U.S. patent number 3,906,937 [Application Number 05/443,130] was granted by the patent office on 1975-09-23 for blood pressure cuff and bladder and apparatus embodying the same.
This patent grant is currently assigned to Para-Medical Instrument Corporation. Invention is credited to Theodore Aronson.
United States Patent |
3,906,937 |
Aronson |
September 23, 1975 |
Blood pressure cuff and bladder and apparatus embodying the
same
Abstract
A blood-pressure cuff comprises an elongated non-elastic cover
having an inflatable portion in which is disposed an inflatable
bladder. Means extends from the inflatable portion for fastening
the cover when the inner surface of the inflatable portion is
applied to a limb of the user preparatory to inflation of the
bladder. An integral, prestressed resilient clip of spiral shape is
freely disposed in the inflatable portion of the cover between the
bladder and outer cover surface to impart its spiral shape to both
the inflatable portion of the cover and the bladder therein. The
inflatable bladder may have a plurality of contiguous chambers each
in fluid communication with adjoining chambers and a single fluid
inlet adapted to have fluid under pressure supplied to the chambers
for inflating the chambers.
Inventors: |
Aronson; Theodore (Fort
Lauderdale, FL) |
Assignee: |
Para-Medical Instrument
Corporation (Fort Lauderdale, FL)
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Family
ID: |
26971824 |
Appl.
No.: |
05/443,130 |
Filed: |
February 15, 1974 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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300507 |
Oct 25, 1972 |
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Current U.S.
Class: |
600/493; 600/499;
606/202 |
Current CPC
Class: |
A61B
5/02141 (20130101); A61B 17/135 (20130101); A61B
5/02233 (20130101); A61B 17/1355 (20130101) |
Current International
Class: |
A61B
17/12 (20060101); A61B 17/135 (20060101); A61B
5/022 (20060101); A61B 005/02 () |
Field of
Search: |
;128/2.5A,2.5C,2.5G,2.5M,2.5Q,2.5R,2.5S,2.5V,327 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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290,046 |
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Nov 1931 |
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IT |
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1,130,963 |
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Jun 1962 |
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DT |
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Primary Examiner: Kamm; William E.
Parent Case Text
The present application is a continuation-in-part of my earlier
application Ser. No. 300,507 filed Oct. 25, 1972, now abandoned.
Claims
What is claimed is:
1. In a blood-pressure cuff including an elongated non-elastic
cover having a hollow inflatable portion having an outer wall and
an inner wall, an inflatable bladder within said inflatable portion
between inner facing surfaces of said outer and inner walls, means
extending from said inflatable portion for fastening the cover with
the inner wall of said flexible portion applied to a limb of the
user, and means operative to inflate said bladder when the cover is
so applied, the improvement comprising an integral, single
component, prestressed resilient clip of spiral shape loosely
disposed within said inflatable portion between the bladder therein
and the inner surface of the outer wall of the inflatable portion,
said clip being substantially co-extensive in length and width with
the length and width of the inflatable portion to impair its spiral
shape to said cover and said bladder.
2. A cuff according to claim 1, wherein said clip has at least two
cut-out portions bounded by transverse end straps and a cross-strap
therebetween.
3. A cuff according to claim 2, including means for electrically
determining blood pressure, said means including a transducer
positioned within said inflatable portion between the bladder and
the inner surface of the inner wall of the inflatable portion and
substantially underlying said cross-strap of the spiral clip for
ensuring intimate contact of the transducer with the artery it
overlies during inflation of the bladder.
4. A cuff according to claim 2, wherein said single component
spiral clip is movable to an open position from its normal
prestressed position for application of the cover about the user's
limb, the cross-strap of said clip being substantially equally
spaced from the transverse end-straps thereof.
5. A cuff according to claim 2, wherein the clip is of about 0.010
inch thick steel and in its fully open position has a length
greater than twice its width, said cut-out portions being
symmetrical with respect to the central longitudinal and transverse
axes of the clip.
6. A cuff according to claim 2, wherein said clip in its fully open
position is about 11 inches along and about 4 inches wide, said
cut-out portions being each about 4 inches long and about 3 inches
wide and being separated by said cross-strap of about three-fourths
inch width, the remaining length of the clip being made up by said
transverse end straps.
7. A blood-pressure cuff comprising an elongated non-elastic cover
having a hollow inflatable portion having an outer wall and an
inner wall, a single inflatable bladder positioned in said
inflatable portion between inner facing surfaces of said outer and
inner walls, single fluid inlet means for inflating said bladder
and for supplying fluid under pressure from said bladder to a fluid
pressure responsive device, means sub-dividing said single bladder
into a plurality of contiguous chambers, each in communication with
the others and with said fluid inlet means, and means for fastening
the cover with said inner wall of the cover applied about a limb of
the user; said bladder having more than two chambers formed
therein, each chamber extending along the length of the bladder in
aligned relation to the other chambers, alternate pairs of
contiguous chambers being in fluid communication at their
respective opposite end portions.
