U.S. patent application number 13/932093 was filed with the patent office on 2013-10-31 for tourniquet cuff for various non-cylindrical limb shapes.
The applicant listed for this patent is Western Clinical Engineering Ltd.. Invention is credited to Kenneth L. Glinz, Michael Jameson, James A. McEwen, Allen J. Upward.
Application Number | 20130289612 13/932093 |
Document ID | / |
Family ID | 38518899 |
Filed Date | 2013-10-31 |
United States Patent
Application |
20130289612 |
Kind Code |
A1 |
McEwen; James A. ; et
al. |
October 31, 2013 |
Tourniquet Cuff for Various Non-Cylindrical Limb Shapes
Abstract
A low-cost contour cuff for surgical tourniquet systems
comprises: a sheath containing an inflatable bladder, the sheath
having an arcuate shape, an outer surface and a centerline
equidistant between first and second side edges; a securing strap
non-releasably attached to the outer surface and formed of
substantially inextensible material having a shape that is
predetermined and substantially flat, wherein the strap includes a
bending portion near a first strap end and a fastening portion near
a second strap end, and wherein the bending portion is adapted to
allow twisting of the bending portion out of the substantially flat
shape to facilitate positioning of the fastening portion into any
of a plurality of positions in the substantially flat shape; and
fastening means for releasably attaching the fastening portion of
the securing strap to the outer surface whenever the sheath is
curved into a position for surrounding a limb.
Inventors: |
McEwen; James A.;
(Vancouver, CA) ; Jameson; Michael; (Vancouver,
CA) ; Glinz; Kenneth L.; (Richmond, CA) ;
Upward; Allen J.; (Vancouver, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Western Clinical Engineering Ltd. |
Vancouver |
|
CA |
|
|
Family ID: |
38518899 |
Appl. No.: |
13/932093 |
Filed: |
July 1, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12828078 |
Jun 30, 2010 |
8480842 |
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13932093 |
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11384695 |
Mar 20, 2006 |
7758607 |
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12828078 |
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Current U.S.
Class: |
606/202 |
Current CPC
Class: |
A61B 17/135
20130101 |
Class at
Publication: |
606/202 |
International
Class: |
A61B 17/135 20060101
A61B017/135 |
Claims
1. A tourniquet cuff apparatus for various non-cylindrical limb
shapes, comprising: an inner sheet joined to an outer sheet to form
a generally arcuate shaped, inflatable cuff, the cuff having
opposing ends and substantially arcuate distal and proximal side
edges extending between the opposing ends, the outer sheet
extending from one opposing end of the cuff to the other opposing
end and consisting of material having an outer fastening surface
formed entirely of a first fastener component; an elongated,
curvable securing strap formed to curve around and conform to the
shape of a limb to which the cuff is applied, the strap including a
first segment and a second segment, the first segment of the strap
including a second fastener component that can releasably engage
the outer fastening surface, an end of the securing strap attached
to the outer fastening surface of the outer sheet near a first end
of the cuff; and wherein the second segment of the strap is
configured to be different from the first segment of the strap so
that the second segment is between the first end of the cuff and
the first segment of the strap and so that the second segment of
the strap twists to facilitate non-twisting movement of the first
segment of the strap toward and away from the substantially arcuate
distal and proximal side edges, thereby to enable engagement of the
second fastener component on the strap with the outer fastening
surface between the arcuate distal and proximal side edges of the
cuff.
2. The apparatus of claim 1 wherein the second segment of the strap
is shaped to be generally planar and narrower than the first
segment such that the second segment may be readily twisted out of
its normally planar orientation; and wherein the second segment of
the strap is formed of a material that can curve around and conform
to the curved shape of the limb.
3. The apparatus of claim 1 wherein the second segment of the strap
is shaped to be generally planar and more flexible than the first
segment such that the second segment may be readily twisted out of
its normally planar orientation; and wherein the second segment of
the strap is formed of a material that can curve around and conform
to the curved shape of the limb.
4. The apparatus of claim 1 wherein the second segment of the strap
and the first segment of the strap are selected from different
materials so that the second segment can be readily twisted to
facilitate the bending of the strap without twisting the first
segment of the strap.
