U.S. patent application number 10/751652 was filed with the patent office on 2004-10-14 for blood pressure meter cuff.
This patent application is currently assigned to OMRON HEALTHCARE CO., LTD.. Invention is credited to Inoue, Tomonori, Ohtani, Toshio, Sano, Yoshihiko, Shirasaki, Osamu.
Application Number | 20040204653 10/751652 |
Document ID | / |
Family ID | 32588514 |
Filed Date | 2004-10-14 |
United States Patent
Application |
20040204653 |
Kind Code |
A1 |
Shirasaki, Osamu ; et
al. |
October 14, 2004 |
Blood pressure meter cuff
Abstract
Provide is a blood pressure meter cuff capable of avoiding an
influence of an edge effect by pressurizing only a portion of a
blood vessel in the downward vicinity of the body surface to
thereby measure a correct blood pressure. A blood pressure meter
cuff 1 includes: a fluid bag into which a fluid is injected; and a
fixing tool fixing the fluid bag on a limb of a human body or the
like, wherein a width, in the axial direction of the limb, of the
fluid bag is a value suitable for selectively pressurizing only a
portion of a blood vessel present in the downward vicinity of the
skin. In a case where pressurization is imposed on only a portion
of the radial artery present in the downward vicinity of the body
surface and adjacent to a radial styloid process of a wrist, a
width, in the axial direction of a limb, of the fluid bag is set to
15 mm or more and 25 mm or less.
Inventors: |
Shirasaki, Osamu; (Osaka,
JP) ; Sano, Yoshihiko; (Kyoto-shi, JP) ;
Ohtani, Toshio; (Kyoto-shi, JP) ; Inoue,
Tomonori; (Kyoto-shi, JP) |
Correspondence
Address: |
MORRISON & FOERSTER LLP
1650 TYSONS BOULEVARD
SUITE 300
MCLEAN
VA
22102
US
|
Assignee: |
OMRON HEALTHCARE CO., LTD.
Kyoto-shi
JP
|
Family ID: |
32588514 |
Appl. No.: |
10/751652 |
Filed: |
January 6, 2004 |
Current U.S.
Class: |
600/499 |
Current CPC
Class: |
A61B 5/02233
20130101 |
Class at
Publication: |
600/499 |
International
Class: |
A61B 005/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 15, 2003 |
JP |
2003-7387 |
Claims
What is claimed is:
1. A blood pressure meter cuff comprising: a fluid bag into which a
fluid is injected; and a fixing tool fixing the fluid bag on a limb
of a human body or the like, wherein a width, in the axial
direction of the limb, of the fluid bag is a value suitable for
selectively pressurizing only a portion of a blood vessel present
in the downward vicinity of the skin.
2. The blood pressure meter cuff according to claim 1, wherein a
width, in the axial direction of the limb, of the fluid bag is a
width suitable for pressurizing a radial artery present in the
downward vicinity of the body surface and adjacent to a radial
styloid process of a wrist.
3. The blood pressure meter cuff according to claim 1, wherein a
width, in the axial direction of the limb, of the fluid bag is a
width suitable for pressurizing a radial artery present in the
downward vicinity of the body surface and in an intermediate
portion between the radial styloid process of a wrist and the first
metacarpal bone base thereof.
4. The blood pressure meter cuff according to any one of claims 1
to 3, wherein a width, in the axial direction of a limb, of the
fluid bag is 15 mm or more and 25 mm or less.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a blood pressure meter cuff
equipped with a fluid bag into which a fluid is injected and a
fixing tool fixing the fluid bag.
[0003] 2. Description of the Prior Art
[0004] There have been available various kinds of non-invasive
blood pressure measuring methods, among which, currently, an
oscillometric method (or an oscillation method) is most widely
proliferated. The oscillometric method is conducted such that a
tourniquet in a belt-like shape called a cuff having a fluid bag
therein is fixedly wrapped around a limb and an internal pressure
is given to the fluid bag to pressurize an artery in the limb to
capture a change in arterial volume determined in a balance between
an pressurization pressure as a reaction and a pressure in the
artery and estimate a blood pressure value. To be more concrete,
since a change in arterial volume is sensed as a change in internal
pressure in the fluid bag (which is a pulse wave) and an amplitude
thereof is altered depending on a blood pressure and an
pressurization pressure, a blood pressure can be estimated from a
change in pulse wave amplitude relative to a pressurization
pressure.
