform pressure distribution can be effectively transmitted to the artery underlying and the artery 105 is occluded 110. This approach provides a possible way to cut the insufficient cuff-edge to reduce the width of the cuff along the axis around which the cuff is wrapped, without sacrificing the accuracy of the measurement.

[0020] The compliance fluid bag 102 improves the compliance between the occlusion component 101 and the body portion of the subject 103. The compliance fluid bag 102 can be encapsulated by a fluid or not. But, an encapsulated compliance fluid bag is preferable to improve the practicality. To improve the compliance, the incompressible fluids such as liquids or gels are preferable.

[0021 ] Flexible bag materials such as polyethylene, polyvinyl chloride, or latex free plastics are preferable.

[0022] Elastic or expandable materials for bags are considerable too, especially for compliance fluid bag 102. It is such that the width of the compliance fluid bag along the axis around which the cuff is wrapped can be smaller than the width of the occlusion component. During the pressurization, it elongates or expands along the axis around which the cuff is wrapped. It is appreciated that during data measurement, the width of the compliance fluid bag 102 is equal to or larger than that of occlusion component 101.

[0023] The interface 113 can contain adhesives or double-sided adhesive layer to fix the occlusion component 101 to the compliance fluid bag 102 for a more stable operation. The interface 112 between compliance fluid bag 102 and the body portion of a subject 103 can contain a textile cover (not shown) to cover the blood pressure cuff.

[0024] Next, our experimental measurement result will be described. The measurement is achieved by the cuff with and without a compliance fluid bag (or a compliance enhancer). The measurement is achieved by a flexible force sensor with a 1 cm diameter on 8 points along the axis around which the commercial cuff is wrapped. FIG. 4 provides data with and without a compliance fluid bag. The commercial cuff has an approximate width of 13.5 cm including the textile cover. The data show that at the edges of the cuff, the pressure is low and it is relatively uniform around the center. The pressure value measured from force sensor is scaled to the percentage of the output of the sensor, when 200 mmHg is read from mercury indicator of commercial blood pressure meter. (The cuff is clamped between 2 flat plates larger than the cuff and the force sensor is positioned on the cuff.) If we assume 75% (or 3/4) of the mercury indicator (i.e. 150 mmHg) is not sufficient to occlude artery for a reliable measurement, then roughly 4 to 5 cm portion in total from the edges (corresponding one third of the cuff) seems not provide a enough pressure to the artery under the cuff. Although this width with this pressure distribution characteristic in typical cuffs is tolerable, decreasing the width enhances cuff-edge effect, and this will probably cause erroneously high readings [NPL 2] due to probably incompletely and/or non-uniformly transmitted pressure to the artery under a narrower cuff (or mis-cuffing). Therefore, if the pressure can be

completely or uniformly transmitted to or distributed over the artery under the cuff by reducing those cuff-edge effects, smaller cuff width for standard adults is realizable and applicable with enough measurement accuracy.

[0025] FIG. 4 shows additional experimental data. Square dots on the graph show pressure distribution along the width of a compliance fluid bag (a compliance enhancer) which is positioned on the occlusion component 101. Actually, it is placed on the textile cover on the commercial cuff. The compliance enhancer was a water-encapsulated bag in this preliminary experiment, and it is approximately 15 cm in width, which is larger than the commercial cuff. In the experiment, water is used due to its availability and simplicity. However, any liquids or gels are possible. The force sensor is positioned on the compliance enhancer placed on the commercial cuff, and the experiment is repeated. FIG. 4 shows that compliance fluid bag achieved enhancement in the pressure distribution uniformity compared to without compliance fluid bag case, where fittings show a clear reduction of cuff-edge effects. For example, force sensor readings at positions

corresponding to the 6% and 94% of the commercial cuff width (i.e. edges) have been enhanced approximately 2 and 4 times, respectively, thanks to a compliance fluid bag (or a compliance enhancer). These results imply that by using a compliance enhancer toward a body portion of a subject to measure blood pressure, it is possible to reduce cuff width by keeping enough pressure uniformity over the artery for occlusion, which seems not possible with commercial cuffs. This approach can lead to reduced mis-cuffing experiences in hospitals or emergencies, more comfortable blood pressure meters and ABPMs with high accuracy of blood pressure measurement.

[0026] Referring now to the graph of FIG. 4, features shared by the blood pressure cuffs of the first and second exemplary embodiments and the third to fourteenth exemplary embodiments (to be described hereinbelow) will next be described.

[0027] The characteristic feature of the blood pressure cuff of the present invention is the overlapping of the occlusion component and the compliance fluid bag. The overlapping of the occlusion component and compliance fluid bag refers to a state in which there is at least a portion in which the occlusion component and the compliance fluid bag overlap in the direction substantially perpendicular to the surface of contact of the measurement subject. The compliance fluid bag may be layered over the occlusion component, or the occlusion component may be layered over the compliance fluid bag. Additionally, the overlapping of the occlusion component and compliance fluid bag includes a case in which an incompressible component material is provided between the occlusion component and compliance fluid bag, such as the third exemplary embodiment which will be described.

[0028] Referring to FIG. 4, the sensor output value is high when the position of the sensor is in a range of from 6% to 35% and in a range of from 65% to 94%. In this experiment, the sensor is not provided at positions of 0% and 100%, but based on the graph of FIG. 4, it can be predicted that the pressure will improve compared to cases in which there is no compliance fluid bag at the positions of 0% and 100%. [0029] If the central position of the occlusion component in the axial direction around which the blood pressure cuff is wrapped is redefined as 0% and if the positions at both ends of the occlusion component are redefined as 50%, it can be seen that in the range of from 15-50%, the effect of improving the occlusion characteristic is high when the fluid bag overlaps with the occlusion component over 10% or more of the entire width of the occlusion component. If the fluid bag and occlusion component thus overlap in a portion, an improvement of the occlusion characteristic of the end portions of the occlusion component can be achieved.

[0030] The reason that the above-described effect is obtained by means of the overlap of the occlusion component and the fluid bag is next explained.

[003 1 ] When air is introduced into the occlusion component, the occlusion component expands to a shape such that the cross section of the bag assumes an elliptical shape due to the tension of the bag. In other words, the central portion expands greatly, and the end portions expand to a lesser degree. At this time, the change in the shape of the occlusion component causes the fluid within the fluid bag to move. The movement of the fluid proceeds in a direction such that pressure between the measured site and the occlusion component becomes uniform.

[0032] If, for example, the fluid bag is not present, the large expansion of the central portion of the occlusion component and the slight expansion of the end portions causes the pressure between the measured site and the cuff to increase in the central portion due to the close contact between the measured site and the occlusion component, but causes the pressure to decrease in the end portions due to poor contact. If the fluid bag is present, the fluid moves from the central portion in which pressure is high to the end portions where the pressure is low. When the fluid moves to the end portions, the close contact between the occlusion component and the measured site improves and the pressure in the vicinity of the end portions improves. As previously described, the fluid moves from portions in which pressure between the occlusion component and the measured site is high and toward portions in which the pressure is low. Accordingly, the movement of fluid is continually generated such that pressure imbalance is minimized, whereby imbalance in pressure is reduced.