5. The apparatus of claim 1 further comprising: a secondary
fastener attached on the inner sheet near the first end of the
cuff, the secondary fastener comprising a third fastener component
that can releasably engage the outer fastening surface of the cuff;
and wherein the securing strap is attached to the secondary
fastener through the outer fastening surface.
6. The apparatus of claim 1 including a secondary fastening surface
on the inner sheet, the secondary fastening surface comprising a
material that releasably engages the outer fastening surface of the
cuff when the cuff is applied to the limb.
7. The apparatus of claim 1 further comprising: a secondary
fastener attached to the inner sheet, the secondary fastener
comprising a third fastener component that can releasably engage
the outer fastening surface of the cuff, and the secondary fastener
being located so that the first end of the cuff is between the
secondary fastener and the outermost end of the securing strap that
is attached near the first end of the cuff.
8. The apparatus of claim 1 wherein the inner and outer sheets are
welded together to form a bladder and wherein an inlet port is
welded to the bladder, and further comprising a masked region of
the inner sheet configured to prevent welding of any material to
the masked region.
9. The apparatus of claim 1 further comprising a stiffener member
inserted between the inner and outer sheets.
10. The apparatus of claim 1 wherein the securing strap includes a
first predetermined color that contrasts with the color of the
outer fastening surface, thereby facilitating visual determination
of complete engagement of the second fastening component to the
outer fastening surface between the side edges of the cuff.
11. The apparatus of claim 1 including a label barrier applied to
cover a region of the outer fastening surface between the distal
side edge and the proximal side edge near a second end of the cuff
to prevent engagement with the region of the outer fastening
surface covered by the label barrier.
12. The apparatus of claim 1 including a barrier applied onto a
region of the outer fastening surface, the barrier preventing
engagement with the outer fastening surface in the region.
13. The apparatus of claim 1 wherein an end of a second securing
strap is attached to the outer sheet near a first end of the cuff
and the strap is configured so that a second segment of the second
securing strap twists to facilitate non-twisting movement of a
first segment of the second securing strap toward and away from the
substantially arcuate distal and proximal side edges, thereby to
enable engagement of a second fastener component on the second
securing strap with the outer fastening surface between the
generally arcuate distal and proximal side edges of the cuff.
14. A tourniquet cuff apparatus for various non-cylindrical limb
shapes, comprising: an inner sheet joined to an outer sheet to form
a generally arcuate shaped, inflatable cuff, the outer sheet
comprising an outer fastening surface formed of a first fastener
component, the cuff having opposing ends and substantially arcuate
distal and proximal side edges extending between the opposing ends;
an elongated securing strap formed to include a first segment and a
second segment, the first segment of the strap including a second
fastener component that can releasably engage the first fastener
component, wherein an end of the second segment of the securing
strap is attached near a first end of the cuff; and wherein the
second segment of the strap is configured to be different from the
first segment of the strap and so that the second segment is
directly connected between the first end of the cuff and the first
segment of the strap and so that the second segment of the strap
twists to facilitate non-twisting movement of the first segment of
the strap toward and away from the substantially arcuate distal and
proximal side edges, thereby to enable engagement of the second
fastener component on the strap with the outer fastening surface
between the arcuate distal and proximal side edges of the cuff; and
so that when twisted, the second segment can also be curved to
conform to the curvature of the limb to which the cuff is
applied.
15. The apparatus of claim 14 wherein the second segment of the
strap is shaped to be generally planar and narrower than the first
segment such that the second segment may be readily twisted out of
its normally planar orientation; and wherein the second segment of
the strap is selected to be a material that can curve around and
conform to the curvature of the limb.
16. The apparatus of claim 14 wherein the second segment of the
strap is shaped to be generally planar and more flexible than the
first segment such that the second segment may be readily twisted
out of its normally planar orientation; and wherein the second
segment of the strap is selected to be a material that can curve
around and conform to the curvature of the limb.
17. The apparatus of claim 14 wherein the outer sheet is selected
to consist of material having an outer fastening surface formed
entirely of a first fastener component that is engageable with a
corresponding second fastener component.