[0005] While the oscillometric method was developed originally as a
method using an arm as a measuring site, commercialization on a
blood pressure meter in recent years has proceeded to provide new
types measuring a blood pressure at sites other than an arm, such
as a wrist and a finger. The new types of blood pressure meters
have been increasing a need for themselves on the market, because
of advantages such as no necessity for taking off clothes in
mounting a cuff, which is necessary for an arm type, and a small
size and high portability.
[0006] Since, especially, a wrist blood pressure meter uses an
artery located near an arm as a measuring site, usefulness is
generally accepted to be higher than a finger type, though with a
convenience at the same level as the wrist type. A cuff of a wrist
blood pressure meter is generally mounted at a site in the forearm
side adjacent to a wrist joint. According to Alexander H. et al.
(see non-patent literature 1), a theory is such that in order to
properly pressurize a blood vessel of a limb for measuring a blood
pressure, it is required that a width, in an axial direction of a
limb, of a fluid bag attached to a cuff in use, that is a cuff
width is of 40% or more of a diameter of the limb at a measuring
site and blood pressure meters currently on the market are designed
according to this theory. Therefore, in a case of a wrist blood
pressure meter put into practice, a cuff width is on the order in
the range of from 50 to 60 mm.
[0007] In actual cases of adopting this kind of cuff, a problem has
been arisen to some of users that a pressurization pressure of a
fluid bag does not correctly act on a target artery and the target
artery is not sufficiently pressurized, therefore disabling a blood
pressure to be correctly measured. There are two arteries called
the radial artery and the ulnar artery in a wrist and the two
arteries each are located in a slightly retreated position
surrounded with the two bones called the radius and the ulna and
tendons extending in parallel thereto. Hence, a pressurization
force of a fluid bag is harder to reach a target artery in the
cases than the brachial artery that is an target having been
conventionally measured and present in a state where no tendon
exists around a bone.
[0008] It has been conventionally known that a cuff pressure is not
sufficiently transmitted to a blood vessel, in the axial direction
of a limb, near both ends of a fluid bag of a cuff of a blood
pressure meter to thereby disable the blood vessel to be
sufficiently pressurized. This phenomenon is called as an edge
effect. If this edge effect occurs, pulsation occurs in a blood
pressure in a blood vessel not sufficiently pressurized near an end
of a cuff fluid bag. In this case, this pulsation is sensed as a
change in cuff pressure, leading to a factor for measurement error
if a chance allows.
[0009] In order to cancel this problem, a cuff has been
conventionally known that pressurizes a wrist joint section easy to
be pressurized because an artery is located in the downward
vicinity of a body surface. Since, in the wrist joint section, a
blood vessel runs outside of the condyle, the blood vessel is
located at a shallower position below the skin than a blood vessel
in the forearm side, located between the radius and the ulna, the
vessel running outside of the condyle is easier to be pressurized.
A prominence called the radial (or ulnar) styloid process 32 is
present at the peripheral end of the radius (or the ulna) 33, in
which portion, especially, a blood vessel 31 is conspicuously
present in the downward vicinity of the body surface (see FIG.
6).
[0010] The non-patent literature is Alexander H. "Criteria in the
choice of an occluding cuff for the indirect measurement of blood
pressure," in Medical & Biological Engineering & Computing,
(U.K.) issued by Institution of Electrical Engineers, 1977, Vol.
15, pp. 2 to 10).
[0011] According to observation by the inventors, it has been found
that in a case where a pressure is applied with a cuff having a
conventional width on a portion including a site on the body
surface in the downward vicinity of which the blood vessel exists,
a good result is not necessarily obtained. To be concrete, a
phenomenon has been experienced by some of patients that
deformation, which is encountered when a blood vessel is not
sufficiently pressurized, occurs on a curve of a change in pulse
wave amplitude changing depending on a cuff pressure.
[0012] Description will be given of a cause for this phenomenon
with reference to FIG. 6. It is only around the radial styloid
process 32, for example, in a case of the radial artery 31, that a
blood vessel is conspicuously present in the downward vicinity of
the body surface near the wrist joint and a length of this section
is roughly on the order in the range of from 15 to 25 mm. This
section is indicated as a section B in FIG. 6. Since a cuff width
for a conventional blood pressure meter is, as described above, in
the range of from 50 to 60 mm and therefore, a blood pressure 31 is
pressurized additionally in sections in the forearm side and the
peripheral side adjacent to the section B (the sections A and C of
FIG. 6), a change in arterial volume, which is a reaction of the
pressurization, that is a pulse wave is also sensed from the blood
vessel 31 in the additional sections.