[0033] Effects resulting from differences in the content of the occlusion component and the fluid bag are next described.

[0034] The content of the fluid bag is preferably an incompressible fluid (such as liquid, gel or micro-solid).

[0035] If the content of the fluid bag is an incompressible fluid, the volume of the fluid bag will be virtually unchanged by outside pressure. As a result, despite increase of the compression pressure applied to a measured site, the close contact between the occlusion component and the measured site can be improved with virtually no decrease of the volume of the fluid bag. Accordingly, imbalances of pressure can be more effectively decreased.

[0036] On the other hand, the content of the occlusion component is preferably air.

[0037] Because air has low viscosity, fluid resistance is limited despite the introduction and expulsion of large volumes of air. Accordingly, the pressure inside the bag can be uniformly and accurately controlled even when pressurizing or depressurizing the occlusion component. In addition, when the content of the fluid bag is an incompressible fluid, unbalanced pressurization that results from insufficient contact between the occlusion component and the measured site can be effectively eliminated. Accordingly, the pressure that is applied to the measured site can be accurately controlled, whereby the accuracy of blood pressure measurement can be improved.

[0038] In addition, when the content of the occlusion component is air and the content of the fluid bag is an incompressible fluid, the flow of blood to an occluded site only results in a change of the volume inside the occlusion component without variation of the volume of the fluid bag. As a result, the S/N of volume fluctuation of the occlusion component due to the flow of blood is improved. Accordingly, pulse waves can be accurately detected, and the accuracy of blood pressure measurement is improved.

[0039] Results of experimentation showing an improvement of the accuracy of blood pressure measurement due to the blood pressure cuff of an embodiment of the present invention will be described hereinbelow.

[0040] US patent no 2010/0106029 Al [PTL 1 ] mentions about a liquid bag in its cuff structure. However, liquid bag width is smaller than the width of the cuff (or occlusion component) along the axis around which the cuff is wrapped, and it is used to improve the mechanical coupling between cuff and the pulse wave in the arteries. In our design, the liquid bag (or compliance fluid bag) has an equal or a bigger width than that of the occlusion component; and its purpose is to improve the compliance and to eliminate or to reduce to cuff-edge effects.

[0041 ] US patent no 6969356 B2 [PTL 2] mentions a liquid component in its cuff structure to improve the compliance. However, it is just a portion of the entire cuff, and it aims the downside portion of the cuff in a body portion such as ankle of a leg. The liquid just provides compliance in a limited portion, and the width is around the size of small bag which measures the pulse wave. In our design, the liquid (or compliance fluid bag) cover the spaces under the occlusion component with an improved reduction of cuff-edge effects.

[Second exemplary embodiment]

[0042] The blood pressure cuff 200 according to the second exemplary embodiment is shown in FIG. 5. The cross-section of the invented cuff is illustrated along an axis around which the cuff is wrapped in FIG. 5. FIG. 5 shows a pressurized cuff 200, where an occlusion component 201 , is wrapped around an axis of a body portion of a subject such as arm or leg 203 (of human or animal). In the blood pressure cuff 200, a flexible hard support 211 is further placed on an occlusion component and a compliance fluid bag. Other elements are the same as those of the blood pressure cuff 100 according to the first exemplary embodiment.

[0043] The freedom or the movement capability of the occlusion component 201 is limited between a flexible hard support 211, and the body portion of a subject 203. The flexible hard support 211 can be plastic materials with enough flexibility and hardness, e.g. a 1 mm PET sheet.

[0044] The interface 214 can contain adhesives or double-sided adhesive layer to fix the occlusion component to the flexible hard support 211 for a more stable operation.

[0045] The blood pressure cuff 200 according to the present exemplary embodiment can also reduce cuff-edge effect.

[0046] An example of the second embodiment of the blood pressure cuff is shown in FIG. 6, where occlusion component 201 can be placed in the compliance fluid bag 222. The occlusion component 201 can be fixed to the wall of the inner surface of the compliance fluid bag 222 at the interface 224 by an adhesive or by a double-sided adhesive layer, and the outer surface compliance fluid bag 222 can be fixed to the flexible hard support 211 by a similar way.

[0047] Another example of the second embodiment of the blood pressure cuff is shown in FIG. 7. In this embodiment, compliance fluid bag 232 is composed of 2 bags; an inner bag (i.e. occlusion component 201) and outer bag. In the space between inner bag and the outer bag, a compliance fluid exists. At the interface 226, the compliance fluid bag 232 is fixed to the flexible hard support 211 by an adhesive or by a double-sided adhesive layer to improve the stability. The interface 227 is just the surface of the inner bag such that the inner bag has a freedom in motion in compliance fluid bag. In addition, it is possible to limit the motion of the inner bag along the axis around which the cuff is wrapped.

[0048] FIG. 8 shows a cross-sectional view in a pressurized condition of the second embodiment of the blood pressure cuff set up to upper arm. For a simpler visualization, artery 205 is illustrated as open near to the bone 215. The flexible hard support 211 is close to the circumference of the body portion of a subject 203. It may occupy 80% to 100% of the circumference of body portion 203. To fix the cuff on a body portion, a fastener 216 like a hook and loop fastener can be employed. The compliance fluid bag 202 longer than the occlusion component 201 along the circumference of the body portion 203 is preferable. Because, when the occlusion component 201 is pressurized, it compresses the compliance fluid bag and the fluid inside runs away to the edges. This leads to occlusion effect in those regions as well, which can be used to achieve effective occlusion length longer than the length of the occlusion component 201 as shown in FIG. 8. Consequently, the volume of the occlusion component and so the necessary air volume is reduced, and therefore we are able to achieve a miniaturized blood pressure meter and cuff compared to commercial ones. This will lead to less dependability on the pump specifications such as size and speed, and more compact and comfortable blood pressure meters or ABPMs are applicable, which increases the impact of this invention.

[0049] In the interfaces 213 and 214, as mentioned before, adhesives or double-sided adhesive layer can be employed to fix the parts for a stable operation. In addition, a textile cover can be used at the interface 212.

[0050] FIG. 9 shows an another cross-sectional view in a pressurized condition of the second embodiment of the blood pressure cuff set up to upper arm. The compliance fluid bag 202 can be divided into multiple bags similar to an example of 202-a, 202-b, and 202-c. The multiple bags can have different lengths, and the total length along the circumference of the body portion of a subject 203 can be bigger than that of the occlusion component 201. In the interfaces 213 and 214, as mentioned before, adhesives or double-sided adhesive layer can be employed to fix the parts for a stable operation. In addition, a textile cover can be used at the interface 212.