18. The apparatus of claim 14 wherein an end of a second securing
strap is attached to the outer fastening surface of the outer sheet
near a first end of the cuff and wherein the strap is configured so
that a second segment of the second securing strap twists to
facilitate non-twisting movement of a first segment of the second
securing strap toward and away from the substantially arcuate
distal and proximal side edges, thereby to enable engagement of a
second fastener component on the second securing strap with the
outer fastening surface between the arcuate distal and proximal
side edges of the cuff.
19. The apparatus of claim 14 including a secondary fastener on the
inner sheet, the secondary fastening surface comprising a material
that releasably engages the outer fastening surface of the cuff
when the cuff is applied to the limb.
20. The apparatus of claim 14 including a stiffener member inserted
between the inner sheet and outer sheet.
Description
FIELD OF THE INVENTION
[0001] This invention pertains to pneumatic tourniquet cuffs
commonly used for stopping arterial blood flow into a portion of a
surgical patient's limb to facilitate the performance of a surgical
procedure, and for facilitating intravenous regional
anesthesia.
BACKGROUND OF THE INVENTION
[0002] Typical surgical tourniquet systems of the prior art include
a tourniquet cuff which encircles the limb of a surgical patient
and a tourniquet instrument which is releasably connected to an
inflatable bladder within the tourniquet cuff through a length of
tubing, thereby establishing a gas-tight passageway between the
cuff and the tourniquet instrument. The tourniquet instrument
contains a pressurized gas source which is used to inflate and
regulate the pressure in the tourniquet cuff above a minimum
pressure required to stop arterial blood flow distal to the cuff,
for a duration suitably long for the performance of a surgical
procedure. Many types of surgical tourniquet systems have been
described in the prior art, such as those described by McEwen in
U.S. Pat. No. 4,469,099, No. 4,479,494, No. 5,439,477 and McEwen
and Jameson in U.S. Pat. No. 5,556,415 and No. 5,855,589.
[0003] Standard cylindrical tourniquet cuffs are ideally suited for
application to patients with cylindrical limbs. However, when
applied to a patient with a tapered limb, a cylindrical cuff will
not optimally match the limb taper, and will typically result in a
snug fit proximally and a loose fit distally. Consequently, a
cylindrical cuff may prove unable to achieve a bloodless field
distal to the cuff at normal pressures or may require a
substantially higher and more hazardous inflation pressure to
achieve a bloodless field, and when inflated may have a tendency to
roll or slide distally on the limb during a surgical procedure. In
an effort to match the taper of a patient's limb at a desired cuff
location, some tourniquet cuffs of the prior art are designed to
have an arcuate shape, and are commonly called contour cuffs. When
a contour cuff surrounds a limb having a matching taper, a
uniformly snug fit can be achieved between the cuff and the limb
from the proximal to distal cuff edges. Wide contour tourniquet
cuffs of the prior art have been shown in the surgical literature
to substantially reduce pressures required to create a bloodless
surgical field distal to the inflated cuff (Younger et al., `Wide
Contoured Thigh Cuffs and Automated Limb Occlusion Measurement
Allow Lower Tourniquet Pressures`, Clin Orthop 428:286-293, 2004).
Lower tourniquet pressures are associated in the surgical
literature with lower risk of injuries to surgical patients.
[0004] Examples of contour cuffs of the prior art are described by
Robinette-Lehman in U.S. Pat. No. 4,635,635, and in commercial
products manufactured in accordance with its teachings (`Banana
Cuff` sterile disposable tourniquet cuffs, Zimmer Arthroscopy
Systems, Englewood Colo.). Cuffs described by Robinette-Lehman have
an arcuate shape (defined by the distal radius), contain a single
fastening system with fixed orientation, and include a rigid
plastic stiffener. The cuff described in the '635 patent matches
only a single limb taper for each particular cuff radius. For a
limb with a differing taper, a cuff with a different arcuate shape
matching that taper must be selected. When the cuff described by
Robinette-Lehman '635 is applied to a limb with a differing taper,
the overlapping proximal and distal edges of the cuff will not be
superimposed upon one another, and will instead need to be skewed
to obtain a sufficiently snug application and maximize the contact
area between the cuff and the limb. The thick laminate construction
and rigid stiffener included by Robinette-Lehman makes skewing the
respective overlapping ends of the cuff difficult, and when skewed
the orientation of the fixed fastening system may not be
appropriate to safely and effectively allow the complete engagement
of the hook and loop-type fastener (hereafter, such fastener being
referred to as "VELCRO.RTM.") to secure the cuff on the limb when
inflated.