[0013] Since the blood vessel 31 is, however, located clearly in
deeper positions in the sections A and C than in the section B and
surrounded with bones and tendons, the vessel 31 is harder to be
pressurized. Therefore, the blood vessel 31 is not occluded even
under a pressure which is higher than a blood pressure and so high
that the blood vessel is to be occluded by nature. It is thought
that the blood vessel 31 in the sections A and C is in a state
lower in cuff pressure than in the section B, that is in a state
where a change in arterial volume is not extinct, in other words in
a state where the blood vessel 31 is pressurized not to be flat,
again in other words, in a state where the edge effect occurs. This
hypothesis has been confirmed to be true as a result after the
inventors conducted experiments using a transparent cuff and
observed pulsation at the upstream and downstream ends of the cuff
under a high cuff pressure.
[0014] The reason why, though the blood vessel is perfectly
occluded at the center of the cuff and a blood flow is blocked,
pulsation occurs not only at the upstream end of the cuff, but also
at the downstream end thereof, is that the radial artery and the
ulnar artery communicate with each other through a thick blood
vessel in the palm section more down stream and in a case of a cuff
in which only the radial artery is selectively pressurized, a blood
flow from the ulnar artery is fed to the cuff down stream end of
the radial artery.
[0015] If a blood vessel located in the downward vicinity of the
body surface is pressurized by a cuff having a fluid bag designed
dimensionally in consideration of a relation with a wrist
circumference according to the conventional Alexander H. et al.'s
theory, an influence from a blood vessel at a site other than a
blood vessel in the downward vicinity of the body surface is
exerted, leading to a problem to cause a result of an incorrect
blood pressure measurement.
SUMMARY OF THE INVENTION
[0016] The invention has been made in order to solve the above
problem and it is accordingly an object of the invention to provide
a blood pressure meter cuff capable of avoiding an influence of an
edge effect by pressurizing only a portion of a blood vessel in the
downward vicinity of the body surface to thereby measure a correct
blood pressure.
[0017] A blood pressure meter cuff based on the invention includes:
a fluid bag into which a fluid is injected; and a fixing tool
fixing the fluid bag on a limb of a human body or the like, wherein
a width, in the axial direction of the limb, of the fluid bag is a
value suitable for selectively pressurizing only a portion of a
blood vessel present in the downward vicinity of the skin.
[0018] With the blood pressure meter cuff adopted, it is possible
to pressurize only a blood vessel present in the downward vicinity
of the skin. As a result, a blood pressure can be correctly
measured without receiving an influence of the cuff edge
effect.
[0019] In the blood pressure meter cuff, a width of the fluid bag
is a width suitable for pressurizing a radial artery present in the
downward vicinity of the body surface and adjacent to a radial
styloid process of a wrist. With such a construction, it is
possible to pressurize only a radial artery in the wrist. Thereby,
it is possible to provide a wrist blood pressure meter capable of
conducting a correct measurement.
[0020] A width of the fluid bag is a width suitable for
pressurizing a radial artery present in the downward vicinity of
the body surface and in an intermediate portion between the radial
styloid process of a wrist and the first metacarpal bone base
thereof. With such a width of a fluid bag adopted, it is possible
to pressurize only the radial artery present in the downward
vicinity of the skin in a wrist. Furthermore, by fixedly wrapping a
cuff around an intermediate portion between the radial styloid
process of a wrist and the first metacarpal bone base, the radial
artery and the cuff are hard to be displaced to thereby enable a
blood vessel to be stably pressurized. Thereby, it is possible to
provide a wrist blood pressure meter capable of measuring a correct
blood pressure.
[0021] In the blood pressure meter cuff, a width, in the axial
direction of a limb, of the fluid bag is preferably 15 mm or more
and 25 mm or less. With such a width of a fluid bag adopted, it is
possible to provide a blood pressure meter cuff suitable for
pressurizing only a portion of a radial artery present in the
downward vicinity of the body surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIGS. 1A and 1B show sectional views of states where a blood
pressure meter cuff in a first embodiment based on the invention is
mounted on a wrist.
[0023] FIG. 2 shows a sectional view taken on line II to II normal
to arrows in FIG. 1A showing a state where the blood pressure meter
cuff in the first embodiment based on the invention is mounted on a
wrist.
[0024] FIG. 3 shows a top plan view of the blood pressure meter
cuff in the first embodiment based on the invention in a state
where the cuff is extended to be flat.