[Third exemplary embodiment]

[005 1 ] The third exemplary embodiment of the blood pressure cuff is shown in FIG. 10. A pulse wave detection component 223 is attached to the cuff of FIG. 5 composed of a flexible hard support 211 to limit the degree of the freedom of motion the components below of it, an occlusion component 201 to occlude the artery underlying and a compliance fluid bag 202 to improve the compliance. Although, it is not mentioned in detail, it is possible to use multiple compliance fluid bags under the occlusion component 201. In this case, with or without overlaps between compliance fluid bags, it is appreciated that the outermost width, i.e. the distance from proximal side to distal side of the compliance fluid bags under the occlusion component 201 must be equal to or larger than the width of occlusion component 201 along said axis. By doing this, the influences of hydraulic pressure difference and/or gravitational influences at the upstream and downstream side in a blood pressure cuff due to liquid content in the compliance fluid bags can be reduced to some extent, and blood pressure measurement errors can be decreased.

[0052] The third exemplary embodiment is different from the second exemplary embodiment in the pulse wave detection component 223 which is provided in the blood pressure cuff of the third exemplary embodiment.

[0053] A pulse wave detection component 223 can be an inflatable/deflatable bag with a gas or air, or a device or module to measure the blood pressure with an improved accuracy. The pulse wave detection component 223 can include a single sensor, or multiple sensors, or an array of sensors to measure the blood pressure. The pulse wave detection component 223 in FIG. 10 can be attached to the cuff composed of flexible hard support 211 , occlusion component 201 and the compliance fluid bag 202, or it can be positioned in the cuff, or it can be positioned near to the cuff on the body portion of a subject 203, along the axis around which the cuff is wrapped.

[0054] The pulse wave detection component 223 may be connected to an external pressure sensor, instead of having an internal pressure sensor. An inner pressure of the pulse wave detection component 223 is measured by the internal or external pressure sensor.

[0055] A preferable position for the pulse wave detection component 223 is under the compliance fluid bag 202 and occlusion bag 201 toward a body portion of a subject 203 at the downstream side to measure blood pressure more effectively and accurately (FIG. 10). A position close to the edge of the occlusion component 201 can be ideal position. This can improve the probability of the uniformity of the pressure distribution on the artery by positioning the pulse wave detection component 223 not near to the center but near to the edge. Because, the space between the compliance fluid bag 202 and the pulse wave detection component 223 on the body portion of a subject 203 may cause degradation of the uniform pressure distributions on those space such as the left and right edges of the pulse wave component 223. To improve the stability of the structure, an adhesive or a double-sided adhesive layer can be employed to fix the bag and the components at the interface 217. (Although it is not shown, an absorber material between compliance fluid bag and pulse wave detection component can be placed to absorb noise and vibrations transmitted through compliance fluid bag and/or occlusion component to improve the signal to noise ratio. Absorber material can be a plastic sheet, composite, porous material, foam, or an encapsulated fluid.)

[0056] The pulse wave detection component 223 is arranged at a position between the compliance fluid bag 202 and the subject 203, as shown in FIG. 10. By the compliance fluid bag, the pulse wave detection component is attached firmly to an object to be measured. Since the compliance fluid bag is not arranged at a position between the subject and the pulse wave detection component, the inner pressure of the pulse wave detection component is almost equal to a pressure which is applied on the the object to be measured. Therefore, the blood pressure can be determined accurately by referring to the inner pressure of the pulse wave detection component.

[0057] FIG. 10 shows a configuration in which the pulse wave detection component, the compliance fluid bag, the occlusion component and the flexible hard support are stacked vertically in order from the side closest to the subject, but the stacked order of these components is not limited to the configuration. For example, the pulse wave detection component, the occlusion component, the compliance fluid bag and the flexible hard support may be stacked vertically in order from the side closest to the subject. In this case, as shown in FIG. 10, it is preferable that the pulse wave detection component be placed between the compliance fluid bag and the subject, and between the occlusion component and the subject. By using this configuration, an accurate measurement of the pressure the object to be measured, can be made.

[0058] Furthermore, it is preferable that the volume of the pulse wave detection component is smaller than the volume of the occlusion component. If the volume of the pulse wave detection component is small, S/N (Signal to Noise) ratio of a change of the volume of the pulse wave detection component will be improved. Therefore, an arterial pulse can be detected accurately and the measurement accuracy of the blood pressure can be improved.

[0059] A width of the pulse wave detection component 223 smaller than the width of the occlusion component 201 along the axis around which the cuff is wrapped is appreciated. However, a width of 10% to 50% of occlusion component is preferable.

[0060] A pulse wave detection component can be any device composed of sensors. However, an inflatable/deflatable bag by a gas or air with pressure measuring ability is preferred. The material of the bag can be flexible materials such as plastics.

[Fourth exemplary embodiment]

[0061 ] The fourth exemplary embodiment of the blood pressure cuff with a further improved occlusion component cross-section along the axis around which the cuff is wrapped is illustrated in FIG. 1 1. An occlusion component 401-a is improved version of occlusion component 201 of FIG. 5. The function of the occlusion component 401-a is improved by an occlusion support component 401-b through a fluidic connection 401 -c. Under this structure, compliance fluid bag 202 toward the body portion of a subject 203 is configured. A pulse wave detection component 223 is configured under the compliance fluid bag toward the body portion of a subject to measure the blood pressure more effectively. (Although it is not shown, an absorber material between compliance fluid bag and pulse wave detection component can be placed to absorb noise and vibrations transmitted through compliance fluid bag and/or occlusion component to improve the signal to noise ratio. Absorber material can be a plastic sheet, composite, porous material, foam, or an encapsulated fluid.)

[0062] Occlusion support component 401-b is connected to the occlusion component 401-a through a fluidic connection 401-c (FIG. 11). The connection side is preferably at the bottom side of the occlusion component toward the body portion of a subject 203. The connection can be provided through a hole in the bags or a pipe. A through hole between bags can be created by circular sealing and opening the hole later. For example, a hot hole opening process by a sharp hot object (e.g. a solder gun) is possible and it opens the hole and seals the bag at the same time.

[0063] The occlusion support component 401-b supports or reinforces the occlusion of the artery underlying the cuff. It is configured to be positioned at the bottom of the occlusion bag 401-a and at the upstream side in FIG. 1 1 . As explained before, during the occlusion of the artery underlying the cuff, the heart continues to pump the blood. Blood flows hit to the walls of the occluded artery. This causes reflected blood flows at the upstream side of the artery and it degrades the accuracy of blood pressure measurement (207, FIG. 5). In this design, the influences of those upstreams are suppressed or reduced by using an occlusion support component 401-b.

[0064] It is preferred that the upstream side edge of occlusion support component 401-b is closer to heart than the upstream side edge of occlusion component 401-a along the axis around which the cuff is wrapped (FIG. 1 1 ). This may lead to a slight inclination of the occlusion support component 401-b along the axis mentioned above. This improves suppressing the upstreams further and improves the blood pressure measurement accuracy and/or signal to noise ratio.

[0065] The occlusion support component 401-b has a width smaller than the width of the occlusion component 401-a along the axis around which the cuff is wrapped. It is preferable that the total width of occlusion component 401-a and occlusion support component 401-b is equal to or smaller than the width of compliance fluid bag 202 in said axis.

[0066] The occlusion support component 401-b is preferably inflatable/deflatable bag by a gas or air through a fluidic connection 401-c through the occlusion component 401-a. A bag material with flexible characteristics such as plastics is preferable.