[0005] Other contour cuffs of the prior are described by McEwen in
U.S. Pat. No. 5,312,431, No. 5,454,831, No. 5,578,055, No.
5,649,954, and No. 5,741,295. McEwen '431 describes a cuff with an
arcuate shape which overcomes the limitations noted above, by
replacing the rigid stiffener with fluted welds in the bladder, and
by including a complex pivoting means for securing the cuff around
a limb having any one of a wide range of limb tapers at the cuff
location. Although the cuff described by McEwen '431 provides
increased safety and improved shape-matching over a wide range of
limb tapers, it does so by including a number of expensive
components and laminated materials, with subassemblies that are
labor-intensive and time-consuming to manufacture. As a result, the
contour cuff of McEwen '431 has a high cost of manufacture,
preventing its cost-effective use as sterile disposable tourniquet
cuff for single surgical procedures.
[0006] The prior-art contour cuff described in McEwen '431 employs
multiple pivoting VELCRO.RTM. hook fastening straps attached to
D-shaped rings so that they may pivot when the cuff is wrapped
around a tapered limb, and align with corresponding VELCRO.RTM.
loop material fastened to the surface of the cuff. These D-shaped
ring assemblies are in turn attached near one end of the cuff. The
ring assemblies allow the straps to pivot over a predetermined
range when the cuff is wrapped around the limb to fully engage with
the corresponding loop material on the outer surface of the cuff.
Manufacturing the ring assemblies described in McEwen '431 requires
relatively large amounts of different materials, and requires
numerous labor-intensive steps including cutting, alignment, sewing
and welding, all of which must be completed by skilled
operators.
[0007] There is a need for a contour cuff for surgical tourniquet
systems that overcomes the hazards, problems and limitations of
performance associated with prior-art contour cuffs, and that can
be manufactured at a cost that is substantially lower than
prior-art contour cuffs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a view of the preferred embodiment applied to a
tapered patient limb.
[0009] FIG. 2 is a view of the preferred embodiment applied to a
cylindrically shaped patient
[0010] FIG. 3 is an exploded view of the preferred embodiment.
[0011] FIG. 4 is a top view of the preferred embodiment.
[0012] FIG. 5 is a section view taken from FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0013] FIG. 1 shows the preferred embodiment in a surgical
application and depicts contour tourniquet cuff 10 secured
circumferentially around a tapered patient limb 12. FIG. 2 depicts
contour cuff 10 secured circumferentially around a substantially
cylindrically shaped patient limb 14.
[0014] Referring to FIG. 1, the inflatable portion of contour
tourniquet cuff 10 completely encircles patient limb 12 and is
inflated by a source of pressurized gas to a pressure that will
occlude the flow of arterial blood in patient limb 12 distal to
cuff 10. Cuff port 15 is comprised of port inlet 16 and tubing 18
and provides a gas tight pneumatic passageway to the inflatable
portion of cuff 10. Tubing 18 is made from flexible thermoplastic
tubing and is permanently bonded to port inlet 16. Tubing 18 is
fitted with a suitable connector (not shown) to permit attachment
to a tourniquet instrument such as that described by McEwen et al.
in U.S. patent application Ser. No. 11/122,600, for the inflation
of cuff 10. Tubing 18 has a length at least equal to the maximum
width of cuff 10 and allows cuff 10 to be used inside a sterile
surgical field. In the preferred embodiment shown, cuff 10 is a
single port cuff, where cuff port 15 provides a single pneumatic
passageway to the inflatable portion of cuff 10. Those skilled in
the art will appreciate that the features described in the
preferred embodiment may also be applied to tourniquet cuffs having
more than one port, such as those described by U.S. Pat. No.
4,469,099, No. 4,479,494, and No. 5,254,087.