8. A cuff according to claim 7, wherein said subdividing means
comprise longitudinally extending, fluid-occluding seams of a
longitudinal extent less than that of the bladder, each of said
seams being between inner surfaces of inner and outer walls of the
bladder.
9. A cuff according to claim 7, wherein the chambers are each equal
in volume, said single fluid inlet means being adjacent one end of
the bladder in communication with a first of said chambergs, the
remaining chambers being arranged in serial serpentine fluid
communication with said first chamber.
10. A cuff according to claim 1, wherein the two chambers of each
pair are separated along the greatest part of their longitudinal
extent by a seam connection between the outer and inner surfaces of
the bladder, said inner and outer surfaces, when the bladder is
inflated, bulging outwardly to define spaced convex surface
portions respectively interconnected by said stem connections.
11. A blood-pressure cuff comprising an elongated non-elastic cover
having a rectangularly shaped hollow inflatable portion having an
outer wall and an inner wall and a fastening portion extending from
the inflatable portion for fastening the cover with the inner wall
of the inflatable portion applied about limb of the user, a
rectangularly shaped inflatable bladder positioned within said
hollow inflatable portion between inner facing surfaces of said
inner and outer walls and having a single fluid inlet, inflating
means connected to said fluid inlet to inflate the bladder, the
latter being formed with a plurality of contiguous chambers each in
communication with adjoining chambers and with said single fluid
inlet, and a single component prestressed resilient clip of spiral
shape loosely disposed within said inflatable portion between the
bladder and the inner surface of the outer wall of the inflatable
portion, said clip being substantially co-extensive in length and
width with the length and width of said inflatable portion to
impart its spiral shape to said cover and said bladder.
12. A cuff according to claim 11, wherein said clip has at least
two cut-out portions bounded by transverse end straps and a
cross-strap therebetween, said cuff including means for
electrically determining blood pressure, said means including a
transducer positioned within said inflatable portion between the
bladder and the inner surface of the inner wall of the inflatable
portion and substantially underlying said cross-strap of the spiral
clip for ensuring intimate contact of the transducer into the
artery it overlies during inflation of the bladder.
13. Blood-pressure measuring apparatus comprising an elongated
non-elastic cuff cover having a rectangularly shaped hollow
inflatable portion and a fastening portion extending therefrom,
said two portions having a common outer wall and a common inner
wall, a rectangularly shaped inflatable bladder within said
inflatable hollow portion between inner facing surfaces of said
inner and outer walls of said hollow portion, cooperative fastening
means on the outer wall of said inflatable portion and on the inner
wall of said fastening portion to fasten the cover when the inner
wall of said inflatable portion is applied to a limb of the user,
means operative to inflate said bladder when the cover is so
applied, a single component, prestressed, resilient clip of spiral
shape loosely disposed within said inflatable portion between the
bladder therein and the inner facing surface of the outer wall of
the hollow portion, said clip having a length and width which
occupy the major part of the length and width of the hollow
inflatable portion for imparting its spiral shape to said cover and
said bladder, transducer means provided in said inflatable portion
between said bladder and the inner facing surface of the inner wall
of the inflatable portion for translating pulse sounds into
electrical signals, indicating means for providing an indication
when the pulse sounds are detected, and electrical circuit means
having an input supplied with said electrical signals from said
transducer means and an output for energizing said indicating means
as a function of said electrical signals.
14. Apparatus according to claim 13, wherein said clip is
substantially co-extensive in length and width with the length and
width of said inflatable portion.
15. Apparatus according to claim 13, which includes a casing, said
inflating means and said indicating means being mounted on said
casing, with said inflating means accessible for operation, and
said electrical circuit means being included within said
casing.
16. Apparatus according to claim 15, wherein said casing is of a
size enabling ready support thereof and operation of said inflating
means with one hand.
17. Apparatus according to claim 13, wherein said electrical
circuit means includes a sensitivity control for controlling the
sensitivity of said electrical circuit means to said electrical
signals from said transducer means, said sensitivity control being
set to provide an indication solely during that interval during
which pressure within the bladder corresponds to the
systolic-diastolic blood pressure range of the user.