[0067] The occlusion support component 411 in FIG. 12 has similar functions and dimensions with the occlusion support component 401-b in FIG. 1 1 . The compliance fluid bag 202 is configured to be positioned under the occlusion component 401-a and the occlusion support component 411 toward the body portion of a subject 203. However, occlusion support component 411-b is non-fluidic, which means that it is not inflatable/deflatable. It can be flexible substance such as plastics, silicone rubber, porous plastics (e.g. sponge-like) or encapsulated fluids.

[0068] The occlusion support component 411 has a width smaller than the width of the occlusion component 401-a along the axis around which the cuff is wrapped. It is preferable that the total width of occlusion component 411 and occlusion support component 401-a is equal to or smaller than the width of compliance fluid bag 202.

[0069] It is preferred that the upstream side edge of occlusion support component 411 is closer to heart than the upstream side edge of occlusion component 411 along the axis around which the cuff is wrapped (FIG. 12). This may lead to a slight inclination of the occlusion support component 411 along the said axis. This improves suppressing or the reduction of the upstreams further and improves the blood pressure measurement accuracy and the signal to noise ratio.

[0070] The occlusion support component 421 in FIG. 13 has similar functions to the occlusion support component 401-b and 411 in FIG. 1 1 and FIG. 12, respectively. The occlusion support component 421 can have a direct contact to the body portion of a subject 203 without compliance fluid bag 202, and it is under the occlusion component 401-a toward a body portion of a subject 203. The compliance fluid bag 202 provides the compliance among the occlusion component 401-a, occlusion support component 421, pulse wave detection component 223, and the body portion of a subject 203. The occlusion support component 421 is not necessarily to be fluidic. It can be flexible substance such as plastics, silicone rubbers, porous plastics (e.g. sponge-like) or encapsulated fluids. (A fluidic bag connected to the occlusion component through a fluidic connection is possible too, similar to FIG. 1 1.)

[0071 ] The occlusion support component 421 in FIG. 13 is configured to be positioned under the occlusion component 401-a toward the body portion of a subject 203, and it is preferably positioned at the upstream side to suppress the influences of upstreams to measure the blood pressure more effectively by pulse wave detection component 223. (Although it is not shown, an absorber material between compliance fluid bag and pulse wave detection component can be placed to absorb noise and vibrations transmitted through compliance fluid bag and/or occlusion component to improve the signal to noise ratio. Absorber material can be a plastic sheet, composite, porous material, foam, or an encapsulated fluid.)

[0072] The occlusion support component 421 has a width smaller than the width of the occlusion component 401-a along the axis around which the cuff is wrapped. A width of 30% to 70% of the width of the occlusion component 401-a along the said axis is preferable (and similarly 401-b in FIG. 1 1 , and 411 in FIG. 12) for the occlusion support component 421 in FIG. 13.

[0073] It is preferred that the upstream side edge of occlusion support component 421 is closer to the heart than the upstream side edge of occlusion component 401-a along the axis around which the cuff is wrapped (FIG. 13). This may lead to a slight inclination of the occlusion support component 421 along the said axis. This improves suppressing or reduction of the upstreams further and improves the blood pressure measurement accuracy and signal to noise ratio.

[0074] At the interface 218, an adhesive or a double-sided adhesive layer can be employed to fix the occlusion component and the occlusion support component.

[0075] It is preferred that the edge of the compliance fluid bag 202 along the axis around which the cuff is wrapped at downstream side is closer to the distal sides (hand or foot), or it has an equal distance similar to occlusion component 401-a.

[0076] The compliance fluid bags 202 in FIG. 1 1 , 12, and 13 can be encapsulated by a fluid or not. But, an encapsulated compliance fluid bag is preferable to improve the practicality. To improve the compliance further, the incompressible fluids such as liquids or gels are preferable. Although, it is not mentioned in detail, it is possible to use multiple compliance fluid bags under the occlusion component 401-a. In this case, with or without overlaps between compliance fluid bags, it is appreciated that the outermost width, i.e. the distance from proximal side to distal side of the compliance fluid bags under the occlusion component 401-a is equal to or larger than the width of said occlusion component along said axis. By doing this, the influences of hydraulic pressure difference and/or gravitational influences at the upstream and downstream side in a blood pressure cuff due to liquid content in the compliance fluid bags can be reduced to some extent, and blood pressure measurement errors can be decreased.

[0077] The pulse wave detection component 223 in FIG. 1 1 , 12, and 13 can be attached to the cuff, or it can be positioned in the cuff, or it can be positioned near to the cuff on the body portion of a subject 203, along the axis around which the cuff is wrapped.

[0078] A preferable position for the pulse wave detection component 223 is under the compliance fluid bag 202 and occlusion bag 401-a towards a body portion of a subject 203 at the downstream side to measure blood pressure more effectively and accurately (FIG. 11 , 12, and 13). The position closer to the edge of the occlusion component 401-a can be preferable. This can improve the probability of the uniformity of the pressure distribution on the arteries by positioning the pulse wave detection component 223 not near to the center but near to the edge. Because, the space between the compliance fluid bag 202 and the pulse wave detection component 223 on the body portion of a subject 203 may cause degradation of the uniform pressure distributions on those space such as the left and right edges of the pulse wave component 223.

[0079] A width of the pulse wave detection component 223 smaller than the width of the occlusion component 401-a along the axis around which the cuff is wrapped is appreciated. However, a width of 10% to 50% of occlusion component 401-a is preferable along the said axis.

[0080] A pulse wave detection component can be any device composed of sensors. However, an inflatable/deflatable bag by a gas or air with pressure measuring ability is preferred. The material of the bag can be flexible materials such as plastics.

[0081 ] The compliance fluid bag in FIG. 5 can have different shapes. FIG. 14A- 14D illustrate different possibilities. Compliance fluid bags 502 can be configured to be positioned at the edges of the occlusion component 501 in FIG. 14A. The outermost width of the compliance fluid bags 502 is equal to or bigger than the width of the occlusion component 501 along the axis around which the cuff is wrapped. Compliance fluid bags 502 can have irregular cross-sections.

[0082] FIG. 14B illustrates another possibility, where a flexible sheet 503 is configured between compliance fluid bags 502. This structure improves the stability of the blood pressure cuff in practical uses.

[0083] FIG. 14C and 14D show the possible top views of the compliance fluid bags in FIG. 14A and 14B. FIG. 14C show a top view with a torus-like shape at the circumference of the occlusion component 501. A rectangular torus-like shape is preferred for a better compliance fluid bag 521. However, multiple compliance fluid bags 522 under the edges of occlusion component 501 are possible.

[0084] Flexible sheet illustrated in FIG. 14B can be configured differently. Flexible sheet can be a complete sheet 503 -a as shown in FIG. 15 A, or it can be composed of flexible sheets 503-b as shown in FIG. 15B.