[0015] As shown in FIGS. 3 and 4 cuff 10 has a substantially
arcuate shape with the width of the cuff reduced near the end
edges. The arcuate shape of cuff 10 and the degree to which the
width near the end edges is reduced are predetermined to allow cuff
10 to be applied to limbs with a predetermined range of tapers such
that cuff 10 remains substantially in contact with the limb along
its width around the circumference of the limb. When cuff 10 is
correctly applied to a patient limb as shown in FIGS. 1 and 2, the
side edge of cuff 10 with the greater radius is proximal and the
side edge with the lesser radius is distal on the limb.
[0016] As shown in FIGS. 1 and 2, cuff 10 is secured around the
limb by securing straps 20 and 22. Securing straps 20 and 22 are
non-releasably attached to a non-inflating region of cuff 10 near
an end edge. Securing straps 20 and 22 have fastening portions
which releasably engage with the outer surface of cuff 10 and
bending portions which permit the fastening portions to be
positioned such that they can completely engage the outer surface
within the side edges of cuff 10. In the preferred embodiment the
outer surface of cuff 10 and the fastening portions of securing
straps 20 and 22 are formed from VELCRO.RTM. materials. The outer
surface of cuff 10 is a loop type material and the fastening
portions of securing straps 20 and 22 are formed from hook type
material.
[0017] Limb 14 shown in FIG. 2, has a substantially cylindrical
shape and has been selected to represent a limb with the minimum
amount of taper to which cuff 10 can be applied. As shown in FIG.
2, the bending portions of securing straps 20 and 22 twist to
permit the fastening portions to move towards the proximal side
edge of the cuff so that they may completely engage the outer
surface of cuff 10 and maintain their substantially flat shape.
[0018] Limb 12 shown in FIG. 1 has a substantially tapered shape
and has been selected to represent a limb with the maximum amount
of taper to which cuff 10 can be applied. As shown in FIG. 1, the
bending portions of securing straps 20 and 22 twist to permit the
fastening portions to move towards the distal side edge of the cuff
so that they may completely engage the outer surface of cuff
10.
[0019] When cuff 10 is properly secured around a limb the fastening
portions of securing straps 20 and 22 are completely engaged within
the side edges of the cuff. The materials comprising the outer
surface of cuff 10 and the fastening portions of securing straps 20
and 22 have contrasting colors. In the preferred embodiment, the
outer surface of cuff 10 is colored black and the fastening
portions of securing straps 20 and 22 are colored white. The
contrasting colors provide a user of cuff 10 with a visual
indication that the securing straps have been correctly positioned
within the side edges of the cuff. When the securing straps are
correctly positioned the outer surface of the cuff will be clearly
visible completely around the perimeter of the ends of the securing
straps.
[0020] As described below, cuff 10 is constructed of materials that
are appropriate for a single-use sterile disposable tourniquet
cuff. To permit cuff 10 to be used in a sterile surgical field,
cuff 10 is sterilized at time of manufacture by exposure to a
sterilizing agent within a sterilizing process determined to be
safe and effective. To prevent deterioration of the cuff, and to
maintain the integrity of the pneumatic passageways within cuff 10,
a sterilization agent and process that will not harm the materials
or components of cuff 10 is selected by the manufacturer. In the
preferred embodiment cuff 10 is sterilized by exposure to gamma
radiation or electron beam radiation.
[0021] The cost of materials and labor are important considerations
in the manufacture of tourniquet cuffs intended for a single use
and then disposal. To minimize the cost of materials and assembly
of cuff 10, materials are selected which are not intended to
withstand exposure to subsequent sterilization and cleaning
processes. The subsequent sterilization or cleaning of cuff 10 by
agents and processes commonly used in health care facilities, such
as ethylene oxide gas sterilization, hydrogen peroxide gas
sterilization, high temperature and pressure steam sterilization,
sterilization by other chemical agents, and pasteurization, are all
capable of adversely affecting the integrity of the materials and
pneumatic passageways of cuff 10.
[0022] FIG. 3 is an exploded view of the individual components that
are joined together as described below to form cuff 10. For
clarity, cuff tubing 18 is not shown in FIG. 3.