18. Blood-pressure measuring apparatus comprising an elongated
non-elastic cuff cover having a rectangularly shaped hollow
inflatable portion and a fastening portion extending therefrom,
said two portions having a common outer wall and a common inner
wall, a rectangularly shaped inflatable bladder within said
inflatable hollow portion between inner facing surfaces of said
inner and outer walls of said hollow portion, cooperative fastening
means on the outer wall of said inflatable portion and on the inner
wall of said fastening portion to fasten the cover when the inner
wall of said inflatable portion is applied to a limb of the user,
means operative to inflate said bladder when the cover is so
applied, said inflating means being connected to said single fluid
inlet for said bladder, the latter having a plurality of contiguous
chambers each in fluid communication with its adjoining chambers
and with single fluid inlet, a single component, prestressed,
resilient clip of spiral shape loosely disposed within said
inflatable portion between the bladder therein and an inner surface
of the outer wall of the hollow inflatable portion of the cover,
said clip having a length and width which occupy the major part of
the length and width of the hollow inflatable portion for imparting
its spiral shape to said cover and said bladder, transducer means
provided in said inflatable portion between said bladder therein
and the inner surface of the inner wall of the inflatable portion
for translating pulse sounds into electrical signals, indicating
means for providing an indication when the pulse sounds are
detected, and electrical circuit means having an input supplied
with said electrical signals from said transducer means and an
output for energizing said indicating means as a function of said
electrical signals.
19. Apparatus according to claim 18, wherein said clip is
substantially co-extensive in length and width with the length and
width of said inflatable portion.
20. In a blood-pressure cuff including an elongated non-elastic
cover having a hollow inflatable portion having an outer wall and
an inner wall terminating in opposed joined longitudinal and
transverse edges, an inflatable bladder within said inflatable
portion between inner facing surfaces of said outer and inner walls
between said longitudinal and transverse edges, means extending
from said inflatable portion for fastening the cover with the inner
wall of said inflatable portion applied to a limb of the user, and
means operative to inflate said bladder when the cover is so
applied, the improvement comprising an integral, single component,
arcuate prestressed resilient clip disposed within said inflatable
portion between the bladder therein and the inner surface of the
outer wall, said clip extending substantially from one transverse
edge to the other so as to be substantially coextensive in length
with the length of the inflatable portion and having a width
extending between the longitudinal edges of the inflatable
portions.
21. A cuff according to claim 20, wherein said arcuate prestressed
resilient clip is free of connection with the outer wall of the
inflatable portion of the cover.
Description
This invention relates to cuff means for use in determining blood
pressure and more particularly to cuff means of the type
incorporating transducer means such as a crystal microphone or the
like.
BACKGROUND OF THE INVENTION
For ascertaining the blood pressure of an individual, it is the
customary practice to mount an air-inflatable cuff in a region of
arterial blood flow, e.g., over the brachial artery. For this
purpose the cuff is applied about, for example, the upper arm in a
region overlying the brachial artery.
Generally, for measuring blood pressure a cuff of substantially
non-elastic, flexible material containing an inflatable bladder is
applied to the upper arm. The bladder is then inflated to a
pressure sufficient to occlude blood flow in the artery, the air
pressure in the bladder being thereupon relieved until the
Korotkoff tapping sounds are detected with a detecting device
comprising a stethoscope or a microphone suitably incorporated in
the cuff structure. In either case the detecting device is applied
to the artery below the blood-occluding portion of the cuff. Should
a stethoscope be used as the detecting device, upon detecting
therewith the first tapping sounds, a reading is noted from a
calibrated pressure gauge connected to measure the pressure in the
cuff. The reading thus obtained is the systolic blood pressure of
the individual. As the pressure in the cuff continues to fall, the
Korotkoff sounds become muffled and finally cease to be heard. At
that point the pressure reading on the pressure gauge is noted,
this being the diastolic blood pressure of the individual. The same
procedure is followed using a microphone instead of the stethoscope
except that the tapping pulse sounds are detected by observing the
flashing of a lamp and/or listening to the pulse sounds emitted by
a speaker, the lamp and/or speaker being energized by the output of
amplifier means whose input is supplied with the output of the
microphone.
A cuff has greatest advantage when it can be self-applied by an
individual using one hand only. Cuffs conventionally used by
doctors require the use of two hands, one for applying the cuff to
the limb and the other for wrapping the remaining cuff length about
the limb while the initially applied cuff portion is held in
place.