[0085] A pulse wave detection component to measure blood pressure more accurately, and an occlusion support component to suppress the influences of upstreams can be attached to the configurations shown in FIG. 14A- 14D, 15A and 15B without departing from the scope of FIG. 5, 1 1 , 12 and 13. [Fifth exemplary embodiment]

[0086] The blood pressure cuff 250 according to the fifth exemplary embodiment is next described with reference to FIG. 16. FIG. 16 is a cross-sectional view of the fifth embodiment of the blood pressure cuff taken along the axis around which the cuff is wrapped.

[0087] In the fifth embodiment of the blood pressure cuff, the occlusion component 201 is arranged on the side of the subject of measurement and the compliance fluid bag 202 is arranged over the occlusion component 201 , as shown in FIG. 16. Regarding the occlusion component 201 and the compliance fluid bag 202, explanation focuses on the width that is length in the direction parallel to the artery 205, i.e., the length in the direction of the axis around which the cuff is wrapped. The width of the compliance fluid bag 202 is greater than the width w2 of the occlusion component 201 by (x2 + y2).

[0088] In the configuration shown in FIG. 16, the order of layering of the occlusion component and the compliance fluid bag is the reverse of the order in the configuration shown in FIG. 3, but as shown in FIG. 3 and FIG. 16, the occlusion component and compliance fluid bag need only be in contact.

[0089] The effect of reducing the cuff-edge effect is obtained in the present exemplary embodiment, as in the first exemplary embodiment. Due to the absence of the compliance fluid bag between the subject of measurement and the occlusion component, the pressure inside the occlusion component is applied to the measurement site with substantially no alteration. As a result, the pressure applied to the measurement site can be accurately controlled by adjustment of the pressure inside the occlusion component, whereby the accuracy of blood pressure measurement is improved.

[Sixth exemplary embodiment]

[0090] The blood pressure cuff according to the sixth exemplary embodiment is next described with reference to FIG. 17. FIG. 17 is a cross-sectional view of the sixth embodiment of the blood pressure cuff taken along the axis around which the cuff is wrapped. Although the depiction of the artery 205 shown in FIG. 16 is omitted in FIG. 17, the notation of the "upstream side" and "downstream side" indicates the upstream side and downstream side of the artery 205. This point holds true for FIG. 19 and subsequent figures.

[0091 ] As shown in FIG. 17, the blood pressure cuff of the sixth exemplary embodiment includes a flexible hard support 211. The blood pressure cuff shown in FIG. 1 7 is of a configuration in which flexible hard support 211 is arranged on the surface of the compliance fluid bag 202 that is opposite the surface of the compliance fluid bag 202 that is in contact with the occlusion component 201 in the blood pressure cuff shown in FIG. 16.

[0092] The present exemplary embodiment also obtains the same effect as the fifth exemplary embodiment. The effect resulting from the contact of the flexible hard support (referred to as the "hard support" hereinbelow) with the compliance fluid bag is further described hereinbelow.

[0093] In the blood pressure cuff construction, if the blood pressure cuff is taken as a reference, the surface at which the blood pressure cuff contacts the subject of measurement is the inside and the opposite side is the outside. For example, in a cuff that originally takes a cylindrical form, the side that is closer to the center of the cylinder is the inside, and the surface that is distant from the center of the cylinder is the outside. In a cuff that is provided with a particular curvature, the direction of the center of the curvature is the inside.

[0094] The hard support has the property of being difficult to deform under pressure, as described in the second exemplary embodiment. Accordingly, when pressure is applied to the occlusion component by way of the hard support, the occlusion component deforms on the inner side without deforming significantly on the outer side. As a result, the measured site can be effectively occluded.

[0095] Still further, when the compliance fluid bag is arranged between the hard support and the occlusion component, the movement of fluid to sites in which the state of close contact between the hard support and the occlusion component is poor makes the state of close contact between the hard support and the occlusion component uniform. As a result, the expansion of the occlusion component toward the outside can be effectively controlled, and the measurement site can therefore be even more effectively occluded.

[0096] As described with reference to FIG. 5 in the second exemplary embodiment, even in the case of a configuration in which the occlusion component is arranged over the fluid bag, the flexible hard support enables the same effects as the present exemplary embodiment to be obtained.

[0097] Contact between the hard support and the compliance fluid bag is not limited to cases in which the hard support and the compliance fluid bag are directly secured. Even when the hard support and the compliance fluid bag are not directly secured, the hard support and the compliance fluid bag may also be in contact by being supported by a component such as fabric or plastic from the outside. Conceivable methods of direct securement include cases in which the hard support and the compliance fluid bag are bonded or in which these components are mechanically fixed. Methods of adhering include a method of fusing by heat or ultrasonic waves and a method of using adhesive or dual-sided tape. Methods of mechanical fixing include a method of securing by stitching, or by a metal or plastic component.

[Seventh exemplary embodiment]

[0098] The blood pressure cuff according to the seventh exemplary embodiment is next described with reference to FIG. 18. FIG. 1 8 is a cross-sectional view of the seventh embodiment of the blood pressure cuff taken along the axis around which the cuff is wrapped.

[0099] As shown in FIG. 18, the blood pressure cuff of the seventh exemplary embodiment is of a configuration in which, compared to the blood pressure cuff shown in FIG. 16, the width of the compliance fluid bag is less than that of the occlusion component. The width w3 of the compliance fluid bag 202 is less than the width of the occlusion component 201 by (x3 + y3). The reason that the width of the compliance fluid bag 202 may also be less than that of the occlusion component 201 is next explained.

[0100] The positions of the width of the occlusion component 201 are defined as in the second embodiment. In other words, in the width of the occlusion component 201 , the center is defined as 0% and the positions of the end portions of the occlusion component 201 of each of the upstream side and downstream side of the artery 205 are defined as 50%. As can be understood by looking at FIG. 18, the compliance fluid bag 202 overlaps with the occlusion component 201 in the range of from 0% to approximately 40% on the upstream side of the artery 205. This range coincides with the range of 15% to 50% described with reference to the graph shown in FIG. 4 and 25% (> 10%) of the overall width of the occlusion component 201 in the second embodiment. If the overlap is remarkably narrow, an area in which the compression pressure is improved will become narrow and a practical advantage is small. Thus, the lower limit of the overlap is 10%.

[0101 ] Further, there is preferably an overlapping portion of the compliance fluid bag 202 and the occlusion component 201 in a range of at least 20%-50%. In particular, the overlap between the compliance fluid bag 202 and the occlusion component 201 in a range of 30%-50% is important because of the conspicuous cuff-edge effect. If the width of the overlapping portion is wide, an effect, in which the compression pressure is improved, will be higher. However, it is unnecessary that the compliance fluid bag overlaps with the occlusion component in the entire width of the occlusion component. If the width of the overlapping portion is narrow, the blood pressure cuff will become lighter. However, if the width of the overlapping portion is remarkably narrow, the effect, in which the compression pressure is improved, will not be obtained. Thus, for example, the width of the overlapping portion is preferably equal to or greater than 10% of the entire width of the occlusion component.