[0023] To reduce manufacturing equipment and labor costs it is
desirable to manufacture cuff 10 in a single dielectric welding
operation. This requires that the thermoplastic polymers comprising
the components of cuff 10 be prevented from welding at selected
surfaces as described below.
[0024] Top sheet 24 forms the outer surface of cuff 10 and is a
flexible knit loop nylon material (for example, 200 Series Loop
Material, Aplix Inc., Charlotte, N.C. 28241) adapted for secure
engagement with the hook material of the fastening portions of
securing straps 20 and 22 and secondary fastener 26. It will be
appreciated that top sheet 24 may be made from other types of
flexible sheet materials to which VELCRO.RTM. materials have been
permanently attached and that the sheet material may not be
completely covered by the VELCRO.RTM. material. For example top
sheet 24 may be comprised of a woven nylon fabric with nylon loop
material bonded to the fabric only in predetermined areas for
engagement with the fastening portions of securing straps 20 and
22.
[0025] Securing straps 20 and 22 are formed from substantially flat
flexible inextensible materials, such as the nylon hook material
that is commonly used in hook and loop VELCRO.RTM. fastening
applications. As described above, securing straps 20 and 22 have a
fastening portion and a bending portion. The bending portion of
securing strap 20 and 22 has a width less than the width of the
fastening portion, the reduced width of the bending portion allows
the bending portion to twist out of its substantially flat shape to
facilitate positioning of the fastening portion. It will be
appreciated that the fastening portion and bending portion of
securing straps 20 and 22 may be comprised of different materials
that are permanently joined together to form the securing strap,
for example the bending portion may be comprised of a material that
is substantially more flexible than the material comprising the
fastening portion. For further example, securing straps 20 and 22
could be comprised of a bending portion formed from a segment of
grosgrain ribbon which is permanently joined to a fastening portion
formed from a segment of nylon hook material. As described above
the material comprising the fastening portion of securing straps 20
and 22 is a contrasting color to the material comprising top sheet
24.
[0026] Secondary fastener 26 is comprised of hook material similar
to the hook material that forms the fastening portions of securing
straps 20 and 22. Secondary fastener 26 is attached to the outer
surface of bottom sheet 30 and engages with the loop material of
top sheet 24. Secondary fastener 26 facilitates cuff application
and alignment by providing a means for maintaining cuff 10 in
position around patient limb 12 while securing straps 20 and 22 are
positioned and engaged. The additional fastening surface area
provided by secondary fastener 26 allows the length of securing
straps to be reduced from what otherwise would be required to
maintain cuff 10 secured around a limb and thereby increases the
range of limb tapers to which cuff 10 can be applied. Secondary
fastener 26 also helps improve the stability of cuff 10 on the limb
by resisting lateral movement of the overlapped cuff end.
[0027] Bottom sheet 30 and middle sheet 32 are made of a flexible
woven nylon cloth, coated on one surface with a thermoplastic
polymer (for example, 70 Denier nylon cloth coated with
thermoplastic polyurethane 0.004'' thick). The thermoplastic
polymer coating prevents the passage of gas through bottom sheet 30
and middle sheet 32 and allows bottom sheet 30 to be welded to
middle sheet 32 in selected areas to form an inflatable bladder 34
as shown in cross-section in FIG. 5. In the preferred embodiment
the thermoplastic coating on bottom sheet 30 and middle sheet 32 is
polyurethane, but it will be appreciated by those skilled in the
art that other thermoplastic polymers may be used as coatings on
bottom sheet 30 and middle sheet 32 providing they can be joined
with sufficient strength to maintain the integrity of cuff 10 when
inflated.
[0028] Tie strap 36 is a soft fabric polymer coated ribbon material
(Grosgrain 5/8'' wide, Dynatex Textiles Inc., Toronto, Ontario,
Canada) that is shown in FIG. 3 positioned between middle sheet 32
and bottom sheet 30 at an end edge of cuff 10. Tie strap 36 is
secured to bottom sheet 30 and middle sheet 32 by welds and
provides a means for the user to align and pull cuff 10 snug around
the limb. When cuff 10 has been secured around a limb the ends of
tie strap 36 are tied together to help maintain the overlapping
portion of the cuff in alignment around the limb by preventing the
cuff from twisting, telescoping and rolling on the limb when
inflated. It will be apparent that tie strap 36 may also be
positioned between top sheet 24 and middle sheet 32 near an end
edge of cuff 10 and secured by stitching at the side edges of cuff
10.