[0025] FIGS. 4A and 4B show perspective views of the blood pressure
meter cuff in the first embodiment based on the invention in a
state where the cuff is mounted on a wrist.
[0026] FIG. 5 shows a top plan view of a skeleton of a wrist
describing a mounting position of a blood pressure meter cuff in a
second embodiment based on the invention.
[0027] FIG. 6 shows a sectional view of a state where a
conventional blood pressure meter cuff is mounted on a wrist.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] (Embodiment 1)
[0029] Description will be given of a blood pressure meter cuff in
this embodiment below with reference to FIGS. 1A and 1B to 4A and
4B. FIGS. 1A and 1B are sectional views showing states where a
blood pressure meter cuff in this embodiment is mounted on a wrist,
FIG. 2 is a sectional view taken on line II to II normal to arrows
in FIG. 1A showing a state where the cuff is mounted on a wrist,
FIG. 3 is a top plan view of the cuff in a state where the cuff is
extended to be flat and FIGS. 4A and 4B are perspective views
showing the cuff in a state where the cuff is mounted on a
wrist.
[0030] (Structure of Blood Pressure Meter Cuff)
[0031] Description will be given of the structure of a blood
pressure meter cuff 1 with reference to FIGS. 1A and 1B to 3. The
blood pressure meter cuff 1 of this embodiment is used in a wrist
blood pressure meter and equipped with a fluid bag 11 into which a
fluid such as air is injected and a band 12 as a fixing tool fixing
the fluid bag 11 on a wrist.
[0032] The fluid bag 11 is made of a substance excellent in
expandability/contractibility such as a thin film silicone rubber
and a latex film and shaped as a rectangle in a top plan view
extending in the length direction of the band 12 as shown in FIG.
3. The fluid bag 11 is in a bag like shape as shown in FIGS. 1A and
1B, and FIG. 2, and fed with air thereinto to be inflated.
[0033] A width W, in the axial direction of a wrist, of the fluid
bag 11 in a state where the bag 11 is wrapped around the wrist is
set to a length suitable for selectively pressurizing only a
portion of a blood vessel present near the skin in the vicinity of
the body surface. In this embodiment, a width of the fluid bag 11
is set to a dimension suitable for pressurizing only a portion of
the radial artery 31 adjacent to the radial styloid process 32 and
present right under the skin in the vicinity of the body surface (a
section B shown in FIG. 1). To be concrete, the width W is 15 mm or
more and 25 mm or less. A length L of the fluid bag 11 shown in
FIG. 3 is set to a dimension of the order of a value at which the
bag 11 pressurizes only the radial artery without pressurizing the
ulnar artery 35 (see FIG. 2).
[0034] A blood pressure meter body 21 is connected to the fluid bag
11. The blood pressure body 21 is equipped with a built-in pump
injecting air as a fluid into the fluid bag 11; a sensor sensing a
pressure in the fluid bag 11; and a control device controlling
workings of the constituents.
[0035] The band 12 fixes the fluid bag 11 on a wrist section and is
slightly wider than the width W of the fluid bag 11 as shown in
FIG. 3, and has a length of the order of a value at which the wrist
section is wrapped around. Hook-loop tape fasteners 13 mutually
engaged with each other are provided to both ends, respectively, of
the band 12.
[0036] (Use Method of Blood Pressure Meter Cuff)
[0037] Description will be given of a use method of the blood
pressure meter cuff 1 of this embodiment. The cuff 1 of this
embodiment is, as shown in FIG. 4, wrapped around a wrist section
when being used. At this time, as shown in FIG. 1A, the cuff 1 is
mounted so that the fluid bag 11 is brought into contact with a
portion of the radial artery 31 adjacent to the radial styloid
process 32 of the radius 33 in the downward vicinity of the body
surface. Air is fed into the fluid bag 11 from the blood pressure
meter body 21 in this state to inflate the fluid bag 11 as shown in
FIG. 1B and pressurize a blood vessel.
[0038] (Action and Effect)
[0039] In this embodiment, since the fluid bag 11 is set to a
dimension suitable for pressurizing only the radial artery 31
adjacent to the radial styloid process 32 in the downward vicinity
of the body surface, the bag 11 can, as shown in FIG. 1B,
pressurize only a blood vessel in the downward vicinity of the body
surface. With such a construction adopted, since the fluid bag 11
does not pressurize a portion of a blood vessel that is hard to be
pressurized, other than in the downward vicinity of the body
surface, thereby enabling avoidance of a malfunction to be caused
by sensing pulsation of the blood vessel of the portion hard to be
pressurized with the sensor of the flood pressure meter body 21
connected to the fluid bag 11. That is, the edge effect encountered
in the use of a conventional fluid bag can be prevented from
occurring.