[0102] In portions in which the compliance fluid bag is not present, the cuff-edge effect occurs because the effect of improving the compliance of the occlusion component is not obtained. However, in portions in which the compliance fluid bag is present, the cuff-edge effect is reduced due improved compliance. Accordingly, the length of wl shown in FIG. 1 8 is longer than in cases in which a compliance fluid bag is completely absent. In other words, despite the reduction of the width of the occlusion component, a good occlusion characteristic can be obtained, and good blood pressure measurement accuracy can be obtained. [0103] Thus, the present exemplary embodiment is not limited to cases in which the length of the fluid bag is equal to or greater than that of the occlusion component and includes cases in which the fluid bag is shorter than the occlusion component. The fluid bag being shorter is also lighter, thereby improving comfort.

[Eighth exemplary embodiment]

[0104] The blood pressure cuff according to the eighth exemplary embodiment is next described with reference to FIG. 19. FIG. 19 is a cross-sectional view of the eighth embodiment of the blood pressure cuff taken along the axis around which the cuff is wrapped.

[0105] As shown in FIG. 19, the blood pressure cuff of the eighth exemplary embodiment is of a configuration in which the compliance fluid bag 202 of the blood pressure cuff shown in FIG. 3 is divided into a plurality of compliance fluid bags. Of the plurality of compliance fluid bags 202, the compliance fluid bag 202a that is arranged on the extreme upstream side overlaps with the occlusion component 201 over at least 10% of the overall width of the occlusion component 201 in a range of 15%-50% of the upstream side from the center (0%) of the width of the occlusion component 201. Therefore, the cuff-edge effect is reduced and good compression characteristic can be obtained. FIG. 19 shows a case in which the compliance fluid bag 202 is divided into four compliance fluid bags, but the number of compliance fluid bags is not limited to four.

[0106] Furthermore, in the present exemplary embodiment, since the compliance fluid bag 202 is divided into the plurality of compliance fluid bags, the non-uniformity of compression pressure due to gravity can be reduced. For example, if the content in the fluid bag is a liquid and if a measurement object person take a stance in which the liquid is forced by gravity in a direction from the upstream side to the downstream side, the compression pressure of the downstream side intends to higher than that of the upstream side by a influence of hydrostatic pressure of the content. On the other hand, in FIG. 19, since the compliance fluid bag is divided into the plurality of compliance fluid bags in a parallel direction to the artery, the influences of the compression pressures of the upstream and downstream sides are decreased. Therefore, the uniformity of the compression pressure is improved and the measurement error of the blood pressure can be decreased. As a result, the influence of differences in hydraulic pressure and/or the influence of gravity at the upstream and downstream sides in a blood pressure cuff that are caused by the liquid content of the compliance fluid bags can be decreased to some extent, and blood pressure measurement errors can therefore be decreased.

[Ninth exemplary embodiment]

[0107] The blood pressure cuff according to the ninth exemplary embodiment is next described with reference to FIG. 20. FIG. 20 is a cross-sectional view of the ninth embodiment of the blood pressure cuff taken along the axis around which the cuff is wrapped.

[0108] As shown in FIG. 20, the fluid bag in the ninth embodiment of the blood pressure cuff is divided into two compliance fluid bags 202a and 202b, compliance fluid bags 202a and 202b being arranged over the occlusion component 201. Compliance fluid bag 202a is arranged in the vicinity of the end portion of the upstream side of the artery of the occlusion component 201 and compliance fluid bag 202b is arranged in the vicinity of the end portion of the downstream side of the artery of the occlusion component 201. A fluid bag is not arranged between these two compliance fluid bags 202a and 202b.

[0109] Although the compliance fluid bags 202a and 202b shown in FIG. 20 resemble the compliance fluid bags and their arrangement shown in FIGs. 15A and 15B, the cross-sectional shapes of the compliance fluid bags are different. Referring to FIGs. 14A and 14B, the shapes of the compliance fluid bags shown in FIGs. 15A and 15B are pre-shaped so as to comply with the curved surface (each bottom surface of occlusion components 501 in shown FIGs. 14A and 14B) that has a crushed elliptical shape. However, the cross-sectional shape of the compliance fluid bags is not limited to the shapes shown in FIGs. 14A and 14B. This is because the compliance fluid bags can change shape to fill in gaps with a confronting object.

[01 10] The arrangement of compliance fluid bag 202a is next described.

[01 1 1 ] The definitions described in the second and seventh exemplary embodiments are used for the positions of the width of the occlusion component 201. Referring to FIG. 20, the compliance fluid bag 202a overlaps with the occlusion component 201 on the upstream side over 10% or more of the entire width of the occlusion component 201 in the range of 15%-50%. More specifically, the compliance fluid bag 202a overlaps the occlusion component 201 in the region of 30%-50% in which the cuff-edge effect is conspicuous. This overlapping portion corresponds to 20% of the entire width of the occlusion component 201.

[01 12] Because the cuff-edge effect is small in the vicinity of the center of the occlusion component, a fluid bag need not be arranged in the vicinity of the center of the occlusion component as in the present exemplary embodiment, and a decrease of the weight of the blood pressure cuff can therefore be achieved.

[Tenth exemplary embodiment]

[01 13] The blood pressure cuff according to the tenth embodiment is next described with reference to FIG. 21 . FIG. 21 is a cross-sectional view of the tenth embodiment of the blood pressure cuff taken along the axis around which the cuff is wrapped.

[01 14] Referring to FIG. 21 , in the blood pressure cuff of the tenth exemplary embodiment, compliance fluid bags 202a and 202b are arranged on the occlusion component 201 similar to the blood pressure cuff shown in FIG. 20, but compliance fluid bag 202b is smaller than the corresponding component shown in FIG. 20. More specifically, the width of the compliance fluid bag 202b shown in FIG. 20 reaches as far as the end portion of the downstream side of the occlusion component 201, but in the present exemplary embodiment, the width of the compliance fluid bag 202b shown in FIG. 21 does not reach the end portion of the occlusion component 201.

[01 15] In the present exemplary embodiment, the position of the compliance fluid bag 202a and the portion of overlap between the compliance fluid bag 202a and the occlusion component 201 are similar to the compliance fluid bag 202a of the ninth exemplary embodiment, and detailed explanation of these points is therefore here omitted.

[01 16] The shapes and positions of the fluid bags may differ on upstream side and downstream side of the flow of blood in the artery, as in the present exemplary embodiment. For example, the fluid bag can be made large on the upstream side where the cuff-edge effect is great to drastically reduce the cuff-edge effect, and the fluid bag can be made small on the downstream side in which the cuff-edge effect is comparatively small. If in a range that allows decrease of the cuff-edge effect, the position and size of the fluid bags can be freely determined according to necessity.

[Eleventh exemplary embodiment]

[01 1 7] The blood pressure cuff according to the eleventh exemplary embodiment is next described with reference to FIG. 22. FIG. 22 is a cross-sectional view of the eleventh embodiment of the blood pressure cuff taken along the axis around which the cuff is wrapped.

[01 1 8] Referring to FIG. 22, in the blood pressure cuff of the eleventh exemplary embodiment, the compliance fluid bag 202a is arranged over the occlusion component 201 similar to the blood pressure cuff shown in FIG. 20, but the compliance fluid bag 202b shown in FIG. 20 is not provided. The fluid bag on the downstream side of the flow of blood of the artery may be omitted according to necessity as in the present exemplary embodiment.