Cuff devices have been proposed for self-application. For example,
U.S. Pat. No. 3,669,096 discloses a cuff device the diameter of
which is preadjusted by connecting connecting means on one side of
a non-elastic portion of the cuff with cooperating connecting means
on the opposite side of the cuff. The diameter of the cuff is
preadjusted for limbs of a predetermined girth. For example, snap
fasteners are generally provided as primary fasteners for
permitting the cuff to be preadjusted to a predetermined diameter,
and secondary fasteners are used for fastening the cuff. A cuff of
this type cannot directly be applied to a limb because its initial
adjustment is in closed-loop form. Accordingly, when the cuff is to
be applied to the upper arm, it must first be slid over the hand
and then the forearm. The cuff, after use, is manually deflated by
applying squeezing forces to the bladder, particularly before each
blood pressure-determining procedure, to enable ready mounting of
the cuff.
U.S. Pat. No. 3,633,567 discloses a pneumatically actuated pressure
device which may be used as a dressing for wounds or as a cuff for
checking blood pressure. Self-application of the device is made
possible by the use of separate, spaced apart, generally C-shaped,
narrow width, springs into pockets formed in the outer surface of
the device. These springs because they can act independently of one
another may affect blood pressure determination, especially when a
transducer is incorporated in the cuff. This is so because the
transducer, e.g., a microphone may be moved away from the brachial
artery during flexure of the springs.
It is also known that errors in determining blood pressure will be
introduced if a cuff of predetermined width is used for measuring
blood pressure in an arm of normal girth as well as arms of slender
and large girths. For example, for an arm of large girth, when
utilizing a bladder intended for a "normal" size arm, the pressure
exerted on the arm by the bladder will be distributed such that
higher pressures will be required to occlude blood flow in the
artery. This will result in not only the systolic but also the
diastolic readings being on the high side. Conversely, for an arm
of slender girth, a smaller pressure will be required to occlude
blood flow in the artery, for which reason the systolic and
diastolic readings will be on the low side.
One way of avoiding the foregoing problem is to provide cuffs of
three different widths, one width for limbs of normal girth, a
second width for limbs of large girth, and a third width for limbs
of slender girth. However, this expedient is impractical for
obvious reasons.
In French Pat. No. 551,084 it is proposed to provide a pneumatic
arm band or cuff which incorporates a plurality of air chambers
arranged in such manner that a substantially continuous surface is
formed on that side of the arm band adapted to engage the limb
about which the arm band is wrapped. The air chambers are isolated
from one another and a separate inlet line for air under pressure,
supplied from a pressurized tank, is provided for each chamber. A
shut-off device is provided for each air inlet line leading from
the pressurized tank. In this known device air flow to each chamber
is separately controlled and the plurality of chambers are
selectively pressurized.
SUMMARY OF THE INVENTION
With the foregoing in mind, the blood-pressure cuff of the present
invention comprises an elongated non-elastic cover including a
rectangularly shaped hollow inflatable portion, in which a
rectangularly shaped inflatable bladder is positioned. A fastening
portion extends from such inflatable portion, with such two
portions having a common outer surface and a common inner surface.
The outer surface of the inflatable portion and the inner surface
of the fastening portion respectively have devices cooperating to
fasten the cover when the inner surface of the inflatable portion
is applied to a limb of the user, means being provided to inflate
the bladder when such cover is so applied.
In accordance with the invention, to permit self-application of
such cuff while obviating the shortcomings of prior self-applied
cuffs, an integral, prestressed resilient clip of spiral shape is
freely disposed in the inflatable portion of the cover between the
bladder and the outer cover surface. Due to its prestressed
resilient characteristic, such clip thereby imparts its spiral
shape to both the cover and the bladder. Generally, the clip is
substantially co-extensive in length and width with the length and
width of the inflatable portion.
Advantageously, the spring clip has at least two cut-out portions
separated by a cross-strap. Preferably, the clip is made of about
0.010-inch thick steel and in its fully open position has a length
greater than twice its width, with the cut-out portions being
symmetrical with respect to the central longitudinal and transverse
axes of the clip.
When the cuff is used with means for electrically determining the
user's blood pressure, it houses a transducer between the bladder
and the inner surface of the cover. The transducer, which may
comprise a crystal microphone or the like, is positioned in
registration with the cross-stop and underlies the same so that,
when the cuff is in use, it presses the microphone against the
user's arm.
The invention also contemplates the provision of a cuff of a single
predetermined width, which will permit accurate determination of
the user's systolic and diastolic pressures without regard to the
size of the user's limbs. This purpose is achieved in accordance
with the invention by providing a blood-pressure cuff comprising a
hollow elongated non-elastic cover having an outer surface and an
inner surface, an elongated inflatable bladder positioned in such
cover and having a single fluid inlet, means operable for inflating
the bladder and being connected to such single fluid inlet for
supplying fluid under pressure thereto, and means for fastening the
cover with its inner surface applied about a limb of the user, the
bladder having a plurality of contiguous chambers each in fluid
communication with its adjoining chambers and with the single fluid
inlet.