[0029] As shown in FIG. 4 and in cross-section in FIG. 5, port
inlet 16 has a right angle configuration and has a flange for
bonding with middle sheet 32. Port inlet 16 is made of a
thermoplastic polymer that is compatible with and can be welded to
the thermoplastic coating of middle sheet 32 to form a gas-tight
seal.
[0030] Port mask 38 is interposed between port inlet 16 and bottom
sheet 30. In the preferred embodiment, port mask 38 is formed from
the same material as bottom sheet 30.
[0031] To permit the cost effective manufacture of cuff 10 it is
desirable to form the welds joining middle sheet 32 to bottom sheet
30 and port inlet 16 in a single dielectric welding operation. To
prevent port inlet 16 from bonding to bottom sheet 30 during the
dielectric welding operation port mask 38 is placed below port
inlet 16 such that the polyurethane coated surface of port mask 38
is facing the polyurethane surface of bottom sheet 30 and the nylon
cloth surface is facing port inlet 16.
[0032] During the welding operation, port mask 38 bonds to bottom
sheet 30 in the region of the weld area joining the flange of port
inlet 16 to middle sheet 32 and forms port mask weld 40 as shown in
the cross-section of cuff 10 depicted in FIG. 5. Port mask weld 40
secures port mask 38 within inflatable bladder 34 preventing it
from interfering with the inflation and deflation of inflatable
bladder 34. The nylon fabric surface of port mask 38 is not
compatible with the material comprising port inlet 16 and thereby
prevents port inlet 16 from bonding to the top surface of port mask
38 during the welding operation.
[0033] FIG. 4 is a top view of the preferred embodiment laid flat
and shows the areas where middle sheet 32 is welded to bottom sheet
30 and port inlet 16. Port inlet 16 is welded to middle sheet 32 at
port weld 42. Middle sheet 32 is also welded to bottom sheet 30 at
bladder perimeter weld 44, non-inflating region weld 46, and flute
welds 48. Top sheet 24 is secured to middle sheet 32 and bottom
sheet 30 by stitching 49 around the perimeter of top sheet 24 as
shown in FIG. 5.
[0034] Bladder perimeter weld 44 defines inflatable bladder 34 of
cuff 10 which is shown in cross-section in FIG. 5. Bladder 34 has
distal and proximal side edges; the proximal side edge of bladder
34 has a greater radius than the distal side edge of bladder 34. In
the preferred embodiment bladder perimeter weld 44 has a greater
width along the distal side edge of bladder 34 than it has along
the proximal side edge of bladder 34. The increased width of the
bladder perimeter weld along the distal edge of bladder 34 acts to
stiffen the edge of the cuff and thereby help improve the cuff's
roll stability when inflated. Only the width of the bladder weld
along the distal edge is increased as inflated cuffs tend to roll
only distally down the limb. By increasing the width of the bladder
weld only along one side edge in the preferred embodiment the width
of the inflatable bladder is maximized for a given overall cuff
width. Prior art cylindrical cuffs that are substantially
rectangular in shape do not have defined proximal and distal side
edges; their orientation when applied to a limb is not
predetermined by their shape. Wide bladder welds in prior art cuffs
to improve stability must be made along both side edges of the
bladder as the cuff may be applied in either orientation, thereby
reducing the maximum possible bladder width for a given cuff
width.
[0035] Middle sheet 32 and bottom sheet 30 are joined together by
several flute welds 48; these welds are perpendicular to the side
edges of cuff 10 and extend radially towards the centerline of cuff
10. Flute welds 48 act in place of a stiffing element to constrain
inflatable bladder 34 of cuff 10 when inflated. Flute welds 48
prevent relative lateral movement between selected areas of bottom
sheet 30 and top sheet 24 reducing the tendency of cuff 10 to roll
along the longitudinal axis of the limb.