[01 19] In the present exemplary embodiment as well, the position of the compliance fluid bags 202 and the portion of overlap of the compliance fluid bag 202 and the occlusion component 201 are similar to the compliance fluid bag 202a of the ninth exemplary embodiment, and detailed explanation of these points is therefore here omitted.

[0120] In the present exemplary embodiment, the blood pressure cuff can be made even lighter than the blood pressure cuff described in the tenth and eleventh exemplary embodiments.

[Twelfth exemplary embodiment]

[0121 ] Working examples of the blood pressure cuff according to the twelfth exemplary embodiment are next described with reference to FIGs. 23A-23D. FIGs. 23A-23D are cross-sectional views of Working Examples 1-4 of the twelfth exemplary embodiment of the blood pressure cuff taken along the axis around which the cuff is wrapped.

[0122] As shown in FIG. 23A, in the blood pressure cuff of Working Example 1 , the fluid bag is divided into two compliance fluid bags 202a and 202b. One compliance fluid bag 202a is arranged over the occlusion component 201 so as to cover the outer end portion on the upstream side of the occlusion component 201, and the other compliance fluid bag 202b is arranged below the occlusion component 201 so as to cover the inner end portion of the downstream side of the occlusion component 201. In this way, a plurality of fluid bags may be provided at different positions on the upstream side and downstream side of the artery in a width direction of the occlusion component.

[0123] As shown in FIG. 23B, in the blood pressure cuff of Working Example 2, the fluid bag is divided into three compliance fluid bags 202a, 202b, and 202c. One compliance fluid bag 202a is arranged over the occlusion component 201 so as to cover the outer end portion of the upstream side of the occlusion component 201 , and another compliance fluid bag 202c is arranged below the occlusion component 201 so as to cover the inner end portion on the upstream side of the occlusion component 201. The last compliance fluid bag 202b is arranged over the occlusion component 201 so as to cover the outer end portion of the downstream side of the occlusion component 201. In this way, fluid bags may be provided on both the inner and outer surfaces of the upstream side of the artery in the width direction of the occlusion component.

[0124] As shown in FIG. 23C, in the blood pressure cuff of Working Example 3, the fluid bag is divided into three compliance fluid bags 202a, 202b, and 202c. One compliance fluid bag 202b, similar to Working Example 2, is arranged over the occlusion component 201 so as to cover the outer end portion of the downstream side of the occlusion component 201. Another compliance fluid bag 202c is arranged over the occlusion component 201 so as to cover the outer end portion of the upstream side of the occlusion component 201 , and the last compliance fluid bag 202a is layered over the outer side of the compliance fluid bag 202c. A plurality of fluid bags may thus be stacked on the upstream side of the artery with respect to the width direction of the occlusion component.

[0125] As shown in FIG. 23D, in the blood pressure cuff of Working Example 4, the fluid bag is divided into three compliance fluid bags 202a, 202b and 202c. Two compliance fluid bags 202a and 202b are arranged over the occlusion component 201 so as to cover the outer end portions of the upstream side and downstream side, respectively, of the occlusion component 201, as in Working Example 2. The last compliance fluid bag 202c is arranged below the occlusion component 201 in the vicinity of the center of the width of the occlusion component 201.

[0126] According to the present exemplary embodiment, by arranging a fluid bag over each of the outer side and inner side of the occlusion component on the upstream side of the artery and by arranging a plurality of fluid bags over the outer side of the occlusion component on the upstream side of the artery, the compliance of these overlapping portions can be markedly improved.

[Thirteenth exemplary embodiment] [0127] The blood pressure cuff according to the thirteenth exemplary embodiment is next described with reference to FIG. 24. FIG. 24 is a cross-sectional view of the thirteenth embodiment of the blood pressure cuff taken along the axis around which the cuff is wrapped. The blood pressure cuff of the present exemplary embodiment has a configuration, in which the occlusion support component in the fourth exemplary embodiment is added to the blood pressure cuff of the fifth exemplary embodiment.

[0128] As shown in FIG. 24, in the blood pressure cuff of the thirteenth exemplary embodiment, compliance fluid bag 202 is arranged over occlusion component 401-a. Similar to the configuration of FIG. 1 1 , an occlusion support component 401-b is connected to the occlusion component 401-a so as to allow the input and output of air, and an occlusion support component 401-b is provided on the upstream side of the artery in the width direction of the occlusion component 401-a.

[0129] Compared to the configuration shown in FIG. 1 1 , the vertical positions of the occlusion component 401-a and the occlusion support component 401-b in the blood pressure cuff of the present exemplary embodiment are reversed. The occlusion component 401-a contacts the arm of the subject of blood pressure measurement, and the occlusion support component 401-b is arranged on the outer side of the occlusion component 401-a. The occlusion support component 401-b can be arranged on the inner side of the occlusion component 401-a.

[0130] In the present exemplary embodiment, the occlusion support component is arranged so as not to contact the arm of the subject of blood pressure measurement, whereby unevenness of the surface of the portion that contacts the arm is reduced. As a result, uniformity of the pressure that is applied to the measurement portion is improved, and the measurement accuracy is improved.

[013 1 ] In each embodiment of the fourth and fifteenth exemplary embodiments, the desired position can be compressed more forcefully by adding the occlusion support component 401-b to the blood pressure cuff. [Fourteenth exemplary embodiment]

[0132] The blood pressure cuff according to the fourteenth exemplary embodiment is next described. The blood pressure cuff of the fourteenth exemplary embodiment is of a configuration in which an incompressible fluid other than liquid and gel is used in the contents of the compliance fluid bag. The substance other than gel is, for example, an aggregate of micro-solids having fluidity such as microbeads. According to the fourteenth embodiment, air enters into the gaps among the microsolids, whereby a lighter weight can be achieved than for a liquid such as a gel.

[0133] In addition, the fluid bag need not be in the desired position described in the above-described embodiments when not being pressed in the direction of the subject of blood pressure measurement.

[0134] When the internal pressure of the occlusion component is lower than the diastolic blood pressure (for example, when lower by 10 mm Hg), the fluid bag should be present in the desired position, but may be in other locations when depressurized. This characteristic includes, for example, cases in which a fluid bag that is positioned in a particular location moves to the desired position when pressurized, or cases in which the outer bag of a fluid bag has elasticity and the bag extends when pressurized to be present in a desired location.

[0135] Whether the bag moves to a desired position when pressurized can be checked by investigating the relative positions of the fluid bag and the occlusion component when, for example, a fixed pressurization is applied to the occlusion component when fitted to a site to be measured, or when the cuff is wrapped around a substantially cylindrical object and a fixed pressurization is applied to the occlusion component. As an example of the fixed pressurization, 40 mmHg can be offered as a pressure that is lower than the diastolic blood pressure of a typical human in a healthy state.

[0136] Next, relating to the accuracy of blood pressure measurements of a blood pressure meter that uses the blood pressure cuff of an embodiment of the present invention, results of experimentation are described in comparison with a blood pressure cuff of the related art.