Preferably, each chamber of the multi-chamber bladder extends along
the length of the bladder in aligned relation to the other
chambers, alternate pairs of contiguous chambers being in fluid
communication at their respective opposite end portions.
Advantageously, the chambers are formed by longitudinally
extending, fluid-occluding seams in the bladder that are shorter
than the bladder in order to afford the indicated communication
between contiguous chambers.
In a preferred embodiment the volumes of the chambers are equal.
Also, the fluid inlet is adjacent one end of the bladder in
communication with a first of such chambers, the remaining chambers
being arranged in serial serpentine fluid communication with the
first chambers.
The cuff of the invention is advantageously so formed that the two
chambers of each pair are separated along the greatest part of
their length by a seam connection between the outer and inner
surfaces of the bladder, such outer and inner surfaces, when the
bladder is inflated, forming convex surface portions spaced by such
seams.
Such multi-chambered cuff construction of the invention may be
employed per se as indicated. It may also be utilized with
advantage, however, in combination with the self-applied cuff of
the invention. Each inventive feature thereby augments and
reinforces the other, to the practical benefit of the user.
An advantage of utilizing a transducer in connection with the
self-applied cuff of the invention is that it thus becomes feasible
for the user to take his own blood pressure very simply and
conveniently. The electrical circuit means associated with the
transducer can be included within a casing or housing, which can be
suitably made of a size to fit the hand of the user. Moreover, such
casing or housing mounts signal-indicating means operated by the
electrical output signals from the circuit means for observation by
the user, the bladder-inflating means, and a pressure gauge from
which blood pressure readings may be made. The invention thus
provides a self-usable system for detecting and measuring blood
pressure without resort by the user to outside assistance.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in greater detail in connection
with the accompanying drawings, in which:
FIG. 1 is a perspective view of the self-applied blood-pressure
cuff in accordance with the invention;
FIG. 2 is a perspective view of such cuff in the process of
application about a limb of the user, the dotted-line position
illustrating the position of the cuff when released;
FIG. 3 is a perspective view illustrating the self-supported
position of the cuff about a limb of the user;
FIG. 4 is a longitudinal section viewed in the direction of the
arrows through line 4--4 of FIG. 1;
FIG. 5 is a plan view of the cuff in its fully open position with
the outer surface of the cuff cover partly broken away;
FIG. 6 is a transverse section viewed in the direction of the
arrows through line 6--6 of FIG. 5;
FIG. 7 is a schematic representation of the cuff together with a
system for electrically determining the blood pressure of the
user;
FIG. 8 is a plan view of a conventional bladder for a cuff;
FIGS. 8A, 8B and 8C illustrate the shape of the FIG. 8 bladder when
it is applied to normal, large and slender limbs, respectively;
FIG. 9 is a plan view of a multi-chambered bladder in accordance
with the invention; and
FIGS. 9A, 9B and 9C are end views of the bladder of FIG. 9 and
illustrate the direction of the forces generated when such bladder
is used on normal, large and slender limbs, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIGS. 1 to 6, the present self-applied cuff comprises
an elongated non-elastic cover 10 divided into two general
sections. One such section constitutes the hollow inflatable
portion 12, which is essentially rectangularly shaped. The other
such section forms the fastening portion 14, which is integral with
and extends from the inflatable portion. Both portions have the
common outer surface 16 and the common inner surface 18, which are
transversely stitched together at 17 and 18 respectively (see FIG.
5) to form such hollow inflatable portion.
Positioned within the hollow inflatable portion is an inflatable
bladder 20, which is also essentially rectangularly shaped and the
dimensions of which are somewhat less than those of the hollow
portion itself. Extending from such ladder outwardly through the
cuff cover is flexible tube 22, which may be connected, as shown in
FIG. 5, to a mid-section of the bladder. Tube 22 communicates at
its other end with a bladder-inflating means such as a conventional
hand-squeezable pressure bulb 24 (see FIG. 2).
The hollow inflatable portion is designed to be wrapped around a
limb such as an upper arm of the user, with the inner surface 18
applied to the limb, when it is desired to take the user's blood
pressure. To maintain such inflatable portion in place, the
fastening portion is then wrapped about the former and suitably
fastened thereto. For this purpose there may be provided on such
two portions any appropriate cooperative fastening means such as
that sold under the trademark "Velcro," which comprises small barbs
26 formed on the outer surface of the inflatable portion and small
loops 28 formed on the inner surface of the fastening portion for
mutual cooperative action.