[0036] The perimeter of non-inflating region weld 46 shown in FIG.
4, defines a non-inflating region near an end edge of cuff 10.
Secondary fastener 26 is attached to the outer surface of bottom
sheet 30 by stitching around its perimeter within the non-inflating
region. Securing straps 20 and 22 are attached to the outer surface
of top sheet 24 within the non-inflating region also by stitching.
The stitching attaching securing straps 20 and 22 passes through
the material of secondary fastener 26 which helps to distribute the
loads at the attachment points of securing straps 20 and 22 across
the end edge of cuff 10.
[0037] As shown in FIG. 4, securing straps 20 and 22 are attached
near the bending portion to the outer surface of top sheet 24 such
that they are substantially parallel to the center line of cuff 10.
Securing strap 20 is attached between the centerline and the
proximal side edge of the cuff. Securing strap 22 is attached
between the centerline and the distal side edge of the cuff. As
described above the bending portions of securing straps 20 and 22
allow the fastening portions to be placed in positions other than
those substantially parallel to the center line of cuff 10.
[0038] It will be apparent that securing straps 20 and 22, and
secondary fastener 26 may be attached by other mechanical fastening
means or by welding or adhesives. It will also be apparent that
bladder 34 could be extended eliminating non-inflating region weld
46 and the non-inflating region of the cuff.
[0039] Cuff 10 includes a label 50, shown in FIGS. 3 and 4. Label
50 has printed marks to indicate to a user of cuff 10: that cuff 10
is intended for a single use; the proximal and distal side edges of
cuff 10; the area of top sheet 24 that secondary fastener 26 and
securing straps 20 and 22 are to be completely engaged with. Label
50 is comprised of printed Tyvek label material with a thermally
activated adhesive backing. Label 50 is die cut to match the shape
of cuff 10 near an end edge and adhered to top sheet 24 near an end
edge as shown in FIGS. 3 and 4. The Tyvek material of label 50 does
not engage with the hook materials of secondary fastener 26 and
securing straps 20 and 22. Label 50 acts as a barrier, preventing
secondary fastener 26 and securing straps 20 and 22 from engaging
with the loop material of top sheet 24 in the region covered by
label 50. To insure that inflatable bladder 34 completely encircles
a limb when secondary fastener 26 and securing straps 20 and 22 are
completely engaged with top sheet 24, the length of label 50 is
selected in the preferred embodiment to be substantially equivalent
to or greater than the length of the non-inflating region of cuff
10 to which securing straps 20 and 22 and secondary fastener 26 are
fixed.
[0040] Label 50 also acts to stiffen the end edge of cuff 10 and
helps prevent the end edge from curling as cuff 10 is pulled snug
around a limb by tension on tie strap 36.
[0041] The preferred embodiment is substantially comprised of top
sheet 24, middle sheet 32 and bottom sheet 30. It will be apparent
that top sheet 24 may be coated with a thermoplastic coating
compatible with the coating on bottom sheet 30 and that middle
sheet 32 may be eliminated and an inflatable bladder formed between
top sheet 24 and bottom sheet 30. This would also eliminate the
need for stitching 49 securing top sheet 24 to middle sheet 32 and
bottom sheet 30.
[0042] In the preferred embodiment flute welds 48 help improve the
roll stability of cuff 10 when inflated on a limb by preventing
middle sheet 32 from moving laterally with respect to bottom sheet
30 at selected locations. It will be apparent that flute welds 48
could be replaced by other means to help prevent roll, such as a
stiffening sheet made from a thermoplastic material less flexible
than middle sheet 32 and having an arcuate shape. A stiffening
sheet may be interposed between top sheet 24 and middle sheet 32 or
be interposed between middle sheet 32 and bottom sheet 30 within
the perimeter of inflatable bladder 34. To further improve
stability, the stiffening sheet may be bonded to the inner surface
of middle sheet 32 such as described in U.S. patent application
Ser. No. 11/304,363.
[0043] The embodiment illustrated is not intended to be exhaustive
or limit the invention to the precise form disclosed. It is chosen
and described in order to explain the principles of the invention
and its application and practical use, and thereby enable others
skilled in the art to utilize the invention.
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