[0040] In this embodiment, since a width W of the fluid bag 11 is
smaller than conventional, the cuff 1 itself can be smaller.
Furthermore, the fluid bag 11 is smaller, a pump feeding air to the
fluid bag 11 and the like can be of a smaller capacity, as a
result, enabling the blood pressure meter body 21 to be smaller in
size. With such constructions combined, the whole of a blood
pressure meter can be reduced in size, thereby enabling a blood
pressure meter capable of being carried and mounted at all times to
be realized.
[0041] Furthermore, since the smaller a width W of the fluid bag
11, the smaller a width of the cuff 1, the cuff 1 can be mounted
with simplicity and convenience and with certainty. Since the
periphery of a wrist joint is located at the base end of a palm,
many of people each have a tapered shape of the periphery thereof.
Therefore, there has been difficulty mounting a cuff on a wrist
fittingly with a larger width as conventional. To the contrary, the
cuff 1 of this embodiment is narrow in width to well fit a tapered
shape of a wrist, thereby enabling uncertain mounting of a cuff,
which is one factor for measurement error, to be prevented.
[0042] (Embodiment 2)
[0043] Description will be given of the second embodiment focussing
on only matters different from the above embodiment with reference
to FIG. 5. Note that FIG. 5 is a top plan view of a skeleton of a
wrist as viewed from the palm side.
[0044] In the above embodiment, the cuff 1 is designed so as to be
suitable for pressurizing the radial artery 31 in the downward
vicinity of the body surface and above the radial styloid process
32. In this embodiment, the cuff 1 is designed so as to be suitable
for pressurizing the radial artery present in the downward vicinity
of the body surface in an intermediate portion M between the radial
styloid process 32 and the first metacarpal bone base 34 as shown
in FIG. 5.
[0045] According to experiments conducted by the inventors, in a
case of the radial artery, it has been confirmed that a pulse wave
can be sensed most stably at a position spaced to the peripheral
side from the top from the top of the radial styloid process 32 by
a distance in the range of from about 5 to about 15 mm therefrom.
The position is on the center line C of a wrist joint. The position
can also be specified as a position between the radial styloid
process 32 and the first metacarpal bone base 34 just bisecting a
distance therebetween.
[0046] The inventors confirmed reproducibility in measurement by
rewrapping the cuff 1 plural times and has found that that the
fluid bag 11 is brought into contact with the bisecting point
between the radial styloid process 32 and the first metacarpal bone
base 34 makes it possible to measure a stabler blood pressure
measurement without error as compared with that the fluid bag 11 is
brought into contact with a portion of the skin right above the
radial styloid process 32.
[0047] The reasons therefor are considered such that the radial
artery 31 is not necessarily at the shallowest position under the
skin near the top of the radial styloid process 32 and that stabler
pressurization can be realized in a portion between the radial
styloid process 32 and the first metacarpal bone base 34 than in a
portion right above the radial styloid process 32 since the radial
artery in the intermediate portion is harder to be displaced in
terms of an anatomical structure than a portion of the skin right
above the top of the radial styloid process 32.
[0048] In this embodiment, a width W, in the axial direction of a
limb, of the fluid bag 11 of the cuff 1 is set to a value of 15 mm
or more and 25 mm or less so as to be suitable for such a use
condition.
[0049] In the above two embodiments, constructions are designed so
as to pressurize only the radial artery present in the downward
vicinity of the body surface in a wrist section. A blood pressure
meter cuff of the invention may be designed so as to pressurize
another artery present in the downward vicinity of the surface of a
limb of a human body. For example, a construction may also be
adopted in which pressurization is conducted on only a portion of
an ulnar artery in the downward vicinity of the body surface or in
which pressurizaton is imposed simultaneously on portions of a
radial artery and ulnar artery in the downward vicinity of the body
surface.
[0050] It should be understood that the embodiments disclosed above
are presented by way of illustration but not by way of limitation
in every respects. The technical scope of the invention is defined
based on the terms of the appended claims without being interpreted
only by the embodiments and includes all alterations and
modifications of the embodiments without departing from the
technical scope and the equivalent thereof.
[0051] According to a blood pressure meter of the invention, it is
possible to pressurize a blood vessel present in the downward
vicinity of the skin. As a result, a correct measurement on a blood
pressure can be realized without receiving an influence of the cuff
edge effect.
* * * * *