The length of such hollow inflatable portion and its enclosed
inflatable bladder should, of course, be sufficient that the
brachial artery is properly overlaid thereby. Any suitable flexible
material, whether a fabric, a plastic, or otherwise, may be
utilized in the manufacture of the cuff cover so long as it is
non-elastic or non-stretchable. In this way, when the bladder is
inflated during a blood-pressure determination, the resultig
bladder pressure serves to occlude the flow of blood through the
artery, as is desired.
Detection of the pulse sounds during a blood-pressure determination
may be done with a stethoscope in the conventional manner. To
facilitate the self-use of the cuff, however, a suitable transducer
such as a microphone 30 is desirably incorporated in the hollow
inflatable portion preferably between the bladder and the inner
surface of the cover. For this purpose, as shown in FIG. 5, such
transducer may be positioned in a pocket or pouch 31 formed in the
cover inner surface adjacent the area where tube 22 extends through
such cover. A conductor 32 leads from the transducer to suitable
means, to be described hereinafter, for electrically indicating the
blood pressure.
In accordance with the invention, an integral prestressed resilient
clip 34 of spiral shape is freely or loosely disposed in the hollow
inflatable portion 12 of the cuff cover in order to render the cuff
fully and readily self-applicable by the user. For maximum
effectiveness such spring clip is positioned between the bladder 20
and the outer surface 16 of the cover.
Because of the prestressed condition, clips 34 imparts its spiral
shape to bladder 20 and the portion of cover 10 encasing such
bladder. The spring clip may be made substantially co-extensive in
length and width with the length and width of the hollow inflatable
portion to ensure that the cuff, when it is applied by the user to
his limb, will be fully self-supportive, as shown in FIG. 3.
The length of the spring clip 34 is such that, in its prestressed
or released condition, its two ends overlap to a considerable
extent, as shown more particularly in FIG. 4. In practice it is
found that, generally speaking, an overlap of about 110.degree. in
its released condition is usually adequate. Desirably, the degree
of such overlap should be sufficient to ensure that, when the cuff
is applied to his limb by the user, the hollow inflatable portion
12 at least almost substantially encircles the limb.
By reason of the described construction, the cuff of the invention
may be easily self-applied directly to one of his upper arms by the
user with his free hand. The overlapping ends of the spiral
resilient clip can be readily separated to permit the direct
placement of the cuff about the upper arm. More particularly, the
cuff may be applied to the upper arm by gripping one end of the
inflatable portion, pressing the other end of such inflatable
portion against the upper arm, and flexing and adjusting such
inflatable portion so that it can be placed about the upper arm, as
shown in FIG. 2. Sliding of the cuff onto the upper arm is thus not
necessary. When the cuff has been properly adjusted, it can be
released and will assume a position such as that shown by the
dashed lines in FIG. 2. Under such circumstances, the resilient
spring clip will maintain the cuff about the upper arm, no further
support being required.
An advantage of the use of such spring clip is that, during its
flexure, it stores energy which serves to instantly and totally
deflate the bladder once the desired systolic and diastolic
pressure readings have been noted and/or recorded. In the absence
of such spiral clip 34, a squeezing force would have to be applied
to the bladder in order to completely deflate the same.
As shown in FIG. 5, the spring clip is provided with two cut-out
portions 36 and 38, desirably substantially equal in size, leaving
a cross-strap 40 and two end-straps 42 and 44. Such cut-out
portions, as illustrated, are symmetrical with respect to the
central longitudinal and transverse axes of the clip.
Any of various resilient materials may be used to fabricate the
clip, which, however, is desirably made of thin metal such as, for
example, 0.010 inch thick steel. The length of the clip is
generally greater than twice its width. A clip of practical
dimensions is about 11 inches long by about 4 inches wide, with
cut-out portions each measuring about 4 inches by 3 inches and
separated by a cross-strap about three-fourths inch in width.
It is an important feature of the invention that, where the hollow
inflatable portion 12 includes a transducer 30, the latter
underlies the cross-strap 40 of the cut-out spring clip. This
relationship ensures intimate contact of the transducer with the
artery it overlies upon inflation of the bladder. This is
significant in providing more accurate pressure determinations and
minimizing spurious signals which may otherwise occur.
As previously indicated, bladder 20 is somewhat less in overall
size than hollow inflatable portion 12 in which it is positioned;
and it is also generally somewhat less in overall size than the
spring clip 34. Where a cut-out spring clip is employed, the length
of the bladder is preferably less than the distance between the two
transverse end-straps 42 and 44 of such clip, as indicated in FIG.
5. To limit undesirable longitudinal movement of the bladder within
the hollow inflatable portion, the outer and inner surfaces of the
inflatable portion are partially transversely stitched together as
shown at 43 and 45, respectively. Stitching 43 and 45 may, however,
be omitted since longitudinal movement of the bladder is limited by
the size of the opening in the cover through which flexible tube 22
extends.