[0137] FIG. 25A is a cross-sectional view of the blood pressure cuff of an embodiment of the present invention that was used in experimentation.

[0138] As shown in FIG. 25A, the blood pressure cuff is of a configuration in which the occlusion support component 401-b is arranged below the occlusion component 401-a and the flexible hard support 211 is arranged over the compliance fluid bag 202, such as the thirteenth embodiment. In the following explanation, the blood pressure cuff shown in FIG. 25A is referred to as the prototype.

[0139] FIG. 25B is a schematic external view showing the state of blood pressure measurement. A reference blood pressure cuff is wrapped around the right arm of the test subject, the prototype is wrapped around the left arm, and the blood pressures of the right and left arms were measured at a time. The difference between measured values of the right and left arms, by assuming the measured value of the right arm (the reference blood pressure cuff) as a reference, is defined as "error". A marketed blood pressure meter which had already obtained medical approval was used as the reference blood pressure cuff. The width Wr of the reference blood pressure cuff is 12 cm, and the width Wp of the prototype is 8 cm. The blood pressure measurement program used a marketed device, and the algorithm of blood pressure measurement was common to the reference blood pressure cuff and the prototype.

[0140] The number of test subjects was 16. Each of the 16 test subjects was measured three times and the total number of data items is therefore 48. The arm circumference of the 16 test subjects ranged from 24 cm to 32 cm.

[0141 ] FIGs. 26A to 26C are pie charts showing the measurement results of the prototype. FIG. 26A shows the average value of measurement accuracy of the Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP), and shows the measurement accuracy of all blood pressure measurement results. FIG. 26B shows the measurement accuracy of the SBP, and FIG. 26C shows the measurement accuracy of the DBP.

[0142] Referring to FIG. 26A, the proportion for which the error of blood pressure measurements was equal to or less than ±5 mmHg was 84% of the total. Referring to FIGs. 26B and 26C, the proportion for which the error of the SBP measurement was equal to or less than ± 5 mmHg was 77% of the total, and the proportion for which the error of the DBP measurement was equal to or less than ±5 mm Hg was 92% of the total.

[01 43] The average value of measurement errors of SBP that was measured by the prototype and the standard deviation thereof were -0.8 mmHg ±4.5 mmHg. The average value of measurement errors of DBP that was measured by the prototype and the standard deviation thereof were 0.6 mm Hg ± 3.0 mmHg.

[0144] The comparative results of the prototype and a comparative example are next described regarding measurement accuracy.

[0145] The width of the reference blood pressure cuff is 12 cm. In the prototype blood pressure cuff, the width is 8 cm and the length in the direction of wrapping on the arm is 16.5 cm for each of the occlusion component and the compliance fluid bag. As the comparative example, only the occlusion component in the prototype blood pressure cuff was prepared. In other words, the comparative example blood pressure cuff is of a configuration that is only provided with an occlusion component having a width of 8 cm and length in the direction of wrapping on the arm of 16.5 cm.

[0146] FIG. 27 is a bar graph showing the measurement accuracy of the prototype, the reference blood pressure cuff, and the comparative example. The accuracy (%), which is the vertical axis of the bar graph, shows the proportion for which the measurement errors of SBP and DBP are equal to or less than ±5 mmHg. In FIG. 27, the measurement accuracy of the reference blood pressure cuff is shown by ( 1 ), the measurement accuracy of the comparative example blood pressure cuff is shown by (2), and the measurement accuracy of the prototype is shown by (3).

[0147] Referring to FIG. 27, the measurement accuracy of the reference blood pressure cuff reached 80%. It can be seen that the measurement accuracy of the prototype is 84%, and therefore the measurement accuracy of the prototype is equal to that of the reference blood pressure cuff that obtained medical approval. In contrast, the measurement accuracy of the blood pressure cuff of the comparative example reaches only 44% and therefore the measurement accuracy of the comparative example is remarkably low level.

[0148] Based on the results shown in FIG. 27, it was confirmed that the measurement accuracy becomes remarkably lower by merely decreasing the width of the blood pressure cuff. It can further be seen from the results shown in FIG. 27 that despite decreasing the width of the blood pressure cuff, the measurement accuracy which is equal to that of a general blood pressure cuff having a wide width, can be obtained by overlapping the occlusion component and the fluid bag as in the blood pressure cuff of the present exemplary embodiment.

[0149] Flexible materials for the bags mentioned above are preferred. Those can be plastic materials or any substance or sheet obtained from plastic materials or polymers. The bags are not permeable to the fluids such air or water. It is possible to use different flexible materials for different bags in the cuff to improve the functionality and the compliance.

[0150] Although flexible materials are appreciated for bag materials, expandable materials can be possible for compliance bag. The compliance bag can elongate along the axis around which the cuff is wrapped. During the measurement of blood pressure, however, it is appreciated to be under the occlusion component to improve the compliance toward the body portion of a subject, and the width can be equal to or bigger than the width of occlusion component at said axis. [015 1 ] It is not shown in detail in the figures, but to fix the bags to each other for a more stable blood pressure measurement to eliminate possible malfunctions, a substance to adhere the bags to each other such as a double-sided adhesive layer can be used. This will improve the stability, durability and reliability of the cuff. Furthermore, other sealing methods and fixing methods can be applicable. Although it is not shown in the figures of the embodiments, an absorber material between compliance fluid bag and pulse wave detection component can be placed to absorb noise and vibrations transmitted through compliance fluid bag and/or occlusion component to improve the signal to noise ratio. Absorber material can be a plastic sheet, composite, porous material, foam, or an encapsulated fluid.

[0152] It is not mentioned here in detail but, a cover layer such as a plastic or a textile layer can be put on the cuff to protect the cuff further. This cover/ layer can be configured between the cuff and the body portion of a subject.

[0153] The present invention is not limited to the above descriptions and illustrations. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention.

Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.

[Industrial Applicability]

[0154] This invention can be applied to the blood pressure meters and ABPMs.

[Reference Signs List]

[0155]

10, 100, 200 blood pressure cuff

1 1 , 101 , 201 , 401 -a, 501 occlusion component

12, 1 03 , 203, 15 1 subject (body portion of arm or leg)

13, 104, 204 heart

14, 19, 105, 1 10, 205, 210 artery

1 5, 106, 206 blood flow

16, 107, 207 upstream flow

17 cuff-edge effect 18 non-uniform pressure distribution

102, 202, 202-a, 202-b, 202-c, 222, 232, 502, 521 , 522 compliance fluid bag

108, 208 reduced cuff-edge effect

109, 209 uniform pressure distribution

1 12, 1 13, 212, 213, 214, 217, 218, 224, 225, 226, 227 interface

150 blood pressure meter

152 blood pressure cuff

153 , 154, 160 fluidic connection

155 measurement unit

156 pressurization and depressurization unit

157 blood pressure measurement unit

158 control and operation unit

159 display unit

21 1 flexible hard support

215 bone

216 fastener

223 pulse wave detection component

401 -b, 41 1 , 421 occlusion support component

401 -c fluidic connection

503 , 503-a, 503-b flexible sheet