For electrically determining blood pressure, I may utilize the
apparatus disclosed in my co-pending application Ser. No. 432,191
filed Jan. 10, 1974, the disclosure of which, by this reference
thereto, is incorporated herein as if fully set forth in this
application. Such apparatus, schematically shown in FIG. 7, which
corresponds essentially to FIG. 1 of such copending application
Ser. No. 432,191, includes the necessary circuitry and devices for
suitably indicating the detected pulse sounds by appropriate
conversion of the electrical signals provided by the
transducer.
As indicated in FIG. 7, the bladder-inflating means comprising the
hand-squeezable pressure bulb 24 is preferably mounted on a casing
or housing 46, which is advantageously designed so as to fit
conveniently in a hand of the user, as shown in FIG. 3. Such
pressure bulb 24 communicates through nozzle tube 48 with the
flexible tube 22 leading to bladder 20. Also mounted on casing 46
is a pressure-indicating device such as an aneroid manometer 50,
which is in communication with nozzle tube 48 through inlet fitting
52 and restricted passage 54. Nozzle tube 48 may also be provided
with a bleed valve 56 upstream of inlet fitting 52.
Casing or housing 46 also contains a conventional amplifier means
58 including a suitable power source. The input of such amplifier
means is supplied via conductor 32 with the electrical signals from
the output of transducer 30; and the output of such amplifier means
energizes suitable pulse sound-indicating means such as lamp L
and/or speaker S as a function of such electrical signals. A
potentiometer sensitivity control V is included in the amplifier
means to bias the trigger circuit of the latter so that the
indicating means such as lamp L will initially flash at systolic
pressure and will continue to flash until the diastolic pressure is
reached, at which point the trigger circuit is rendered
inoperative. As a matter of convenience, lamp L and/or speaker S
are mounted on the casing.
The compact construction of casing 46, as indicated above, permits
the casing to be readily carried in a hand of the user. The
pressure bulb 24 should be so mounted on such casing, of course,
that it is readily accessible for operation, preferably by the same
hand of the user. To facilitate such hand support of the casing and
such hand operation of the pressure bulb, the casing may be
provided with a suitable hand grip (not shown) that also enables
squeezing of the pressure bulb to be more readily accomplished. For
convenience, flexible tube 22 and conductor 32 may be jointly
sheathed within conduit 60. An on-off switch 62 is provided on
casing 46 for the desired control of its operation.
The reduction of pressure through the systolic-diastolic range is
accomplished by controlled bleeding through the bleed valve 56. As
will be apparent, then, once the cuff has been inflated to a
pressure above the systolic, no further positive action is required
by the user except to take two readings from the pressure gauge,
the first when the lamp L starts flashing and the second when it
stops flashing.
Further in accordance with the invention, there is provided a cuff
equipped with a multi-chambered bladder, the purpose of which is to
enable consistently accurate blood-pressure determinations to be
made regardless of the size of the user's limbs. So that the
advantages of such improved cuff can be more fully appreciated,
there will first be described the manner in which the usual cuff
respectively operates with limbs of different sizes.
Such a usual cuff, as indicated above, has a given or "standard"
width and is customarily employed for all blood-pressure
measurements. It includes an inflatable bladder B which, as shown
in FIG. 8, conventionally comprises a single uninterrupted chamber.
When such a cuff is applied to a normal arm and inflated, the
bladder pressure, as shown by the arrows in FIG. 8A, is transmitted
generally perpendicularly over the width of the bladder to and
through the surface flesh F and the muscle M to the artery A, which
is shown squeezed to the point of blood cut-off. As the bladder
pressure is reduced, the systolic pressure, which can be assumed to
be 120 for purpose of illustration, is first noted. Thereafter,
upon continued reduction of the bladder pressure, the diastolic
pressure, which can be assumed to be 80 also for purpose of
illustration, is then noted. Thus, the blood-pressure readings for
such "normal" arm are 120 over 80.
When such cuff is applied to a large or obese arm having the same
basic arterial blood pressure and inflated, the shape of the
bladder becomes distorted, as shown in FIG. 8B, due to the
thickness of the flesh F. As a result, the bladder pressure over
the width of the bladder will no longer be normal to the flesh and
muscle and will be dispersed because of the bladder distortion, as
shown by the arrows. Excess bladder pressure is thus required to
stop the flow of blood in artery A, with the consequence that false
blood-pressure readings, for example on the order of 140 over 100,
are obtained.
Conversely, when such cuff is applied to a slender or thin arm
having the same basic arterial pressure and inflated, the shape of
the bladder also becomes distorted but in a different manner, as
shown in FIG. 8C, due to the thinness of the flesh F. The bladder
pressure over the width of the bladder again will no longer be
normal to the flesh and muscle and will be directed, because of the
bladder distortion, as shown by the arrows. Less bladder pressure
is thereby required to cut off the blood flow in artery A, with the
result that false blood-pressure readings in the opposite
direction, for example on the order of 110 over 70, result.
As shown in FIG. 9, bladder 64 of the present invention is
comprised of a plurality of individual contiguous or adjoining
pressure-fluid chambers ore compartments, each of which is in fluid
communication with its neighboring chambers. Bladder 64 is also
provided with a single fluid inlet 66 for the purpose of inflating
such chambers, each of which is also in fluid communication with
such single inlet. While bladder 64 may contain any appropriate
number of such chambers or compartments, for purposes of
illustration only three such chambers 68, 70 and 72 have been
shown.
Desirably each such chamber extends along the length of the bladder
in aligned relation to the other chambers. The formation of each
chamber and the separation of the same from each other are
accomplished by means of longitudinally extending, fluid-occluding
seams such as seams 74 and 76 provided between the inner and outer
surfaces of the bladder. Such seams are, of course, longitudinally
shorter than the bladder in order to provide the indicated fluid
communication between adjoining chambers.
Preferably, alternate pairs of contiguous chambers are in fluid
communication with each other at their respective opposite end
portions, as indicated by the arrows in FIG. 9. Generally, each
chamber or compartment is equal in volume to each of the other
chambers. In this manner equilization of the pressure applied
against an arm or other limb results upon inflation of the
bladder.
Advantageously, the indicated single fluid inlet 66 is positioned
adjacent one end of the bladder 66 in communication with the first
chamber, such as chamber 68, formed along the corresponding side of
the bladder. The remaining chambers are thereby arranged in serial
serpentine flow with such first chamber under the preferred form of
construction, such feature also serving to equalize the application
of bladder pressure across the entire width of the bladder.
It has also been found desirable to form the fluid-occluding seams
or seam connections between the inner and outer surfaces of the
bladder in such manner that, when the bladder is inflated, such
surfaces bulge outwardly between the respective pairs of seam
connections so as to define spaced convex surface portions. Such
surface formation also assists the desired equal distribution of
bladder pressure when the cuff containing such bladder is placed in
position on an arm and inflated.
As will be appreciated, when a cuff containing such multi-chambered
bladder is applied to a normal arm and inflated, the bladder
pressure, as shown by the arrows in FIG. 9A, is directed normally
across the width of the bladder against the surface flesh and
muscle (not shown) and has the same effect on blood-flow occlusion
in the arm artery as indicated in FIG. 8A.
When such cuff of the invention is applied to an obese arm and
inflated, the bladder pressure, as shown in FIG. 9B, will maintain
substantially the same distribution across the width of the bladder
as shown in FIG. 9A. This result is due to the resistance provided
against distortion of the bladder because of its
compartmentalization into discrete chambers each materially smaller
in size than the single uninterrupted chamber of the prior-art
bladder shown in FIG. 8. Thus, an equally accurate blood-pressure
determination can be obtained notwithstanding the use of such
multi-chambered cuff on a large-size limb.
Essentially the same result is obtained when such present cuff is
applied to a thin arm and inflated, the bladder pressure over the
width of the bladder, as shown in FIG. 9C, also having basically
the same distribution as shown in FIG. 9A.
Such multi-chambered bladder may, of course, be utilized as such in
connection with a standard cuff-cover construction as basically
shown in FIG. 1. Because of its bladder pressure-equalization
characteristic, however, it is particularly advantageous to employ
such multi-chambered bladder in combination with the self-applied
spring-backed cuff described above in connection with FIGS. 1 to 6.
Of still further advantage is the use of such multi-chambered
bladder in conjunction with such spring-backed cuff when the latter
also includes a system for electrically determining and indicating
the user's blood pressure.
Because of the ability of the user to apply the cuff of the
invention to one of his limbs without outside assistance, it
becomes feasible for such user to measure his blood pressure at
frequent intervals. This advantage is extremely important to a
hypertensive patient, particularly one on medication to relieve
high blood-pressure conditions. When such a patient's blood
pressure consistently falls within a more normal range, the amount
of the medication can thus be stabilized; and any accompanying side
effects can be minimized.
The invention thus not only provides a cuff which can be
self-applied to a limb without preadjustment and is self-supportive
when so applied but also provides a cuff which enables accurate
measurement of blood pressure regardless of the size of the user's
limbs.
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